Propylene polymers for three-dimensional printing

Abstract

A propylene copolymer composition includes a propylene copolymer of 70 to 95 wt% propylene and 3.0 to 25 wt% of at least two alpha-olefin comonomers. 0.3 to 10 wt% of an alpha-olefin comonomer having a lower molar mass may be included. The propylene copolymer composition may have a melt flow rate (MFR) in the range of 5.4 to 250 g / 10 min, a polydispersity index (PI) in the range of 1.0 to 3.7, and an analysis temperature rise elution fractionation full width at half maximum (ATREF FWHM) in the range of 1.0 to 15.4 DEG C. Methods include reacting propylene with at least two alpha-olefin comonomers in one or more vertically stirred gas phase reactors, extruding with additives, and optionally visbreaking to produce a propylene copolymer composition.

Description

Technical Field

[0001] Embodiments disclosed herein generally relate to propylene copolymer compositions for three-dimensional (3D) printing applications. In more specific embodiments, embodiments disclosed herein relate to propylene copolymers including at least two α-olefin comonomers and the use of such materials for 3D printing applications. Background Art

[0002] Additive manufacturing (commonly known as 3D printing technology) is one of the fastest growing applications of polymers. Currently, there are four main methods for additive manufacturing of polymers, including fused filament fabrication (FFF), Arburg Plastic Freeforming (APF), stereolithography (SLA) and selective laser sintering (SLS).

[0003] The SLA process requires a liquid plastic resin (a photopolymer) which is then cured by an ultraviolet (UV) laser. SLA machines require an excess of photopolymer to complete a print, and the common g-code format can be used to convert CAD models into assembly instructions for the printer. SLA machines typically store the excess photopolymer in a tank below the print bed, and as the printing process continues, the print bed is lowered into the tank, curing successive layers along the way. Due to the small cross-sectional area of ​​the laser, SLA is considered one of the slower additive manufacturing methods, as small parts can take hours or even days to complete. In addition, due to the proprietary nature and limited availability of photopolymers, material costs are relatively high.

[0004] The SLS process is similar to SLA, using a high-energy pulsed laser to form a part layer by layer. However, in SLS, the process starts with a tank filled with powdered bulk material. As printing continues, the bed lowers itself to print each new layer, advantageously using excess bulk powder not used to form the lower layer to support the overhang of the upper layer. For ease of handling, the bulk material is usually heated to just below its transition temperature to allow faster particle melting and printing movement, as described in US5648450. SLS requires large facilities to safely handle plastic powders, so it is not suitable for home or professional desktop applications.

[0005] Fused Filament Fabrication (FFF) and Arburg Plastic Free Forming (APF) are examples of processes that perform 3D printing by extrusion of material. Rather than using lasers to form polymers or sinter particles together, these processes work by extruding and laying down successive layers of material at high temperatures, allowing adjacent layers to cool and bond together before depositing the next layer. The FFF process typically feeds a continuous polymer filament to a print head, melts, extrudes, and prints the polymer to form a part. APF generally refers to a process in which a polymer in powder, flake, or pellet form is fed to a print head, melts, extrudes, and prints the polymer in droplet form to form a 3D part, such as described in EP2739460.

[0006] The desktop and home 3D printing market, as well as professional and industrial applications using FFF or APF, mainly use PLA (polylactic acid), PETG (polyethylene terephthalate), ABS (acrylonitrile butadiene styrene), PC (polycarbonate) and PA (polyamide) as printing media.

[0007] Polypropylene is an ideal material of choice with its lower cost and lower density (resulting in lighter weight printed parts), but current technology does not favor its use. The disadvantages of currently used polypropylene grades are lower tensile modulus, poor print bed adhesion, higher shrinkage, and higher warpage compared to PLA, PETG, ABS, PC, and PA.

[0008] In most 3D printing technologies, engineering plastics are used due to their excellent properties in tensile modulus, print bed adhesion, shrinkage, and warpage. Compared with these high-cost engineering plastics, polypropylene generally shows slight disadvantages in mechanical properties, but shows advantages in low-temperature printing, density, and the formation of odorous components such as volatile organic compounds (VOCs).

[0009] Prior art practices for direct 3D printing with polypropylene are cross-linked materials that require additional linkers in addition to peroxides, such as dienes in CN103980402 or silanes in CN103497414. Due to poor or even impossible extrusion, the cross-linking process is in most cases carried out after the printing process, so both patent applications describe the use of this polymer in a wide range of SLS technologies. The cross-linked polypropylene present in the interconnected network exhibits such very poor extrudability that it is almost impossible to produce the filaments required for the FFF technology. Poor extrudability also hinders the application of the APF technology.

[0010] GB2515348 discloses a special polypropylene which is flexible at room temperature and is used to produce soft and elastic objects that deform under gravity. This polymer is not suitable for a large number of applications.

[0011] CN104211876 and CN104031316 focus on complex composites of polypropylene with high loadings of starch, silane, microspheres and toughening agents. This further complicates the manufacturing process and increases costs, which is generally undesirable.

[0012] US2012 / 0070619 describes a consumable filament for an extrusion-based additive manufacturing system, wherein the consumable filament comprises a first portion of a first semi-crystalline polymer material and a second portion of a second semi-crystalline polymer material, and wherein the crystallization temperature of the second semi-crystalline polymer material is higher than the crystallization temperature of the first semi-crystalline polymer material. Summary of the invention

[0013] This Summary is intended to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0014] In one aspect, embodiments disclosed herein relate to propylene copolymer compositions, comprising propylene copolymers of 70 to 95 weight percent (wt%) propylene and 3.0 to 25 wt% at least two α-olefin comonomers. The at least two α-olefin comonomers may be selected from the group of ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene. 0.3 to 10 wt% of α-olefin comonomers with lower molar mass may be included. The propylene copolymer composition may have a melt flow rate (MFR) in the range of 5.4 to 250 g / 10 min, a polydispersity index (PI) in the range of 1.0 to 3.7, and an analytical temperature rising elution fractionation full width at half maximum (ATREF FWHM) in the range of 1.0 ° C to 15.4 ° C.

[0015] In another aspect, embodiments disclosed herein relate to a method for making a propylene copolymer composition, comprising reacting propylene with at least two α-olefin comonomers in one or more vertically stirred gas phase reactors to produce a propylene copolymer. The method may also include extruding the propylene copolymer together with an additive and optionally visbreaking to produce a propylene copolymer composition. The produced propylene copolymer composition may have a melt flow rate (MFR) in the range of 5.4 to 250 g / 10 min, a polydispersity index (PI) in the range of 1.0 to 3.7, and an analytical temperature rising elution fractionation half-peak full width (ATREF FWHM) in the range of 1.0°C to 15.4°C.

[0016] Other aspects and advantages of the claimed subject matter will be apparent from the following description and appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A fused filament fabrication (FFF) system for printing an article according to an embodiment of the present invention is illustrated.

[0018] Figure 2 Illustrated is a 3D printed specimen for determining tensile modulus according to an embodiment of the present invention.

[0019] Figure 3 Illustrated is a 3D printed specimen for determining dimensional accuracy according to an embodiment of the present invention.

[0020] Figure 4 3D printed specimens for determining relative warpage according to embodiments herein are illustrated.

[0021] Figure 5 is a bar graph comparing tensile moduli according to embodiments herein.

[0022] Figure 6 is a graph comparing ATREF FWHM according to embodiments herein. DETAILED DESCRIPTION

[0023] As mentioned above, Fused Filament Fabrication (FFF) and Arburg Plastic Free Forming (APF) are methods of rapid prototyping. The process works by laying down successive layers of material at high temperatures, allowing adjacent layers to cool and bond together before depositing the next layer.

[0024] refer to Figure 1 In the molten filament manufacturing process, filament 10 can be fed from a spool 11 to an extruder 12. The extruder can use a torque and clamping system 14 to feed and retract the filament as needed. A heater block 16 melts the filament at the appropriate temperature, and the heated filament is forced out of a heated die 18, laying the extruded material 20 where it is needed. As the printing process progresses, the print head 8 and / or bed 20 can be moved to the correct xyz position to place the material.

[0025] Although described with respect to a particular type of fused filament manufacturing process and illustrated with a single spool, those skilled in the art will recognize that there are many different types of fused filament manufacturing systems, many of which may include multiple spools and multiple print heads. Likewise, those skilled in the art will recognize that an Arburg plastic free-form molding system (e.g., a system that can use polymer pellets or sheets) can similarly extrude and print polymers into three-dimensional objects.

[0026] Embodiments herein relate to propylene copolymer compositions and the use of such compositions for FFF and APF 3D printing applications (i.e., embodiments of the present disclosure provide 3D printing grade polymers having desirable properties suitable for use in FFF and APF). FFF and APF printing technologies use in principle the same printing process, namely laying down molten polymer beads / droplets, but differ in how the polymer is fed to the 3D printer. In FFF technology, filaments pre-extruded from a polymer are introduced into the 3D printer, while APF uses polymer pellets directly from a polymer or compounding device. The 3D printed propylene copolymer compositions exhibit improved tensile properties and dimensional accuracy compared to existing compositions. The improvements in these properties correspond to the propylene copolymer compositions having a higher melt flow rate, a narrower molecular weight distribution, a narrower chemical composition distribution, and a higher degree of crystallinity than existing compositions.

[0027] Propylene copolymer composition

[0028] On the one hand, embodiments disclosed herein relate to propylene copolymers. Propylene copolymers may include propylene as a main monomer. In some embodiments, propylene in the range of 75 to 95 weight percent (wt%) is included. Propylene copolymers may also include at least two α-olefin comonomers. At least two α-olefin comonomers may be selected from the group including ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene. In some embodiments, comonomers include ethylene and 1-butene. Propylene copolymers may include at least two α-olefin comonomers in the range of 3.0 to 25 wt%. In other embodiments, the total amount of the at least two α-olefin comonomers may be 4.0 to 22 wt%, 5.2 to 20 wt%, 6.0 to 15 wt%, 6.5 to 14 wt%, 7.0 to 13 wt%, 7.5 to 12 wt%, 8.1 to 11 wt%, 8.5 to 10.5 wt%, 9.1 to 10 wt% or 9.2 to 9.9 wt%.

[0029] In the at least two alpha-olefin comonomers, the alpha-olefin comonomer with the lowest molar mass can be present in the propylene copolymer in an amount of 0.3 to 10 wt%. In one or more embodiments, the alpha-olefin comonomer with the lowest molar mass can be present in the propylene copolymer in an amount of 0.5 to 8.0 wt%, 1.0 to 6.0 wt%, 1.5 to 5.0 wt%, 1.6 to 4.0 wt%, 1.7 to 3.9 wt%, 1.8 to 3.8 wt%, 1.9 to 3.7 wt%, 2.0 to 3.6 wt%, 2.1 to 3.5 wt%, 2.2 to 3.4 wt%, or 2.3 to 3.3 wt%. In one or more embodiments, the alpha-olefin comonomer with the lowest molar mass is ethylene.

[0030] Among the at least two α-olefin comonomers, the α-olefin comonomer with the highest molar mass can be present in the propylene copolymer in an amount of 3.0 to 20 wt%, wherein the total content of the at least two α-olefin comonomers is not greater than the above-mentioned amount range. In one or more embodiments, the α-olefin comonomer with the highest molar mass can be present in the propylene copolymer in an amount of 3.5 to 18 wt%, 4.0 to 15 wt%, 4.5 to 12 wt%, 5.0 to 10 wt%, or 6.5 to 8.5 wt%, wherein the total content of the at least two α-olefin comonomers is not greater than the above-mentioned amount range. In one or more embodiments, the α-olefin comonomer with the highest molar mass is 1-butene.

[0031] According to embodiments of the present invention, the propylene copolymer composition may include the above-mentioned propylene copolymer and one or more additives. In some embodiments, the additive may be included in the range of 0.01 to 5 wt %. In other embodiments, one or more additives may be included in the range of 0.02 to 4 wt %, 0.03 to 3 wt %, 0.04 to 2 wt %, or 0.05 to 1 wt %.

[0032] According to one or more embodiments, the one or more additives may be selected from the group consisting of stabilizers, acid scavengers, nucleating agents, antistatic agents, slip agents, antiblocking agents (or anti-caking agents), and combinations thereof.

[0033] According to one or more embodiments, one or more additives may include a stabilizer. The stabilizer may include any suitable stabilizer known in the art. Non-limiting examples of stabilizers may include phosphites (e.g., BASF IRGAFOS 168), phosphonites (e.g., CLARIANT HOSTANOX P-EPQ), sterically hindered phenols (e.g., BASF IRGANOX 1010, IRGANOX 1076, IRGANOX 1330, IRGANOX 3114), hindered amines (e.g., BASF TINUVIN622) and thiodipropionate (e.g., BASF IRGANOX PS 802FL).

[0034] According to one or more embodiments, one or more additives may include an acid scavenger. The acid scavenger may include any suitable acid scavenger known in the art. The acid scavenger may be selected from the group including metal stearates, hydrotalcites, hydrocalumites, metal oxides, metal carbonates, and combinations thereof. For example, the metal stearates may include calcium stearate and zinc stearate. For example, the hydrotalcites may include Mg 4.3 Al2(OH) 12.6CO3·mH2O(DHT). For example, hydrocalumite may include [Ca2Al(OH)6]OH·mH2O, [Ca2Al(OH)6]CO3·mH2O, [Ca2Al(OH)6]HPO3·mH2O, [Ca2Al(OH)6]SO4·mH2O, [Ca2Al(OH)6]Cl·mH2O, and combinations thereof. For example, the metal oxide may include zinc oxide, calcium oxide, magnesium oxide, and combinations thereof. For example, the metal carbonate may include zinc carbonate, calcium carbonate, magnesium carbonate, and combinations thereof.

[0035] According to one or more embodiments, the one or more additives may include a nucleating agent.The nucleating agent may include any suitable nucleating agent known in the art. For example, the nucleating agent may include talc, sodium benzoate, 1,2,3-tridesoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]nonitol, 1,3:2,4-bis(3,4-dimethylbenzylidene)sorbitol, 1,2-cyclohexanedicarboxylic acid metal salt, bicyclo[2.2.1]heptane-2,3-dicarboxylic acid metal salt, 2,2'-methylene-bis-(4,6-di-tert-butylphenyl)phosphate metal salt, 2,2'-methylene-bis-(4,6-di-tert-butylphenyl)benzoic acid metal salt or hydroxy-bis(2,2'-methylene-bis(4,6-di-tert-butylphenyl)phosphate metal salt, wherein the metal ion may be selected from, for example, lithium, aluminum, sodium, calcium, magnesium. Commercial examples may include Milliken HPN-600ei / HPN-68L / HPN-20E / HPN-715, Adeka NA-11 / NA-21 / NA-71 / NA-27.

[0036] According to one or more embodiments, the one or more additives may include an antistatic agent. The antistatic agent may include any suitable antistatic agent known in the art. The antistatic agent may include glyceryl monostearate (GMS-55, GMS-90) or an ethoxylated alkylamine.

[0037] According to one or more embodiments, the one or more additives may include a slip agent. The slip agent may include any suitable slip agent known in the art. The slip agent may include erucamide and oleamide.

[0038] According to one or more embodiments, the one or more additives may include an anti-blocking agent. The anti-blocking agent may include any suitable anti-blocking agent known in the art. The anti-blocking agent may include silicon dioxide.

[0039] Embodiments of the present disclosure may include 3D printed articles of the propylene copolymer composition. The 3D printed articles may be printed according to any method known in the art. The 3D printed articles may include articles printed using fused filament fabrication (FFF), Arburg plastic freeform molding (APF), stereolithography (SLA), or selective laser sintering (SLS).

[0040] The propylene copolymer composition may have a melt mass flow rate (MFR). The melt mass flow rate may be determined according to standard method ISO 1133 at 230°C and a load of 2.16 kg. In one or more embodiments, the propylene copolymer composition may have an MFR in the range of 5.4 to 250 grams per 10 minutes (g / 10 min). In other embodiments, the propylene copolymer composition may have an MFR in the range of 5.5 to 200 g / 10 min, 6.0 to 180 g / 10 min, 7.0 to 150 g / 10 min, 8.0 to 120 g / 10 min, 10 to 100 g / 10 min, 16 to 90 g / 10 min, 21 to 75 g / 10 min, 30 to 60 g / 10 min, or 35 to 43 g / 10 min.

[0041] The propylene copolymer composition may have a polydispersity index (PI). The PI may be related to the molecular weight distribution of the propylene copolymer composition. In the present specification and the appended claims, the PI may be determined as follows. Rheological oscillation frequency sweep experiments may be performed on a compression molded disc using a parallel plate geometry at 210°C, an oscillation strain amplitude γ0=10%, an angular frequency ω=389 to 0.1 rad / s, and a DHR-2 rheometer (TA Instruments, New Castle, USA). The storage modulus G' and loss modulus G" data may be analyzed by performing a least squares polynomial fit: ln(G')=a2×[ln(G")] 2 +a1×ln(G”)+a0. Cross-over modulus G C The fitting parameters can be calculated using the following formula:

[0042]

[0043] PI can be calculated from the cross modulus G C The calculation results in:

[0044]

[0045] In one or more embodiments, the propylene copolymer composition can have a PI in the range of 1.0 to 3.7. In other embodiments, the propylene copolymer composition can have a PI in the range of 1.2 to 3.6, 1.5 to 3.4, 1.7 to 3.0, 1.8 to 2.7, or 1.9 to 2.5.

[0046] A measure of the crystallinity of the propylene copolymer composition may include the enthalpy of fusion (ΔH f ). ΔH f It can be determined by standard method ISO 11357-3. In some embodiments, the propylene copolymer composition may have a ΔH of 61.3 to 150 Joules / gram (J / g). f In other embodiments, the propylene copolymer composition may have a ΔH from 61.5 to 140.0 J / g, from 61.8 to 120.0 J / g, from 62.5 to 100.0 J / g, from 63.0 to 90.0 J / g, from 65.0 to 80.0 J / g, or from 68.0 to 78.0 J / g. f .

[0047] A measure of the breadth of the chemical composition distribution of the propylene copolymer composition may include the ATREF FWHM. The ATREF FWHM may be determined using an automated CRYSTAF-TREF instrument equipped with a heated infrared concentration detector with a composition sensor in which stabilization, crystallization, and elution cycles are performed. Data from the CRYSTAF-TREF instrument may generate an ATREF curve in which the full width at half maximum (FWHM) may be determined. In one or more embodiments, the propylene copolymer composition may have an ATREF FWHM of 1.0 to 15.4°C. In other embodiments, the propylene copolymer composition may have an ATREF FWHM of 2.0 to 14.0°C, 3.0 to 12.0°C, 4.0 to 10.0°C, 5.0 to 9.5°C, 5.5 to 9.0°C, 6.0 to 8.5°C, or 6.5 to 8.0°C.

[0048] 3D printing performance

[0049] The measure of the tensile properties of the propylene copolymer composition may include tensile modulus. The tensile test can be carried out on Z020 (Zwick / Roell, Germany) similar to ISO 527 using a preload of 2N, a speed of 1mm / min (up to 0.25% elongation), a speed of 50mm / min (elongation>0.25%). The tensile modulus can be determined by 3D printing of the sample. The sample can be conditioned at room temperature and 50% humidity before testing. Sample 200 can be printed by material extrusion. In one or more embodiments, the propylene copolymer composition may have a tensile modulus of at least 700 megapascals (MPa). In other embodiments, the propylene copolymer composition may have a tensile modulus of at least 720MPa, 750MPa, 780MPa or 800MPa.

[0050] According to one or more embodiments, the sample 200 for determining the tensile modulus is Figure 2 . Sample 200 may be type 1BA as defined in ISO 527. Sample 200 may include a first width 210. The first width 210 may be 10 mm. Sample 200 may include a second width 220. The second width 220 may be 5 mm. Sample 200 may include a first length 230. The first length 230 may be 75 mm. Sample 200 may include a second length 240. The second length 240 may be 30 mm. Sample 200 may include a height 250. The height 250 may be 2 mm.

[0051] According to embodiments of the present invention, the propylene copolymer composition has dimensional accuracy. The dimensional accuracy can be determined by 3D printing of the sample. According to one or more embodiments, the sample 300 for determining the dimensional accuracy is Figure 3 . The specimen 300 may include a first length 310. The specimen 300 may include a second length 320. The specimen may include a first width 330. The specimen may also include a second width 340. The specimen may include a height 350. The specimen 300 may be conditioned at room temperature and 50% humidity prior to testing. The specimen 300 may be printed by material extrusion, with the goal of forming a structure having a first length 310 of 5 mm, a second length 320 of 5 mm, a first width 330 of 10 mm, a second width 340 of 10 mm, and a height 350 of 10 mm. Due to the printing process, the laying down and cooling of the molten polymer layers, the gradual building of the structure, and the change in density as the polymer cools and solidifies, the resulting structure may not completely conform to the specified dimensions. The difference between the target size and the actual size can be used to provide a measure of the dimensional accuracy of the polymer.

[0052] Dimensional accuracy can be determined from the cumulative deviation. The cumulative deviation can be calculated from the following equation:

[0053]

[0054] L1 may correspond to a first length 310. L2 may correspond to a second length 320. W1 may correspond to a first width 330. W2 may correspond to a second width 340. H may correspond to a height 350. L1, L2, W1, W2, H may be determined using a digital caliper.

[0055] Dimensional accuracy can be calculated from the cumulative deviation according to the following equation:

[0056] Dimensional accuracy [%] = 100% - (cumulative deviation [%]) / 5

[0057] In one or more embodiments, the propylene copolymer composition may have a dimensional accuracy of at least 88.5% when 3D printing is performed using a die temperature of 190°C. In other embodiments, the propylene copolymer composition may have a dimensional accuracy of at least 89.0%, 89.5%, or 89.9% when 3D printing is performed using a die temperature of 190°C. In one or more embodiments, the propylene copolymer composition may have a dimensional accuracy of at least 96.0% when 3D printing is performed using a die temperature of 240°C. In other embodiments, the propylene copolymer composition may have a dimensional accuracy of at least 96.5%, 97.0%, or 97.3% when 3D printing is performed using a die temperature of 240°C. The propylene copolymer composition may have a relative warpage. The relative warpage can be determined by 3D printing of the specimen. According to one or more embodiments, the specimen 400 used to determine the relative warpage is Figure 4 . Sample 400 may include a height 410. Sample 400 may include a width 420. Sample 400 may also include a wall thickness 430. Sample 400 may be conditioned at room temperature and 50% humidity prior to testing. Sample 400 may be printed by material extrusion with a target of forming a structure having a height 410 of 10 mm, a width 420 of 10 mm, a wall thickness 430 of 2 mm, a length 440 of 80 mm, and a gap height 460 of 0 mm. Due to the printing process, the laying down and cooling of the molten polymer layers, the gradual building of the structure, and the change in density of the polymer as it cools and solidifies, the resulting structure may warp. The difference between the target size and the actual size can be used to provide a measure of the relative warpage of the polymer.

[0058] The relative warpage can be calculated based on the following equation:

[0059] Relative warpage (%) = h warp (mm) / l warp (mm)×100%

[0060] l warpThis may be determined by measuring the length 440 of the specimen 400 in the x-direction (which may be the longest dimension) using a digital caliper. warp It can be determined by measuring the gap height 460 between the edge of the sample 400 and the flat surface 450 at half of the length 440 (the center of the sample 400) using a feeler gauge. The propylene copolymer composition may have a relative warpage of 0 to 5%. In other embodiments, the propylene copolymer composition may have a relative warpage of 0.05% to 3%, 0.08% to 2%, 0.1% to 1%.

[0061] Process for producing a propylene copolymer composition

[0062] Embodiments of the present disclosure may be directed to a method for making a propylene copolymer composition. The method may include reacting propylene with at least two α-olefin comonomers in one or more vertically stirred gas phase reactors to produce a propylene copolymer. The method may then include extruding the propylene copolymer with additives and visbreaking to produce the propylene copolymer composition. The propylene copolymer composition may have an MFR in the range of 5.4 to 250 grams per 10 minutes (g / 10min). The propylene copolymer composition may have a PI in the range of 1.0 to 3.7. The propylene copolymer composition may have a melting enthalpy (ΔH) of 61.3 to 150 J / g. f ). The propylene copolymer composition may have an ATREF FWHM of 1.0 to 15.4°C. The propylene copolymer composition may have a tensile modulus of at least 700 MPa. When 3D printing is performed using a die temperature of 190°C, the propylene copolymer composition may have a dimensional accuracy of at least 88.5%. The propylene copolymer composition may also have a relative warpage of 0 to 5%.

[0063] Reacting propylene with at least two alpha-olefin comonomers in one or more vertically stirred gas phase reactors may include using any known isospecific catalyst for the polymerization of alpha-olefins. In one or more embodiments, the catalyst may include an isospecific Ziegler-Natta catalyst. In other embodiments, the catalyst may include an isospecific supported Ziegler-Natta catalyst containing an internal donor. The support may include SiO2-MgCl2, MgCl2, or MgCl2-nROH. The internal donor may include diisobutyl phthalate (DIBP), 2-isopropyl-2-isopentyl-1,3-dimethoxypropane (I3I5), dibutyl succinate (DBS), diethylcyclohexyl succinate (DECS), diethyl-2-ethyl-2-methyl succinate (DEEMS), or 5-tert-butyl-3-methyl-1,2-phenylene dibenzoate (BMPD).

[0064] According to embodiments of the present disclosure, the catalyst may include an isospecific Ziegler-Natta catalyst in the presence of any known silane. The silane may include cyclohexylmethyl-dimethoxysilane, isobutyl(isopropyl)-dimethoxysilane, dicyclopentyl-dimethoxysilane, diisopropyl-dimethoxysilane, diisobutyl-dimethoxysilane, diphenyl-dimethoxysilane, diethylamino-triethoxysilane, and combinations thereof.

[0065] The visbreaking of the propylene copolymer may include any visbreaking method known in the art. According to one or more embodiments, the visbreaking may be carried out using a peroxide. The peroxide may include di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane or 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane.

[0066] Extruding the propylene copolymer may include any extrusion method known in the art. According to one or more embodiments, extrusion may be performed using a twin screw extruder. Extrusion may include adding one or more additives. One or more additives may be selected from the group of stabilizers, acid scavengers, nucleating agents, antistatic agents, slip agents, antiblocking agents and combinations thereof.

[0067] Embodiments of the present disclosure may include methods of making propylene copolymer compositions, wherein the propylene copolymer compositions may have a melt mass flow rate (MFR). The melt mass flow rate may be determined according to standard method ISO 1133 at 230°C and a load of 2.16 kg. In some embodiments, the propylene copolymer composition may have an MFR in the range of 5.4 to 250 grams per 10 minutes (g / 10 min). In other embodiments, the propylene copolymer composition may have an MFR in the range of 5.5 to 200 g / 10 min, 6.0 to 180 g / 10 min, 7.0 to 150 g / 10 min, 8.0 to 120 g / 10 min, 10 to 100 g / 10 min, 16 to 90 g / 10 min, 21 to 75 g / 10 min, 30 to 60 g / 10 min, or 35 to 43 g / 10 min.

[0068] Embodiments of the present disclosure may include methods of making propylene copolymer compositions, wherein the propylene copolymer compositions may have a polydispersity index (PI). The PI may be related to the molecular weight distribution of the propylene copolymer composition. In the present specification and the appended claims, the PI may be determined as follows. Rheological oscillation frequency sweep experiments may be performed on compression molded discs using parallel plate geometry at 210°C, oscillation strain amplitude γ0=10%, angular frequency ω=389 to 0.1 rad / s, and a DHR-2 rheometer (TA Instruments, New Castle, USA). The storage modulus G' and loss modulus G" data may be analyzed by performing a least squares polynomial fit: ln(G')=a2×[ln(G")] 2 +a1×ln(G”)+a0. Cross modulus G C The fitting parameters can be calculated using the following formula:

[0069]

[0070] PI can be calculated from the cross modulus G C The calculations show that:

[0071]

[0072] In some embodiments, the propylene copolymer composition may have a PI in the range of 1.0 to 3.7. In other embodiments, the propylene copolymer composition may have a PI in the range of 1.2 to 3.6, 1.5 to 3.4, 1.7 to 3.0, 1.8 to 2.7, or 1.9 to 2.5.

[0073] Embodiments of the present disclosure may include methods of making a propylene copolymer composition, wherein the propylene copolymer composition may have a melting enthalpy (ΔH f ). ΔH fIt can be determined by standard method ISO 11357-3, which may include differential scanning calorimetry (DSC). In some embodiments, the propylene copolymer composition may have a ΔH of 61.3 to 150 Joules / gram (J / g). f In other embodiments, the propylene copolymer composition may have a ΔH from 61.5 to 140.0 J / g, from 61.8 to 120.0 J / g, from 62.5 to 100.0 J / g, from 63.0 to 90.0 J / g, from 65.0 to 80.0 J / g, or from 68.0 to 78.0 J / g. f .

[0074] Embodiments of the present disclosure may include methods of making propylene copolymer compositions, wherein the propylene copolymer compositions may have an analytical temperature rising elution fractionation half-peak full width (ATREF FWHM). The ATREF FWHM may be determined using an automated CRYSTAF-TREF instrument equipped with a heated infrared concentration detector with a composition sensor in which stabilization, crystallization, and elution cycles are performed. Data from the CRYSTAF-TREF instrument may generate an ATREF curve, in which the full width at half maximum (FWHM) may be determined. The resulting ATREF FWHM may be a measure of the width of the chemical composition distribution of the propylene copolymer composition. In one or more embodiments, the ATREF FWHM may be in the range of 1.0 to 15.4°C. In other embodiments, the ATREFFWHM may be in the range of 2.0 to 14.0°C, 3.0 to 12.0°C, 4.0 to 10.0°C, 5.0 to 9.5°C, 5.5 to 9.0°C, 6.0 to 8.5°C, or 6.5 to 8.0°C.

[0075] Embodiments of the present disclosure may include methods for making propylene copolymer compositions, wherein the propylene copolymer compositions may have a tensile modulus. Tensile testing may be performed on a Z020 (Zwick / Roell, Germany) using a preload of 2 N, a speed of 1 mm / min (up to 0.25% elongation), a speed of 50 mm / min (elongation>0.25%) according to the procedure described in ISO 527. The tensile modulus may be determined by 3D printing of the specimen. The specimen may be conditioned at room temperature and 50% humidity prior to testing. In some embodiments, the propylene copolymer composition may have a tensile modulus of at least 700 megapascals (MPa). In other embodiments, the propylene copolymer composition may have a tensile modulus of at least 720 MPa, 750 MPa, 780 MPa, or 800 MPa.

[0076] Embodiments of the present disclosure may include methods for making propylene copolymer compositions, wherein the propylene copolymer compositions may have dimensional accuracy. The dimensional accuracy may be determined by 3D printing of a specimen. In some embodiments, the propylene copolymer composition may have a dimensional accuracy of at least 88.5% when 3D printing is performed using a die temperature of 190°C. In other embodiments, the propylene copolymer composition may have a dimensional accuracy of at least 89.0%, 89.5%, or 89.9% when 3D printing is performed using a die temperature of 190°C. In some embodiments, when 3D printing is performed using a die temperature of 240°C, the propylene copolymer composition may have a dimensional accuracy of at least 96.0%. In some embodiments, when 3D printing is performed using a die temperature of 240°C, the propylene copolymer composition may have a dimensional accuracy of at least 96.5%, 97.0%, or 97.3%.

[0077] Embodiments of the present disclosure may include methods of making propylene copolymer compositions, wherein the propylene copolymer compositions may have a relative warpage. The relative warpage may be determined by 3D printing of a specimen. In some embodiments, the propylene copolymer composition may have a relative warpage of 0 to 5%. In other embodiments, the propylene copolymer composition may have a relative warpage of 0.05% to 3%, 0.08% to 2%, 0.1% to 1%.

[0078] Methods for making 3D objects

[0079] Embodiments of the present disclosure may include methods for manufacturing 3D articles from the above-mentioned propylene copolymer composition. The method may include melting the propylene copolymer composition. The resulting molten composition is then deposited onto a surface using a die. The method also includes forming a 3D article by moving the die and / or the surface relative to each other in xyz space. Various 3D printing systems such as fused filament fabrication (FFF), Arburg plastic free-form forming (APF) and selective laser sintering (SLS) may be used to form 3D articles.

[0080] The propylene copolymer composition can be in the form of filaments, pellets or flakes to suit the corresponding printing system. The filaments, pellets or flakes can be supplied to an extruder, which may include a heater block. The energy provided by the heater block and the extruder can melt the propylene copolymer composition, raising the temperature of the propylene copolymer composition to a melting temperature higher than the propylene copolymer composition. The energy provided can also be used to raise the temperature of the polymer melt to a desired extrusion temperature or die temperature, at which the polymer melt is forced to pass through the die of a print head and is deposited on the print surface. The die temperature available for the propylene copolymer composition herein may include a temperature in the range of, for example, about 150°C to 280°C.

[0081] The molten composition is then deposited onto the surface using a die. The melting and deposition of the molten composition can be carried out, for example, using a single screw extruder equipped with a melt pump and a die. The die can have a diameter of 0.04 to 2 mm. After the polymer is deposited onto the surface, the propylene copolymer composition can be cooled and solidified to provide a final printed product.

[0082] According to one or more embodiments, the surface may include a print bed. In some embodiments, the print bed may be heated and may be operated at a temperature ranging from room temperature to a maximum temperature of about 150° C., for example. The print bed temperature should be below the melting temperature of the propylene copolymer composition to provide melt cooling and solidification into the desired 3D object. In some embodiments, the print bed may have a print size (x, y, z) of 300 mm×200 mm×260 mm, but larger or smaller print beds may also be used. For example, the print bed may be made of PEI.

[0083] Embodiments of the present disclosure may include forming 3D articles by moving the die and / or surface relative to each other in xyz space and depositing the propylene copolymer composition. Movement may include placing the propylene copolymer extrudate in the correct xyz position required to form the 3D article. The shape of the deposited propylene copolymer composition may include a droplet, a strand, a rod or a disk. The propylene copolymer composition may be deposited in a patterned form to form a layer. Forming a 3D article may include depositing a multilayer propylene copolymer composition.

[0084] As described above, 3D printing of polymers has challenges associated with changes in shape and size during the cooling and solidification of the polymer after extrusion and deposition onto the printing surface. However, it has been found that propylene copolymer compositions according to embodiments of the present invention overcome some or all of these challenges, as detailed in the examples below.

[0085] Embodiments of the present disclosure may provide at least one of the following advantages. Propylene copolymer compositions may provide higher dimensional accuracy and higher tensile modulus at similar low relative warpage compared to prior art compositions. These improvements in properties may be due to the use of a composition of a copolymer of propylene and at least two α-olefin comonomers and additives, which has a higher melt flow rate, a narrower molecular weight distribution (PI), a narrower chemical composition distribution (ATREF FWHM), and a higher crystallinity (ΔH) than prior art compositions. f). Compositions with lower average molecular weights (higher melt flow rates) may not be expected to exhibit excellent processing behavior as shown in compositions with low relative warpage and high dimensional accuracy. The prior art teaches that materials with lower crystallinity may exhibit better processing behavior, such as lower relative warpage and higher dimensional accuracy. Therefore, it may not be expected or predicted that materials with higher crystallinity will exhibit excellent processing behavior.

[0086] The prior art does not mention the effect of the width of the molecular weight distribution (PI) and the chemical composition distribution (ATREF FWHM) on the properties of 3D printed objects. For other applications, such as heat seal layers, it is known that a wide molecular weight distribution (PI) and a wide chemical composition distribution (ATREF FWHM) are advantageous. The embodiments of the present disclosure report PI values ​​as evidence of a narrower molecular weight distribution. The embodiments of the present disclosure also report ATREF FWHM values ​​as evidence of a narrower chemical composition distribution. The compositions described herein may be advantageous for 3D printing because the reported PI and ATREF FWHM values ​​are associated with 3D printed objects with low relative warpage and high dimensional accuracy.

[0087] Embodiments according to the present disclosure may be particularly advantageous for 3D printing by material extrusion and may be used in the form of pellets, powders, or filaments. The compositions described herein can be successfully printed at temperatures below 200°C, which makes them useful in a variety of consumer-grade 3D printers with lower maximum printhead temperatures.

[0088] Example

[0089] In Table 1, the material parameters of all comparative examples and inventive examples are summarized. Comparative Example CE1 is a commercial copolymer of propylene, ethylene and 1-butene (Adsyl 5C30F, LyondellBasell, USA). Comparative Example CE2 is a 3D printing filament based on a copolymer of propylene, ethylene and 1-butene (Innofil3D PP Natural, d = 1.75 mm, BASF 3D Printing Solutions, Germany). CE3 is a 3D printing filament based on a copolymer of propylene and ethylene (PP Transparent, d = 1.75 mm, Verbatim Europe, Germany). Inventive Example IE was prepared by synthesizing a copolymer of propylene, ethylene and 1-butene in a single vertical stirred gas phase reactor (Novolen type) at 26 barg and 75°C using an isospecific SiO2-MgCl2-supported Ziegler-Natta catalyst containing diisobutyl phthalate (DIBP) as an internal donor. An external donor (cyclohexylmethyldimethoxysilane) was supplied to the reactor to control the incorporation of the comonomer and to improve the isospecificity of the catalyst. Hydrogen was supplied to the reactor to control the polymer molecular weight and the supply rate was adjusted to achieve an MFR of about 1 g / 10 min (ISO 1133, 230° C., 2.16 kg). The powder obtained was extruded on a twin-screw extruder using 650 ppm Irganox 1010 (BASF SE, Germany), 1350 ppm Irgafos 168 (BASF SE, Germany) and 500 ppm DHT-4A (Kisuma Chemicals B.V., Netherlands) relative to the total composition. During the extrusion process, the polymer was visbroken using peroxide to achieve an MFR (ISO 1133, 230° C., 2.16 kg) of about 43 g / 10 min.

[0090] Melt mass flow rate (MFR) was determined at 230°C and a load of 2.16 kg according to ISO 1133. Peak melting temperature T was determined according to ISO 11357-3 pm and melting enthalpy ΔH f The heating and cooling schedule was as follows: [1] +20 K / min from 0 to 200 °C, [2] 5 min at 200 °C, [3] -20 K / min from 200 to 0 °C, [4] 5 min at 0 °C, [5] +20 K / min from 0 to 200 °C. For the peak melting temperature T pm and melting enthalpy ΔH f, the second heating cycle (step [5]) was evaluated. "Ethylene content" (C2) refers to the fraction of -CH2-CH2- units in the polymer obtained by ethylene polymerization, expressed in weight %. "Butene content" (C4) refers to the fraction of -CH2-C3H6- units in the polymer obtained by 1-butene polymerization, expressed in weight %. The total comonomer content refers to the sum of all comonomer contents expressed in weight %. Ethylene (C2) and 1-butene (C4) contents were determined by Fourier transform infrared (FTIR) spectroscopy on 200±50μm films using a Tensor 27 FTIR spectrometer (Bruker Corp., USA). The films were prepared using a hot press at 200°C and 50 bar, and the spectral absorption was corrected according to the actual film thickness. The FTIR spectra were acquired at 4000-400cm -1 The PLS algorithm was used to evaluate the 900-600 cm -1 The band between the 13 The spectra of reference samples calibrated with C NMR were compared (Haaland et al., Anal. Chem. 1988, 60, 1193-1202). Rheological oscillation frequency sweep experiments were performed on compression molded discs using parallel plate geometry at 210°C, oscillation strain amplitude γ0 = 10%, angular frequency ω = 389 to 0.1 rad / s and a DHR-2 rheometer (TA Instruments, New Castle, USA). The storage modulus G' and loss modulus G" data were analyzed by performing a least squares polynomial fit: ln(G') = a2×[ln(G")] 2 +a1×ln(G”)+a0. Cross modulus G C The fitting parameters can be calculated using the following formula:

[0091]

[0092] As a measure of the breadth of the molecular weight distribution, several rheological parameters were calculated. PI and Dispersion Index M w / M n Relatedly, PDR provides a measure of shear thinning strength and ER is related to the breadth of the high molecular weight side of the molecular weight distribution.

[0093]

[0094] Among them, in |G * |=500Pa At |G*|=5,000Pa In |G * |=50,000Pa All |η*| values ​​are in poise.

[0095]

[0096] Where G' is at G" = 500Pa ER =G'.

[0097] To determine the width of the chemical composition distribution, an analytical temperature rising elution fractionation (ATREF) was performed using an automated CRYSTAF-TREF instrument (PolymerChar S.A., Spain), which was equipped with a heated infrared (IR) concentration detector with a composition sensor and a capillary viscometer detector. A polymer solution with a concentration of 3 ± 0.25 mg / mL was prepared in 1,2-dichlorobenzene (stabilized with 500 ppm 2,6-di-tert-butyl-4-methylphenol) at 150 ° C for 90 minutes. After dissolution was complete, the sample was transferred to the ATREF column, where stabilization, crystallization and elution cycles were performed. During the stabilization process, the column was cooled from 150 ° C to 95 ° C at -40 ° C / min and then kept at 95 ° C for 45 minutes. The crystallization step was performed by cooling from 95 ° C to 35 ° C at a cooling rate of -0.5 ° C / min. At the end of the crystallization step, the column was kept at 35 ° C for 10 minutes. Subsequently, the contents of the column were eluted for 10 minutes to collect the soluble fraction. The elution step was performed with heating from 35°C to 140°C at a heating rate of +1°C / min while maintaining a constant solvent flow rate of 0.5 mL / min. The ATREF data obtained in the range of 35 to 140°C (excluding the soluble fraction) were divided by the respective maximum signal intensity to obtain the rescaled data. As a measure of the breadth of the chemical composition distribution, the full width at half maximum (FWHM) was determined by calculating the temperature difference between two points on the ATREF curve for which the rescaled signal intensity was in each case 0.5.

[0098] Table 1: Analytical parameters of different propylene polymer compositions. (*) Comparative example. Invention example.

[0099]

[0100] Arburg Plastic Freeformer (APF) 3D printing tests were performed on a Freeformer 200-3X 3D printer (Arburg GmbH+Co KG, Germany) with a maximum build volume temperature of 120°C, a maximum processing temperature of 350°C, and a maximum print size (x, y, z) of 189 mm × 134 mm × 230 mm. Arburg Freeformer technology is based on a high-frequency nozzle closure that discharges molten polymer droplets onto a moving part carrier. The process parameters used for the tests are summarized in Table 2. The process conditions (temperature, throughput, etc.) were optimized to achieve the best printing performance, as recommended by the instrument supplier for new material qualification.

[0101] Table 2: Processing parameters for the Arburg Plastic Free Forming (APF) 3D printing tests using the inventive examples and comparative examples selected from Table 1. (*) Comparative example. Invention example.

[0102] The invention example IE in Table 1 was extruded into filaments of d = 1.75 ± 0.05 mm using an FT-E 20 single screw extruder (Collin Lab Solution & Pilot GmbH, Germany) equipped with a melt pump and a 2 mm die. The extruded strands were cooled using a room temperature water bath and then air dried. The material diameter was monitored using a Sikora 2050T plug gauge (Sikora, Germany) and collected using a traction / winding system (Collin Lab Solution & Pilot GmbH, Germany). Fused filament fabrication (FFF) 3D printing tests were performed on a Triple FMini 3D printer (SKZ KFE gGmbH, Germany), with a maximum print bed temperature of 150 ° C, a maximum processing temperature of 395 ° C, and a maximum print size (x, y, z) of 300 mm × 200 mm × 260 mm. The process parameters for the test are summarized in Table 3.

[0103] Table 3: Process parameters for fused filament fabrication (FFF) 3D printing tests using the inventive and comparative examples selected from Table 1. (*) Comparative example. Invention example.

[0104] Sample

[0105] Different specimens were printed to determine the performance of the selected comparative and inventive examples in Table 1 in 3D printing by material extrusion. Figure 3The specimen used to quantify dimensional accuracy is shown. The cumulative deviation from the required dimension is determined according to Equation 5, and the dimensional accuracy is calculated using Equation 6.

[0106]

[0107] Dimensional accuracy [%] = 100% - (cumulative deviation [%]) / 5 (6)

[0108] The curves used to quantify the degree of warpage ( Figure 4 ) and determine the mechanical properties of the 3D printed samples of the inventive examples and comparative examples selected in Table 1 ( Figure 2 The absolute warpage is calculated by measuring the gap height h in the z direction between the printed sample (inverted) and the build platform. warp The relative warpage is calculated based on Equation 7, where l warp is the actual length of the sample in the x-direction (longest dimension).

[0109] Relative warpage [%] = h warp [mm] / l warp [mm]×100%(7)

[0110] The mechanical properties of the selected inventive examples and comparative examples in Table 1 were determined by analyzing the 1BA type 3D printed specimens defined in ISO 527 ( Figure 2 ). Tensile tests can be performed on a Z020 (Zwick / Roell, Germany) similar to ISO 527 using a preload of 2 N, a speed of 1 mm / min (up to 0.25% elongation), a speed of 50 mm / min (elongation > 0.25%). All specimens were conditioned at room temperature and 50% humidity before testing.

[0111] The tensile strength, dimensional accuracy and relative warpage test results of the inventive examples and comparative examples selected in Table 1 are summarized in Tables 4 and 5. Compared with the prior art compositions, the inventive example IE1 shows the highest tensile modulus E t This makes the inventive composition useful in applications requiring high stiffness (e.g. automotive / aerospace). Surprisingly, a higher dimensional accuracy can be achieved with inventive example IE1 than with the prior art composition, despite the higher MFR (lower average molecular weight) and higher crystallinity (as evidenced by the higher melting enthalpy ΔH f This is particularly beneficial for complex and functional parts that require high dimensional accuracy. Despite the high degree of crystallinity (e.g., through the higher melting enthalpy ΔH f ), but samples based on Inventive Example IE1 have similar relative warpage compared to prior art compositions. This is unexpected because the prior art teaches that warpage is related to crystallinity.

[0112] Table 4: Tensile test results, dimensional accuracy results, and warpage results of the Arburg Plastic Free Forming (APF) 3D printing test of the inventive examples and comparative examples selected in Table 1. (*) Comparative example. Invention example.

[0113] Table 5: Tensile test results, dimensional accuracy results, and warpage results of fused filament fabrication (FFF) 3D printing tests of the inventive examples and comparative examples selected in Table 1. (*) Comparative example. Invention example.

[0114] Figure 5 It is a bar graph comparing the tensile modulus of the inventive example (IE1) and the comparative examples (CE1, CE2, CE3).

[0115] Figure 6 This is a graph comparing the ATREF FWHM of the invention example (IE1) and the comparative examples (CE1, CE2, CE3).

[0116] Although only a few exemplary embodiments are described in detail above, those skilled in the art will readily appreciate that many modifications may be made in the exemplary embodiments without substantially departing from the present invention. Therefore, all such modifications are intended to be included within the scope of the present disclosure as defined by the appended claims.

Claims

1. A propylene copolymer composition comprising: A propylene copolymer, comprising: propylene in the range of 70 to 95 wt. %; and 3.0 to 25 weight percent of at least two alpha-olefin comonomers as determined by Fourier transform infrared (FTIR) spectroscopy, wherein the at least two α-olefin comonomers are selected from the group consisting of ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene, and wherein the comonomer having a lower molar mass is in the range of 0.3 to 10 wt % as determined by FTIR; The propylene copolymer composition has a melt flow rate (MFR) in the range of 5.4 to 250 g / 10 min measured at 230° C. and a load of 2.16 kg according to ISO 1133, and a polydispersity index (PI) in the range of 1.0 to 3.7 measured at 210° C. by rheological oscillation frequency scanning, wherein PI=10 5 Pa / G c And G c =G'=G" (crossover modulus), analytical temperature rising elution fractionation half maximum full width (ATREF FWHM) in the range of 1.0 to 15.4°C as determined by CRYSTAF-TREF in 1,2-dichlorobenzene by 1) cooling from 150°C to 95°C at -40°C / min, 2) holding at 95°C for 45 minutes, 3) cooling from 95°C to 35°C at -0.5°C / min, 4) holding at 35°C for 10 minutes, 5) heating from 35°C to 140°C at +1°C / min and evaluating the full width at half maximum (FWHM) of the peak between 35°C and 140°C.

2. The composition of claim 1, wherein the at least two α-olefin comonomers are ethylene and 1-butene.

3. The composition according to any one of claims 1 to 2, further comprising 0.01 to 5 wt% of one or more additives selected from the group consisting of stabilizers, acid scavengers, nucleating agents, antistatic agents, slip agents, antiblocking agents and combinations thereof.

4. The composition according to any one of claims 1 to 3, wherein the propylene copolymer composition has a melting enthalpy ΔH as determined by differential scanning calorimetry according to ISO 11357-3. f 61.3 to 150 J / g.

5. The composition according to any of claims 1 to 4, wherein the propylene copolymer composition has a tensile modulus of at least 700 MPa as determined by tensile testing of 3D printed specimens similar to ISO 527.

6. A three-dimensional printed article comprising the composition according to any one of claims 1 to 5.

7. A method for producing a propylene copolymer composition, the method comprising: reacting propylene with at least two α-olefin comonomers in one or more vertically stirred gas phase reactors to produce a propylene copolymer; and extruding and optionally visbreaking the propylene copolymer together with additives to produce a propylene copolymer composition; The propylene copolymer composition has a melt flow rate (MFR) in the range of 5.4 to 250 g / 10 min measured at 230° C. and a load of 2.16 kg according to ISO 1133, and a polydispersity index (PI) in the range of 1.0 to 3.7 measured at 210° C. by rheological oscillation frequency scanning, wherein PI=10 5 Pa / G c And G c =G'=G" (crossover modulus), analytical temperature rising elution fractionation half maximum full width (ATREF FWHM) in the range of 1.0 to 15.4°C as determined by CRYSTAF-TREF in 1,2-dichlorobenzene by 1) cooling from 150°C to 95°C at -40°C / min, 2) holding at 95°C for 45 minutes, 3) cooling from 95°C to 35°C at -0.5°C / min, 4) holding at 35°C for 10 minutes, 5) heating from 35°C to 140°C at +1°C / min and evaluating the full width at half maximum (FWHM) of the peak between 35°C and 140°C.

8. The method of claim 7, wherein reacting propylene with at least two alpha-olefin comonomers comprises reacting with a Ziegler-Natta catalyst, an internal donor, and an external donor.

9. The method of claim 8, wherein the Ziegler-Natta catalyst comprises an isospecific supported Ziegler-Natta catalyst containing diisobutyl phthalate (DIBP) as an internal donor.

10. The method of claim 8, wherein the external donor comprises a silane selected from the group consisting of cyclohexylmethyldimethoxysilane, isobutyl(isopropyl)dimethoxysilane, dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, diphenyldimethoxysilane, diethylaminotriethoxysilane, and combinations thereof.

11. The process according to any one of claims 7 to 10, wherein extruding and optionally visbreaking the propylene copolymer composition comprises visbreaking with a peroxide.

12. The process according to any one of claims 7 to 11, wherein the propylene copolymer composition has a melting enthalpy ΔH as determined by differential scanning calorimetry according to ISO 11357-3: f 61.3 to 150 J / g.

13. Process according to any of claims 7 to 12, wherein the propylene copolymer composition has a tensile modulus of at least 700 MPa as determined by tensile testing of 3D printed specimens similar to ISO 527.

14. A method of manufacturing a three-dimensional object, the method comprising: Melting the composition according to any one of claims 1 to 5 to form a molten composition; depositing the molten composition onto a surface using a die; and A three-dimensional object is formed by moving the die and / or the surface relative to each other in xyz space.

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