Shaped article and method for manufacturing shaped article

Abstract

Provided are: a shaped article which is shaped by a 3D printer and has a further improved linear expansion coefficient; and a method for manufacturing a shaped article.　This shaped article is shaped by a 3D printer and has a linear expansion coefficient of less than 0.1×10-6 / ºC in a direction of at least one axis among an X axis, a Y axis, and a Z axis.　Moreover, the shaped article preferably has a negative linear expansion coefficient in a direction of at least one axis among an X axis, a Y axis, and a Z axis.　Further, the shaped article is preferably composed of a liquid crystal polymer.　Furthermore, the 3D printer is preferably a fused deposition modeling 3D printer.

Description

Molded objects and methods for manufacturing molded objects

[0001] This disclosure relates to molded objects and methods for manufacturing molded objects.

[0002] In recent years, 3D printers, which can create three-dimensional objects of desired shapes without using molds, have been used in a variety of fields.

[0003] For example, Patent Document 1 describes a mounting platform equipped with a base. The second member of the base constituting the mounting platform is formed by a 3D printer, and the coefficient of linear expansion of the second member is a positive value as shown in Figure 3 of Patent Document 1.

[0004] As shown in Patent Document 1, the object fabricated by the 3D printer is 5.0 × 10 －６ Although it is below / K, it has a positive coefficient of thermal expansion as shown in Figure 3. Therefore, there are limitations to the applications of objects fabricated with 3D printers.

[0005] Japanese Patent Publication No. 2021-197457

[0006] The purpose of this disclosure is to provide a 3D-printed object and a method for manufacturing such an object, which is fabricated using a 3D printer and has a more improved coefficient of thermal expansion.

[0007] [1] A 3D printed object having a coefficient of thermal expansion of 0.1 × 10 in the direction of at least one axis of the X, Y, and Z axes. －６[1] The molded object is less than / ℃. [2] The molded object according to [1], wherein the coefficient of linear expansion in the direction of at least one axis of the X, Y, and Z axes of the molded object is negative. [3] The molded object according to [1] or [2], wherein the molded object is made of liquid crystal polymer. [4] The molded object according to any one of [1] to [3], wherein the 3D printer is a fused deposition modeling (FDM) 3D printer. [5] The molded object according to any one of [1] to [4], wherein the relative speed of the head of the 3D printer along the surface of the stage with respect to the stage of the 3D printer is 5 mm / s or more. [6] The molded object according to any one of [1] to [5], wherein the hole diameter d of the nozzle of the 3D printer is 1.0 mm or less. [7] The object according to any one of [1] to [6] above, wherein the ratio (t / d) of the layer thickness t of the object to the nozzle diameter d of the 3D printer is less than 0.75. [8] The coefficient of linear expansion of the object in the direction of at least one axis of the X, Y, and Z axes is -3.0 × 10 －６ A molded object according to any one of [1] to [7] above, wherein the temperature is below / ℃. [9] A method for manufacturing a molded object according to any one of [1] to [8] above, wherein the molded object is manufactured using a liquid crystal polymer filament for a 3D printer, the filament containing a liquid crystal polyester resin having repeating units represented by the following formulas (1), (2) and (3).

[0008] (In formulas (1) to (3) above, Ar1 is a phenylene group, a naphthylene group, or a biphenylylene group; Ar2 and Ar3 are each independently a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by formula (4) below; X and Y are each independently an oxygen atom or an imino group; one or more hydrogen atoms in Ar1, Ar2, and Ar3 may each be independently substituted with a halogen atom, an alkyl group, or an aryl group.)

[0009] (In formula (4), Ar4 and Ar5 are each independently a phenylene group or a naphthylene group; Z is an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.)

[10] A method for manufacturing a molded object according to [9] above, wherein the linear expansion coefficient of the molded object is controlled by controlling at least one of the following: the relative speed of the 3D printer head along the surface of the stage with respect to the stage of the 3D printer, the hole diameter d of the nozzle of the 3D printer, and the nozzle temperature of the 3D printer.

[0010] According to this disclosure, it is possible to provide a fabricated object and a method for manufacturing such an object, which are fabricated using a 3D printer and have an improved coefficient of thermal expansion.

[0011] The following will provide a detailed explanation based on the embodiments.

[0012] As a result of diligent research, the inventors have discovered that by using a liquid crystal polymer filament for 3D printers containing a liquid crystal polyester resin having a predetermined repeating unit as a raw material, the coefficient of thermal expansion of objects fabricated by a 3D printer can be improved compared to conventional techniques. Based on this finding, the inventors have completed the present invention.

[0013] The object of this embodiment is fabricated by a 3D printer and has a coefficient of thermal expansion of 0.1 × 10 in the direction of at least one axis of the X, Y, and Z axes. －６ It is below / ℃.

[0014] The object is fabricated using a 3D printer. The coefficient of thermal expansion of the object in the direction of at least one axis of the X, Y, and Z axes is 0.1 × 10⁻⁶. －６ The temperature is below / °C, and the coefficient of thermal expansion of the fabricated object in the direction of at least two axes, the X, Y, and Z axes, is 0.1 × 10⁻⁶. －６ The temperature is preferably less than / °C, and the coefficient of linear expansion in all axes of the molded object (X, Y, and Z axes) is 0.1 × 10⁻⁶. －６ It is more preferable that the temperature be below / ℃.

[0015] The coefficient of thermal expansion of the printed object in the direction of at least one axis of the X, Y, and Z axes is 0.1 × 10⁻⁶. －６ If the temperature is below / ℃, the coefficient of linear expansion is 0.1 × 10⁻⁶.－６ The axis with a coefficient of linear expansion less than / °C is not particularly limited and may be the X-axis, the Y-axis, or the Z-axis, and may be appropriately selected according to the use of the shaped object or the like.

[0016] When the coefficient of linear expansion in the direction of at least two axes of the X-axis, Y-axis, and Z-axis of the shaped object is 0.1×10 －６ / °C or less, the axis with a coefficient of linear expansion of 0.1×10 －６ / °C or less is not particularly limited and may be the X-axis and the Y-axis, the X-axis and the Z-axis, or the Y-axis and the Z-axis, and may be appropriately selected according to the use of the shaped object or the like.

[0017] Further, it is preferable that the coefficient of linear expansion in the direction of at least one axis of the X-axis, Y-axis, and Z-axis of the shaped object is negative, more preferably that the coefficient of linear expansion in the direction of at least two axes of the X-axis, Y-axis, and Z-axis of the shaped object is negative, and even more preferably that the coefficient of linear expansion in the direction of all axes of the X-axis, Y-axis, and Z-axis of the shaped object is negative.

[0018] When the coefficient of linear expansion in the direction of at least one axis of the X-axis, Y-axis, and Z-axis of the shaped object is negative, the axis with a negative coefficient of linear expansion is not particularly limited and may be the X-axis, the Y-axis, or the Z-axis, and may be appropriately selected according to the use of the shaped object or the like.

[0019] When the coefficient of linear expansion in the direction of at least two axes of the X-axis, Y-axis, and Z-axis of the shaped object is negative, the axes with a negative coefficient of linear expansion are not particularly limited and may be the X-axis and the Y-axis, the X-axis and the Z-axis, or the Y-axis and the Z-axis, and may be appropriately selected according to the use of the shaped object or the like.

[0020] Further, it is preferable that the coefficient of linear expansion in the direction of at least one axis of the X-axis, Y-axis, and Z-axis of the shaped object is -3.0×10 －６ / °C or less, more preferably that the coefficient of linear expansion in the direction of at least two axes of the X-axis, Y-axis, and Z-axis of the shaped object is -3.0×10 －６ / °C or less, and even more preferably that the coefficient of linear expansion in the direction of all axes of the X-axis, Y-axis, and Z-axis of the shaped object is -3.0×10 －６ / °C or less.

[0021] The coefficient of thermal expansion of the printed object in the direction of at least one axis of the X, Y, and Z axes is -3.0 × 10⁻⁶. －６ If the temperature is below / ℃, the coefficient of linear expansion is -3.0 × 10 －６ The axis that is below / ℃ is not particularly limited; it may be the X-axis, Y-axis, or Z-axis, and may be selected as appropriate depending on the intended use of the printed object.

[0022] The coefficient of thermal expansion of the printed object in the direction of at least two axes, the X, Y, and Z axes, is -3.0 × 10⁻⁶. －６ If the temperature is below / ℃, the coefficient of linear expansion is -3.0 × 10 －６ The axes that are below / ℃ are not particularly limited; they may be the X and Y axes, the X and Z axes, or the Y and Z axes, and may be selected as appropriate depending on the intended use of the printed object.

[0023] From the viewpoint of further reducing the coefficient of thermal expansion of the fabricated object, it is preferable that the 3D printer used to manufacture the object be a fused deposition modeling (FDM) 3D printer. In this case, the object is fabricated using a FDM 3D printer. A FDM 3D printer is a 3D printer whose fabrication method is FDM.

[0024] A 3D printer uses 3D printer filament to extrude molten, heated 3D printer filament onto a build plate through a nozzle in the print head, thereby manufacturing an object.

[0025] Fused deposition modeling (FDM) is a method of creating a desired object by first fluidizing a thermoplastic resin, which has a shape such as pellets or filaments, using a heating mechanism inside the extrusion head, then extruding it onto a platform through a nozzle, and gradually layering and cooling it to solidify it.

[0026] From the viewpoint of further reducing the coefficient of thermal expansion of the fabricated object, the relative speed of the 3D printer head along the surface of the 3D printer stage is preferably 5 mm / s or more, and more preferably 50 mm / s or more. The resulting fabricated object is fabricated by a 3D printer with a relative speed of 5 mm / s or more of the head along the surface of the stage.

[0027] Further, from the viewpoint of further reducing the linear expansion coefficient of the shaped object, the hole diameter d of the nozzle of the 3D printer is preferably 1.0 mm or less, and more preferably 0.8 mm or less. The shaped object thus obtained is formed by a 3D printer having a nozzle with a hole diameter d of 1.0 mm or less.

[0028] Further, from the viewpoint of further reducing the linear expansion coefficient of the shaped object, the ratio (t / d) of the layer thickness t (mm) of the shaped object to the hole diameter d (mm) of the nozzle of the 3D printer is preferably less than 0.75, and more preferably less than 0.50. The layer thickness t of the shaped object is the so-called lamination pitch.

[0029] When the shaped object is composed of a liquid crystal polymer, the linear expansion coefficient of the shaped object can be further reduced. Among them, the more the components of the liquid crystal polymer filament for 3D printers containing the liquid crystal polyester resin described later are in the shaped object, the more efficiently the linear expansion coefficient of the shaped object can be reduced.

[0030] Also, in the shaped object, the linear expansion coefficient in the X-axis direction, the linear expansion coefficient in the Y-axis direction, and the linear expansion coefficient in the Z-axis direction may all be the same, may be partially different, or may all be different.

[0031] The shaped object of such an embodiment is formed by a 3D printer, has an improved linear expansion coefficient compared to a conventional 3D printed shaped object, and preferably has a negative linear expansion coefficient. Such a shaped object can expand the application field compared to a conventional 3D printed shaped object.

[0032] Next, a method for manufacturing the shaped object of the embodiment will be described.

[0033] The manufacturing method of the molded object of the embodiment manufactures a molded object with a 3D printer using a liquid crystal polyester resin containing a repeating unit represented by the following formula (1) (hereinafter also referred to as repeating unit (1)), a repeating unit represented by the following formula (2) (hereinafter also referred to as repeating unit (2)), and a repeating unit represented by the following formula (3) (hereinafter also referred to as repeating unit (3)). The molded object manufactured by the manufacturing method of the molded object of the embodiment is the molded object of the above embodiment.

[0034]

[0035] In the above formulas (1) to (3), Ar1 is a phenylene group, a naphthylene group or a biphenylylene group; Ar2 and Ar3 are each independently a phenylene group, a naphthylene group, a biphenylylene group or a group represented by the following formula (4); X and Y are each independently an oxygen atom or an imino group (—NH—); one or more hydrogen atoms in Ar1, Ar2 and Ar3 may each independently be substituted with a halogen atom, an alkyl group or an aryl group.

[0036]

[0037] In the above formula (4), Ar4 and Ar5 are each independently a phenylene group or a naphthylene group; Z is an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidene group.

[0038] The halogen atoms that can substitute one or more hydrogen atoms in Ar1, Ar2 and Ar3 are preferably a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0039] The alkyl group that can substitute one or more hydrogen atoms in Ar1, Ar2 and Ar3 is preferably an alkyl group having 1 to 10 carbon atoms, and more preferably a methyl group, an ethyl group, a 1-propyl group, an isopropyl group, a 1-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a 1-hexyl group, a 2-ethylhexyl group, a 1-octyl group and a 1-decyl group.

[0040] The aryl group that can be substituted for one or more hydrogen atoms in Ar1, Ar2, and Ar3 is preferably an aryl group having 6 to 20 carbon atoms, and more preferably a monocyclic aromatic group such as a phenyl group, orthotolyl group, metatolyl group, or paratolyl group, or a fused aromatic group such as a 1-naphthyl group or a 2-naphthyl group.

[0041] When one or more hydrogen atoms in Ar1, Ar2, and Ar3 are substituted with the above substituents, the number of such substituents is preferably one or two, and more preferably one, for each group represented by Ar1, Ar2, Ar3, Ar4, or Ar5, independently of each other.

[0042] The alkylidene group of Z is preferably an alkylidene group having 1 to 10 carbon atoms, and more preferably a methylene group, ethylidene group, isopropylidene group, 1-butylidene group, or 2-ethylhexylidene group.

[0043] One or more hydrogen atoms in Ar4 and Ar5 may be independently substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0044] The repeating unit (1) is a repeating unit derived from a predetermined aromatic hydroxycarboxylic acid.

[0045] In this specification, "derived from" means that the chemical structure of the raw material monomer changes due to polymerization, but no other structural changes occur.

[0046] Preferred aromatic hydroxycarboxylic acids include 4-hydroxybenzoic acid, meta-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 2-hydroxy-3-naphthoic acid, 1-hydroxy-5-naphthoic acid, 4-hydroxy-4'-carboxydiphenyl ether, and aromatic hydroxycarboxylic acids in which some of the hydrogen atoms in the aromatic ring of these aromatic hydroxycarboxylic acids are substituted with substituents selected from the group consisting of alkyl groups, aryl groups, and halogen atoms.

[0047] Aromatic hydroxycarboxylic acids may be used individually or in combination of two or more in the production of liquid crystal polyester resins.

[0048] The repeating unit (1) is preferably a unit in which Ar1 is a 1,4-phenylene group (a repeating unit derived from 4-hydroxybenzoic acid) and a unit in which Ar1 is a 2,6-naphthylene group (a repeating unit derived from 6-hydroxy-2-naphthoic acid), and more preferably a unit in which Ar1 is a 1,4-phenylene group.

[0049] The repeating unit (2) is a repeating unit derived from a predetermined aromatic dicarboxylic acid.

[0050] Preferably, the aromatic dicarboxylic acids are terephthalic acid, isophthalic acid, biphenyl-4,4'-dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenylthioether-4,4'-dicarboxylic acid, or aromatic dicarboxylic acids in which some of the hydrogen atoms in the aromatic ring of these aromatic dicarboxylic acids are substituted with substituents selected from the group consisting of alkyl groups, aryl groups, and halogen atoms.

[0051] Aromatic dicarboxylic acids may be used individually or in combination of two or more in the production of liquid crystal polyester resins.

[0052] The repeating unit (2) is preferably a unit in which Ar2 is a 1,4-phenylene group (for example, a repeating unit derived from terephthalic acid), a unit in which Ar2 is a 1,3-phenylene group (for example, a repeating unit derived from isophthalic acid), a unit in which Ar2 is a 2,6-naphthylene group (for example, a repeating unit derived from 2,6-naphthalenedicarboxylic acid), and a unit in which Ar2 is a diphenyl ether-4,4'-diyl group (for example, a repeating unit derived from diphenyl ether-4,4'-dicarboxylic acid), with units in which Ar2 is a 1,4-phenylene group and units in which Ar2 is a 1,3-phenylene group being preferred.

[0053] The repeating unit (3) is a repeating unit derived from a predetermined aromatic diol, aromatic hydroxyamine, or aromatic diamine.

[0054] Preferably, the aromatic diol, aromatic hydroxyamine, or aromatic diamine is 4,4'-dihydroxybiphenyl, hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl ether, bis(4-hydroxyphenyl)methane, 1,2-bis(4-hydroxyphenyl)ethane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl thioether, 2,6-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 4-aminophenol, 1,4-phenylenediamine, 4-amino-4'-hydroxybiphenyl, or 4,4'-diaminobiphenyl.

[0055] Aromatic diols, aromatic hydroxyamines, or aromatic diamines may be used individually or in combination of two or more in the production of liquid crystal polyester resins.

[0056] The repeating unit (3) is preferably a unit in which Ar3 is a 1,4-phenylene group (for example, a repeating unit derived from hydroquinone, 4-aminophenol, or 1,4-phenylenediamine), and preferably a unit in which Ar3 is a 4,4'-biphenylylene group (for example, a repeating unit derived from 4,4'-dihydroxybiphenyl, 4-amino-4'-hydroxybiphenyl, or 4,4'-diaminobiphenyl), and more preferably a unit in which Ar3 is a 4,4'-biphenylylene group.

[0057] As the repeating unit (3), a unit in which X and Y are each oxygen atoms is preferred.

[0058] When the manufactured object requires particularly good heat resistance and thermal stability, it is preferable that the repeating units (1) to (3) have fewer substituents. Furthermore, when the manufactured object requires particularly good heat resistance and thermal stability, it is preferable that it does not have heat-sensitive substituents (e.g., alkyl groups).

[0059] The heat resistance of the above-mentioned molded object refers to the property of the resin material used to form the object to be resistant to softening in high-temperature environments. The heat resistance of a molded object can be determined by measuring its deflection temperature under load. The deflection temperature is measured in accordance with ASTM D648 under a load of 1.82 MPa. The higher the deflection temperature measured in this way, the higher the heat resistance of the molded object.

[0060] Furthermore, the thermal stability of a molded object refers to its property of being resistant to decomposition or degradation of the resin when the molded object is held at the temperature at which the resin is molded (melting temperature).

[0061] Furthermore, from the viewpoint of improving the tensile strength of the molded object, it is preferable that the liquid crystal polyester resin contains a naphthalene skeleton.

[0062] Below, we will describe in detail, based on the examples of structural units described above, a liquid crystal polyester resin that is particularly suitable for application to liquid crystal polymer filaments used as raw materials for molded objects, regarding combinations of its structural units.

[0063] Specific examples of preferred liquid crystal polyester resins include, for example, resins composed of constituent units (repeating units) derived from the following monomers.

[0064] (a) 6-hydroxy-2-naphthoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer (b) 4-hydroxybenzoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl copolymer (c) 4-hydroxybenzoic acid / terephthalic acid / isophthalic acid / 4,4'-dihydroxybiphenyl copolymer (d) 4-hydroxybenzoic acid / terephthalic acid / isophthalic acid / 4,4'-dihydroxybiphenyl / hydroquinone copolymer (e) 4-hydroxybenzoic acid / terephthalic acid / hydroquinone copolymer (f) 2-hydroxy-6-naphthoic acid / terephthalic acid / hydroquinone copolymer (g) 4-hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl copolymer (h) 2-hydroxy-6-naphthoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl copolymer (i) 4-hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / hydroquinone copolymer (j) 4-hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / hydroquinone / 4,4'-dihydroxybiphenyl copolymer (k) 4-hydroxybenzoic acid / 2,6-naphthalenedicarboxylic acid / 4,4'-dihydroxybiphenyl copolymer (l) 4-hydroxybenzoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer (m) 4-hydroxybenzoic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer (n) 4-hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer (o) 4-hydroxybenzoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone / 4,4'-dihydroxybiphenyl copolymer (p) 4-hydroxybenzoic acid / terephthalic acid / 4-aminophenol copolymer (q) 2-hydroxy-6-naphthoic acid / terephthalic acid / 4-aminophenol copolymer (r) 4-hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / 4-aminophenol copolymer (s) 4-hydroxybenzoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl / 4-aminophenol copolymer (t) 4-hydroxybenzoic acid / terephthalic acid / ethylene glycol copolymer (u) 4-hydroxybenzoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl / ethylene glycol copolymer (v) 4-hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / ethylene glycol copolymer (w) 4-hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl / ethylene glycol copolymer (x) 4-hydroxybenzoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / 4,4'-dihydroxybiphenyl copolymer.

[0065] Among the above examples, (a), (g), and (x) are preferred, with (a) being more preferred. Specifically, it is more preferable that Ar1 is a 2,6-naphthylene group, Ar2 is a 2,6-naphthylene group and a 1,4-phenylene group, Ar3 is a 1,4-phenylene group, and X and Y are oxygen atoms, respectively.

[0066] Furthermore, the proportion of the total amount of repeating units containing 2,6-naphthylene groups in the liquid crystal polyester resin is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, and particularly preferably 70 mol% or more, relative to the total amount of all repeating units constituting the liquid crystal polyester resin. The total amount of all repeating units constituting the liquid crystal polyester resin is the sum of the amounts of substance (moles) of each repeating unit obtained by dividing the mass of each repeating unit constituting the liquid crystal polyester resin by the formula weight of each repeating unit.

[0067] When the proportion of repeating units containing 2,6-naphthylene groups is 40 mol% or more, orientation is more likely to occur when the object is fabricated with a 3D printer, which further improves the tensile strength of the fabricated object and makes the coefficient of thermal expansion of the fabricated object more likely to be negative.

[0068] The proportion of the total amount of repeating units (1) of the liquid crystal polyester resin is preferably 30 mol% or more, more preferably 30 mol% to 80 mol%, even more preferably 30 mol% to 70 mol%, and particularly preferably 35 mol% to 65 mol%, relative to the total amount of all repeating units constituting the liquid crystal polyester resin.

[0069] When the proportion of repeating units (1) in the liquid crystal polyester resin is 30 mol% or more, the heat resistance and hardness of the molded object tend to improve. Furthermore, when the proportion of repeating units (1) is 80 mol% or less, the melt viscosity can be reduced. Therefore, the temperature required for molding the liquid crystal polyester resin tends to be lower.

[0070] From the viewpoint of improving the heat resistance of the molded product, the ratio of the total amount of repeating units (2) of the liquid crystal polyester resin is preferably 35 mol% or less, more preferably 10 mol% to 35 mol%, even more preferably 15 mol% to 35 mol%, and particularly preferably 17.5 mol% to 32.5 mol% or less, relative to the total amount of all repeating units constituting the liquid crystal polyester resin.

[0071] From the viewpoint of improving the heat resistance of the molded product, the ratio of the total amount of repeating units (3) of the liquid crystal polyester resin is preferably 35 mol% or less, more preferably 10 mol% to 35 mol%, even more preferably 15 mol% to 35 mol%, and particularly preferably 17.5 mol% to 32.5 mol% or less, relative to the total amount of all repeating units constituting the liquid crystal polyester resin.

[0072] In liquid crystal polyester resin, the ratio of the total amount of repeating units (2) to the total amount of repeating units (3) ([total amount of repeating units (2)] / [total amount of repeating units (3)] (moles / moles)) is preferably 0.90 or more and 1.10 or less, more preferably 0.95 or more and 1.05 or less, and even more preferably 0.98 or more and 1.02 or less.

[0073] In liquid crystal polyester resin, the ratio of the total amount of repeating units (3) to the total amount of repeating units (1) ([total amount of repeating units (3)] / [total amount of repeating units (1)] (moles / moles)) is preferably 0.20 or more and 1.00 or less, more preferably 0.25 or more and 0.85 or less, and even more preferably 0.30 or more and 0.75 or less.

[0074] In the liquid crystal polyester resin, the molar ratio y / x of repeating units (2) is preferably greater than 0 and 1.0 or less, more preferably between 0.1 and 0.9, and even more preferably between 0.2 and 0.8. Here, x represents the molar content of repeating units in which Ar2 is a 1,4-phenylene group. Also, y represents the molar content of repeating units in which Ar2 is a 1,3-phenylene group.

[0075] The liquid crystal polyester resin may have only one type of repeating unit (1) to (3), independently of each other, or it may have two or more types. In addition, the liquid crystal polyester resin may have one or more types of repeating units other than repeating units (1) to (3), but the proportion of the total amount of repeating units other than repeating units (1) to (3) is preferably 10 mol% or less, more preferably 5 mol% or less, with respect to the total amount of all repeating units constituting the liquid crystal polyester resin.

[0076] Furthermore, the flow initiation temperature of the liquid crystal polyester resin is preferably 270°C or higher, more preferably 270°C to 400°C, and even more preferably 280°C to 380°C. Using a liquid crystal polyester resin with a flow initiation temperature within the above range can improve the heat resistance of the molded object. In addition, the thermal stability of the liquid crystal polymer filament is improved during 3D printing to obtain the molded object, and thermal degradation can be avoided.

[0077] The flow initiation temperature, also called the flow temperature or fluid temperature, is the temperature at which a liquid crystal polyester resin exhibits a viscosity of 4800 Pa·s (48000 poise) when melted under a load of 9.8 MPa and heated at a rate of 4°C / min using a capillary rheometer, and extruded from a nozzle with an inner diameter of 1 mm and a length of 10 mm. This temperature serves as an indicator of the molecular weight of the liquid crystal polyester resin (see, for example, Naoyuki Koide (ed.), "Liquid Crystal Polymers - Synthesis, Molding, and Applications," pp. 95-105, CMC, published June 5, 1987).

[0078] A liquid crystal polyester resin with a suitable flow initiation temperature can be easily obtained by appropriately optimizing the structural units that make up the liquid crystal polyester resin. In other words, improving the linearity of the molecular chains of the liquid crystal polyester resin tends to increase its flow initiation temperature.

[0079] For example, structural units derived from terephthalic acid improve the linearity of the molecular chains of liquid crystal polyester resin. On the other hand, structural units derived from isophthalic acid improve the flexibility (decreases linearity) of the molecular chains of liquid crystal polyester resin. Therefore, by controlling the copolymerization ratio of terephthalic acid and isophthalic acid, a liquid crystal polyester resin with a desired flow initiation temperature can be obtained.

[0080] Furthermore, it is preferable to optimize the copolymerization ratio of terephthalic acid and isophthalic acid in the liquid crystal polyester resin. This allows for control of the linearity of the molecular chains of the liquid crystal polyester resin, as described above. As a result, multiple types of liquid crystal polyester resins with different flow initiation temperatures can be produced.

[0081] Furthermore, at a temperature 20°C higher than the flow temperature (flow start temperature) of the liquid crystal polyester resin (flow temperature + 20°C), and at a shear rate of 1000 / s, the melt viscosity of the liquid crystal polyester resin is preferably 10 Pa·s or more and 200 Pa·s or less, and more preferably 70 Pa·s or more and 150 Pa·s or less. When the melt viscosity of the liquid crystal polyester resin is within the above range, even better molding becomes possible.

[0082] Furthermore, the lower limit of the melt tension of the liquid crystal polyester resin at a temperature 20°C higher than the flow temperature of the liquid crystal polyester resin is preferably 5 mN or more, more preferably 50 mN or more, and the upper limit of the melt tension is preferably 150 mN or less, more preferably 100 mN or less. When the melt tension of the liquid crystal polyester resin is 5 mN or more, filament sagging during molding can be suppressed, and when the melt tension is 150 mN or less, filament breakage during molding can be suppressed. Thus, when the melt tension is within the above range, even better molding can be achieved.

[0083] The liquid crystal polymer filament may contain only one type of liquid crystal polyester resin. Alternatively, the liquid crystal polymer filament may contain a mixture of multiple types of liquid crystal polyester resins, which further improves the melt-flow properties of the liquid crystal polymer filament and effectively suppresses warping of the resulting molded object.

[0084] Here, we assume a mixture of liquid crystal polyester resins with different flow initiation temperatures as the liquid crystal polymer filament. In the liquid crystal polymer filament, the one with the higher flow initiation temperature is designated as the first liquid crystal polyester resin, and the one with the lower flow initiation temperature is designated as the second liquid crystal polyester resin.

[0085] The flow initiation temperature of the first liquid crystal polyester resin is preferably 300°C or higher, more preferably 310°C or higher, and even more preferably 315°C or higher. Furthermore, the flow initiation temperature of the first liquid crystal polyester resin is preferably 400°C or lower, more preferably 360°C or lower, and even more preferably 345°C or lower. The upper and lower limits of the flow initiation temperature can be arbitrarily combined.

[0086] When the flow initiation temperature of the first liquid crystal polyester resin is within the above range, it tends to be possible to achieve both the melting fluidity of the resin and the heat resistance of the resulting molded object.

[0087] The flow initiation temperature of the second liquid crystal polyester resin is preferably 260°C or higher, more preferably 270°C or higher, and even more preferably 285°C or higher. Furthermore, the flow initiation temperature of the second liquid crystal polyester resin is preferably 350°C or lower, more preferably 320°C or lower, and even more preferably 315°C or lower. The upper and lower limits of the flow initiation temperature can be arbitrarily combined.

[0088] When the flow initiation temperature of the second liquid crystal polyester resin is within the above range, the fluidity in the thin-walled sections of the mold (thin-wall fluidity) tends to be good, and the load deflection temperature of the resulting molded object tends to be sufficiently high.

[0089] Furthermore, in the liquid crystal polymer filament, the content of the second liquid crystal polyester resin is preferably 10 parts by mass or more and 150 parts by mass or less, more preferably 30 parts by mass or more and 120 parts by mass or less, and even more preferably 50 parts by mass or more and 100 parts by mass or less, per 100 parts by mass of the first liquid crystal polyester resin.

[0090] The above-mentioned content of the second liquid crystal polyester resin relative to the first liquid crystal polyester resin should be set appropriately so that the balance between the load deflection temperature and thin-wall fluidity of the liquid crystal polymer filament is in a desired state.

[0091] Furthermore, the liquid crystal polymer filament may also contain liquid crystal polyester resins other than the first and second liquid crystal polyester resins. In this case, the resin with the highest flow initiation temperature in the liquid crystal polymer filament is designated as the first liquid crystal polyester resin, and the resin with the lowest flow initiation temperature is designated as the second liquid crystal polyester resin. In substance, a liquid crystal polymer filament mixture consisting of the first liquid crystal polyester resin and the second liquid crystal polyester resin is preferred.

[0092] In the liquid crystal polymer filament mixture, α / β is preferably 0.1 to 0.6, and more preferably 0.3 to 0.6. α represents the molar ratio y / x of the first liquid crystal polyester resin. β represents the molar ratio y / x of the second liquid crystal polyester resin. As described above, x represents the molar content of repeating units where Ar2 is a 1,4-phenylene group, and y represents the molar content of repeating units where Ar2 is a 1,3-phenylene group.

[0093] Furthermore, in a liquid crystal polymer filament mixture, if at least one liquid crystal polyester resin is a polymer obtained by polymerizing raw material monomers containing aromatic hydroxycarboxylic acid in the presence of an imidazole compound, the liquid crystal polymer filament mixture exhibits very high fluidity during melting and excellent thermal stability.

[0094] Furthermore, the liquid crystal polymer filament may also contain fillers and thermoplastic resins in addition to the liquid crystal polyester resin.

[0095] The filler material may be used alone or in combination of two or more types.

[0096] The filler may be a fibrous filler, a plate-shaped filler, or other granular fillers such as spherical ones other than fibrous or plate-shaped ones.

[0097] Preferred examples of fibrous fillers include glass fibers; carbon fibers such as pan-carbon fibers and pitch-carbon fibers; ceramic fibers such as silica fibers, alumina fibers, and silica-alumina fibers; and metal fibers such as stainless steel fibers. Whiskers such as potassium titanate whiskers, barium titanate whiskers, wollastonite whiskers, aluminum borate whiskers, silicon nitride whiskers, and silicon carbide whiskers are also preferred, with glass fibers being the most preferred among them.

[0098] Suitable examples of plate-shaped fillers include talc, mica, graphite, wollastonite, glass flakes, barium sulfate, and calcium carbonate. Among these, talc or mica are preferred.

[0099] Suitable examples of granular fillers include silica, alumina, titanium oxide, glass beads, glass balloons, boron nitride, silicon carbide, and calcium carbonate.

[0100] Furthermore, from the viewpoint of improving the mechanical strength of the molded object, it is preferable that the content of the filler in the liquid crystal polymer filament is 0.01 parts by mass or more per 100 parts by mass of liquid crystal polyester resin. Furthermore, from the viewpoint of maintaining high interlayer adhesion in the molded object, it is preferable that the content of the filler be 10.00 parts by mass or less, more preferably 5.00 parts by mass or less, and even more preferably 3.00 parts by mass or less.

[0101] Furthermore, from the viewpoint of improving interlayer adhesion in the molded product, it is preferable that the content of thermoplastic resin in the liquid crystal polymer filament is 0.01 parts by mass or more per 100 parts by mass of liquid crystal polyester resin. Furthermore, from the viewpoint of maintaining high interlayer adhesion in the molded product, it is preferable that the content of the thermoplastic resin be 200.00 parts by mass or less, and more preferably 50.00 parts by mass or less.

[0102] The thermoplastic resin contained in the liquid crystal polymer filament is preferably at least one selected from the group consisting of polyester resins, polyacetal resins, polycarbonate resins, aliphatic polyamide resins, semi-aromatic polyamide resins, polyphenylene sulfide resins, polyethersulfone resins, polyether aromatic ketone resins, polyetherimide resins, polyamideimide resins, and thermoplastic polyimide resins.

[0103] Furthermore, the liquid crystal polymer filament may also contain biomass-derived materials or recycled materials.

[0104] The method for manufacturing liquid crystal polymer filaments is not particularly limited, but examples include an extrusion step in which a liquid crystal polyester resin manufactured by the method described below is extruded as a molten strand from the die hole of an extruder and guided into a cooling water bath to obtain the strand, a stretching step in which the strand is stretched to obtain a filament, and a winding step in which the stretched filament is wound up.

[0105] Next, we will describe an example of a method for manufacturing liquid crystal polyester resin.

[0106] The liquid crystal polyester resin contained in the liquid crystal polymer filament is preferably produced by the following acylation and polymerization steps.

[0107] The acylation process is a process in which an acylated product is obtained by acyling the phenolic hydroxyl group of a raw material monomer with a fatty acid anhydride (for example, acetic anhydride).

[0108] In the polymerization process, a liquid crystal polyester resin is obtained by polymerizing the acyl group of the acylated product obtained in the acylation process with the carboxyl group of the acylated products of aromatic dicarboxylic acid and aromatic hydroxycarboxylic acid through transesterification.

[0109] The acylation and polymerization steps may be carried out in the presence of a heterocyclic organic base compound as represented by the following formula (5).

[0110]

[0111] In the above formula (5), R １ ~R ４ Each of these is independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxymethyl group, a cyano group, a cyanoalkyl group having 1 to 4 carbon atoms, a cyanoalkoxy group having 1 to 4 carbon atoms, a carboxyl group, an amino group, an aminoalkyl group having 1 to 4 carbon atoms, an aminoalkoxy group having 1 to 4 carbon atoms, a phenyl group, a benzyl group, a phenylpropyl group, or a formyl group.

[0112] The heterocyclic organic base compound in formula (5) above is R １ is an alkyl group having 1 to 4 carbon atoms, and R ２ ~R ４ Preferably, each of these atoms is an imidazole derivative with a hydrogen atom. This improves the reactivity of the acylation reaction in the acylation step and the transesterification reaction in the polymerization step. It also improves the color tone of the fabricated object obtained using the liquid crystal polymer filament.

[0113] Among heterocyclic organic base compounds, 1-methylimidazole and 1-ethylimidazole, or both, are particularly preferred due to their availability.

[0114] Furthermore, the amount of heterocyclic organic base compound used is preferably 0.005 parts by mass or more and 1.000 parts by mass or less, when the total amount of raw material monomers of the liquid crystal polyester resin is 100 parts by mass. Moreover, from the viewpoint of the color tone of the molded product and productivity, the amount of heterocyclic organic base compound used is more preferably 0.050 parts by mass or more and 0.500 parts by mass or less, per 100 parts by mass of raw material monomers.

[0115] The heterocyclic organic base compound only needs to be present at a specific point during the acylation and transesterification reactions. Its addition can occur immediately before the start of the acylation reaction, during the acylation reaction, or between the acylation and transesterification reactions. The resulting liquid crystal polyester resin exhibits very high melt fluidity and excellent thermal stability.

[0116] The amount of fatty acid anhydride used is determined considering the amount of aromatic diol and aromatic hydroxycarboxylic acid used as raw material monomers. Specifically, the amount of fatty acid anhydride used is preferably 1.00 equivalent to 1.20 equivalents, more preferably 1.00 equivalent to 1.15 equivalents, even more preferably 1.03 equivalent to 1.12 equivalents, and particularly preferably 1.05 equivalent to 1.10 equivalents, relative to the total amount of phenolic hydroxy groups contained in these raw material monomers.

[0117] When the amount of fatty acid anhydride used is 1.00 equivalent or more relative to the total amount of phenolic hydroxyl groups in the raw material monomers, the acylation reaction proceeds easily, and unreacted raw material monomers are less likely to remain in the subsequent polymerization step, resulting in efficient polymerization. Furthermore, when the acylation reaction proceeds sufficiently in this way, there is less possibility of unacylated raw material monomers sublimating and clogging the fractional distiller used during polymerization. On the other hand, when the amount of fatty acid anhydride used is 1.20 equivalent or less, the resulting liquid crystal polyester resin is less likely to be colored.

[0118] In the acylation step, the acylation reaction is preferably carried out at a temperature range of 130°C to 180°C for 30 minutes to 20 hours, and more preferably at a temperature range of 140°C to 160°C for 1 hour to 5 hours.

[0119] The aromatic dicarboxylic acid used in the polymerization step may be present in the reaction system during the acylation step. That is, the aromatic diol, aromatic hydroxycarboxylic acid, and aromatic dicarboxylic acid may be present in the same reaction system during the acylation step. This is because the carboxyl group and optionally substituted substituents on the aromatic dicarboxylic acid are not affected in any way by the fatty acid anhydride.

[0120] Therefore, the process can be carried out by sequentially performing the acylation step and polymerization step after charging the aromatic diol, aromatic hydroxycarboxylic acid, and aromatic dicarboxylic acid into the reactor, or by charging the aromatic diol and aromatic dicarboxylic acid into the reactor, performing the acylation step, and then charging the aromatic dicarboxylic acid into the reactor to perform the polymerization step. From the viewpoint of simplifying the manufacturing process, the former method is preferred.

[0121] The transesterification reaction in the polymerization step is preferably carried out while increasing the temperature from 130°C to 400°C at a heating rate of 0.1°C / min to 50.0°C / min, and more preferably while increasing the temperature from 150°C to 350°C at a heating rate of 0.3°C / min to 5.0°C / min.

[0122] Furthermore, when carrying out the transesterification reaction in the polymerization process, it is preferable to evaporate and distill off by-product fatty acids (e.g., acetic acid) and unreacted fatty acid anhydrides (e.g., acetic anhydride) to shift the equilibrium. At this time, by refluxing a portion of the distilled fatty acids back into the reactor, the raw material monomers that evaporated or sublimated along with the fatty acids can be condensed or back-sublimated and returned to the reactor.

[0123] In the acylation reaction of the acylation step and the transesterification reaction of the polymerization step, either a batch apparatus or a continuous apparatus may be used as the reaction apparatus. Regardless of the reaction apparatus used, a liquid crystal polyester resin suitable for use in liquid crystal polymer filaments can be obtained.

[0124] Furthermore, in the method for producing liquid crystal polyester resin, a step may be performed after the polymerization step to increase the molecular weight of the liquid crystal polyester resin obtained in the polymerization step.

[0125] For example, a liquid crystal polyester resin obtained in a polymerization process can be cooled and then pulverized to produce a powdered liquid crystal polyester resin, and this powder can then be heated to increase the molecular weight of the liquid crystal polyester resin. Alternatively, the powdered liquid crystal polyester resin obtained by cooling and pulverization can be granulated to produce a pelletized liquid crystal polyester resin, and this pelletized liquid crystal polyester resin can then be heated to increase its molecular weight. In this technical field, the process of increasing molecular weight using these methods is called solid-phase polymerization.

[0126] Solid-phase polymerization is particularly effective as a method for increasing the molecular weight of liquid crystal polyester resins. By increasing the molecular weight of liquid crystal polyester resins, it becomes easier to obtain liquid crystal polyester resins with a suitable flow initiation temperature.

[0127] The conditions for solid-phase polymerization typically involve heat-treating a solid resin under an inert gas atmosphere or reduced pressure for 1 to 20 hours. These polymerization conditions can be optimized after determining the flow initiation temperature of the resin obtained by melt polymerization. Examples of equipment used in solid-phase polymerization include known dryers, reactors, inert ovens, and electric furnaces.

[0128] Furthermore, from the viewpoint of further reducing the coefficient of thermal expansion of the fabricated object, it is preferable to control at least one of the following: the relative speed of the 3D printer head along the stage surface with respect to the 3D printer stage (hereinafter also simply referred to as the relative speed of the head), the nozzle diameter d of the 3D printer, and the nozzle temperature of the 3D printer; more preferably, at least two of the relative speed of the 3D printer head, the nozzle diameter d, and the nozzle temperature are controlled; and even more preferably, all of the relative speed of the 3D printer head, the nozzle diameter d, and the nozzle temperature are controlled to control the coefficient of thermal expansion of the fabricated object. The temperature of the molten liquid crystal polymer filament extruded onto the stage depends on the nozzle temperature.

[0129] From the viewpoint of further lowering the coefficient of thermal expansion of the molded object, the lower limit of the nozzle temperature is preferably 300°C or higher, more preferably 310°C or higher, and even more preferably 315°C or higher. The upper limit of the nozzle temperature is preferably 400°C or lower, more preferably 380°C or lower, and even more preferably 370°C or lower. The above upper and lower limits of the nozzle temperature can be arbitrarily combined.

[0130] Furthermore, from the viewpoint of further reducing the coefficient of thermal expansion of the fabricated object, it is preferable that the relative speed of the 3D printer head be 5 mm / s or higher.

[0131] Furthermore, from the viewpoint of further reducing the coefficient of thermal expansion of the fabricated object, it is preferable that the nozzle diameter d of the 3D printer be 1.0 mm or less.

[0132] Furthermore, from the viewpoint of further reducing the coefficient of thermal expansion of the fabricated object, it is preferable that the ratio (t / d) of the layer thickness t (mm) of the fabricated object to the nozzle diameter d (mm) of the 3D printer is less than 0.75.

[0133] Furthermore, from the viewpoint of further lowering the coefficient of thermal expansion of the fabricated object, the diameter of the liquid crystal polymer filament is preferably 1.00 mm or more and 5.00 mm or less, and more preferably 1.00 mm or more and 3.00 mm or less.

[0134] In the manufacturing method of the molded object according to this embodiment, since the above-mentioned liquid crystal polymer filament is used as the raw material for the 3D printer, the resulting molded object can have an improved coefficient of thermal expansion compared to conventional 3D printed objects. Furthermore, the coefficient of thermal expansion of the molded object is preferably smaller than the coefficient of thermal expansion of the liquid crystal polymer filament and preferably negative.

[0135] According to the embodiments described above, the coefficient of thermal expansion of an object fabricated using a liquid crystal polymer filament containing a liquid crystal polyester resin having a predetermined repeating unit can be improved compared to conventional 3D printed objects.

[0136] Although embodiments have been described above, the present invention is not limited to the embodiments described above, and includes all aspects included in the concepts and claims of this disclosure, and can be modified in various ways within the scope of this disclosure.

[0137] Examples and comparative examples will be described next, but this disclosure is not limited to these examples.

[0138] (Example 1) In a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer and reflux condenser, 6-hydroxy-2-naphthoic acid (1034.99 g, 5.5 mol), 2,6-naphthalenedicarboxylic acid (378.33 g, 1.75 mol), terephthalic acid (83.07 g, 0.5 mol), hydroquinone (272.52 g, 2.475 mol, 0.225 mol excess relative to the total amount of 2,6-naphthalenedicarboxylic acid and terephthalic acid), and acetic anhydride (1226.87 g, 12 mol) were charged, 0.17 g of 1-methylimidazole was added as a catalyst, and the reactor was thoroughly purged with nitrogen gas.

[0139] Subsequently, the mixture was heated from room temperature to 145°C over 15 minutes while being stirred with a nitrogen gas stream, and then refluxed at 145°C for 1 hour.

[0140] Next, while distilling off the by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 145°C to 310°C over 3.5 hours, and after being held at 310°C for 3 hours, the contents were removed and cooled to room temperature.

[0141] The obtained solid was pulverized to a particle size of 0.1 to 1 mm using a pulverizer, and then solid-phase polymerization was carried out under a nitrogen atmosphere by raising the temperature from room temperature to 250°C over 1 hour, raising the temperature from 250°C to 320°C over 10 hours, and holding at 320°C for 5 hours. After solid-phase polymerization, it was cooled to obtain a powdered liquid crystal polymer. The flow initiation temperature of the obtained liquid crystal polymer was 333°C. The obtained liquid crystal polymer was melt-kneaded at 350°C in an extruder, extruded from a die, and water-cooled to obtain a liquid crystal polymer filament with a diameter of Φ1.75 mm.

[0142] Using liquid crystal polymer filament, a JIS 7161-2 small test piece 1BA (thickness 0.4 mm) was fabricated using a fused deposition modeling (FDM) 3D printer with a bed temperature of 120°C, a nozzle hole diameter d of 0.4 mm, a nozzle temperature of 360°C, a layer thickness t of 0.10 mm, and a head relative speed along the stage surface to the stage of 400 mm / s.

[0143] (Example 2) Using the liquid crystal polymer filament obtained in Example 1, a JIS 7161-2 small test piece 1BA (thickness 0.4 mm) was fabricated using a fused deposition modeling (FDM) 3D printer with a bed temperature of 120°C, a nozzle hole diameter d of 0.4 mm, a nozzle temperature of 360°C, a layer pitch t of 0.02 mm, and a head relative speed along the stage surface to the stage of 400 mm / s.

[0144] (Example 3) Using the liquid crystal polymer filament obtained in Example 1, a JIS 7161-2 small test piece 1BA (thickness 0.4 mm) was fabricated using a fused deposition modeling (FDM) 3D printer with a bed temperature of 120°C, a nozzle hole diameter d of 0.8 mm, a nozzle temperature of 360°C, a layer pitch t of 0.01 mm, and a relative speed of the head along the stage surface to the stage of 400 mm / s.

[0145] (Example 4) Using the liquid crystal polymer filament obtained in Example 1, a JIS 7161-2 small test piece 1BA (thickness 0.4 mm) was fabricated using a fused deposition modeling (FDM) 3D printer with a bed temperature of 120°C, a nozzle hole diameter d of 0.4 mm, a nozzle temperature of 360°C, a layer pitch t of 0.10 mm, and a relative speed of the head along the stage surface relative to the stage of 50 mm / s.

[0146] (Comparative Example 1) Using the liquid crystal polymer filament obtained in Example 1, a JIS 7161-2 small test piece 1BA (thickness 0.4 mm) was fabricated using a fused deposition modeling (FDM) 3D printer with a bed temperature of 120°C, a nozzle hole diameter d of 0.4 mm, a nozzle temperature of 360°C, a layer pitch t of 0.30 mm, and a head relative speed along the stage surface to the stage of 5 mm / s.

[0147] (Comparative Example 2) Using the liquid crystal polymer filament obtained in Example 1, a JIS 7161-2 small test piece 1BA (thickness 0.4 mm) was fabricated using a fused deposition modeling (FDM) 3D printer with a bed temperature of 120°C, a nozzle hole diameter d of 0.4 mm, a nozzle temperature of 360°C, a layer pitch t of 0.30 mm, and a relative speed of the head along the stage surface relative to the stage of 10 mm / s.

[0148] (Comparative Example 3) Using the liquid crystal polymer filament obtained in Example 1, a JIS 7161-2 small test piece 1BA (thickness 0.4 mm) was fabricated using a fused deposition modeling (FDM) 3D printer with a bed temperature of 120°C, a nozzle hole diameter d of 0.4 mm, a nozzle temperature of 360°C, a layer pitch t of 0.30 mm, and a relative speed of the head along the stage surface to the stage of 25 mm / s.

[0149] [Measurement and Evaluation] The following measurements and evaluations were performed on the molded objects obtained in the above examples and comparative examples. The results are shown in Table 1.

[0150] [1] A 20 × 4.5 × 0.4 mm thick specimen was cut from the small specimen 1BA for measuring the coefficient of linear thermal expansion. The coefficient of linear thermal expansion in the Y-axis (forming direction) of the specimen at 50 to 150°C was measured in accordance with JIS 7197.

[0151]

[0152] As shown in Table 1, in the above embodiment, a liquid crystal polymer filament containing a liquid crystal polyester resin having a predetermined repeating unit was used, so the coefficient of linear expansion of the fabricated object made by the 3D printer was improved compared to the above comparative example.

Claims

1. It is manufactured using a 3D printer and has a coefficient of thermal expansion of 0.1 × 10 in the direction of at least one axis of the X, Y, and Z axes. －６ A molded object that is below / ℃.

2. The fabricated object according to claim 1, wherein the coefficient of thermal expansion in the direction of at least one axis of the X, Y, and Z axes is negative.

3. The molded object according to claim 1, wherein the molded object is made of a liquid crystal polymer.

4. The 3D printer is a fused deposition modeling (FDM) 3D printer, the manufactured object according to claim 1.

5. The molded object according to claim 1, wherein the relative speed of the 3D printer head along the surface of the stage with respect to the stage of the 3D printer is 5 mm / s or more.

6. The molded object according to claim 1, wherein the nozzle diameter d of the 3D printer is 1.0 mm or less.

7. The object according to claim 1, wherein the ratio (t / d) of the layer thickness t of the object to the nozzle diameter d of the 3D printer is less than 0.

75.

8. The coefficient of linear expansion in the X, Y, and Z axes of the fabricated object is -3.0 × 10⁻⁶. －６ The molded object according to claim 1, wherein the temperature is below / ℃.

9. A method for manufacturing a molded object according to any one of claims 1 to 8, wherein the molded object is manufactured using a liquid crystal polymer filament for a 3D printer, the filament containing a liquid crystal polyester resin having repeating units represented by the following formulas (1), (2), and (3). (In formulas (1) to (3) above, Ar1 is a phenylene group, a naphthylene group, or a biphenylylene group; Ar2 and Ar3 are each independently a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by formula (4) below; X and Y are each independently an oxygen atom or an imino group; one or more hydrogen atoms in Ar1, Ar2, and Ar3 may each be independently substituted with a halogen atom, an alkyl group, or an aryl group.) (In formula (4) above, Ar4 and Ar5 are each independently a phenylene group or a naphthylene group; Z is an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group.) 10. A method for manufacturing a molded object according to claim 9, wherein the coefficient of linear expansion of the molded object is controlled by controlling at least one of the following: the relative speed of the 3D printer head along the surface of the stage with respect to the stage of the 3D printer, the hole diameter d of the 3D printer nozzle, and the nozzle temperature of the 3D printer.

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