Three-dimensional fabricated article and method for producing same

Abstract

The present invention provides a three-dimensional fabricated article with a low permittivity and method for producing the same.　Provided is a three-dimensional fabricated article comprising a thermoplastic resin, wherein the thermoplastic resin contains 55-100 mass% of a liquid-crystalline resin with respect to the entirety of the thermoplastic resin, and the ratio [(ρ2 / ρ1)×100(%)] of the apparent density (ρ2) of the three-dimensional fabricated article to the true density (ρ1) of the thermoplastic resin is 40-95%.

Description

Three-dimensional molded object and method for manufacturing the same

[0001] This disclosure relates to three-dimensional objects and methods for manufacturing them.

[0002] Liquid crystal polymers (LCPs) are widely used in various fields because they possess high rigidity and elasticity, as well as excellent heat resistance, insulation, impact resistance, and chemical resistance. Due to their molecular structure, LCPs have a tendency to easily undergo molecular orientation, resulting in strong anisotropy where the properties exhibited in molded products differ depending on the direction. If the molecular orientation of LCPs can be controlled, the properties of LCPs can be controlled to desired locations and directions. In recent years, 3D printing technologies such as fused filament fabrication (FFF) have made it possible to manufacture more complex shapes without using molds or large-scale melting equipment, and the application of LCPs to 3D printing technology is being considered. However, LCPs have a fast solidification rate and are transparent to light such as lasers, making them unsuitable for application to 3D printing technology.

[0003] Patent Document 1 describes a resin composition for three-dimensional molding using the FFF (Fused Deposition Modeling (FDM)) method, characterized in that the thermoplastic resin contains a liquid crystalline resin, and the liquid crystalline resin content in the thermoplastic resin is 0.5 to 40% by mass. Patent Document 2 describes an additive manufacturing method in which a filament-like unit formed from a polymer composition containing a thermotropic liquid crystal polymer and having a predetermined minimum thickness is used.

[0004] Japanese Patent Publication No. 2018-123263, Japanese Patent Publication No. 2021-529685

[0005] The resin composition for three-dimensional molding described in Patent Document 1 mainly consists of a crystalline or amorphous resin, which has different properties from LCP, as the thermoplastic resin. Patent Document 1 does not describe three-dimensional molding of thermoplastic resins containing LCP as the main component. Furthermore, while Patent Document 2 describes improving the mechanical properties of the resulting object by adjusting the minimum thickness of the filamentous unit, it does not describe improving the properties of the object obtained by the physical properties of LCP or the manufacturing conditions of the additive manufacturing method.

[0006] In injection molding, the process requires melting and flowing, making it difficult to control molecular orientation. For example, to achieve a low dielectric constant, it was necessary to modify the material itself, such as by using additives to reduce dielectric constant, such as glass balloons, to create a composite.

[0007] The object of this disclosure is to provide a three-dimensional fabricated object with a low dielectric constant and a method for manufacturing the same.

[0008] This disclosure includes the following embodiments: A three-dimensional molded object comprising a thermoplastic resin, wherein the thermoplastic resin comprises 55 to 100% by mass of a liquid crystalline resin in the total amount of the thermoplastic resin, and the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin [(ρ2 / ρ1) × 100 (%)] is 40 to 95%.

[0009] According to this disclosure, it is possible to provide a three-dimensional object with a low dielectric constant and a method for manufacturing the same.

[0010] These are schematic diagrams showing the printing direction during the preparation of the test specimens for Examples 1 and 2. These are schematic diagrams showing the printing direction during the preparation of the test specimen for Comparative Example 1. These are schematic diagrams showing the printing direction during the preparation of the test specimens for Examples 3 and 4. These are schematic diagrams showing the printing direction during the preparation of the test specimen for Comparative Example 2.

[0011] One embodiment of the present disclosure will be described in detail below, but the scope of the present disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the present disclosure. Each embodiment disclosed herein can be combined with any other features disclosed herein. If multiple upper and lower limits are given for a particular parameter, any combination of these upper and lower limits can be used to create a suitable numerical range. The lower and / or upper limits of the numerical ranges described herein may be replaced with numerical values ​​within that range, as shown in the examples. The expression "X to Y" indicating a numerical range means "X or greater and Y or less". If a particular description given for one embodiment also applies to other embodiments, that description may be omitted in the other embodiments.

[0012] [Three-Dimensional Manufactured Objects] The first embodiment of this disclosure relates to three-dimensional manufactured objects. The three-dimensional manufactured object according to this embodiment is a three-dimensional manufactured object comprising a thermoplastic resin, wherein the thermoplastic resin comprises 55 to 100% by mass of liquid crystalline resin in the total amount (100% by mass) of the thermoplastic resin, and the ratio of the apparent density (ρ2) of the three-dimensional manufactured object to the true density (ρ1) of the thermoplastic resin [(ρ2 / ρ1) × 100 (%)] is 40 to 95%.

[0013] Liquid crystal resins solidify quickly due to the properties of liquid crystal polymers (hereinafter also referred to as LCPs). Therefore, in the filament melting process, when molten filaments are layered, the layer that is layered first tends to solidify more easily. If molten filaments are layered onto a solidified layer, the bonding between each print line may not be sufficient, resulting in an incomplete print. For this reason, thermoplastic resins, including liquid crystal resins, have properties that make them unsuitable for the filament melting process.

[0014] The inventors have diligently conducted research and discovered that by setting the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin containing liquid crystalline resin [(ρ2 / ρ1) × 100 (%)] within a predetermined range, the dielectric constant can be reduced without using additives such as glass balloons for dielectric reduction, thus completing the present invention. When fabricating this three-dimensional molded object by filament melting, by controlling the printing direction of the filament to the direction of molecular orientation, it is possible to create a three-dimensional molded object that exhibits excellent dielectric properties in specific locations and / or directions. Furthermore, while foam molding is a method for reducing the weight of molded products, there are no foaming agents that can withstand the high processing temperature of liquid crystalline resin, and even when foamed, it is difficult to form uniform pores due to the high gas barrier properties, so the only known method for weight reduction is to add glass balloons or the like. However, in this embodiment, the apparent density (ρ2) of the three-dimensional object is smaller than the true density (ρ1) of the thermoplastic resin containing the liquid crystalline resin, resulting in a lightweight three-dimensional object even without the incorporation of glass balloons.

[0015] <Thermoplastic Resin> In this embodiment, the three-dimensional molded object includes a thermoplastic resin. The thermoplastic resin contains 55 to 100% by mass of liquid crystalline resin in the total amount (100% by mass) of the thermoplastic resin. By including the liquid crystalline resin within the above range in the three-dimensional molded object, a three-dimensional molded object having excellent properties derived from LCP can be obtained.

[0016] In one embodiment, the thermoplastic resin preferably contains 60 to 100% by mass of liquid crystalline resin, more preferably 70 to 100% by mass of liquid crystalline resin, even more preferably 80 to 100% by mass of liquid crystalline resin, and particularly preferably 90 to 100% by mass of liquid crystalline resin. In one embodiment, the entire thermoplastic resin may be a thermoplastic liquid crystalline resin, that is, the three-dimensional molded object may be made of a liquid crystalline resin.

[0017] In one embodiment, the total content of thermoplastic resin in the three-dimensional molded object may be 50 to 100% by mass, 55 to 100% by mass, 60 to 100% by mass, or 70 to 100% by mass, based on the total amount (100% by mass) of the three-dimensional molded object. In one embodiment, the content of liquid crystalline resin in the three-dimensional molded object may be 50 to 100% by mass, 55 to 100% by mass, 60 to 100% by mass, or 70 to 100% by mass, based on the total amount (100% by mass) of the three-dimensional molded object.

[0018] (Liquid Crystalline Resins) "Liquid crystallinity" refers to the property of being able to form an optically anisotropic molten phase. The properties of the anisotropic molten phase can be confirmed by conventional polarization testing methods using orthogonal polarizers. More specifically, the anisotropic molten phase can be confirmed by using a Leitz polarizing microscope and observing a molten sample placed on a Leitz hot stage under a nitrogen atmosphere at 40x magnification. Liquid crystalline resins, when tested between orthogonal polarizers, usually transmit polarization even in a molten, stationary state, exhibiting optical anisotropy.

[0019] In one embodiment, the liquid crystalline resin preferably contains at least one selected from liquid crystalline polyesters and liquid crystalline polyesteramides. The liquid crystalline polyesters and liquid crystalline polyesteramides are not particularly limited, but are preferably aromatic polyesters or aromatic polyesteramides, more preferably contain at least one resin selected from all aromatic polyesters and all aromatic polyesteramides, and even more preferably be aromatic polyesters or aromatic polyesteramides containing a constituent unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and their derivatives. Examples of aromatic hydroxycarboxylic acid derivatives include alkyl esters (e.g., C1-C4), halides, acylids, etc. A polyester partially containing aromatic polyester or aromatic polyesteramide in the same molecular chain can also be used. By including the above-mentioned liquid crystalline resin in the thermoplastic resin, it is possible to manufacture three-dimensional molded objects that exhibit excellent dielectric properties in specific locations and / or directions by utilizing the molecular orientation of the liquid crystalline resin in the filament melting method.

[0020] The aromatic polyester or aromatic polyesteramide is particularly preferably an aromatic polyester or aromatic polyesteramide having an aromatic hydroxycarboxylic acid as a constituent component.

[0021] More specifically, aromatic polyesters or aromatic polyesteramides include: (1) polyesters mainly composed of one or more aromatic hydroxycarboxylic acids and their derivatives; (2) polyesters mainly composed of (a) one or more aromatic hydroxycarboxylic acids and their derivatives, and (b) one or more aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives; (3) polyesters mainly composed of (a) one or more aromatic hydroxycarboxylic acids and their derivatives, (b) one or more aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives, and (c) one or more aromatic diols, alicyclic diols, aliphatic diols, and their derivatives; (4) polyesteramides mainly composed of (a) one or more aromatic hydroxycarboxylic acids and their derivatives, (b) one or more aromatic hydroxyamines, aromatic diamines, and their derivatives, and (c) one or more aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives; (5) Examples of polyester amides mainly comprising (a) one or more aromatic hydroxycarboxylic acids and their derivatives, (b) one or more aromatic hydroxyamines, aromatic diamines, and their derivatives, (c) one or more aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives, and (d) one or more aromatic diols, alicyclic diols, aliphatic diols, and their derivatives. Furthermore, molecular weight adjusters may be used in combination with the above components as needed. Examples of "derivatives" in (1) to (5) above include alkyl esters (e.g., C1 to C4), halides, acylids, etc.

[0022] Preferred specific examples of the compounds (monomers) that constitute liquid crystalline polyesters and liquid crystalline polyesteramides include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid; aromatic diols such as 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, hydroquinone, resorcinol, compounds represented by the following general formula (I), and compounds represented by the following general formula (II); aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and compounds represented by the following general formula (III); and aromatic amines such as 4-aminophenol, 1,4-phenylenediamine, and N-acetyl-p-aminophenol. (X: Alkylene (C) １ ~C ４ ), alkylidene, -O-, -SO-, -SO ２ (These are groups selected from -, -S-, and -CO-.) (Y: -(CH ２ ) ｎ - (n = 1 to 4) and -O (CH ２ ) ｎ It is a group selected from O- (n=1 to 4).

[0023] The method for producing liquid crystalline polyesters and liquid crystalline polyesteramides is not particularly limited. They can be produced by known methods using the above-mentioned monomer compounds (or mixtures of monomers) by direct polymerization or transesterification. However, typically, melt polymerization, solution polymerization, slurry polymerization, solid-phase polymerization, or a combination of two or more of these methods is used, with melt polymerization or a combination of melt polymerization and solid-phase polymerization being preferred. If the compound has ester-forming ability, it may be used in polymerization as is, or it may be used in a step prior to polymerization in which the precursor has been modified into a derivative having ester-forming ability using an acylating agent. Examples of acylating agents include carboxylic acids such as acetic anhydride.

[0024] Various catalysts can be used during polymerization. Typical examples of usable catalysts include metal salt catalysts such as potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, antimony trioxide, and tris(2,4-pentanedionato)cobalt(III), as well as organic compound catalysts such as N-methylimidazole and 4-dimethylaminopyridine. The amount of catalyst used is generally 0.001 to 1% by mass relative to the total weight of the monomer, and 0.01 to 0.2% by mass is particularly preferred.

[0025] Liquid crystal resins can be compounded with various fibrous, granular, or plate-shaped inorganic and organic fillers during the manufacturing process. Specific examples of fillers are similar to those that may be included in three-dimensional molded objects, as described later. The filler content can be, for example, 0 to 100 parts by mass per 100 parts by mass of liquid crystal resin, or it may be 0 to 80 parts by mass, 5 to 75 parts by mass, or 10 to 50 parts by mass. In addition, liquid crystal resins may contain other additives such as antioxidants, heat stabilizers, ultraviolet absorbers, lubricants, pigments, and crystal nucleating agents.

[0026] (Other Thermoplastic Resins) The thermoplastic resin may contain thermoplastic resins other than liquid crystalline resins. The types of thermoplastic resins that can be included other than liquid crystalline resins are not particularly limited and any thermoplastic resin used in the filament melting method is acceptable, such as polylactic acid (PLA), acrylonitrile butadiene styrene copolymer (ABS), nylon, polypropylene, polycarbonate, polyarylate, polyetherimide, polyaryletherketone, etc. Including thermoplastic resins other than liquid crystalline resins slows down the solidification rate and tends to improve the adhesion of the laminated interface. The content of thermoplastic resins other than liquid crystalline resins is preferably 40% by mass or less, more preferably 0 to 30% by mass, even more preferably 5 to 25% by mass, and particularly preferably 5 to 20% by mass, relative to the total thermoplastic resin.

[0027] (Resin Composition) Thermoplastic resins can be blended with various fibrous, granular, and plate-shaped inorganic and organic fillers from the viewpoint of reducing the shrinkage rate and coefficient of thermal expansion of the molded object. Examples of fibrous fillers include glass fibers, milled glass fibers, carbon fibers, asbestos fibers, silica fibers, silica-alumina fibers, alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, silicate fibers such as potassium titanate and wollastonite, magnesium sulfate fibers, aluminum borate fibers, and inorganic fibrous materials such as stainless steel, aluminum, titanium, copper, and brass. Glass fibers are a particularly representative fibrous filler. High-melting-point organic fibrous materials such as polyamides, fluororesins, polyester resins, and acrylic resins can also be used. Examples of granular fillers include carbon black, graphite, silica, quartz powder, glass beads, glass balloons, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, silicates such as wollastonite, metal oxides such as iron oxide, titanium oxide, zinc oxide, antimony trioxide, and alumina, metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, and other materials such as ferrite, silicon carbide, silicon nitride, boron nitride, and various metal powders. Examples of plate-type fillers include mica, glass flakes, talc, and various metal foils. These inorganic and organic fillers can be used individually or in combination of two or more.

[0028] The filler content can be, for example, 0 to 100 parts by mass per 100 parts by mass of thermoplastic resin, and may be 0 to 80 parts by mass, 5 to 75 parts by mass, 10 to 50 parts by mass, or 20 to 40 parts by mass. In addition, the resin composition may contain other additives such as antioxidants, heat stabilizers, ultraviolet absorbers, lubricants, pigments, and crystal nucleating agents.

[0029] <Ratio of apparent density (ρ2) of three-dimensional molded object to true density (ρ1) of thermoplastic resin> In this embodiment, the ratio of apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin [(ρ2 / ρ1) × 100 (%)] is 40 to 95%. By having a ratio of apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin within the above range, it is possible to create a three-dimensional molded object with a low dielectric constant. Furthermore, it is possible to create a three-dimensional molded object that has excellent properties derived from LCP and is lightweight. The true density (ρ1) of the thermoplastic resin can be calculated by measuring the density of a test piece of injection-molded thermoplastic resin using a hydrometer, provided that there are no molding defects such as insufficient filling or voids.

[0030] (Apparent density of a three-dimensional object (ρ²)) In this disclosure, "apparent density of a three-dimensional object (ρ²)" means the density calculated by dividing the mass of the three-dimensional object by its volume.

[0031] (Ratio of apparent density (ρ2) of three-dimensional molded object to true density (ρ1) of thermoplastic resin) In this disclosure, "ratio of apparent density (ρ2) of three-dimensional molded object to true density (ρ1) of thermoplastic resin" means the value calculated from the true density (ρ1) of the thermoplastic resin contained in the three-dimensional molded object and the apparent density (ρ2) of the three-dimensional molded object using the following formula: Ratio of apparent density (ρ2) of three-dimensional molded object to true density (ρ1) of thermoplastic resin = (ρ2 / ρ1) × 100 (%) The apparent density (ρ2) of the three-dimensional molded object can be adjusted by intentionally creating voids in the three-dimensional molded object or by adjusting the specific gravity by mixing in fillers. The method for adjusting the apparent density (ρ²) of a three-dimensional object when creating a three-dimensional object using a filament melting method with a thermoplastic resin filament is described below, but in short, it can be done by setting the infill (internal filling rate) setting of a typical 3D printer to a predetermined value of less than 100%.

[0032] In one embodiment, the ratio of the apparent density (ρ2) of the three-dimensional object to the true density (ρ1) of the thermoplastic resin is preferably 45 to 90%, more preferably 50 to 90%, even more preferably 50 to 85%, and particularly preferably 55 to 85%. By having the ratio of the apparent density (ρ2) of the three-dimensional object to the true density (ρ1) of the thermoplastic resin within the above range, it is easier to obtain a three-dimensional object with a low dielectric constant. Furthermore, it is easier to obtain a three-dimensional object that is lighter while maintaining the excellent properties derived from LCP and its mechanical properties.

[0033] In one embodiment, the three-dimensional object is used in an environment where an electric field is applied, and it is preferable that the thermoplastic resin is molecularly oriented in at least a part of the three-dimensional object, and that at least one of the directions of molecular orientation is the direction of the electric field applied to the three-dimensional object. By having the thermoplastic resin molecularly oriented in at least a part of the three-dimensional object, it is possible to make a three-dimensional object that has superior properties in desired locations and / or directions. In this disclosure, "molecularly oriented" means that in at least a part of the three-dimensional object, almost all molecules are molecularly oriented in one direction, and is not limited to all molecules being molecularly oriented in one direction, but some molecules may be molecularly oriented in other directions. Molecular orientation can be confirmed by calculating the scattering intensity value of (direction d of the electric field applied to the three-dimensional object) / (plane direction perpendicular to direction d) (Equation I) in two-dimensional wide-angle X-ray diffraction. For example, if a three-dimensional fabricated object is in the shape of a plate, the degree of molecular orientation in the thickness direction can be confirmed by calculating the value of (scattering intensity in the thickness direction / scattering intensity in the plane direction) (Equation II) in two-dimensional wide-angle X-ray diffraction. In this case, a larger value of scattering intensity in the thickness direction / scattering intensity in the plane direction means a greater degree of molecular orientation in the thickness direction. The values ​​of (Equation I) and (Equation II) in two-dimensional wide-angle X-ray diffraction are preferably greater than 1.0, more preferably greater than 2.0, even more preferably greater than 3.0, and particularly preferably greater than 4.0. The degree of molecular orientation (degree of molecular orientation) can be adjusted by adjusting the fabrication speed, which is the relative movement speed between the nozzle and the stage of the three-dimensional fabrication apparatus, the distance from the nozzle to the stage (layer height), the difference between the melting point Tm2 and the crystallization temperature Tc of the filament measured by a differential scanning calorimeter (Tm2-Tc), the diameter of the filament, and the nozzle diameter. For example, by setting Tm2-Tc within the numerical range described later and increasing the printing speed, the degree of molecular orientation tends to increase. Also, the smaller the filament diameter and nozzle diameter, and the faster the nozzle movement speed, the higher the degree of molecular orientation tends to be.

[0034] Three-dimensional fabricated objects are used in environments where an electric field is applied. Thermoplastic resins are molecularly oriented in the direction of the electric field applied to the three-dimensional fabricated object, making it easier for the object to exhibit superior dielectric properties in that direction. In this specification, "direction of the electric field applied to the three-dimensional fabricated object" refers to the direction of the electric field acting on the three-dimensional fabricated object in the environment in which it is used. LCP is known to have low dielectric properties in the high-frequency band and excellent high insulation properties. Dielectric loss tangent is a numerical representation of the ratio of energy converted into heat when an alternating electric field is applied to a dielectric. Because the molecular orientation of thermoplastic resins containing LCP is more controlled in relation to the direction of the electric field applied to the three-dimensional fabricated object, it exhibits a low dielectric loss tangent in the direction of the electric field applied to the three-dimensional fabricated object. This three-dimensional fabricated object can be suitably used in applications where low dielectric properties are required, such as flexible circuit boards and substrates for millimeter-wave radar.

[0035] In one embodiment, when the three-dimensional molded object has a plate shape, the thermoplastic resin may be molecularly oriented in the thickness direction of the plate-shaped three-dimensional molded object, or molecularly oriented in the longitudinal direction. The orientation of the molded object may be changed to control the molecular orientation so that better properties are expressed in the direction in which the desired properties are to be expressed. By having the molecular orientation in the thickness direction or longitudinal direction of the plate-shaped three-dimensional molded object, the three-dimensional molded object can be easily positioned so that better properties are expressed in the direction in which the desired properties are to be expressed. "Having a plate shape" means that at least a part or the whole of the three-dimensional molded object has a plate shape, and the detailed shape is selected according to the application. The shape of the main surface in the plate shape is not particularly limited and examples include polygonal shapes (e.g., quadrilateral shapes), circular shapes, elliptical shapes, etc. The shape of the surface in the thickness direction of the plate shape (shape of the surface perpendicular to the main surface) is also not particularly limited and examples include polygonal shapes (e.g., quadrilateral shapes), circular shapes, elliptical shapes, etc. When creating a three-dimensional object in the shape of a plate, it is common practice to create the object so that the main surface is parallel to the build stage of the 3D printer. In this case, the thermoplastic resin molecules are oriented in the direction in which the main surface extends. Therefore, in this embodiment, it is preferable to create the object so that the thickness direction is parallel to the build stage of the 3D printer.

[0036] Since the thermoplastic resin in the three-dimensional molded object of the present embodiment is molecularly oriented, the dielectric properties in that direction are excellent. In one embodiment, for the direction in which the thermoplastic resin is molecularly oriented, the three-dimensional molded object preferably has a dissipation factor at 1 kHz measured at 23°C of 0.035 or less, more preferably 0.032 or less, still more preferably 0.030 or less, and particularly preferably 0.028 or less when measured using a cavity resonator perturbation method complex dielectric constant evaluation apparatus in accordance with IEC 60250. In one embodiment, for the direction in which the thermoplastic resin is molecularly oriented, the three-dimensional molded object preferably has a dissipation factor at 1 MHz measured at 23°C of 0.025 or less, more preferably 0.022 or less, still more preferably 0.020 or less, and particularly preferably 0.018 or less when measured using a cavity resonator perturbation method complex dielectric constant evaluation apparatus in accordance with IEC 60250.

[0037] Since the thermoplastic resin in the three-dimensional molded object of the present embodiment is molecularly oriented, the dielectric properties in the direction perpendicular to that direction are excellent. In one embodiment, for the direction perpendicular to the direction in which the thermoplastic resin is molecularly oriented, the three-dimensional molded object preferably has a relative dielectric constant at 1 kHz measured at 23°C of 4 or less, more preferably 3.8 or less, still more preferably 3.6 or less, and particularly preferably 3.4 or less when measured using a cavity resonator perturbation method complex dielectric constant evaluation apparatus in accordance with IEC 60250. In one embodiment, for the direction perpendicular to the direction in which the thermoplastic resin is molecularly oriented, the three-dimensional molded object preferably has a relative dielectric constant at 1 MHz measured at 23°C of 3.6 or less, more preferably 3.4 or less, still more preferably 3.2 or less, and particularly preferably 3.0 or less when measured using a cavity resonator perturbation method complex dielectric constant evaluation apparatus in accordance with IEC 60250.

[0038] Since the three-dimensional object of the present embodiment has the molecular orientation controlled, it can be preferably used as a component that is desired to have excellent properties at desired locations and in desired directions in various fields, and can be used as a component for a connector or a printed circuit board. Examples of the connector include a DDR connector, a SATA connector, a board-to-board connector (B-to-B connector), a connector for a flexible printed circuit board (FPC connector), a CPU socket, and the like. Examples of the printed circuit board include a rigid board, a flexible board (FPC), a rigid-flexible board, and the like.

[0039] The three-dimensional object of the first embodiment can be manufactured by the manufacturing method of the three-dimensional object of the following second embodiment.

[0040] [Manufacturing Method of Three-Dimensional Object] The second embodiment in the present disclosure relates to a manufacturing method of a three-dimensional object. The manufacturing method of the three-dimensional object according to the present embodiment includes forming the three-dimensional object by a filament melting manufacturing method using the filament containing the above-described thermoplastic resin, and the forming includes controlling the ratio [(ρ2 / ρ1)×100(%)] of the apparent density (ρ2) of the three-dimensional object to the true density (ρ1) of the thermoplastic resin to be less than 100%. The "filament melting manufacturing method" is a kind of layered manufacturing method, and is a method of laminating thermoplastic filaments in layers while melting them with heat to produce a shaped object. The "filament" means a solidified product obtained by extruding a thermoplastic resin softened by heating into a string-like or thread-like shape (strand).

[0041] <Filament> In this embodiment, the filament includes a thermoplastic resin. The thermoplastic resin includes 55 to 100% by mass of liquid crystalline resin relative to the total thermoplastic resin. By including the liquid crystalline resin in the filament within the above range, a three-dimensional molded product can be obtained in which the characteristics derived from LCP are more strongly expressed. In one embodiment, the thermoplastic resin preferably includes 60 to 100% by mass of liquid crystalline resin, more preferably 70 to 100% by mass of liquid crystalline resin, even more preferably 80 to 100% by mass of liquid crystalline resin, and particularly preferably 90 to 100% by mass of liquid crystalline resin relative to the total thermoplastic resin. In one embodiment, the entire thermoplastic resin may be a thermoplastic liquid crystalline resin, that is, the filament may consist of a thermoplastic liquid crystalline resin. The filament may also contain thermoplastic resins other than the liquid crystalline resin that may be included in the thermoplastic resin described above, and other components that may be included in the three-dimensional molded product. The descriptions of the liquid crystalline resin, thermoplastic resins other than the liquid crystalline resin, and other components, as well as their content, are as described above and are therefore omitted here. In one embodiment, the content of thermoplastic resin in the filament may be 50 to 100% by mass, 55 to 100% by mass, 60 to 100% by mass, or 70 to 100% by mass, based on the total amount of filament (100% by mass). In one embodiment, the content of liquid crystalline resin in the filament may be 50 to 100% by mass, 55 to 100% by mass, 60 to 100% by mass, or 70 to 100% by mass, based on the total amount of filament (100% by mass).

[0042] <Controlling the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin [(ρ2 / ρ1) × 100 (%)] to less than 100%> In this embodiment, the method for manufacturing a three-dimensional molded object includes controlling the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin [(ρ2 / ρ1) × 100 (%)] to less than 100%. By including the control of the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin to less than 100% during the molding process, a three-dimensional molded object can be obtained in which the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin is 40 to 95%. In this disclosure, "apparent density (ρ2) of the three-dimensional molded object" is as described above. One method for adjusting the apparent density (ρ2) of a three-dimensional object using a filament melting method is to set the infill (internal filling ratio) setting of a typical 3D printer to a predetermined value less than 100%. In this disclosure, "infill (internal filling ratio)" refers to the proportion of the volume that constitutes the interior of a three-dimensional object. By adjusting the infill (internal filling ratio) setting to less than 100%, for example, in the printing direction shown in Figures 1 and 3, the apparent density (ρ2) of the three-dimensional object can be adjusted by creating gaps between the print lines inside the three-dimensional object. In Figures 1 and 3, linear gaps (D) are provided between linear print lines (C), but it is sufficient for the three-dimensional object as a whole to have gaps, and the pattern of the print lines and the shape of the gaps are not limited.

[0043] In one embodiment, fabricating a three-dimensional object involves controlling the filament printing direction to the direction of molecular orientation. By controlling the filament printing direction to the direction of molecular orientation, the molecular orientation of LCP is improved, and a three-dimensional object can be made in which the properties of LCP are more pronounced in specific locations and / or directions. The direction of molecular orientation usually coincides with the filament printing direction. Furthermore, the degree of molecular orientation can be controlled by adjusting the nozzle movement speed and nozzle diameter.

[0044] (Difference between the filament's melting point Tm2 and crystallization temperature Tc (Tm2-Tc)) In one embodiment, the difference between the filament's melting point Tm2 and crystallization temperature Tc (Tm2-Tc), measured by a differential scanning calorimeter, is preferably 25 to 60°C, more preferably 30 to 60°C, even more preferably 30 to 50°C, and particularly preferably 30 to 45°C. In one embodiment, the difference between the filament's melting point Tm2 and crystallization temperature Tc (Tm2-Tc), measured by a differential scanning calorimeter, may be 40 to 60°C. By having Tm2-Tc within the above range, the solidification rate during molding becomes suitable, enabling three-dimensional molding by a high-speed filament melting method using a filament containing liquid crystalline resin, and allowing the production of three-dimensional molded objects with improved molecular orientation. In this embodiment, the filament's melting point Tm2 and crystallization temperature Tc, measured by a differential scanning calorimeter, are determined as follows. According to the method based on JIS K-7121 (1999), a differential scanning calorimeter is used to measure the peak temperature (melting point Tm1) of the endothermic peak observed when the sample is heated from room temperature at a heating rate of 20°C / min (1st RUN). The sample is then held at (melting point Tm1 + 40)°C for 2 minutes, and then cooled to room temperature at a cooling rate of 20°C / min. The peak temperature of the exothermic peak observed at this time is defined as the crystallization temperature Tc. Subsequently, the peak temperature of the endothermic peak observed during the 2nd RUN, when the sample is heated again from room temperature at a heating rate of 20°C / min, is defined as the melting point Tm2.

[0045] The method for adjusting the difference between the melting point Tm2 and the crystallization temperature Tc (Tm2-Tc) of the filament is not limited and can be performed by, for example, the following methods: (1) By increasing the content of constituent units derived from aromatic hydroxycarboxylic acid and its derivatives in the liquid crystalline resin (for example, 50% by mass or more relative to 100% by mass of total monomers), the difference between the melting point Tm2 and the crystallization temperature Tc (Tm2-Tc) can be adjusted to a large value. By decreasing the content of constituent units derived from aromatic hydroxycarboxylic acid and its derivatives (for example, 0.1 to 3.0% by mass relative to 100% by mass of total monomers), the difference between the melting point Tm2 and the crystallization temperature Tc (Tm2-Tc) can be adjusted to a small value. (2) By blending a thermoplastic resin other than the liquid crystalline resin, the melting point Tm2 and the crystallization temperature Tc can be adjusted to a difference between the melting point Tm2 and the crystallization temperature Tc (Tm2-Tc) of 25 to 60°C. (3) By adding a certain amount of monomer having a kink structure to the filament, the crystallization temperature Tc can be lowered and the difference between the melting point Tm2 and the crystallization temperature Tc (Tm2-Tc) can be adjusted. A kink structure refers to a monomer that changes the molecular chain direction (the direction in which monomers are linked) in a liquid crystalline polymer. Examples of monomers having a kink structure include 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 7-hydroxy-2-naphthoic acid, 6-hydroxy-1-naphthoic acid, 6-hydroxy-5-methyl-2-naphthoic acid, 6-hydroxy-5-methoxy-2-naphthoic acid, 6-hydroxy-5-chloro-2-naphthoic acid, 6-hydroxy-7-chloro-2-naphthoic acid, 6-hydroxy-5,7-dichloro-2-naphthoic acid, and isophthalic acid. In this case, the amount of monomer having a kink structure is preferably 10 to 70% by mass, and more preferably 20 to 50% by mass, relative to the total monomer (100% by mass), from the viewpoint of easily adjusting the difference between the melting point Tm2 and the crystallization temperature Tc (Tm2-Tc) to the range of 25 to 60°C. (4) When the filament contains a transesterifiable polymer such as polycarbonate, the crystallization temperature Tc can be lowered by transesterification.Therefore, if the crystallization temperature Tc is high, the crystallization temperature Tc can be lowered by mixing a certain amount of transesterifiable polymer, thereby adjusting the difference between the melting point Tm2 and the crystallization temperature Tc (Tm2-Tc). In this case, the content of the transesterifiable polymer is preferably less than 30% by mass, and more preferably 0-25% by mass, relative to the total thermoplastic resin, from the viewpoint of easily adjusting the difference between the melting point Tm2 and the crystallization temperature Tc (Tm2-Tc) to the range of 25-60°C.

[0046] In one embodiment, the melting point Tm2 of the filament, as measured by a differential scanning calorimeter, is preferably 250 to 400°C, more preferably 260 to 380°C, and even more preferably 280 to 360°C or lower. By setting the melting point Tm2 to 250 to 400°C, the heat resistance of the three-dimensionally fabricated object can be further improved. In one embodiment, the crystallization temperature Tc of the filament, as measured by a differential scanning calorimeter, is preferably 200 to 400°C, more preferably 210 to 350°C, and even more preferably 220 to 330°C. By setting the crystallization temperature Tc to 200 to 400°C, the heat resistance of the three-dimensionally fabricated object can be further improved.

[0047] (Filament Diameter) In one embodiment, the diameter of the filament is preferably 0.5 to 3.0 mm, more preferably 0.5 to 2.5 mm, even more preferably 1.0 to 2.5 mm, and particularly preferably 1.0 to 2.0 mm. By setting the filament diameter within the above range, it is possible to easily manufacture three-dimensional objects with improved molecular orientation of the liquid crystalline resin when used as a molding material in commercially available three-dimensional molding machines. "Filament diameter" means the average diameter of the solidified filament cross-section. Specifically, it is the arithmetic mean of the values ​​obtained by taking out 5 m of filament, randomly selecting 20 locations, measuring their diameters (or the longest straight-line distance in the cross-section) to three decimal places using a micrometer, and rounding the third decimal place. The filament diameter can be adjusted, for example, by adjusting the winding speed when winding the extruded strand from a filament winding machine after cooling and solidifying it with water, so that it reaches the desired diameter. In one embodiment, the filament can be in the form of a winding body wound around a core material. By creating a rolled-up form, it becomes easier to attach to commercially available 3D printers using the filament melting method, and the fabrication process using these 3D printers becomes easier.

[0048] (Melting viscosity) In one embodiment, the cylinder temperature is 15°C higher than the melting point Tm2 and the shear rate is 1000 sec. －１ The melt viscosity of the filament measured under these conditions is preferably 15 to 50 Pa·s, more preferably 17.5 to 50 Pa·s, even more preferably 20 to 50 Pa·s, and particularly preferably 20 to 48 Pa·s. By setting the melt viscosity of the filament within the above range, the properties of the print line during molding can be set to a suitable range, and three-dimensional molded objects with improved molecular orientation of the liquid crystalline resin can be easily manufactured. The melt viscosity can be adjusted, for example, by adjusting the final polymerization temperature during the melt polymerization of the liquid crystalline resin.

[0049] (Modeling speed) In one embodiment, the method for manufacturing a three-dimensional object includes controlling, in a filament melting manufacturing method, the modeling speed, which is the relative movement speed between the nozzle part and the stage of the three-dimensional modeling apparatus, to be faster than 35 mm / sec and slower than 1000 mm / sec (that is, a speed exceeding 35 mm / sec and less than 1000 mm / sec). The modeling speed can be controlled, for example, by inputting a numerical value within the above-mentioned predetermined range as the relative movement speed between the nozzle part and the stage into the software attached to the three-dimensional modeling apparatus, or by inputting the movement speed of the nozzle part and the movement speed of the stage so that the relative movement speed between the nozzle part and the stage falls within the above-mentioned predetermined range. In this specification, the "nozzle part" is the part having the nozzle from which the filament is discharged in the three-dimensional modeling apparatus of the filament melting manufacturing method, and is the part controlled to be movable freely in three-dimensional space. The "stage" means the base on which the filament is laminated and the three-dimensional object is modeled in the three-dimensional modeling apparatus of the filament melting manufacturing method. The "relative movement speed between the nozzle part and the stage" means the relative speed between any two points on the "nozzle part" and the "stage" during modeling. In the three-dimensional modeling apparatus of the filament melting manufacturing method, there are those in which the stage on which the object is formed is not movable and only the nozzle part that discharges the filament is movable during modeling, and those in which not only the nozzle part that discharges the filament but also the stage on which the object is formed is movable during modeling. In any of these methods, the relative movement speed between the nozzle part and the stage is defined as the modeling speed. More specifically, the relative movement speed V between the nozzle part and the stage of the three-dimensional modeling apparatus by the filament melting manufacturing method is defined as follows: V = [(dX ２ + dY ２ + dZ ２ )( １／２] / dt (wherein dX, dY, and dZ are the distances traveled by the stage at any point on the nozzle in the X, Y, and Z axes at time dt, respectively.) As described above, due to the properties of liquid crystal polymers, liquid crystal resins solidify quickly, so in the filament melting method, when molten filaments are stacked, the previously stacked layers solidify easily. When molten filaments are stacked on a solidified layer, strain is easily generated, and stress relaxation makes it difficult for the molecular orientation of the resin to be aligned. By controlling the above-mentioned printing speed to a high speed such as faster than 35 mm / sec and slower than 1000 mm / sec, high shear orientation can be easily obtained, and the molecular orientation of the liquid crystal resin can be further improved to manufacture three-dimensional objects. As a result, three-dimensional objects with superior properties (e.g., dielectric properties, etc.) in desired locations and directions can be obtained. In addition, because the printing speed is high, the printing time is further shortened, and productivity is improved.

[0050] In one embodiment, a method for manufacturing a three-dimensional object by a filament melting method using a filament containing a thermoplastic resin preferably includes controlling the molding speed, which is the relative movement speed between the nozzle and the stage of the three-dimensional printing apparatus, to a speed faster than 35 mm / sec and slower than 800 mm / sec, more preferably to a speed of 40 mm / sec or more and 700 mm / sec or less, even more preferably to a speed of 45 mm / sec or more and 600 mm / sec or less, and particularly preferably to a speed of 50 mm / sec or more and 500 mm / sec or less. From the viewpoint of obtaining a three-dimensional object that has superior characteristics in desired locations and directions, as well as a smooth surface and superior appearance, the manufacturing method of the three-dimensional object preferably includes controlling the printing speed to a speed faster than 35 mm / sec and slower than 500 mm / sec, more preferably to a speed of 40 mm / sec or more and 450 mm / sec or less, even more preferably to a speed of 45 mm / sec or more and 300 mm / sec or less, and particularly preferably to a speed of 50 mm / sec or more and 200 mm / sec.

[0051] (Other conditions) In one embodiment, the nozzle temperature can be, for example, 5 to 25°C higher than the melting point Tm2 of the filament. In one embodiment, the extrusion rate of the molten filament from the nozzle is not limited, for example, 0.5 to 10 mm ３ / sec can be used. In the method for manufacturing a three-dimensional object according to this embodiment, there may be a step of cooling and drying the three-dimensional object after it has been manufactured, or there may be a step of heat-treating the three-dimensional object at a high temperature (for example, a temperature up to the melting point -10°C) such that the three-dimensional object does not substantially deform.

[0052] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of the present disclosure is disclosed below: [1] A three-dimensional molded object comprising a thermoplastic resin, wherein the thermoplastic resin comprises 55 to 100% by mass of a liquid crystalline resin in the total amount of the thermoplastic resin, and the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin [(ρ2 / ρ1) × 100 (%)] is 40 to 95%. [2] The three-dimensional molded object according to [1], wherein the three-dimensional molded object is used in an environment in which an electric field is applied, the thermoplastic resin is molecularly oriented in at least a part of the three-dimensional molded object, and at least one of the directions of molecular orientation is the direction of the electric field applied to the three-dimensional molded object. [3] The three-dimensional molded object according to [1] or [2], wherein the liquid crystalline resin is an aromatic polyester or aromatic polyesteramide having constituent units derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and their derivatives. [4] The three-dimensional molded object according to any one of [1] to [3], wherein the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin [(ρ2 / ρ1) × 100 (%)] is 50 to 90%. [5] A method for manufacturing a three-dimensional molded object according to any one of [1] to [4], comprising molding the three-dimensional molded object by a filament melting method using a filament containing the thermoplastic resin, wherein the molding includes controlling the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin [(ρ2 / ρ1) × 100 (%)] to less than 100%. [6] The method for manufacturing a three-dimensional molded object according to [5], wherein the molding includes controlling the printing direction of the filament to the direction of molecular orientation. [7] The manufacturing method according to [5] or [6], wherein the difference between the melting point Tm2 and the crystallization temperature Tc of the filament measured by a differential scanning calorimeter (Tm2-Tc) is 25 to 60°C, and the manufacturing is performed by controlling the manufacturing speed, which is the relative movement speed between the nozzle and the stage of the three-dimensional printing apparatus, to a speed faster than 35 mm / sec and slower than 1000 mm / sec.[8] The manufacturing method according to [7], wherein the molding is controlled to a speed faster than 35 mm / sec and slower than 500 mm / sec. [9] The manufacturing method according to any one of [5] to [8], wherein the diameter of the filament is 0.5 to 3.0 mm.

[10] The manufacturing method according to any one of [5] to [9], wherein the three-dimensional molded object is used in an environment in which an electric field is applied, and the molding is controlled to control at least one of the printing directions of the filament in the direction of the electric field applied to the three-dimensional molded object.

[11] The manufacturing method according to any one of [5] to

[10] , wherein the liquid crystalline resin is an aromatic polyester or aromatic polyesteramide having a constituent unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and their derivatives.

[0053] The present disclosure will be further illustrated by the following examples, but these examples will not limit the interpretation of the present disclosure.

[0054] (Preparation of liquid crystalline resin) The following raw material monomers, fatty acid metal salt catalyst, and acyling agent were charged into a polymerization vessel equipped with a stirrer, reflux column, monomer inlet, nitrogen inlet, and vacuum / outlet line, and nitrogen purging was started. Raw material monomers (I) 4-hydroxybenzoic acid: 1660 g (73 mol%) (HBA) (II) 6-hydroxy-2-naphthoic acid: 837 g (27 mol%) (HNA) Fatty acid metal salt catalyst Potassium acetate catalyst: 165 mg Acyling agent Acetic anhydride: 1714 g After charging the raw materials into the polymerization vessel, the temperature of the reaction system was raised to 140°C and the reaction was carried out at 140°C for 1 hour. Then, the temperature was further raised to 325°C over 3.5 hours, and from there the pressure was reduced to 5 Torr (i.e., 667 Pa) over 20 minutes, and melt polymerization was carried out while distilling off acetic acid, excess acetic anhydride, and other low-boiling components. After the stirring torque reached a predetermined value, nitrogen was introduced to change the pressure from reduced pressure to atmospheric pressure and then to a pressurized state. The polymer was then discharged from the bottom of the polymerization vessel, and the strands were pelletized.

[0055] [Preparation of Thermoplastic Resin-Containing Filaments] [Preparation Example 1] Using the liquid crystalline resin pellets obtained above, thermoplastic resin-containing filaments with a diameter of 1.75 mm were prepared by the following method. The liquid crystalline resin pellets were fed into a single-screw extruder (Collin, product name: Tech-Line® E20 T) and extruded under the following conditions. After cooling and solidifying the extruded strands in a water bath, the thermoplastic resin-containing filaments were obtained by winding them with a filament winder at a winding speed such that the filament diameter was 1.75 mm ± 0.1 mm. Barrel temperature: Example 1: 290°C Screw speed: 60 rpm

[0056] The melting point Tm2 and crystallization temperature Tc of the obtained thermoplastic resin-containing filament were measured by the following method. The results are shown in Table 1. (Melting point Tm2, ​​crystallization temperature Tc) Using a differential scanning calorimeter (Hitachi High-Tech Science Co., Ltd., product name: DSC7000X), the temperature of the peak top of the endothermic peak observed when heating from room temperature at a heating rate of 20°C / min (1st RUN) was measured. Then, the temperature was held at (melting point Tm1 + 40)°C for 2 minutes, and then the temperature of the peak top of the exothermic peak observed when cooling to room temperature at a cooling rate of 20°C / min was measured as the crystallization temperature Tc. Subsequently, the temperature of the peak top of the endothermic peak observed in the 2nd RUN when heating again from room temperature at a heating rate of 20°C / min was measured as the melting point Tm2.

[0057] [Examples 1-4, Comparative Examples 1 and 2] [Manufacturing of Test Specimens of Three-Dimensional Objects] Three-dimensional objects were manufactured using the obtained thermoplastic resin-containing filament by the following method. The prepared thermoplastic resin-containing filament was set in a 3D printer using the filament melting method (manufactured by NematX, product name: NEX01), and the object was manufactured under the manufacturing conditions shown in Table 1. Two types of test specimens were manufactured for each of the examples and comparative examples: a test specimen with overall dimensions of 35 mm × 35 mm × 3 mm (hereinafter referred to as Test Specimen I) and a test specimen with overall dimensions of 80 mm × 10 mm × 4 mm (hereinafter referred to as Test Specimen II). Hereinafter, "thickness direction of the test specimen" refers to the measurement direction of the relative permittivity and dielectric loss tangent, and means the same direction as the Z direction in Figures 1 to 4. For Examples 1 and 2 and Comparative Example 1, the longitudinal plane (X-Y plane) of the test specimen was positioned horizontally to the plane of the 3D printer stage, and the test specimen was fabricated such that the thickness direction (Z direction) was the fabrication direction and the longitudinal direction (X direction) was the printing direction. For the test specimens of Examples 1 and 2, the 3D printer's infill (internal filling rate) was set to 80% and 50%, respectively, as shown in Table 1. As a result, as shown in Figure 1, test specimens with gaps between the print lines were fabricated in the printing direction. On the other hand, for the test specimen of Comparative Example 1, the 3D printer's infill (internal filling rate) was set to 100%, and as shown in Figure 2, there were no intentionally created gaps between the print lines. For Examples 3 and 4 and Comparative Example 2, the thickness direction plane (Y-Z plane) of the test specimen was positioned horizontally to the plane of the 3D printer stage, and the test specimen was fabricated such that the longitudinal direction (X direction) was the fabrication direction (layering direction) and the thickness direction (Z direction) was the printing direction. For the test specimens of Examples 3 and 4, the 3D printer's infill (internal filling rate) was set to 80% and 50%, respectively, as shown in Table 1. As a result, as shown in Figure 3, test specimens with gaps between the print lines were fabricated in the printing direction. On the other hand, for the test specimen of Comparative Example 2, the 3D printer's infill (internal filling rate) was set to 100%, so as shown in Figure 4, there were no intentionally created gaps between the print lines.In the fabrication methods shown in Figures 1 to 4, the symbol B indicates the printing direction, which is the direction in which the nozzle moves, and the symbol A indicates the end of the filament. In Figure 1, the first layer, a plane in the thickness direction of the test specimen (Y-Z plane), is formed on the plane of the 3D printer stage. Once the first layer is formed, the second layer, a plane in the thickness direction of the test specimen (Y-Z plane), is further formed on top of it. This is repeated in the X direction until a predetermined height (width of the test specimen) is reached, thereby fabricating the test specimen. In Figure 2, the first layer, the main surface of the test specimen (X-Y plane), is formed on the plane of the 3D printer stage. Once the first layer is formed, the second layer, the main surface of the test specimen (X-Y plane), is further formed on top of it. This is repeated in the Z direction until a predetermined height (thickness of the test specimen) is reached, thereby fabricating the test specimen. As described above, when fabricating three-dimensional objects, the main surface is generally fabricated so that it is parallel to the 3D printer's build stage. In this case, the thermoplastic resin molecularly orients in the direction in which the main surface extends. Therefore, the three-dimensional objects of Examples 1 and 2 and Comparative Example 1, where the longitudinal direction of the test specimen (the X direction in Figures 1 to 4) is the printing direction, are molecularly oriented in the longitudinal direction of the main surface (the X direction in Figures 1 to 4), while the three-dimensional objects of Examples 3 and 4 and Comparative Example 2, where the thickness direction of the test specimen (the Z direction in Figures 1 to 4) is the printing direction, are molecularly oriented in the thickness direction (the X direction in Figures 1 to 4). This can be confirmed by using an X-ray diffractometer to calculate the ratio of the scattering intensity in the thickness direction to the scattering intensity in the surface direction (perpendicular to the thickness direction) from the two-dimensional intensity profile obtained by wide-angle X-ray diffraction. The value of scattering intensity in the thickness direction / scattering intensity in the surface direction indicates the degree of molecular orientation; a larger value means that the molecules are more oriented in the thickness direction.

[0058] [Comparative Example 3] The above liquid crystalline resin pellets were molded using a molding machine (Sumitomo Heavy Industries, Ltd., "SE100DU") under the following molding conditions to produce test pieces I and II with the same shape as Examples 1 to 4 and Comparative Examples 1 and 2. [Molding conditions] Cylinder temperature: 300°C Mold temperature: 80°C Injection speed: 33 mm / sec

[0059] (Apparent density (ρ²) of three-dimensional molded objects) The density of each test piece I in Examples 1 to 4 and Comparative Examples 1 and 2 was measured using an electronic hydrometer (SD-120L, manufactured by Alpha Mirage Co., Ltd.) and the apparent density (ρ²) of each test piece I was determined.

[0060] (Ratio of apparent density (ρ2) of three-dimensional molded object to true density (ρ1) of thermoplastic resin) The density of test piece I of Comparative Example 3 was measured using an electronic hydrometer (SD-120L, manufactured by Alpha Mirage Co., Ltd.) and was taken as the true density (ρ1) of the thermoplastic resin contained in the thermoplastic resin-containing filament. True density (ρ1) of thermoplastic resin contained in thermoplastic resin-containing filament: 1.4 kg / m ３ Based on the apparent density (ρ2) of each test specimen, the ratio of the apparent density (ρ2) of the three-dimensional object to the true density (ρ1) of the thermoplastic resin was calculated using the following formula: Ratio of apparent density (ρ2) of three-dimensional object to true density (ρ1) of thermoplastic resin = (ρ2 / ρ1) × 100 (%)

[0061] (Dielectric Properties) For each specimen I, measurements were performed using a Concept 42 measurement system manufactured by Novocontrol Technologies (Montabaur, Germany) in accordance with IEC 62631-2-1. Each sample, with one surface of the test specimen coated with Dotite (Fujikura Chemical Industries, Ltd., "D-500"), was placed between two optically polished brass discs (36 mm in diameter), and the relative permittivity and dielectric loss tangent were measured at 1 kHz and 1 MHz at 23°C in the thickness direction of the specimen (Z direction in Figures 1 to 4).

[0062] (Flexural Modulus) The flexural modulus was measured for each specimen II in accordance with ISO 178. The results are shown in Table 1.

[0063]

[0064] As shown in Table 1, when comparing the examples with the comparative examples in the groups of Examples 1 and 2 and Comparative Example 1, and Examples 3 and 4 and Comparative Example 2, the dielectric constant of the three-dimensional molded objects in Examples 1 and 2, where the longitudinal direction (X direction) of the test specimen is the printing direction, decreases as the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin decreases. This is because, in the three-dimensional molded objects of Examples 3 and 4, where the thickness direction (Z direction) of the test specimen is the printing direction, decreases as the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin decreases. Furthermore, when comparing examples and comparative examples that differ only in the printing direction as a printing condition (for example, comparing Example 1 with Example 3, and Comparative Example 1 with Comparative Example 2), the values ​​of relative permittivity and dielectric loss tangent were clearly different. This is due to the different directions of molecular orientation. This indicates that the three-dimensional printed objects of Examples 1, 2 and Comparative Example 1, where the longitudinal direction of the test piece (the X direction in Figures 1 to 4) is the printing direction, are molecularly oriented in the longitudinal direction of the main surface (the X direction in Figures 1 to 4), while the three-dimensional printed objects of Examples 3, 4 and Comparative Example 2, where the thickness direction of the test piece (the Z direction in Figures 1 to 4) is the printing direction, are molecularly oriented in the thickness direction (the X direction in Figures 1 to 4). In other words, it can be seen that the molecular orientation of the three-dimensional printed objects of this embodiment is controlled at specific locations and / or in specific directions. Because the molecular orientation is controlled, the properties can be controlled to desired locations and / or directions. For example, as shown in Table 1, the dielectric properties of the three-dimensional fabricated object are controlled to lower the dielectric constant and lower the dielectric loss tangent in specific locations and / or directions. Furthermore, regarding the flexural modulus, it was expected that it would decrease proportionally as the ratio of the apparent density (ρ2) of the three-dimensional fabricated object to the true density (ρ1) of the thermoplastic resin decreased. However, contrary to expectations, the decrease in the flexural modulus was suppressed.For example, comparing Example 2 with Comparative Example 1, the flexural modulus of Example 2 was expected to decrease to about 5700 MPa if it were proportional to the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin. Similarly, comparing Example 3 with Comparative Example 2, the flexural modulus of Example 3 was expected to decrease to about 6300 MPa, but in reality, no such decrease in flexural modulus occurred. Furthermore, compared to Comparative Example 3, which has no voids and where the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin is 100%, Examples 1 to 3 had flexural moduli equal to or better than those of Comparative Example 3. In other words, the three-dimensional molded objects of this embodiment can be made lighter without using foaming agents or the like for weight reduction by reducing the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin. As described above, the three-dimensional molded objects of this embodiment were able to achieve a low dielectric constant without using additives such as glass balloons for low dielectric constant reduction. Furthermore, this three-dimensional object was a lightweight three-dimensional object in which the dielectric properties were controlled in specific locations and / or directions. In other words, this means that a three-dimensional object with controlled dielectric properties in specific locations and / or directions and lightweight can be manufactured by the method of the embodiment that satisfies the configuration of this embodiment.

[0065] Because the three-dimensionally fabricated object of this embodiment has excellent dielectric properties, it can be suitably used as a component for connectors or printed circuit boards, and thus has industrial applicability.

[0066] 1. Test specimen A. Filament end B. Bidirectional arrow indicating printing direction C. Print line D. Gap

Claims

1. A three-dimensional molded object comprising a thermoplastic resin, wherein the thermoplastic resin contains 55 to 100% by mass of liquid crystalline resin in the total amount of thermoplastic resin, and the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin [(ρ2 / ρ1) × 100 (%)] is 40 to 95%.

2. The three-dimensional object according to claim 1, wherein the three-dimensional object is used in an environment in which an electric field is applied, the thermoplastic resin is molecularly oriented in at least a part of the three-dimensional object, and at least one of the directions of molecular orientation is the direction of the electric field applied to the three-dimensional object.

3. The three-dimensional molded product according to claim 1 or 2, wherein the liquid crystalline resin is an aromatic polyester or aromatic polyesteramide having a constituent unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and their derivatives.

4. The three-dimensional molded object according to claim 1 or 2, wherein the ratio of the apparent density (ρ2) of the three-dimensional molded object to the true density (ρ1) of the thermoplastic resin [(ρ2 / ρ1) × 100 (%)] is 50 to 90%.

5. A method for manufacturing a three-dimensional object according to claim 1, comprising forming the three-dimensional object by a filament melting method using a filament containing the thermoplastic resin, wherein the forming process includes controlling the ratio of the apparent density (ρ2) of the three-dimensional object to the true density (ρ1) of the thermoplastic resin [(ρ2 / ρ1) × 100 (%)] to less than 100%.

6. The manufacturing method according to claim 5, wherein the molding process includes controlling the printing direction of the filament to the direction of molecular orientation.

7. The manufacturing method according to claim 6, wherein the difference between the melting point Tm2 and the crystallization temperature Tc of the filament, as measured by a differential scanning calorimeter (Tm2 - Tc), is 25 to 60°C, and the manufacturing process is controlled to a speed faster than 35 mm / sec and slower than 1000 mm / sec, which is the relative movement speed between the nozzle and the stage of the three-dimensional printing apparatus.

8. The manufacturing method according to claim 7, wherein the molding process includes controlling the molding speed to a speed faster than 35 mm / sec and slower than 500 mm / sec.

9. The manufacturing method according to claim 5 or 6, wherein the diameter of the filament is 0.5 to 3.0 mm.

10. The manufacturing method according to claim 5 or 6, wherein the three-dimensional object is used in an environment in which an electric field is applied, and the manufacturing process includes controlling at least one of the printing directions of the filament to be in the direction of the electric field applied to the three-dimensional object.

11. The manufacturing method according to claim 5 or 6, wherein the liquid crystalline resin is an aromatic polyester or aromatic polyesteramide having a structural unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and their derivatives.

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