Polycarbonate resin composition for 3d printing having excellent shape retention and interfacial adhesion, and particles and filaments for 3d printing comprising the same

Abstract

The present invention relates to a polycarbonate resin composition for 3D printing, which is excellent in shape retention and interfacial adhesion, and a filament for 3D printing and a granule for 3D printing comprising the same. In more detail, the present invention relates to a polycarbonate resin composition for 3D printing, and a granule for 3D printing and a filament for 3D printing comprising the same, in which the polycarbonate resin composition comprises a specific combination of a polycarbonate (PC) resin, a polybutylene terephthalate (PBT) resin, a carbon black master batch, and a carbon fiber, and maintains excellent mechanical properties of the polycarbonate resin, and specific physical properties required for the filament for 3D printing, such as shape retention and interfacial adhesion, are excellently balanced.

Description

Technical Field

[0001] This invention relates to a polycarbonate resin composition for 3D printing with excellent shape retention and interfacial adhesion, as well as 3D printing filaments and 3D printing particles comprising the polycarbonate resin composition. More specifically, it relates to a polycarbonate resin composition for 3D printing, as well as 3D printing particles and filaments comprising the polycarbonate resin composition, wherein the polycarbonate resin composition comprises a specific combination of polycarbonate resin, polybutylene terephthalate (PBT) resin, carbon black masterbatch, and carbon fiber, and maintains the excellent mechanical properties of polycarbonate resin while maintaining an excellent balance of the specific physical properties required for 3D printing filaments, such as shape retention and interfacial adhesion. Background Technology

[0002] The output method of 3D printing varies depending on the application, but considering factors such as equipment price, material supply and demand, and output difficulty, the most widely used output method in industry and home is material extrusion. Material extrusion is a method in which material provided in filament form is melted and stacked in a nozzle. The resins used for 3D printing filaments in this method include polylactic acid (PLA), acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC), and polyimide (PI).

[0003] Existing 3D printers consist of an extruder that supplies filaments, a hot-end nozzle that melts and ejects the filaments, and so on. The filaments supplied by the extruder are melted by the heater of the hot-end nozzle and ejected in the form of beads. Three-dimensional objects are created by stacking the beads while the hot-end nozzle moves in three axes.

[0004] To ensure that three-dimensional objects possess appropriate quality, it is crucial that the material exhibits properties that allow for consistent print quality. Specifically, shape retention and interfacial adhesion are important factors determining print quality. Shape retention refers to the property of beads ejected from the nozzle and stacked layer by layer, maintaining their original circular shape (not compressed into an ellipse) and the shape retention property after three-dimensional stacking.

[0005] Among them, polylactic acid (PLA) resin is the most commonly used resin for 3D printing filaments. PLA resin is odorless during output and can be output at relatively low temperatures, thus eliminating the need for expensive output devices. However, due to the poor mechanical properties of PLA resin itself, there is a need for 3D printing filament resins such as PLA that can be output at relatively low temperatures while exhibiting excellent mechanical properties such as high strength.

[0006] Polycarbonate resin is an engineering plastic with excellent mechanical properties, thermal properties, and dimensional stability, and is used in various industrial fields. However, when polycarbonate resin is used as a resin for 3D printing filaments, collapse occurs, and the interfacial adhesion is weak, which may lead to a decrease in rigidity.

[0007] Therefore, there is a need to develop a polycarbonate resin composition for 3D printing filaments that has excellent shape retention, interfacial adhesion, and other specific physical properties required for 3D printing filaments. Summary of the Invention

[0008] Technical problems to be solved

[0009] The purpose of this invention is to provide a polycarbonate resin composition for 3D printing, 3D printing particles and filaments comprising the polycarbonate resin composition, wherein the polycarbonate resin composition retains the excellent mechanical properties of polycarbonate resin, while maintaining an excellent balance of the specific physical properties required for 3D printing filaments, such as shape retention force and interfacial adhesion.

[0010] Technical solution

[0011] To solve the above-mentioned technical problems, the present invention provides a resin composition for 3D printing, wherein, based on a total of 100 parts by weight of the composition, the resin composition comprises: (1) 62-76 parts by weight of polycarbonate resin, (2) 1-11 parts by weight of polybutylene terephthalate resin, (3) 1-9.5 parts by weight of carbon black masterbatch and (4) 11-25 parts by weight of carbon fiber.

[0012] According to another aspect of the present invention, 3D printing particles comprising the polycarbonate resin composition of the present invention are provided.

[0013] According to another aspect of the present invention, a filament for 3D printing comprising the polycarbonate resin composition of the present invention is provided.

[0014] Beneficial effects

[0015] The polycarbonate resin composition of the present invention retains the unique and excellent mechanical properties of polycarbonate resin while exhibiting excellent interfacial adhesion. Therefore, it offers excellent output and shape retention during 3D printing, preventing collapse, and its excellent interfacial adhesion prevents stiffness reduction, making it suitable for use as 3D printing particles or filaments. Attached Figure Description

[0016] Figure 1 This is a graph illustrating the evaluation criteria for the shape retention of filaments used in 3D printing. The fewer collapses that occur during 3D printing, the higher the score (maximum 5 points).

[0017] Figure 2 This is a graph illustrating the evaluation criteria for interfacial adhesion of filaments used in 3D printing. The less gap between the interfaces during 3D printing, the higher the score (maximum 5 points). Detailed Implementation

[0018] The present invention will now be described in detail.

[0019] The 3D printing resin composition of the present invention comprises (1) polycarbonate resin, (2) polybutylene terephthalate resin, (3) carbon black masterbatch and (4) carbon fiber. Furthermore, the 3D printing resin composition of the present invention may optionally further comprise (5) one or more other additives.

[0020] (1) Polycarbonate (PC) resin

[0021] The polycarbonate resin that may be included in the 3D printing resin composition of the present invention is preferably an aromatic polycarbonate resin, but the type is not particularly limited thereto as long as the technical concept of the present invention can be realized, and thermoplastic aromatic polycarbonate resins commonly used in the art can be used.

[0022] In one specific embodiment of the present invention, the aromatic polycarbonate resin may be prepared from diphenols, carbonate precursors and molecular weight regulators, and may contain linear and / or branched polycarbonate homopolymers and polyester copolymers.

[0023] The diphenol is one of the monomers that make up aromatic polycarbonate resins and can be represented by the following chemical formula 1.

[0024] [Chemical Formula 1]

[0025]

[0026] In the chemical formula 1, X represents an alkylene group; a linear, branched, or cyclic alkylene group without a functional group; or a linear, branched, or cyclic alkylene group having one or more functional groups selected from thioethers, ethers, sulfoxides, sulfones, ketones, naphthyl or isobutylphenyl. Preferably, X is a linear alkylene group having 1 to 10 carbon atoms, a branched alkylene group having 3 to 10 carbon atoms, or a cyclic alkylene group having 3 to 10 carbon atoms.

[0027] R1 and R2 can each independently represent a halogen atom, a straight-chain alkyl group with 1 to 20 carbon atoms, a branched alkyl group with 3 to 20 carbon atoms, or a cyclic alkyl group with 3 to 20 carbon atoms.

[0028] n and m can each independently represent integers from 0 to 4.

[0029] As a non-limiting example of the aforementioned diphenols, they may be selected from bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)naphthylmethane, bis(4-hydroxyphenyl)-(4-isobutylphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1-ethyl-1,1-bis(4-hydroxyphenyl)propane, 1-phenyl-1,1-bis(4-hydroxyphenyl)ethane, 1-naphthyl-1,1-bis(4-hydroxyphenyl)ethane, 1,2-bis(4-hydroxyphenyl)ethane, 1,10-bis(4-hydroxyphenyl)decane, 2-methyl-1,1-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)propane, etc. 2,2-Bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxyphenyl)hexane, 2,2-bis(4-hydroxyphenyl)nonane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-fluoro-4-hydroxyphenyl)propane, 4-methyl-2,2-bis(4-hydroxyphenyl)pentane, 4,4-bis(4-hydroxyphenyl)heptane, diphenylbis(4-hydroxyphenyl)methane, resorcinol, hydroquinone, 4,4'-dihydroxyphenyl ether (bis(4-hydroxyphenyl) ether), 4,4'-dihydroxy-2,5-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether, bis(3,5-dimethyl-4-hydroxyphenyl) ) ether, bis(3,5-dichloro-4-hydroxyphenyl) ether, 1,4-dihydroxy-2,5-dichlorobenzene, 1,4-dihydroxy-3-methylbenzene, 4,4'-dihydroxydiphenol (p,p'-dihydroxyphenyl), 3,3'-dichloro-4,4'-dihydroxyphenyl, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(3,5-dimethyl-4-hydroxyphenyl)cyclohexane, 1,1-bis(3,5-dichloro-4-hydroxyphenyl)cyclohexane, 1,1-bis(3,5-dichloro-4-hydroxyphenyl)cyclododecane, 1,1-bis(4-hydroxyphenyl)cyclododecane, 1,1-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)decane, 1,4 - bis(4-hydroxyphenyl)propane, 1,4-bis(4-hydroxyphenyl)butane, 1,4-bis(4-hydroxyphenyl)isobutane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(3-chloro-4-hydroxyphenyl)propane, bis(3,5-dimethyl-4-hydroxyphenyl)methane, bis(3,5-dichloro-4-hydroxyphenyl)methane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 2,4-bis(4-hydroxyphenyl)-2-methyl-butane, 4,4'-thiobiphenyl (bis(4-hydroxyphenyl)sulfone), bis(3,5-Dimethyl-4-hydroxyphenyl) sulfone, bis(3-chloro-4-hydroxyphenyl) sulfone, bis(4-hydroxyphenyl) sulfide, bis(4-hydroxyphenyl) sulfoxide, bis(3-methyl-4-hydroxyphenyl) sulfide, bis(3,5-dimethyl-4-hydroxyphenyl) sulfide, bis(3,5-dibromo-4-hydroxyphenyl) sulfoxide, 4,4'-dihydroxybenzophenone, 3,3',5,5'-tetramethyl-4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl, methylhydroquinone, 1,5-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene, but not necessarily limited to these. Representatively, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) can be listed. Other functional dihydric phenols can be found in US patents US2,999,835, US3,028,365, US3,153,008, and US3,334,154, etc., and these dihydric phenols can be used alone or in combination of two or more.

[0030] The carbonate precursor is another monomer constituting the aromatic polycarbonate resin, and non-limiting examples include phosgene, bromocarbonate, dihalocarbamate, diphenyl carbonate, or dimethyl carbonate. Preferably, phosgene can be used.

[0031] As the molecular weight regulator, substances known in the art can be used, namely monofunctional substances (monofunctional compounds) similar to the monomers used to prepare thermoplastic aromatic polycarbonate resins. Non-limiting examples of the molecular weight regulator include phenol-based derivatives (e.g., p-isopropylphenol, p-tert-butylphenol (PTBP), p-cumylphenol, p-isooctylphenol, p-isononylphenol, etc.), fatty alcohols, etc. Preferably, p-tert-butylphenol (PTBP) can be used.

[0032] The viscosity-average molecular weight of the polycarbonate resin included in the resin composition of the present invention is preferably from 15,000 to 50,000, more preferably from 16,000 to 30,000.

[0033] In the 3D printing resin composition of the present invention, based on a total of 100 parts by weight of the composition, the content of the polycarbonate resin is 62-76 parts by weight. When the content of the polycarbonate resin in the total of 100 parts by weight of the composition is less than 62 parts by weight, there may be a problem of reduced mechanical strength of the 3D printed product; when the content of the polycarbonate resin exceeds 76 parts by weight, collapse may occur.

[0034] More specifically, the content of polycarbonate resin in the resin composition based on a total of 100 parts by weight of the 3D printing resin composition of the present invention can be 62 parts by weight or more, 63 parts by weight or more, 64 parts by weight or more, or 65 parts by weight or more, or it can be 76 parts by weight or less, 75 parts by weight or less, 74 parts by weight or less, or 72 parts by weight or less. Preferably, the content of polycarbonate resin in 100 parts by weight of the composition can be, for example, 62-76 parts by weight, more preferably 63-75 parts by weight, and even more preferably 65-72 parts by weight.

[0035] (2) Polybutylene terephthalate (PBT) resin

[0036] The polybutylene terephthalate resin contained in the 3D printing resin composition of the present invention is a polymer that is polycondensed by direct esterification or transesterification reaction using 1,4-butanediol and terephthalic acid or dimethyl terephthalate as monomers.

[0037] In a preferred embodiment of the present invention, the melting temperature of the polybutylene terephthalate resin can be 215°C-235°C, more preferably 220°C-230°C. Furthermore, the intrinsic viscosity (IV) of the polybutylene terephthalate resin is preferably 0.45-1.6 dl / g, more preferably 0.80-1.3 dl / g.

[0038] In the 3D printing resin composition of the present invention, based on a total of 100 parts by weight of the composition, the content of polybutylene terephthalate resin is 1-11 parts by weight. When the content of polybutylene terephthalate resin in a total of 100 parts by weight of the composition is less than 1 part by weight, it is difficult to improve the collapse phenomenon of 3D printed products. When the content of polybutylene terephthalate resin in a total of 100 parts by weight of the composition exceeds 11 parts by weight, the mechanical and physical properties of the 3D printed products decrease, and the interfacial adhesion may decrease.

[0039] More specifically, the content of polybutylene terephthalate resin in the resin composition based on a total of 100 parts by weight of the 3D printing resin composition of the present invention can be 1 part by weight or more, 2 parts by weight or more, 3 parts by weight or more, or 4 parts by weight or more, and can be 11 parts by weight or less, 10.5 parts by weight or less, 10 parts by weight or less, 9.5 parts by weight or less, 9 parts by weight or less, or 8 parts by weight or less. Preferably, the content of polybutylene terephthalate resin in 100 parts by weight of the composition can be, for example, 1-11 parts by weight, more preferably 2-10 parts by weight, and even more preferably 3-8 parts by weight.

[0040] (C) Carbon black masterbatch

[0041] The carbon black masterbatch refers to a mixture in which carbon black is dispersed in a thermoplastic resin, preferably in the aforementioned polycarbonate resin. By using a carbon black masterbatch in which carbon black is dispersed in polycarbonate resin, carbon black is easily dispersed, thereby effectively improving lightfastness.

[0042] The type of carbon black contained in the carbon black masterbatch is not particularly limited; for example, Ketjen black, acetylene black, channel black, or combinations thereof can be used. The particle size of the carbon black is preferably in the range of 10-40 nm. The nitrogen adsorption specific surface area (NSA) of the carbon black is not particularly limited, but is preferably 150-250 m². 2 / g, more preferably 180-240m 2 / g. Among them, the nitrogen adsorption specific surface area (NSA) is the value of the amount of nitrogen adsorbed on the surface of carbon black according to JIS K6217-2:2001 "Part II: Methods for calculating specific surface area - Nitrogen adsorption method - Single point method".

[0043] In the 3D printing resin composition of the present invention, based on a total of 100 parts by weight of the composition, the content of the carbon black masterbatch can be 1-9.5 parts by weight. When the content of the carbon black masterbatch in the total of 100 parts by weight of the composition is less than 1 part by weight, it is difficult to expect an improvement in interfacial adhesion due to the insufficient carbon black content. When the content of the carbon black masterbatch in the total of 100 parts by weight of the composition exceeds 9.5 parts by weight, the mechanical and physical properties may decrease.

[0044] More specifically, the content of carbon black masterbatch in the resin composition based on a total of 100 parts by weight of the 3D printing resin composition of the present invention can be 1 part by weight or more, 2 parts by weight or more, 3 parts by weight or more, or 4 parts by weight or more, and can be 9.5 parts by weight or less, 9 parts by weight or less, 8.5 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, or 6 parts by weight or less. Preferably, the content of carbon black masterbatch in 100 parts by weight of the composition can be, for example, 1-9.5 parts by weight, more preferably 2-8 parts by weight, and even more preferably 4-6 parts by weight.

[0045] (D) Carbon fiber

[0046] The carbon fibers can generally be classified according to their diameter, morphology, and degree of graphitization. This characteristic can be determined by the method used to synthesize the carbon fibers. In this invention, the carbon fibers are not particularly limited, but are preferably pitch- or polyacrylonitrile (PAN) based fibers, and can exist in the composition in the form of monofilaments or multiple filaments. For example, they can be used alone or in combination with other types of fibers through co-weaving, core / sheath, side-by-side, orange-petal type, or matrix and fibril structures. Furthermore, as reinforcing compositions for the carbon fibers, they can be used in the composition in the form of, for example, woven fiber reinforcing materials such as rovings and 0-90 degree fabrics, nonwoven fiber reinforcing materials such as continuous filament mats, chopped filament mats, tissue paper, paper, and felt, and three-dimensional braided reinforcing materials such as preforms and braids.

[0047] The diameter of carbon fibers is typically about 1-30 μm, and according to one embodiment of the present invention, the diameter of the fibers can be 2-20 μm, preferably 3-10 μm.

[0048] In the 3D printing resin composition of the present invention, the carbon fiber content is 11-25 parts by weight, based on a total of 100 parts by weight of the composition. When the carbon fiber content in a total of 100 parts by weight of the composition is less than 11 parts by weight, it may not show improvement in collapse phenomenon, and when the carbon fiber content exceeds 25 parts by weight, extrusion processing may be difficult.

[0049] More specifically, the carbon fiber content in the resin composition based on a total of 100 parts by weight of the 3D printing resin composition of the present invention can be 11 parts by weight or more, 12 parts by weight or more, 13 parts by weight or more, or 15 parts by weight or more, and can be 25 parts by weight or less, 24 parts by weight or less, 23 parts by weight or less, 22 parts by weight or less, 21 parts by weight or less, or 20 parts by weight or less. Preferably, the carbon fiber content in 100 parts by weight of the composition can be, for example, 11-25 parts by weight, more preferably 13-22 parts by weight, and even more preferably 15-20 parts by weight.

[0050] (E) Other additives

[0051] In addition to components (A), (B), (C), and (D) described above, the resin compositions of the present invention may further include one or more other additives typically added to thermoplastic resin compositions for injection molding or extrusion molding. The resin compositions of the present invention may further include one or more additives selected from, for example, inorganic particles, antioxidants, slip agents, ultraviolet absorbers, light stabilizers, impact modifiers, matting agents, flame retardants, or mixtures of two or more thereof.

[0052] Specifically, the inorganic particles may be selected from at least one of talc, whiskers, glass beads, glass sheets, glass fibers, carbon fibers, clay, kaolin, mica, calcium carbonate, and barium sulfate.

[0053] Specifically, the antioxidant may be phenolic, phosphite, thioester, or a mixture of two or more thereof.

[0054] Specifically, the slip agent may be polyvinyl alcohol, vinyl ester, ethylene glycol-glycerol ester, lignite, ethylene glycol-glycerol lignite ester, or a mixture of two or more thereof.

[0055] There are no particular restrictions on the ultraviolet absorber, and commercially available products can be used.

[0056] Specifically, the light stabilizer may be a benzotriazole compound, a hydroxyphenyltriazine compound, a pyrimidinyl compound, a cyanoacrylate compound, or a mixture of two or more thereof.

[0057] The impact modifier may be one or more core-shell copolymers selected from acrylate-based copolymers, ethylene-acrylate-based copolymers, silicone-containing copolymers, or polymethyl methacrylate-based copolymers, but is not limited thereto. The impact modifier not only provides impact reinforcement but also improves the compatibility between thermoplastic resins in the composition or between components in the composition, thereby stabilizing excellent and uniform physical properties.

[0058] Furthermore, flame retardants are substances that reduce flammability and may be selected from, but are not limited to, one or more compounds selected from phosphate-based compounds, phosphonate-based compounds, polysiloxanes, phosphazene compounds, hypophosphite-based compounds, or melamine-based compounds. Matting agents may be inorganic or organic compounds. The inorganic compounds may be silica, magnesium oxide, zirconium oxide, aluminum oxide, titanium dioxide, or mixtures of two or more of these. The organic compounds are cross-linked vinyl copolymers, and the monomers of the vinyl copolymers may be selected from, or more monomers selected from, styrene, acrylonitrile, methyl methacrylate, ethyl methacrylate, or butyl methacrylate.

[0059] The content of the other additives is not particularly limited, and can be in an amount that is used to increase further functionality, within the range that does not impair the desired physical properties of the 3D printing resin composition of the present invention.

[0060] According to a specific embodiment of the present invention, based on a total of 100 parts by weight of the composition of the present invention, the content of other additives can be 0.1-10 parts by weight, preferably 0.5-10 parts by weight, and more preferably 1-8 parts by weight. When the content of the other additives in the total of 100 parts by weight is less than 0.1 parts by weight, the improvement effect of the various functions brought about by the use of other additives may be minimal; when the content of the other additives exceeds 10 parts by weight, the mechanical and physical properties of the resin composition may deteriorate.

[0061] According to another aspect of the present invention, a 3D printing pellet comprising the polycarbonate resin composition of the present invention is provided.

[0062] According to another aspect of the present invention, a filament for 3D printing comprising the polycarbonate resin composition of the present invention is provided.

[0063] The filament for 3D printing can be prepared by extruding the resin composition of the present invention. Specifically, the filament for 3D printing can be prepared by using the resin composition of the present invention to prepare particles and then further processing the particles (such as extrusion molding).

[0064] The present invention will now be described in more detail through examples and comparative examples. However, the scope of the present invention is not limited thereto.

[0065] [Example]

[0066] The specific components used in this embodiment and comparative example are as follows.

[0067] (A) Polycarbonate resin: Bisphenol A type linear polycarbonate with a viscosity-average molecular weight of approximately 17,000.

[0068] (B) Polybutylene terephthalate resin: Polybutylene terephthalate with an intrinsic viscosity (IV) of 0.8-1.1 dl / g

[0069] (C) Carbon black masterbatch: Woosung Chemical NB9086

[0070] (D) Carbon fiber: MITSUBISHI PYROFIL TR06UL

[0071] (E) Other additives: impact modifiers, antioxidants, and lubricants

[0072] A thermoplastic resin composition was prepared by thoroughly mixing and uniformly dispersing polycarbonate copolymer resin, polybutylene terephthalate resin, and carbon black masterbatch according to the components and contents of the examples and comparative examples shown in Tables 1 and 2 below using a mixer. The prepared thermoplastic resin composition was then extruded using a 32π twin-screw extruder (L / D = 40, 25 mm) at 260°C-280°C and 200-250 rpm, with carbon fibers added to the sides. Injection molded specimens were prepared using an injection molding machine with a clamping force of 100-200 tons under the same temperature conditions. For injection molded specimens used to measure mechanical and physical properties, specimens conforming to various ASTM standards were prepared to suit the measurement of tensile strength and impact strength.

[0073] <Evaluation of physical properties>

[0074] (1) Tensile strength

[0075] Evaluation was conducted according to ASTM D638.

[0076] (2) Bending strength and bending modulus

[0077] Evaluation was conducted according to ASTM D790.

[0078] (3) Impact strength

[0079] Evaluated according to ASTM D256 (1 / 8-inch thickness, notched-cantilever beam).

[0080] (4) Heat distortion temperature

[0081] According to ASTM D648, at 18.6 kg / cm² 2 The load is evaluated.

[0082] (5) Shape retention force (collapse)

[0083] A 200mm x 100mm quadrilateral sample was printed using a 3D printer at the appropriate output temperature. When the shape retention force was insufficient, the output could not maintain the quadrilateral shape, resulting in dents. The location of the dent, where the output product failed to maintain its shape and where the dents were most pronounced, was observed and assigned a score from 1 to 5 based on the following criteria. (Reference) Figure 1 )

[0084] 5 points: Indentation less than 0.5cm

[0085] 4 points: The dent is 0.5-1.0cm.

[0086] 3 points: The dent is 1.0-1.5cm.

[0087] 2 points: The dent is 1.5-2.0cm.

[0088] 1 point: Dents exceeding 2.0cm

[0089] (6) Interfacial adhesion

[0090] At the appropriate output temperature, a 200mm x 100mm quadrilateral specimen was printed using a 3D printer. Then, five edge sections of the quadrilateral specimen were observed using SEM. The phenomenon of incomplete bonding between resin interfaces that is still distinguishable is termed interface separation. No interface separation was observed, and 1 point was awarded for each observed interface separation. A total of five observations were conducted and summarized, with scores ranging from 5 to 0 points assigned according to the following criteria. (Reference) Figure 2 )

[0091] 5 points: No interface separation

[0092] 4 points: Interface separation was observed at 1 out of 5 locations.

[0093] 3 points: Interface separation was observed at 2 out of 5 locations.

[0094] 2 points: Interface separation was observed at 3 out of 5 locations.

[0095] 1 point: Interface separation was observed at 4 out of 5 locations.

[0096] 0 points: Five interface separations were observed in five locations.

[0097] [Table 1]

[0098]

[0099] [Table 2]

[0100]

[0101]

[0102] The polycarbonate resin composition according to the present invention retains the unique and excellent mechanical properties of polycarbonate resin, while exhibiting excellent shape retention and preventing collapse during 3D printing, and excellent interfacial adhesion. As shown in Table 1 above, compared with the resin compositions proposed in the comparative examples, the resin compositions according to the embodiments of the present invention show increased interfacial adhesion and improved collapse phenomenon, and exhibit an excellent balance in mechanical and physical properties such as tensile strength, flexural strength, and impact strength. This polycarbonate resin composition is suitable for use as a 3D printing material.

[0103] On the other hand, as can be seen from Table 2, when there is no carbon masterbatch in Comparative Example 1, the interfacial adhesion is reduced. On the other hand, it can be seen that the carbon masterbatch content in Comparative Example 2 is high, which may lead to a decrease in physical properties.

[0104] In Comparative Examples 3 and 4, the carbon fiber content was low, indicating that collapse occurred.

[0105] In Comparative Example 5, it was found that when there was no polybutylene terephthalate resin, the curing speed was slower, and therefore collapse occurred. In Comparative Example 6, since the content of polybutylene terephthalate resin was high, it was confirmed that the physical properties were reduced and the interfacial adhesion was reduced.

Claims

1. A resin composition for 3D printing, wherein, Based on a total of 100 parts by weight of the composition, the resin composition comprises: (1) 65-72 parts by weight of polycarbonate resin, (2) 3-8 parts by weight of polybutylene terephthalate resin, (3) 4-6 parts by weight of carbon black masterbatch, (4) 15-20 parts by weight of carbon fiber, and (5) 1-8 parts by weight of at least one additive selected from inorganic particles, antioxidants, lubricants, light stabilizers, impact modifiers, matting agents, flame retardants, or mixtures thereof. The intrinsic viscosity (IV) of polybutylene terephthalate resin is 0.8-1.1 dl / g. Carbon black masterbatch is a form of carbon black dispersed in polycarbonate resin.

2. The resin composition for 3D printing according to claim 1, wherein, The viscosity-average molecular weight of the polycarbonate resin is between 15,000 and 50,000.

3. The resin composition for 3D printing according to claim 1, wherein, The melting temperature of polybutylene terephthalate resin is 215℃-235℃.

4. The resin composition for 3D printing according to claim 1, wherein, The carbon black has a particle size of 10-40 nm and a nitrogen adsorption surface area (NSA) of 150-250 m². 2 / g.

5. The resin composition for 3D printing according to claim 1, wherein, The diameter of the carbon fiber is 1-30 μm.

6. The resin composition for 3D printing according to claim 1, wherein, The light stabilizer is an ultraviolet absorber.

7. A 3D printing particle comprising the composition of any one of claims 1 to 6.

8. A filament for 3D printing comprising the composition of any one of claims 1 to 6.

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