Molded article and method for manufacturing the same

Abstract

The present application provides a molding product manufacturing method which is easy to manufacture and can effectively improve mechanical properties in molding using a three-dimensional printer. The molding product manufacturing method includes: a step of preparing a resin composition containing inorganic fibers having an average fiber length of 1 μm to 300 μm and an average aspect ratio of 3 to 200 and a thermoplastic resin; and a step of molding using the resin composition by a thermal fusion lamination type three-dimensional printer, thereby manufacturing a molding product. The lamination interval when molding using the thermal fusion lamination type three-dimensional printer is lower than 0.20 mm, and the molding line width is lower than 0.20 mm.

Description

Technical Field

[0001] This invention relates to shaped objects obtained using a resin composition containing inorganic fibers and thermoplastic resin, and a method for manufacturing the same. Background Technology

[0002] 3D printers, because they do not require the molds used in injection molding, can create complex three-dimensional structures that are impossible to form in injection molding. Therefore, they have gained attention in recent years as a technology for producing a wide variety of products in small quantities. 3D printers calculate the shape of a thin cross-section from three-dimensional data input from CAD or other sources. Based on this calculation, they stack multiple layers of material to create three-dimensional objects; this technology is also known as additive manufacturing technology. On the other hand, in injection molding, the flow pattern of resin varies depending on the location within the mold cavity, making it difficult to improve fiber orientation. Lower fiber orientation means it is difficult to obtain the reinforcing effect of fibrous fillers and improve mechanical properties.

[0003] Regarding materials used in 3D printers (also known as additive manufacturing materials), various methods are known. Among them, the extrusion method, which uses a heating unit inside the extruder to fluidize thermoplastic resin with filament-like or other shapes, and then discharges it from the nozzle onto a platform, is widely used because it is cost-effective. This method involves layering small amounts of material while cooling and solidifying it according to the cross-sectional shape of the desired object.

[0004] In thermoplastic laminate 3D printers, when using unadulterated thermoplastic resin (so-called pure resin) for modeling, problems such as interlayer delamination and warping of the modeled object occur. Furthermore, when using thermoplastic resin compositions with fibrous fillers such as glass fiber and carbon fiber in thermoplastic laminate 3D printers, problems such as extruder clogging and wear make modeling more difficult. It is also believed that the addition of inorganic fillers hinders interlayer fusion, reduces interlayer peel strength, and consequently lowers the mechanical properties of the modeled object.

[0005] In contrast, Patent Document 1 describes a method that uses a resin composition containing inorganic fibers with an average fiber length of 1 μm to 300 μm and an average aspect ratio of 3 to 200 and a thermoplastic resin, which makes manufacturing easier and improves interlayer delamination and warping / shrinkage of the model in the use of a 3D printer.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2018 / 043231 Summary of the Invention

[0009] The technical problem that the invention aims to solve

[0010] In recent years, molded parts reinforced with fibrous fillers have been explored for a variety of applications, such as automotive parts and electronic equipment components, and their mechanical properties need further improvement.

[0011] However, the model in Patent Document 1 also suffers from the problem of insufficiently improving mechanical properties. Furthermore, while increasing the amount of inorganic fibers could be considered to improve mechanical properties, it is known that melt flowability decreases with high inorganic fiber content. Therefore, there is a difficulty in using a 3D printer to model resin compositions with high inorganic fiber content.

[0012] The purpose of this invention is to provide a model that is easy to manufacture and can effectively improve mechanical properties when using a 3D printer, as well as a method for manufacturing the same.

[0013] Technical solutions for solving the problem

[0014] The present invention provides the following shaped objects and their manufacturing methods.

[0015] Item 1. A method for manufacturing a shaped object, comprising:

[0016] A process for preparing a resin composition containing inorganic fibers with an average fiber length of 1 μm to 300 μm and an average aspect ratio of 3 to 200 and a thermoplastic resin; and a process for manufacturing a shaped object by using the above resin composition and molding it using a thermomelting lamination method 3D printer, wherein the lamination spacing when molding using the above thermomelting lamination method 3D printer is less than 0.20 mm and the molding line width is less than 0.20 mm.

[0017] Item 2. A method for manufacturing a shaped object as described in Item 1, wherein,

[0018] When the MFR value of the above-mentioned thermoplastic resin is set as MFR1 and the MFR value of the above-mentioned resin composition is set as MFR2, the MFR ratio expressed as MFR2 / MFR1 is 0.10 or more and 0.90 or less.

[0019] Item 3. A method for manufacturing a model as described in Item 1 or Item 2, wherein,

[0020] In the total mass percentage of the above resin composition, the content of the above inorganic fiber is 1% or more and 45% or less.

[0021] Item 4. A method for manufacturing a shaped object as described in any one of Items 1 to 3, wherein,

[0022] The shaping speed is above 20mm / second and below 200mm / second.

[0023] Item 5. A method for manufacturing a shaped object as described in any one of Items 1 to 4, wherein,

[0024] The Mohs hardness of the aforementioned inorganic fibers is below 5.

[0025] Item 6. A method for manufacturing a shaped object as described in any one of Items 1 to 5, wherein,

[0026] The aforementioned inorganic fibers are at least one of potassium titanate and wollastonite.

[0027] Item 7. A method for manufacturing a shaped object as described in any one of Items 1 to 6, wherein,

[0028] The thermoplastic resin mentioned above is selected from at least one of polyolefin resins, polystyrene resins, polyester resins, polyacetal resins, polycarbonate resins, aliphatic polyamide resins, semi-aromatic polyamide resins, polyphenylene sulfide resins, polyetherimide resins, and polyetheretherketone resins.

[0029] Item 8. A shaped object, which is obtained by the manufacturing method of any one of items 1 to 7.

[0030] Item 9. A three-dimensionally printed model, which is a model made of a resin composition comprising inorganic fibers having an average fiber length of 1 μm to 300 μm and an average aspect ratio of 3 to 200 and a thermoplastic resin, wherein the layer spacing of the model is less than 0.20 mm and the model line width is less than 0.20 mm.

[0031] Item 10. The shape as described in Item 9, wherein,

[0032] When the MFR value of the above-mentioned thermoplastic resin is set as MFR1 and the MFR value of the above-mentioned resin composition is set as MFR2, the MFR ratio expressed as MFR2 / MFR1 is 0.10 or more and 0.90 or less.

[0033] Item 11. The shape as described in Item 9 or Item 10, wherein,

[0034] In the total mass percentage of the above resin composition, the content of the above inorganic fiber is 1% or more and 45% or less.

[0035] Invention Effects

[0036] According to the present invention, a model that is easy to manufacture and whose mechanical properties can be effectively improved when using a 3D printer, and a method thereof, can be provided. Attached Figure Description

[0037] Figure 1 This is a schematic top view showing the shape of the bending test piece.

[0038] Figure 2 This is a schematic top view showing the shape of the tensile test specimen. Detailed Implementation

[0039] Hereinafter, an example of a preferred embodiment of the present invention will be described. However, the following embodiment is merely illustrative. The present invention is not limited to any of the following embodiments.

[0040] [Methods for manufacturing sculpted objects]

[0041] The method for manufacturing a model according to the present invention includes: a step (step I) of preparing a resin composition containing inorganic fibers with an average fiber length of 1 μm to 300 μm and an average aspect ratio of 3 to 200 and a thermoplastic resin; and a step (step II) of using the resin composition to create a model using a thermomelting lamination method 3D printer. In the present invention, the lamination spacing when creating the model using a thermomelting lamination method 3D printer is less than 0.20 mm, and the modeling line width is less than 0.20 mm.

[0042] In the method for manufacturing shaped objects according to the present invention, since a resin composition containing inorganic fibers with an average fiber length of 1 μm to 300 μm and an average aspect ratio of 3 to 200 is used, it is possible to improve interlayer delamination and warping of shaped objects in the process of shaping using a 3D printer.

[0043] In addition, because the layer spacing and molding line width are less than 0.20 mm when using a thermal melting layering 3D printer, it is easy to manufacture and can give the modeled object superior mechanical properties.

[0044] It should be noted that currently, there is a problem with fully improving the mechanical properties of models obtained using 3D printers. Furthermore, while increasing the amount of inorganic fibers can improve mechanical properties, high levels of inorganic fibers tend to reduce melt flowability. Therefore, there is a difficulty in using 3D printers to model resin compositions with high inorganic fiber content.

[0045] In contrast, the inventors focused on the layer spacing and modeling line width when using a thermal melting layering 3D printer for modeling, and discovered that by making the layer spacing and modeling line width lower than a certain value, it is possible to give the modeled object superior mechanical properties.

[0046] Furthermore, the inventors discovered that by setting the layer spacing and molding line width below the aforementioned specific values, contrary to expectations, even when using a resin composition with highly filled inorganic fibers, the resin flows stably during melting, making it possible to create shapes using a 3D printer. It can be argued that because the resin is stably discharged, the resin layers easily adhere to each other, thus improving mechanical strength.

[0047] Therefore, the method for manufacturing the model according to the present invention can be easily manufactured, and in modeling using a 3D printer, it can improve interlayer peeling, warping, etc. of the model, and can also effectively improve mechanical properties.

[0048] It should be noted that in this invention, "shape" also includes "shape body", "molded body", and "molded object".

[0049] The following describes each step of the manufacturing method of the model involved in this invention.

[0050] <Process I>

[0051] In step I, a resin composition is prepared, which contains inorganic fibers (A) with an average fiber length of 1 μm to 300 μm and an average aspect ratio of 3 to 200, and a thermoplastic resin (B), and may also contain other additives (C) as needed.

[0052] (Inorganic fiber (A))

[0053] The inorganic fibers used in this invention are powders composed of fibrous particles, with an average fiber length of 1 μm to 300 μm and an average aspect ratio of 3 to 200. The average fiber length is preferably 1 μm to 200 μm, more preferably 3 μm to 100 μm, and even more preferably 5 μm to 50 μm. The average aspect ratio is preferably 3 to 100, more preferably 5 to 50, and even more preferably 8 to 40. By using inorganic fibers with the above-mentioned average fiber length and aspect ratio, interlayer delamination and warping of the model can be further improved in the modeling process using a 3D printer. By increasing the peel strength of the model, the mechanical properties of the model can be further improved.

[0054] Regarding the inorganic fibers used in this invention, from the viewpoint of extruder wear, a Mohs hardness of 5 or less is preferred, more preferably 1 to 5, and even more preferably 2 to 5. Examples of inorganic fibers include potassium titanate, wollastonite, aluminum borate, magnesium borate, calcareous silica, zinc oxide, and basic magnesium sulfate. From the viewpoint of mechanical properties, at least one of potassium titanate and wollastonite is preferred among the aforementioned inorganic fibers. Mohs hardness is an index indicating the hardness of a substance; when minerals are rubbed together, the one that is damaged is the substance with lower hardness.

[0055] Potassium titanate can be widely used from existing known materials, such as potassium tetratitanate, potassium hexatitanate, and potassium octatitanate. The size of the potassium titanate is not particularly limited as long as it falls within the size range of the aforementioned inorganic fibers, but typically the average fiber diameter is 0.01 μm to 1 μm, preferably 0.05 μm to 0.8 μm, more preferably 0.1 μm to 0.7 μm; the average fiber length is 1 μm to 50 μm, preferably 3 μm to 30 μm, more preferably 10 μm to 20 μm; and the average aspect ratio is 10 or more, preferably 10 to 100, more preferably 15 to 35. Commercially available products can also be used in this invention, such as "TISMO D" (average fiber length 15 μm, average fiber diameter 0.5 μm) and "TISMO N" (average fiber length 15 μm, average fiber diameter 0.5 μm) manufactured by Otsuka Chemicals Co., Ltd.

[0056] Wollastonite is an inorganic fiber composed of calcium metasilicate. The size of the wollastonite is not particularly limited as long as it falls within the aforementioned range of inorganic fiber sizes, but typically the average fiber diameter is 0.1 μm to 15 μm, preferably 1 μm to 10 μm, more preferably 2 μm to 7 μm; the average fiber length is 3 μm to 180 μm, preferably 10 μm to 100 μm, more preferably 20 μm to 40 μm; and the average aspect ratio is 3 or more, preferably 3 to 30, more preferably 5 to 15. Commercially available products can also be used in this invention, such as "Bistal W" (average fiber length 25 μm, average fiber diameter 3 μm) manufactured by Otsuka Chemicals Co., Ltd.

[0057] The average fiber length and average fiber diameter mentioned above can be determined by observation using a scanning electron microscope (SEM). The average aspect ratio (average fiber length / average fiber diameter) can be calculated from the average fiber length and average fiber diameter. For example, using a scanning electron microscope (SEM), multiple inorganic fibers are photographed. From this image, 300 inorganic fibers are randomly selected, and their fiber length and fiber diameter are measured. The total fiber diameter is calculated cumulatively and divided by the number of fibers, and the resulting value is taken as the average fiber length. The total fiber diameter is calculated cumulatively and divided by the number of fibers, and the resulting value is taken as the average fiber diameter.

[0058] In this invention, fibrous particles refer to particles in which, when the longest side of the cuboid with the smallest volume (the circumscribed cuboid) is defined as the major axis L, the second longest side as the minor axis B, and the shortest side as the thickness T (B > T), both L / B and L / T are 3 or greater. The major axis L corresponds to the fiber length, and the minor axis B corresponds to the fiber diameter. Plate-like particles refer to particles where L / B is less than 3 and L / T is 3 or greater.

[0059] Regarding inorganic fibers, in order to improve wettability with thermoplastic resins and further improve the physical properties such as mechanical properties of the resulting resin composition, a treatment layer containing a surface treatment agent may be formed on the surface of the inorganic fibers used in this invention. Examples of surface treatment agents include silane coupling agents and titanium coupling agents. Among these, silane coupling agents are preferred, and amino-based silane coupling agents, epoxy-based silane coupling agents, vinyl-based silane coupling agents, and alkyl-based silane coupling agents are more preferred. One of these can be used alone, or two or more can be used in combination.

[0060] Examples of amino-based silane coupling agents include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-ethoxysilyl-N-(1,3-dimethylbutylene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane.

[0061] Examples of epoxy silane coupling agents include 3-epoxypropoxypropyl(dimethoxy)methylsilane, 3-epoxypropoxypropyltrimethoxysilane, diethoxy(3-epoxypropoxypropyl)methylsilane, triethoxy(3-epoxypropoxypropyl)silane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0062] Examples of vinyl-based silane coupling agents include vinyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, and 3-methacryloyloxypropyltriethoxysilane.

[0063] Examples of alkyl silane coupling agents include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, and n-decyltrimethoxysilane.

[0064] As a method for forming a treatment layer containing a surface treatment agent on the surface of inorganic fibers, known surface treatment methods can be used, such as a wet method that involves dissolving the surface treatment agent in a hydrolysis-promoting solvent (e.g., water, alcohol, or a mixture thereof) to form a solution and then spraying the solution onto the inorganic fibers, or an integral blending method that incorporates the inorganic fibers and the surface treatment agent into a resin composition.

[0065] When the surface treatment agent is applied to the surface of the inorganic fibers of the present invention, the amount of the surface treatment agent is not particularly limited. In the wet method, a solution of the surface treatment agent is sprayed, preferably 0.1 to 5 parts by weight, more preferably 0.3 to 2 parts by weight, relative to 100 parts by weight of the inorganic fibers. Alternatively, in the bulk blending method, the surface treatment agent is incorporated into the resin composition at 0.1 to 20 parts by weight relative to 100 parts by weight of the inorganic fibers. By keeping the amount of surface treatment agent within the above range, the adhesion to the thermoplastic resin can be further improved, and the dispersibility of the inorganic fibers can be further improved.

[0066] (Thermoplastic resin (B))

[0067] The thermoplastic resin used in the resin composition is a resin suitable for use in 3D printers employing a melt-melt stacking method. Both crystalline and amorphous resins can be used, provided they exhibit stable flow characteristics during melting without reducing the head feed speed (described later). From a flowability perspective, crystalline resins are preferred. A crystalline resin refers to a thermoplastic resin exhibiting ordered molecular chain arrangement and a defined melting point. It should be noted that the melting point can be determined using differential scanning calorimetry (DSC).

[0068] More specifically, examples of thermoplastic resins include polyolefin resins such as polypropylene (PP) resin, polyethylene (PE) resin, cyclic polyolefin (COP) resin, and cyclic olefin copolymer (COC) resin; polystyrene-based resins such as polystyrene (PS) resin, syndiotactic polystyrene (SPS) resin, high-impact polystyrene (HIPS) resin, and acrylonitrile-butene-styrene copolymer (ABS) resin; polyester-based resins such as polylactic acid (PLA) resin, polyethylene terephthalate (PET) resin, and polybutylene terephthalate (PBT) resin; polyacetal (POM) resin; polycarbonate (PC) resin; polyamide 6 resin, polyamide 66 resin, polyamide 11 resin, polyamide 12 resin, polyamide 46 resin, and copolymers of polyamide 6 resin and polyamide 66 resin. Aliphatic polyamide (PA) resins such as polyamide 6 / 66 resin and copolymers of polyamide 6 resin and polyamide 12 resin (polyamide 6 / 12 resin); semi-aromatic polyamide (PA) resins such as polyamide MXD6 resin, polyamide MXD10 resin, polyamide 6T resin, polyamide 9T resin, and polyamide 10T resin, which are composed of structural units with and without aromatic rings; polyphenylene sulfide (PPS) resin; polyethersulfone (PES) resin; liquid crystal polyester (LCP) resin; polyether ketone (PEK) resin, polyether ether ketone (PEEK) resin, polyether ketone ketone (PEKK) resin, and polyether ether ketone ketone (PEEKK) resin; polyetherimide (PEI) resin; polyamide imide (PAI) resin; thermoplastic polyimide (TPI) resin, etc.

[0069] Among the aforementioned thermoplastic resins, polyolefin resins, polystyrene resins, polyester resins, polyacetal resins, polycarbonate resins, aliphatic polyamide resins, semi-aromatic polyamide resins, polyphenylene sulfide resins, polyetherimide resins, and polyetheretherketone resins are preferred, with aliphatic polyamide resins, semi-aromatic polyamide resins, polyphenylene sulfide resins, and polyetheretherketone resins being more preferred.

[0070] Alternatively, a mixture of two or more compatible thermoplastic resins selected from the above-mentioned thermoplastic resins, such as polymer alloys, can be used.

[0071] (Other additives (C))

[0072] The resin composition used in this invention may contain other additives within a range that does not impair its preferred physical properties. Examples of other additives include impact modifiers; aramid fibers, polyphenylene benzoxazole (PBO) fibers, glass fibers, carbon fibers, alumina fibers, boron fibers, silicon carbide fibers, calcium carbonate, barium sulfate, mica, sericite, illite, talc, kaolin, montmorillonite, boehmite, montmorillonite, vermiculite, titanium dioxide, silicon dioxide, potassium titanate, sodium titanate, potassium magnesium titanate, potassium lithium titanate, boehmite, glass beads, alumina, and other inorganic fibers (A) mentioned above. External inorganic filler materials; polyolefin resins such as polytetrafluoroethylene (PTFE), low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, and ultra-high molecular weight polyethylene; solid lubricants such as graphite, molybdenum disulfide, tungsten disulfide, and boron nitride; heat stabilizers such as copper compounds; light stabilizers such as hindered phenolic light stabilizers; nucleating agents; antistatic agents such as anionic, cationic, and nonionic antistatic agents; anti-aging agents (antioxidants); weathering agents; gold It belongs to the category of passivating agents; ultraviolet absorbers such as benzophenone-based, benzotriazole-based, triazine-based, and salicylic acid ester-based ultraviolet absorbers; antibacterial and antifungal agents; deodorizing agents; conductive agents such as carbon-based, metal-based, and metal oxide-based conductive agents, and surfactants; dispersants; softening agents (plasticizers) such as polyester-based, glycerol-based, polycarboxylic acid ester-based, phosphate ester-based, polyalkylene glycol-based, and epoxy-based plasticizers. Colorants such as carbon black and titanium dioxide pigments and dyes; flame retardants such as phosphazene compounds, phosphate esters, condensed phosphate esters, inorganic phosphorus flame retardants, halogen flame retardants, organosilicon flame retardants, metal oxide flame retardants, metal hydroxide flame retardants, organometallic salt flame retardants, nitrogen flame retardants, and boron compound flame retardants; anti-drip agents; damping agents; neutralizing agents; anti-blocking agents; flowability improvers; release agents such as fatty acids and fatty acid metal salts; lubricants, etc., which may contain one or more of these.

[0073] Examples of impact modifiers include olefin polymers such as (ethylene and / or propylene)-α-olefin copolymers, (ethylene and / or propylene)-(α,β-unsaturated carboxylic acids and / or unsaturated carboxylic esters) copolymers, and ionomer polymers; elastomers such as styrene-based elastomers, polyurethane-based elastomers, fluoropolymers, vinyl chloride-based elastomers, polyester-based elastomers, and polyamide-based elastomers; synthetic rubbers such as polysulfide rubber, polysulfide rubber, acrylic rubber, silicone rubber, polyether rubber, and epichlorohydrin rubber; and natural rubber. From the viewpoint of heat resistance, olefin copolymers are preferred. These may contain one or more of these modifiers.

[0074] The aforementioned (ethylene and / or propylene)-α-olefin copolymers are polymers obtained by copolymerizing ethylene and / or propylene with α-olefins having 3 or more carbon atoms. Examples of α-olefins having 3 or more carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetracene, 1-tetradecene, 1-pentadecadecene, 1-hexadecene, 1-heptadecene, and 1-octadecene. Alkenes, 1-nonadecanene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, and combinations thereof. Alternatively, 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,4-octadiene, 1,5-octadiene, 1,6-octadiene, 1,7-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene, 4-ethylidene-8-methyl-1,7-nonadiene, 4,8-dimethyl-1,4,8-decanetriene (DMDT), dicyclopentadiene, and cyclopentadiene can also be used. Polyene copolymers of non-conjugated dienes such as hexadiene, dicyclooctadiene, methylene norbornene, 5-vinyl norbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, and 2-propenyl-2,2-norbornene.

[0075] The aforementioned (ethylene and / or propylene)-(α,β-unsaturated carboxylic acid and / or unsaturated carboxylic acid ester) copolymers are polymers obtained by copolymerizing ethylene and / or propylene with α,β-unsaturated carboxylic acid and / or unsaturated carboxylic acid ester monomers. Examples of α,β-unsaturated carboxylic acid monomers include acrylic acid and methacrylic acid. Examples of α,β-unsaturated carboxylic acid ester monomers include methyl ester, ethyl ester, propyl ester, butyl ester, pentyl ester, hexyl ester, heptyl ester, octyl ester, nonyl ester, decyl ester, etc., or mixtures thereof.

[0076] The aforementioned ionomer polymer is a substance in which at least a portion of the carboxyl groups of an olefin-α,β-unsaturated carboxylic acid copolymer is ionized due to the neutralization of metal ions. Ethylene is preferably used as the olefin, and acrylic acid or methacrylic acid is preferably used as the α,β-unsaturated carboxylic acid, but it is not limited to the substances exemplified herein; copolymerization of unsaturated carboxylic acid ester monomers is also possible. Furthermore, examples of metal ions include alkali metals and alkaline earth metals such as Li, Na, K, Mg, Ca, Sr, and Ba, as well as other metals such as Al, Sn, Sb, Ti, Mn, Fe, Ni, Cu, Zn, and Cd.

[0077] The aforementioned impact modifiers can also be used with polymers modified with carboxylic acids and / or their derivatives. By modifying the molecule with such components, functional groups with affinity for polyamide resins can be introduced, for example, into the molecule. Examples of functional groups with affinity for polyamide resins include carboxylic acid groups, carboxylic anhydride groups, carboxylic acid ester groups, carboxylic acid metal salt groups, carboxylic acid amide groups, and epoxy groups.

[0078] (Method for manufacturing the resin composition)

[0079] The resin composition can be manufactured by mixing and heating (especially melt-blending) the components of inorganic fibers (A) and thermoplastic resin (B) and other additives (C) as needed.

[0080] During melt mixing, known melt mixing equipment such as twin-screw extruders can be used. Specifically, it can be manufactured using the following methods: (1) premixing the components using a mixer (drum, Henschel mixer, etc.), melt mixing using a melt mixing equipment, and granulating using a granulation unit (granulator, etc.); (2) preparing a masterbatch of the desired components, mixing other components as needed, melt mixing using a melt mixing equipment, and granulating; (3) feeding the components to a melt mixing equipment for granulation, etc.

[0081] There is no particular limitation on the processing temperature during melt mixing, as long as it is the temperature at which the thermoplastic resin (B) can melt. Typically, the barrel temperature of the melt mixing apparatus used for melt mixing is adjusted to this range.

[0082] Regarding the melt viscosity characteristics of the resin composition, when the MFR value of the thermoplastic resin (B) is designated as MFR1 and the MFR value of the resin composition is designated as MFR2, the MFR ratio expressed as MFR2 / MFR1 is preferably 0.10 or more, more preferably 0.20 or more, more preferably 0.40 or more, and particularly preferably 0.60 or more. Furthermore, the MFR ratio is preferably 0.90 or less, more preferably 0.80 or less, more preferably 0.75 or less, and particularly preferably 0.70 or less. When the MFR ratio is within the above range, it can impart more superior mechanical properties to the molded object.

[0083] The MFR (Mel Flow Rate) value defined in this invention is an indicator of the viscosity (flowability) of the resin when it melts. It is measured using an MFR measuring device under a 5 kg load, based on JIS K7210. A high MFR value indicates low viscosity (easy to flow) when melted, while a low MFR value indicates high viscosity (difficult to flow). The set temperature of the MFR measuring device can be appropriately selected according to the nozzle temperature of the 3D printer. For example, if the thermoplastic resin (B) is a crystalline resin, it can be set to a temperature approximately 50°C higher than its melting point. If the thermoplastic resin (B) is a non-crystalline resin that does not have a melting point but has a glass transition temperature, it can be set to a temperature approximately 100°C higher than its glass transition temperature.

[0084] Of 100% by mass of the resin composition, the content of inorganic fiber (A) is preferably 1% by mass or more, more preferably 15% by mass or more, more preferably more than 25% by mass, preferably 50% by mass or less, more preferably 45% by mass or less, and more preferably 40% by mass or less. When the content of inorganic fiber (A) is above the aforementioned lower limit, it can impart more superior mechanical properties to the molded object. Furthermore, when the content of inorganic fiber (A) is below the aforementioned upper limit, it can further improve productivity.

[0085] Of the total 100% by mass of the resin composition, the content of thermoplastic resin (B) is preferably 40% by mass or more, more preferably 45% by mass or more, more preferably 50% by mass or more, preferably 99% by mass or less, more preferably 97% by mass or less, and more preferably 93% by mass or less. When the content of thermoplastic resin (B) is at or above the aforementioned lower limit, productivity can be further improved. Furthermore, when the content of thermoplastic resin (B) is at or below the aforementioned upper limit, the molded object can be endowed with superior mechanical properties.

[0086] Regarding the content of additives other than the aforementioned essential components that can be used in this invention, i.e., other additives (C), there are no particular limitations as long as they do not impair the preferred properties of the resin composition of this invention. Generally, it is less than 10% by mass, preferably less than 5% by mass, more preferably 0.1% by mass or more, and more preferably 1% by mass or more in 100% by mass of the total amount of the resin composition.

[0087] By adjusting the components of the resin composition to the aforementioned range, it is possible to improve issues such as interlayer delamination and warping in 3D printing. Furthermore, it is possible to improve the mechanical properties of the 3D model.

[0088] In this way, it is possible to manufacture resin compositions that constitute the molded objects of the present invention that achieve the desired effects.

[0089] <Process II>

[0090] In step II, the resin composition prepared in step I is used to create a model using a thermal melting stacking 3D printer (also known as an additive manufacturing device), thereby producing the model.

[0091] The thermoplastic lamination method refers to a method of manufacturing desired shapes by using a heating unit inside an extruder to flow thermoplastic resin in granular or filamentous form, then extruding it from a nozzle onto a platform, laminating it in small batches while cooling and curing. By using the aforementioned resin composition as the molding material, extruder head clogging and wear, as seen with resin compositions containing fibrous fillers such as glass fibers or carbon fibers, can be avoided when using a 3D printer. For example, even with a nozzle with a diameter of less than 0.5 mm, extruder head clogging and wear can be avoided. Furthermore, while the exact reasons are uncertain, it can be speculated that not only can the use of inorganic fibers (A) improve the warpage of the molded object, but interlayer delamination can also be suppressed by increasing the interfacial strength between the layers.

[0092] There is no particular limitation on the method of manufacturing filaments. Methods that include the following steps can be listed: an extrusion step in which the resin composition manufactured by the above method is extruded from the die of a molding machine into a molten filament bundle and introduced into a cooling water tank to obtain a filament bundle; a stretching step in which the filament bundle is heated and stretched to obtain filaments; and a step in which the stretched filaments are wound.

[0093] The shape of the aforementioned filaments is not particularly limited. For example, the cross-sectional shape can be circular, square, flat, elliptical, cocoon-shaped, trefoil-shaped, and non-circular shapes similar to these. From an operational point of view, a circular shape is preferred. The length of the filaments is not limited and can be set to any value depending on industrial manufacturing conditions or within the range that does not impair its use as a thermomelting lamination method 3D printer. Furthermore, the diameter of the filaments is not particularly limited and can be 0.5 mm to 3 mm, particularly 1 mm to 2 mm. It should be noted that the diameter of the filaments refers to the largest diameter obtained by measuring a cross-section perpendicular to the length direction of the filament.

[0094] The aforementioned filaments can also be combined with resin components other than the aforementioned resin composition to form composite filaments. Examples of cross-sectional structures for composite filaments include radial arrangement, side-by-side arrangement, island-type, or core-sheath type structures.

[0095] In the method for manufacturing the model of the present invention, for example, filaments composed of the above-described resin composition can be supplied to a thermomelting lamination method 3D printer to form a model. Specifically, the filaments can be supplied to the thermomelting lamination method 3D printer, fluidized by a heating unit inside the extruder head, discharged from the nozzle onto a platform, and manufactured by laminating in small quantities according to the cross-sectional shape of the desired model while cooling and solidifying.

[0096] In the manufacturing method of the present invention, the layer spacing during molding using a thermal melting layer-by-layer 3D printer is less than 0.20 mm, and the molding line width is less than 0.20 mm. The layer spacing is preferably less than 0.15 mm, more preferably less than 0.10 mm, and even more preferably less than 0.08 mm. The molding line width is preferably less than 0.18 mm, and more preferably less than 0.16 mm. By making the layer spacing and molding line width less than or below the above-mentioned upper limits, the molded object can be endowed with superior mechanical properties. In this specification, the layer spacing refers to the thickness of a resin layer formed during molding using a 3D printer, and the molding line width refers to the diameter of the resin composition discharged from the nozzle.

[0097] It should be noted that there is no specific limit to the lower limit of the layer spacing when using a thermal melting layer-by-layer 3D printer for modeling, but from a manufacturing point of view, it can be, for example, 0.04 mm. Similarly, there is no specific limit to the lower limit of the model line width, but from a manufacturing point of view, it can be, for example, 0.07 mm.

[0098] Regarding the printing speed (head feed speed) of a thermomelting stacking 3D printer, from the viewpoints of shortening the manufacturing time of the model and the orientation of the inorganic fibers, a speed of 20 mm / s or higher is preferred, and 40 mm / s or higher is more preferred. However, if the printing speed is too fast, the modeling quality deteriorates, so the upper limit of the printing speed is usually 200 mm / s or lower.

[0099] Regarding the diameter of the extruder head, from the viewpoint of head conveying speed, it is preferably less than 0.5 mm, more preferably less than 0.4 mm, more preferably less than 0.3 mm, and also preferably more than 0.1 mm. Furthermore, the stack spacing is preferably 20% to 50% of the extruder head diameter, and the molding line width is preferably 60% to 80% of the extruder head diameter.

[0100] Regarding the temperature of the molten resin discharged from the extruder head (discharge temperature), it can be appropriately selected according to the thermoplastic resin used in order to obtain the aforementioned head conveying speed.

[0101] It can be considered that in a thermomelting lamination 3D printer, when the head feed speed is controlled within the aforementioned range, the inorganic fibers in the molten resin are oriented in the discharge direction, and the filamentous resin is laminated in a certain direction. Therefore, the orientation of the inorganic fibers in the model is further improved. Furthermore, while manufacturing the model by laminating the filamentous resin discharged from the extruder in a certain direction, deviations in the orientation of the inorganic fibers due to different parts of the model are less likely to occur. It can be considered that this can endow the model with superior mechanical properties.

[0102] [Sculptural Objects]

[0103] The model of the present invention is a 3D printed model made by a thermoplastic lamination method, comprising an inorganic fiber containing an average fiber length of 1 μm to 300 μm and an average aspect ratio of 3 to 200, and a thermoplastic resin. By using a resin composition containing inorganic fibers with an average fiber length of 1 μm to 300 μm and an average aspect ratio of 3 to 200, it is easy to manufacture and improves interlayer delamination and warping of the model during 3D printing. It should be noted that the model of the present invention can be manufactured, for example, by the model manufacturing method described above. Therefore, the resin composition described in the section on the manufacturing method can be used.

[0104] The layer spacing (thickness of each layer) of the molded article of the present invention is less than 0.20 mm, and the molding line width is less than 0.20 mm. The layer spacing is preferably less than 0.15 mm, more preferably less than 0.10 mm, and even more preferably less than 0.08 mm. The molding line width is preferably less than 0.18 mm, more preferably less than 0.16 mm. By making the layer spacing and molding line width less than or below the above-mentioned upper limits, the molded article can be endowed with superior mechanical properties.

[0105] In the molded articles of the present invention, regarding the melt viscosity characteristic value of the resin composition, when the MFR value of the thermoplastic resin (B) is set as MFR1 and the MFR value of the resin composition is set as MFR2, the MFR ratio expressed as MFR2 / MFR1 is preferably 0.10 or more, more preferably 0.20 or more, more preferably 0.40 or more, and particularly preferably 0.60 or more. Furthermore, the above-mentioned MFR ratio is preferably 0.90 or less, more preferably 0.80 or less, more preferably 0.75 or less, and particularly preferably 0.70 or less. When the MFR ratio is within the above range, the molded articles can be endowed with more superior mechanical properties.

[0106] In the molded object of the present invention, the maximum thickness in the molded layer direction is preferably 1 mm or more, more preferably 2 mm or more, and even more preferably 4 mm or more. The minimum thickness is preferably 1 mm or more, more preferably 2 mm or more, and even more preferably 4 mm or more. In such a molded object, excellent effects that cannot be obtained by injection molding can be achieved.

[0107] In the molded articles of the present invention, the orientation angle of the inorganic fibers is preferably 24° or less. When the orientation angle of the inorganic fibers is below the above-mentioned upper limit, the reinforcing effect of the matrix resin brought by the inorganic fibers can be maximized, and the molded articles can be endowed with superior mechanical properties.

[0108] It should be noted that the orientation angle of inorganic fibers is a parameter representing the orientation state of inorganic fibers within the molded object. In this invention, it refers to the angle formed by the long axis of the inorganic fiber relative to the molding direction when the direction parallel to the molding direction is set to 0° and the direction perpendicular to the molding direction is set to 90°. The angle is set to 0° when the inorganic fiber is completely oriented in the molding direction, 45° when it is unoriented, and 90° when it is perpendicular to the molding direction. It should also be noted that when the molded object is a part obtained by injection molding, the molding direction refers to the resin flow direction.

[0109] The mechanical properties of the model of the present invention are excellent. Therefore, it can be used for structural components that require mechanical properties, such as gear components, rolling bearing cages, and production fixtures.

[0110] Example

[0111] The following detailed description is based on examples and comparative examples, but the present invention is not limited by these examples. It should be noted that the raw materials used in these examples and comparative examples are as follows. Furthermore, the average fiber length, average fiber diameter, and average aspect ratio of the inorganic fibers were measured using a field emission scanning electron microscope (SEM, manufactured by Hitachi High Technology Co., Ltd., S-4800).

[0112] (Inorganic fibers)

[0113] Potassium titanate (trade name: TISMO D102, manufactured by Otsuka Chemical Co., Ltd., average fiber length: 15μm, average fiber diameter: 0.5μm, average aspect ratio: 30)

[0114] (Thermoplastic resin)

[0115] Polyamide MXD10 resin (trade name: LEXTER8000, manufactured by Mitsubishi Gas Chemical Co., Ltd., melting point 188°C)

[0116] Polyphenylene sulfide (PPS) resin (trade name: TORELINA PPS L2120-60, manufactured by Toray Industries, Inc., melting point 280℃)

[0117] Polyetheretherketone (PEEK) resin (trade name: PEEK 381G, manufactured by VICTREX, melting point 343℃)

[0118] It should be noted that, when determining the melting point, a differential scanning calorimeter (DSC) was used to heat the sample to a temperature above the desired melting point at a heating rate of 10 °C / min. Then, the sample was cooled to 0 °C at a cooling rate of 10 °C / min and left at this state for 1 minute. Afterward, the sample was heated again at a heating rate of 10 °C / min, and the melting peak at this point was measured and taken as the melting point.

[0119] <Preparation of Resin Compositions and Filaments>

[0120] Using the proportions shown in Table 1, granules were produced by melt mixing using a twin-screw extruder. It should be noted that the barrel temperature of the twin-screw extruder was 190℃~220℃ when using polyamide MXD10 resin, 280℃~300℃ when using PPS resin, and 330℃~380℃ when using PEEK resin.

[0121] The obtained granules were fed into a fiber extruder to obtain fibers with a diameter of 1.75 mm.

[0122] [Table 1]

[0123]

[0124] <The Creation of Shaped Objects>

[0125] (Examples 1-8, Comparative Examples 1-4)

[0126] In Examples 1-8 and Comparative Examples 1-2, the filaments obtained above were used in a thermal melting stacking 3D printer to fabricate [products] under the printing conditions shown in Table 2. Figure 1 The bending test piece shown is based on ISO 178. It should be noted that in Examples 1-6 and Comparative Examples 1-2, the Raise 3D N2 (trade name: Raise 3D N2) manufactured by Raise Corporation was used as the thermal melt stacking 3D printer. Furthermore, in Examples 7-8, the MothMath S3DP222 (trade name: MothMath S3DP222) manufactured by S-Lab Corporation was used as the thermal melt stacking 3D printer, and specifically, the upper limit temperature of the nozzle head was adjusted to 450°C.

[0127] When styling, follow... Figure 1 The direction indicated by the middle arrow X is used to shape the material from the center outwards in concentric circles. The layering direction is set to the thickness direction of the bending test piece. It should be noted that cases where the lines are not tightly joined and peel off like a thousand-layer cake are considered unsuitable for shaping.

[0128] In addition, in Comparative Examples 3 and 4, using the granules shown in Table 1 as raw materials for filaments, the gate was set in such a way that the resin flow direction was the same as the modeling direction of the 3D printer, and injection molding was performed to produce... Figure 1 The bending test piece shown (based on ISO 178).

[0129] In addition, in Examples 1-7 and Comparative Examples 1-2, the filaments obtained above were used in a 3D printer with a thermal melting and stacking method to fabricate, under the printing conditions shown in Table 3. Figure 2 Tensile test specimens of the shape shown (ASTM D638 Type I). It should be noted that in Examples 1-6 and Comparative Examples 1-2, the Raise 3D N2 (trade name: Raise 3D N2) manufactured by Raise Corporation was used as the thermal melt stacking 3D printer. Furthermore, in Example 7, the MothMath S3DP222 (trade name: MothMath S3DP222) manufactured by S-Lab Corporation was used as the thermal melt stacking 3D printer, and specifically, the upper limit temperature of the nozzle head was adjusted to 450°C.

[0130] When styling, along Figure 2The shape is created from the center outwards in concentric circles, as indicated by the middle arrow X. The layering direction is set to the thickness direction of the tensile test specimen. It should be noted that cases where the lines are not tightly joined and peel off like a thousand-layer cake are considered unsuitable for shaping.

[0131] In addition, in Comparative Examples 3 and 4, using the granules shown in Table 3 as raw materials for filaments, the gate was set in such a way that the resin flow direction was the same as the modeling direction of the 3D printer, and injection molding was performed to produce... Figure 2 Tensile test specimens of the shape shown (ASTM D638 Type I).

[0132] <Evaluation>

[0133] (1) Bending strength and flexural modulus

[0134] For the bending test pieces prepared under the conditions in Table 2, the bending strength and bending modulus were determined by a 3-point bending test using an AUTOGRAPH AG-5000 (manufactured by Shimadzu Corporation) based on ISO 178. The results are shown in Table 2.

[0135] (2) Tensile strength and tensile modulus of elasticity

[0136] For the tensile test specimens prepared under the conditions in Table 3, the tensile strength and tensile modulus of elasticity were determined using an AUTOGRAPH AG-1 (manufactured by Shimadzu Corporation) based on ISO 0527-1, and the results are shown in Table 3.

[0137] (3) MFR ratio

[0138] Based on JIS K 7210, the MFR values ​​of thermoplastic resins and resin compositions were determined under the following conditions: test temperature (polyamide MXD10 resin: 240℃, PPS resin: 330℃, PEEK resin: 400℃) and test load of 5 kg. The MFR value of the thermoplastic resin was designated as MFR1, and the MFR value of the resin composition was designated as MFR2. The MFR ratio (MFR2 / MFR1) was calculated from the obtained MFR values. The results are shown in Table 1 above.

[0139] [Table 2]

[0140]

[0141] [Table 3]

[0142]

[0143] As shown in Tables 2 and 3, in Examples 1-4, setting the layer spacing and molding line width to less than 0.20 mm during modeling using a thermoplastic lamination 3D printer improved mechanical properties. Furthermore, in Examples 5-8, even when PPS or PEEK resins were used as thermoplastic resins, setting the layer spacing and molding line width to less than 0.20 mm during modeling using a thermoplastic lamination 3D printer also improved mechanical properties compared to cases where at least one of the layer spacing and molding line width was 0.20 mm or more.

[0144] It should be noted that, as can be seen from the comparison between Comparative Example 1 and Comparative Example 2, resin compositions with high inorganic fiber content are generally difficult to shape using a 3D printer. In contrast, as in Examples 1-8, when the layer spacing is set to less than 0.20 mm and the molding line width is set to less than 0.20 mm, 3D printing can be used to shape the resin composition, resulting in excellent mechanical properties and achieving unexpected effects.

Claims

1. A method of manufacturing a molded article, characterized by, comprises: a step of preparing a resin composition containing inorganic fibers having an average fiber length of 1 μm to 300 μm and an average aspect ratio of 3 to 200 and a thermoplastic resin; and a step of manufacturing a molded article by molding using a fused deposition modeling three-dimensional printer using the resin composition, a layer interval of a resin layer as a thickness of a layer formed when the molded article is molded using the fused deposition modeling three-dimensional printer is lower than 0.20 mm, and a molding line width of a diameter of the resin composition discharged from a nozzle when the molded article is molded using the fused deposition modeling three-dimensional printer is lower than 0.20 mm, when the molded article is molded using the fused deposition modeling three-dimensional printer, the layer interval is 20% to 50% of a diameter of an extrusion head, and the molding line width is 60% to 80% of the diameter of the extrusion head.

2. The method of manufacturing a molded article according to claim 1, wherein: a ratio of MFRs expressed by MFR2 / MFR1 is 0.10 or more and 0.90 or less, when a MFR value of the thermoplastic resin is set to MFR1 and a MFR value of the resin composition is set to MFR2.

3. The method of manufacturing a molded article according to claim 1 or 2, wherein: a content of the inorganic fibers is 1% by mass or more and 45% by mass or less in 100% by mass of a total amount of the resin composition.

4. The method of manufacturing a molded article according to claim 1 or 2, wherein: a molding speed is 20 mm / sec or more and 200 mm / sec or less.

5. The method of manufacturing a molded article according to claim 1 or 2, wherein: a Mohs hardness of the inorganic fibers is 5 or less.

6. The method of manufacturing a molded article according to claim 1 or 2, wherein: the inorganic fibers are at least one of potassium titanate and wollastonite.

7. The method of manufacturing a molded article according to claim 1 or 2, wherein: the thermoplastic resin is at least one selected from the group consisting of a polyolefin resin, a polystyrene resin, a polyester resin, a polyacetal resin, a polycarbonate resin, an aliphatic polyamide resin, a semi-aromatic polyamide resin, a polyphenylene sulfide resin, a polyetherimide resin, and a polyether ether ketone resin.

8. A molded article, wherein: it is a molded article obtained by the method of manufacturing a molded article according to any one of claims 1 to 7.

9. A molded article, wherein: it is a fused deposition modeling three-dimensional printed molded article composed of a resin composition containing inorganic fibers having an average fiber length of 1 μm to 300 μm and an average aspect ratio of 3 to 200 and a thermoplastic resin, wherein: a layer interval of a resin layer as a thickness of a layer formed when the molded article is molded using a fused deposition modeling three-dimensional printer is lower than 0.20 mm, and a molding line width of a diameter of the resin composition discharged from a nozzle when the molded article is molded using the fused deposition modeling three-dimensional printer is lower than 0.20 mm, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ When molding is performed using the fused deposition modeling three-dimensional printer, the layer interval is 20% to 50% of the diameter of the extrusion head, and the line width is 60% to 80% of the diameter of the extrusion head.

10. The molded article according to claim 9, wherein: When the MFR value of the thermoplastic resin is MFR1 and the MFR value of the resin composition is MFR2, the MFR ratio represented by MFR2 / MFR1 is 0.10 or more and 0.90 or less.

11. The molded article according to claim 9 or 10, wherein: The content of the inorganic fiber is 1% by mass or more and 45% by mass or less in 100% by mass of the total amount of the resin composition.

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