A polycarbonate composition for 3D printing, its preparation method and application

Abstract

The present invention provides a polycarbonate composition for 3D printing, a preparation method thereof, and an application thereof. The polycarbonate composition for 3D printing provided by the present invention comprises polycarbonate, an aliphatic-aromatic copolyester, a graphene dispersion, and optionally a functional auxiliary agent. The polycarbonate composition for 3D printing provided by the present invention can reduce the temperatures of a printing nozzle and a base plate, and simultaneously has a high printing dimensional accuracy.

Description

Technical Field

[0001] The present invention relates to a polycarbonate composition for 3D printing, a preparation method thereof, and an application thereof. Background Art

[0002] Graphene is a novel two-dimensional single-layer sheet-like nano-carbon material composed of sp2 hybridized carbon atoms. It has received extensive attention due to its excellent properties and is expected to trigger revolutionary changes in many fields such as optoelectronic products, energy technologies, functional composite materials, microelectronic devices, and biomedicine.

[0003] 3D printing, also known as rapid prototyping technology, belongs to a type of additive manufacturing. The principle is to first obtain a digital three-dimensional model by computer modeling or directly scanning a prototype, and then use software to cut it into two-dimensional cross-sectional data along a certain coordinate axis, and finally form a solid by layer-by-layer printing and stacking using a 3D printer. After nearly 30 years of development, 3D printing technology has been regarded as one of the core technologies that may change the laboratory and industrial production methods. This additive manufacturing technology can save materials, shorten the R & D cycle, and reduce costs, and has great potential applications in mold manufacturing, product design, medical treatment, education, and aerospace.

[0004] Currently, the main forming methods of 3D printing mainly include: Fused Deposition Modeling (FDM), Stereo Lithography Apparatus (SLA), and Selective Laser Sintering (SLS), etc. Among them, the FDM technology does not require a laser, is relatively simple in use and maintenance, has a low cost, and has been more widely used. Its technical principle is that a thermoplastic polymer is heated and melted and then extruded through a nozzle, cooled and solidified to form a thin layer with a contour shape, and then stacked layer by layer to finally form a product. Therefore, it is required that the thermoplastic polymer used for FDM 3D printing has excellent fluidity and a fast curing rate. Currently, the commonly used FDM 3D printing consumables on the market are mainly ABS (acrylonitrile-butadiene-styrene terpolymer) and PLA (polylactic acid), and in addition, there are also a small amount of PC (polycarbonate), TPU (thermoplastic polyurethane), and PA (nylon), etc.

[0005] PC is a high molecular polymer containing carbonate groups in its molecular chain. According to the structure of the ester group, it can be divided into various types such as aliphatic, aromatic, and aliphatic-aromatic. Among them, aromatic PC, especially bisphenol A type PC, has excellent mechanical properties and is widely used in fields such as the glass assembly industry, the automotive industry, and the electronic and electrical industry. As a commonly used transparent engineering plastic, bisphenol A type PC is odorless, non-toxic, has a low molding shrinkage rate, and good flame retardancy, and has excellent mechanical properties that other transparent high molecular materials (such as PMMA, PS) do not have. Currently, PC has been successfully developed for use as a 3D printing material. However, compared with commonly used 3D printing high molecular materials such as ABS and PLA, in the fused deposition 3D printing technology, PC has problems such as too high printing temperature and serious warping problems. This is mainly related to the fluidity of PC itself and the thermal stress caused by its thermal properties. Although by increasing the nozzle temperature and the hot bed temperature, the warping can be slowed down, but the problem cannot be completely solved. In order to be able to reduce the nozzle temperature and the bottom plate temperature required by PC during printing, polymers such as polycaprolactone (PCL) [CN 108034217 A], polyethylene terephthalate-1,4-cyclohexanedimethanol ester (PETG) [CN 104672880 A], polylactic acid (PLA) [CN 106543672 A], and polybutylene terephthalate (PBT) [CN 105419260 A] are added. Although adding polymers can reduce the printing nozzle temperature and the bottom plate temperature, it will significantly reduce the impact strength of the blend. In response to the problem that the impact strength of the blend decreases significantly after blending PC and PBT, many toughening agents have been developed and used to effectively improve the impact strength of the blend (Yao Jun, Xue Dongsheng, Gu Chunhui, etc., "Plastics Industry", 2008) (Xu Xiaoqiang, Lu Bo, "Plastics Industry", 2005), however, the warping during its 3D printing is still relatively obvious. In response to this problem, a technology needs to be invented to prepare a new type of modified polycarbonate / aliphatic-aromatic copolyester composition, which can reduce the nozzle temperature and the bottom plate temperature during the 3D printing process and improve the dimensional accuracy of the parts at the same time.

[0006] Polymer composites such as graphene-modified ABS (WEI X., LI D., WEI J., et al. 3D printable graphene composite. Scientific Reports, 2015, 11181 - 11188, CN 108102283), PLA (PADDUBSKAYA A, VALYNETS NJKUZHIR P, et al. Electromagnetic and thermal properties of three-dimensional printed multilayered nano-carbon / poly(lactic) acid structures. Journal of Applied Physics, 2016, 119, 924 - 1186), PA12 (ZIIU D, REN Y, LIAO G, et al. Thermal and mechanical properties of polyamide 12 / graphene nanoplatelets nanocomposites and parts fabricated by fused deposition modeling. Journal of the Applied Polymer Science, 2017, 134, 45332), polystyrene (CN109054275), etc. are used in FDM technology. However, in these technologies, either graphene oxide or graphene microplates are used, which cannot fully utilize the performance characteristics of graphene, or holes are easily formed during the process of preparing composite material wires, affecting the printing effect, or the parts are prone to warping when the thermal stress is uneven. Summary of the Invention

[0007] Aiming at the deficiencies in the prior art, the present invention provides a polycarbonate composition for 3D printing, which can effectively reduce the printing nozzle temperature and the bottom plate temperature while having high printing dimensional accuracy.

[0008] The first aspect of the present invention provides a polycarbonate composition for 3D printing, which comprises polycarbonate, aliphatic-aromatic copolyester, graphene dispersion liquid and optional functional additives.

[0009] According to some embodiments of the present invention, in parts by mass, the polycarbonate composition comprises:

[0010] (a) 50 to 99 parts of polycarbonate;

[0011] (b) 1 to 50 parts by mass of an aliphatic-aromatic copolyester;

[0012] (c) 0.01 to 5 parts by mass of a graphene dispersion; and optionally

[0013] (d) 0.5 to 5 parts by mass of a functional additive.

[0014] According to a preferred embodiment of the present invention, by mass, the polycarbonate composition comprises:

[0015] (a) 60 - 90 parts by mass of polycarbonate;

[0016] (b) 10 - 40 parts by mass of an aliphatic-aromatic copolyester;

[0017] (c) 0.5 - 3 parts by mass of a graphene dispersion; and optionally

[0018] (d) 0.5 to 5 parts by mass of a functional additive.

[0019] According to a further preferred embodiment of the present invention, by mass, the polycarbonate composition comprises 1 - 3 parts by mass of a graphene dispersion.

[0020] According to some embodiments of the present invention, the polycarbonate is obtained by melt polycondensation of bisphenol A and diphenyl carbonate and / or by direct esterification polymerization of bisphenol A and phosgene.

[0021] According to some embodiments of the present invention, in the graphene dispersion, the number of layers of the graphene is not more than 10 layers.

[0022] According to some embodiments of the present invention, the graphene has at least one surface functional group selected from carboxyl, anhydride, hydroxyl, amino, amide, imide and their derivative groups.

[0023] According to some embodiments of the present invention, the solvent of the graphene dispersion is selected from at least one of mineral oil, silicone oil, ethylene glycol and glycerol and their derivatives.

[0024] According to some embodiments of the present invention, in the graphene dispersion, the mass concentration of the graphene is 0.1% - 10%.

[0025] According to some embodiments of the present invention, the aliphatic-aromatic copolyester is selected from copolyesters condensed from α,ω-aliphatic dicarboxylic acids or their derivatives and aromatic dicarboxylic acids or their derivatives and aliphatic diols.

[0026] According to some embodiments of the present invention, the aliphatic-aromatic copolyester includes a chain-extended copolyester.

[0027] According to some embodiments of the present invention, the α,ω-aliphatic diacid is selected from substituted or unsubstituted α,ω-aliphatic diacids containing 2 to 22 main-chain carbon atoms.

[0028] According to some embodiments of the present invention, the substituted α,ω-aliphatic diacid is selected from α,ω-aliphatic diacids substituted with a substituent selected from at least one of C1-C6 straight-chain alkyl, C3-C6 branched-chain alkyl, C3-C6 alkyl, and C2-C6 unsaturated alkyl.

[0029] According to some embodiments of the present invention, the derivatives of the α,ω-aliphatic diacid include acid anhydrides, esters, acyl halides, etc. corresponding to the α,ω-aliphatic diacid.

[0030] According to some embodiments of the present invention, the α,ω-aliphatic diacid is selected from at least one of succinic acid, adipic acid, and suberic acid.

[0031] According to some embodiments of the present invention, the aromatic diacid is selected from substituted or unsubstituted aromatic diacids containing 8 to 22 main-chain carbon atoms.

[0032] According to some embodiments of the present invention, the substituted aromatic diacid is selected from aromatic diacids substituted with a substituent selected from at least one of C1-C6 straight-chain alkyl, C3-C6 branched-chain alkyl, C3-C6 alkyl, and C2-C6 unsaturated alkyl.

[0033] According to some embodiments of the present invention, the derivatives of the aromatic diacid include acid anhydrides, esters, acyl halides, etc. corresponding to the aromatic diacid.

[0034] According to some embodiments of the present invention, the aromatic diacid is selected from at least one of terephthalic acid and 2,6-naphthalenedicarboxylic acid.

[0035] According to some embodiments of the present invention, the derivative of the aromatic diacid is selected from dimethyl terephthalate.

[0036] According to some embodiments of the present invention, the aliphatic diol is selected from diols containing 2 to 10 carbon atoms.

[0037] According to some embodiments of the present invention, the aliphatic diol is selected from at least one of 1,4-butanediol, 1,6-hexanediol, and 1,8-octanediol.

[0038] According to some embodiments of the present invention, the functional auxiliary is selected from at least one of compatibilizers, inorganic fillers, antioxidants, lubricants, colorants, and flame retardants.

[0039] The second aspect of the present invention provides a method for preparing the polycarbonate composition according to the first aspect, which includes mixing the polycarbonate, the aliphatic-aromatic copolyester, and the graphene dispersion liquid and optionally functional additives in a molten state, and extruding and pelletizing to obtain the polycarbonate composition.

[0040] According to some embodiments of the present invention, the polycarbonate composition is prepared by a melt blending method.

[0041] According to some embodiments of the present invention, the melt blending method adopts a twin-screw continuous extrusion method.

[0042] According to some embodiments of the present invention, the melt blending method includes uniformly mixing the polycarbonate, the aliphatic-aromatic copolyester, the graphene dispersion liquid, and optionally functional additives in a required ratio, and then preparing the polycarbonate composition through continuous extrusion and pelletizing.

[0043] According to some embodiments of the present invention, the melt blending method includes separately metering and adding the polycarbonate, the aliphatic-aromatic copolyester, and a toughening agent to a twin-screw extruder according to a certain feeding ratio for extrusion and pelletizing to obtain the polycarbonate composition.

[0044] According to some embodiments of the present invention, in the melt blending method, the screw speed is 50 rpm - 1500 rpm.

[0045] According to some embodiments of the present invention, in the melt blending method, the temperature is 160 °C - 260 °C.

[0046] The third aspect of the present invention provides an application of the polycarbonate composition according to the first aspect or the polycarbonate composition obtained by the preparation method according to the second aspect in 3D printing.

[0047] The fourth aspect of the present invention provides a method for preparing a 3D printing material, which includes melt extruding the polycarbonate composition according to the first aspect or the polycarbonate composition obtained by the preparation method according to the second aspect, cooling, and orientation drawing to obtain the 3D printing material.

[0048] According to some embodiments of the present invention, the polycarbonate composition after extrusion and pelletizing is further processed by a method of melt extruding the polycarbonate composition melt while cooling and simultaneously drawing and winding it into a wire, preferably a single-screw extrusion method. The polycarbonate composition particles are melt extruded through a single-screw extruder, cooled in a water bath at two different temperatures while being drawn and wound to form a 3D printing wire.

[0049] In the present invention, the graphene functional groups interact with the matrix resin, improving the dispersion state of graphene. Its heat conduction effect reduces the thermal stress of the printed parts. Combined with the size stabilization effect of graphene, the dimensional accuracy of the printed parts is improved. At the same time, the orientation of graphene during the extrusion printing process or the inhibition of the relaxation of polymer random coils reduces the viscosity, thereby reducing the printing temperature and the hot bed temperature, achieving good technical effects. The polycarbonate composition for 3D printing provided by the present invention can reduce the printing nozzle and bottom plate temperatures, and at the same time has high printing dimensional accuracy. Detailed implementation mode

[0050] The materials and preparation methods used in the present invention are briefly introduced as follows:

[0051] 1. Polycarbonate (PC)

[0052] The PC in the present invention is a high molecular polymer containing carbonate groups in the molecular chain, generally obtained by melt polycondensation of bisphenol A and diphenyl carbonate or direct esterification of bisphenol A and phosgene.

[0053] 2. Aliphatic-aromatic copolyester

[0054] The aliphatic-aromatic copolyester of the present invention is a copolyester formed by condensation of aromatic dicarboxylic acids or their derivatives and α,ω-aliphatic dicarboxylic acids or their derivatives with at least one aliphatic diol. It includes but is not limited to poly(ethylene terephthalate-co-ethylene oxalate), poly(ethylene terephthalate-co-ethylene malonate), poly(ethylene terephthalate-co-ethylene succinate), poly(ethylene terephthalate-co-ethylene glutarate), poly(ethylene terephthalate-co-ethylene adipate), poly(ethylene terephthalate-co-ethylene suberate), poly(propylene terephthalate-co-propylene oxalate), poly(propylene terephthalate-co-propylene malonate), poly(propylene terephthalate-co-propylene succinate), poly(propylene terephthalate-co-propylene glutarate), poly(propylene terephthalate-co-propylene adipate), poly(propylene terephthalate-co-propylene suberate), poly(propylene terephthalate-co-propylene sebacate), poly(butylene terephthalate-co-butylene oxalate), poly(butylene terephthalate-co-butylene malonate), poly(butylene terephthalate-co-butylene succinate), poly(butylene terephthalate-co-butylene glutarate), poly(butylene terephthalate-co-butylene adipate), poly(butylene terephthalate-co-butylene suberate), poly(hexylene terephthalate-co-hexylene oxalate), poly(hexylene terephthalate-co-hexylene malonate), poly(hexylene terephthalate-co-hexylene succinate), poly(hexylene terephthalate-co-hexylene glutarate), poly(hexylene terephthalate-co-hexylene adipate) or poly(hexylene terephthalate-co-hexylene suberate), etc.

[0055] 3. Graphene

[0056] The graphene of the present invention is modified by physical or chemical methods, and carboxyl groups, hydroxyl groups, carboxyl groups, acid anhydrides, hydroxyl groups, amino groups, amide groups, imide groups and their derivative groups are introduced onto the graphene. Preferred graphene includes carboxyl group, hydroxyl group and their derivative group modified graphene. The modified graphene forms a homogeneous dispersion in an organic solvent, and the solvent is preferably mineral oil, silicone oil, glycerol and their derivatives, etc.

[0057] 4. Method for preparing polycarbonate composition for 3D printing

[0058] A method for preparing a polycarbonate composition of the present invention is to uniformly mix the required amounts of PC, the required amount of aliphatic-aromatic copolyester and the required amount of graphene dispersion in a molten state in a continuous process, and extrude and pelletize. In the continuous melting preparation method of the present invention, PC particles, aliphatic-aromatic copolyester particles and graphene dispersion are mixed evenly in a certain proportion, and then fed into the feeding port of a twin-screw extruder by a feeder at a certain feeding rate. The feeder can be a loss-in-weight feeder or a volumetric feeder. Another specific embodiment is to use multiple feeders to separately meter and add PC particles, aliphatic-aromatic copolyester particles and graphene dispersion to a twin-screw extruder according to a certain feeding ratio for reactive extrusion, and the extruded spline is granulated through a water bath or underwater pelletizing to prepare blend particles. The extrudate can also be granulated by air cooling through an anhydrous method.

[0059] The extrusion temperature suitable for the present invention is preferably from 160 °C to the lower of the thermal decomposition temperatures of PC and aliphatic-aromatic copolyester, and more preferably from 180 °C to 240 °C; the rotational speed of the extruder is from 50 rpm to 1500 rpm, preferably from 100 rpm to 400 rpm.

[0060] There are many kinds of melt blending devices applicable to the present invention, including kneaders, Farrel continuous mixers, Banbury mixers, single-screw extruders, twin-screw extruders, multi-screw extruders (more than two screws), reciprocating single-screw extruders such as Buss Ko-Kneader, etc. A better method is the continuous melting and blending extrusion method including the twin-screw extrusion method. The continuous twin-screw extruders applicable to the present invention include twin-screw extruders with different designs, such as ZSK Mcc produced by Coperion in Germany 18 Co-rotating parallel twin-screw extruders, etc.

[0061] 5. Method for preparing 3D printing material

[0062] The 3D printing material (3D printing wire) provided by the present invention is obtained by melting and extruding the polycarbonate composition prepared by the continuous melting extrusion blending method described above in a single-screw extruder, and cooling and simultaneously stretching and winding into a wire.

[0063] A method for 3D printing filaments provided by the present invention is a single-screw extrusion method. In this method, a pre-prepared blend is added to a single-screw extruder. The single-screw extruder is generally divided into three stages along its effective length. The first stage is the conveying section, where the blend is preheated and extruded. The second stage is the compression section, where the depth of the thread grooves decreases from large to small and the melt temperature reaches the level that plasticizes and melts the polycarbonate composition. The third stage is the metering section, where the blend melt is conveyed to the 3D printing filament die at a certain melt flow rate under the rotation of the screw. There is one or more circular small holes on the die, and the diameter of the circular holes can be selected according to the needs of the printer, generally 1.75 mm or 3.00 mm. The extruded printing filament is cooled and drawn, and then wound up after detection. There are various cooling methods, including water cooling or air cooling.

[0064] The extrusion temperature of the blend for 3D printing filaments is 100 °C to 260 °C, and a better extrusion temperature is 200 °C to 240 °C. The rotation speed of the single-screw extruder is 10 rpm to 200 rpm, and a better rotation speed is 25 rpm to 100 rpm.

[0065] The 3D printing filaments of the present invention can be used in the fused deposition modeling (FDM) method to prepare 3D printed products, with not only lower printing temperature and bed temperature, but also better impact strength.

[0066] The performance of the present invention is measured according to the following method:

[0067] Impact strength test: Measured according to the ISO 179 / 1eA standard using a CEAST 6957 type material testing machine.

[0068] The present invention will be further described below through examples, but these examples do not limit the scope of the present invention in any way.

[0069] In the following examples, polycarbonate (PC) is all HF1130 from SABIC;

[0070] The aliphatic-aromatic copolyester is C1200 (PBAT, polybutylene adipate / terephthalate) from BASF;

[0071] Graphene is the GRN2000 mineral oil dispersion (graphene concentration 5%) from Huangjie New Energy Technology (Shanghai) Co., Ltd.

[0072]

Comparative Example 1

[0073] Weigh each raw material according to the following ratio: the mass fraction of PC is 80 parts, and the mass fraction of PBAT is 20 parts. Mix PC and PBAT evenly, feed them through the hopper in the first section of the twin-screw extruder, melt and extrude them, cut the strands into pellets after cooling in a water bath. The screw speed is 200 r / min, the feeding speed is 1 kg / h, and the temperature of each section of the extruder is 180 - 220 °C. The collected pellets are dried at 85 °C for 4 h and then sealed for standby.

[0074]

Comparative Example 2

[0075] Weigh each raw material according to the following ratio: the mass fraction of PC is 80 parts, the mass fraction of PBAT is 20 parts, the mass fraction of graphene microflakes is 0.6 parts, and the mass fraction of antioxidant is 0.08 parts. Mix PC, PBAT, graphene microflakes, and antioxidant evenly, feed them through the hopper in the first section of the twin-screw extruder, melt and extrude them, cut the strands into pellets after cooling in a water bath. The screw speed is 200 r / min, the feeding speed is 1 kg / h, and the temperature of each section of the extruder is 180 - 220 °C. The collected pellets are dried at 85 °C for 4 h and then sealed for standby.

[0076]

Comparative Example 3

[0077] Weigh each raw material according to the following ratio: the mass fraction of PC is 80 parts, the mass fraction of PBAT is 20 parts, the mass fraction of graphene oxide is 0.03 parts (oxygen content 40%), the mass fraction of antioxidant is 0.08 parts, and white oil is 0.57 parts. Mix PC, PBAT, graphene oxide, antioxidant, and white oil evenly, feed them through the hopper in the first section of the twin-screw extruder, melt and extrude them, cut the strands into pellets after cooling in a water bath. The screw speed is 200 r / min, the feeding speed is 1 kg / h, and the temperature of each section of the extruder is 180 - 220 °C. The collected pellets are dried at 85 °C for 4 h and then sealed for standby.

[0078]

Example 1

[0079] Weigh each raw material according to the following ratio: the mass fraction of PC is 80 parts, the mass fraction of PBAT is 20 parts, the mass fraction of graphene dispersion is 0.6 parts (graphene mass concentration 5%, oxygen content in graphene 10%), and the mass fraction of antioxidant is 0.08 parts. Mix PC, PBAT, graphene dispersion, and antioxidant evenly, feed them through the hopper in the first section of the twin-screw extruder, melt and extrude them, cut the strands into pellets after cooling in a water bath. The screw speed is 200 r / min, the feeding speed is 1 kg / h, and the temperature of each section of the extruder is 180 - 220 °C. The collected pellets are dried at 85 °C for 4 h and then sealed for standby.

[0080]

Example 2

[0081] Weigh each raw material according to the following ratio: the mass fraction of PC is 80 parts, the mass fraction of PBAT is 20 parts, the mass fraction of graphene dispersion is 1 part, and the mass fraction of antioxidant is 0.08 part. Mix PC, PBAT, graphene dispersion, and antioxidant evenly, feed them through the hopper in the first section of the twin-screw extruder, melt and extrude them, cool the extruded strips through a water bath and then pelletize them. The screw speed is 200 r / min, the feeding speed is 1 kg / h, and the temperature of each section of the extruder is 180 - 220 °C. The collected pellets are dried at 85 °C for 4 h and then sealed for standby.

[0082]

Example 3

[0083] Weigh each raw material according to the following ratio: the mass fraction of PC is 80 parts, the mass fraction of PBAT is 20 parts, the mass fraction of graphene dispersion is 2 parts, and the mass fraction of antioxidant is 0.08 part. Mix PC, PBAT, and graphene dispersion evenly, feed them through the hopper in the first section of the twin-screw extruder, melt and extrude them, cool the extruded strips through a water bath and then pelletize them. The screw speed is 200 r / min, the feeding speed is 1 kg / h, and the temperature of each section of the extruder is 180 - 220 °C. The collected pellets are dried at 85 °C for 4 h and then sealed for standby.

[0084]

Preparation Example 1

[0085] Feed the 6 kinds of blend particles in Examples 1 - 3 and Comparative Examples 1 - 3 through the hopper in the first section of the single-screw extruder, melt and extrude them, cool the extruded strips through a water bath at two different temperatures, and at the same time, after passing the drawdown test and the wire diameter being qualified, wind them into a wire. The screw speed is 15 r / min, the temperature of each section of the extruder is 200 - 230 °C, and the drawdown speed is adjusted in real time according to the measured wire diameter to ensure that the wire diameter is about 1.75 mm or 3.00 mm.

[0086]

Test Example 1

[0087] Print the wire made in Preparation Example 1 on a Makerbot Replicator 2X printer, select different temperatures for printing, and determine the suitable printing temperature conditions.

[0088] The test results of the 6 kinds of blend samples prepared according to Test Example 1 for Examples 1 - 3 and Comparative Examples 1 - 3 are shown in Table 1. It can be clearly seen from the results that adding graphene and the like can improve the dimensional accuracy of the printed parts and reduce the 3D printing temperature. Among them, when the amount of graphene dispersion added exceeds 1 part, the dimensional error can be reduced to within the error range of the standard specified test sample. At the same time, the 3D printing temperature drops from 280 °C to 250 °C, making the material easier to print.

[0089] Table 1

[0090]

[0091]

[0092] It should be noted that the above-described embodiments are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described by referring to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words rather than limiting words. Modifications can be made to the present invention within the scope of the claims of the present invention as stipulated, and the present invention can be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A polycarbonate composition for 3D printing, which comprises polycarbonate, aliphatic-aromatic copolyester, graphene dispersion, and optional functional additives, The graphene has surface functional groups selected from at least one of carboxyl, anhydride, hydroxyl, amino, amide, imide, and their derivative groups, By mass, the polycarbonate composition comprises: (a) 50 to 99 parts of polycarbonate; (b) 1 to 50 parts of aliphatic-aromatic copolyester; (c) 1 - 2 parts of graphene dispersion; and optionally (d) 0.5 to 5 parts of functional additives, In the graphene dispersion, the mass concentration of graphene is 5% - 10%; In the graphene dispersion, the number of layers of the graphene is not more than 10 layers, and the solvent of the graphene dispersion is selected from at least one of mineral oil, silicone oil, ethylene glycol, glycerol, and their derivatives.

2. The polycarbonate composition according to claim 1, characterized in that, The polycarbonate is obtained by melt polycondensation of bisphenol A and diphenyl carbonate and / or by direct esterification polymerization of bisphenol A and phosgene.

3. The polycarbonate composition according to any one of claims 1-2, characterized in that The aliphatic-aromatic copolyester is selected from copolyesters condensed from α,ω-aliphatic diacids or their derivatives and aromatic diacids or their derivatives with aliphatic diols.

4. The polycarbonate composition according to claim 3, characterized in that, The aliphatic-aromatic copolyester includes chain-extended copolyesters.

5. The polycarbonate composition according to claim 4, characterized in that, The α,ω-aliphatic diacids are selected from substituted or unsubstituted α,ω-aliphatic diacids containing 2 to 22 main-chain carbon atoms; and / or The aromatic diacids are selected from substituted or unsubstituted aromatic diacids containing 8 to 22 main-chain carbon atoms; and / or The aliphatic diols are selected from diols containing 2 - 10 carbon atoms.

6. The polycarbonate composition according to claim 5, wherein The α,ω-aliphatic diacids are selected from at least one of succinic acid, adipic acid, and suberic acid; and / or The aromatic diacids are selected from at least one of terephthalic acid and 2,6-naphthalenedicarboxylic acid; and / or The aliphatic diols are selected from at least one of 1,4-butanediol, 1,6-hexanediol, and 1,8-octanediol.

7. The polycarbonate composition according to any one of claims 1-2, characterized in that The functional additives are selected from at least one of compatibilizers, inorganic fillers, antioxidants, lubricants, colorants, and flame retardants.

8. A method for preparing the polycarbonate composition according to any one of claims 1 - 7, which comprises mixing the polycarbonate, the aliphatic-aromatic copolyester, the graphene dispersion, and optional functional additives in a molten state, and extruding and pelletizing to obtain the polycarbonate composition.

9. Use of the polycarbonate composition according to any one of claims 1 - 7 or the polycarbonate composition obtained by the preparation method according to claim 8 in 3D printing.

10. A method for preparing a 3D printing material, which comprises melt-extruding the polycarbonate composition according to any one of claims 1 - 7 or the polycarbonate composition obtained by the preparation method according to claim 8, cooling, and orientation drawing to obtain the 3D printing material.

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