Liquid crystalline polyester, liquid crystalline polyester production method, pellets, and molded article

Abstract

Provided is a liquid crystalline polyester wherein a peak position (G) as calculated by formula (1) is 4.50-4.87, and a peak top of a molecular weight distribution curve is 5.05 or more as indicated by a log (M) value. [In formula (1), A1, A2, μ1, and μ2 indicate values obtained when the molecular weight distribution curve measured by GPC (vertical axis: the differential molecular weight distribution, horizontal axis: the logarithm of the molecular weight in terms of polystyrene with a base of 10) is fitted according to formula (2), where μ1 < μ2.] [In formula (2), M indicates the molecular weight, and log (M) indicates the logarithm of the molecular weight.]

Description

Liquid crystal polyester, manufacturing method of liquid crystal polyester, pellets and molded products

[0001] The present disclosure relates to a liquid crystal polyester, a method for producing a liquid crystal polyester, pellets, and molded articles.

[0002] Liquid crystal polyesters are used in a variety of applications due to their high fluidity, heat resistance and dimensional accuracy.

[0003] For example, Patent Document 1 describes a liquid crystal polymer composition containing 15% by mass or more of specific flat glass fibers and 20% by mass or more of a specific plate-like filler.

[0004] Japanese Patent Application Laid-Open No. 2003-268252

[0005] In recent years, there has been a demand for improving the properties of liquid crystalline polyesters themselves in order to expand their applications to more diverse uses and to apply them to more precise parts.

[0006] An object of the present disclosure is to provide a liquid crystalline polyester that can achieve both good fluidity in a melt and excellent mechanical properties of a molded article. Another object of the present disclosure is to provide a method for producing the liquid crystalline polyester, and pellets and molded articles containing the liquid crystalline polyester.

[0007] The present disclosure provides, for example, the following: [1] A liquid crystal polyester having a peak position (G) calculated by formula (1) of 4.50 or more and 4.87 or less, and a peak top of a molecular weight distribution curve having a log(M) value of 5.05 or more. [In formula (1), A １ , A ２ , μ １ and μ ２ The molecular weight distribution curve measured by GPC (vertical axis: differential molecular weight distribution, horizontal axis: logarithm of molecular weight in polystyrene equivalent with base 10) is calculated by the following formula (2): μ １ <μ ２ The values ​​shown are those obtained by fitting as follows.] [In formula (2), M represents a molecular weight, and log(M) represents a logarithm of the molecular weight.] [2] The liquid crystal polyester according to [1], wherein the peak top in the molecular weight distribution curve has a log(M) value of 5.05 or more and 5.30 or less. [3] A １ <A ２[4] The liquid crystal polyester according to any one of [1] to [3], having a weight average molecular weight (Mw) of 100,000 or more and 250,000 or less. [5] The liquid crystal polyester according to any one of [1] to [4], having a number average molecular weight (Mn) of 35,000 or more and 60,000 or less. [6] The liquid crystal polyester according to any one of [1] to [5], having a ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 3.20 or more and 3.96 or less. [7] The liquid crystal polyester according to any one of [1] to [6], containing a first monomer unit having a condensed aromatic ring and a second monomer unit having a benzene ring. [8] The liquid crystal polyester according to [7], wherein the condensed aromatic ring is a naphthalene ring. [9] The liquid crystal polyester according to any one of [1] to [8], comprising two or more liquid crystal polyesters.

[10] A liquid crystalline polyester according to any one of [1] to [9], comprising: a first liquid crystalline polyester having a first molecular weight distribution curve; and a second liquid crystalline polyester having a second molecular weight distribution curve, wherein the log(M) value of a peak top of the first molecular weight distribution curve is smaller than the log(M) value of a peak top of the second molecular weight distribution curve.

[11] A method for producing the liquid crystalline polyester according to any one of [1] to

[10] , comprising a step of mixing two or more liquid crystalline polyesters.

[12] The method according to

[11] , wherein the step is a step of mixing a first liquid crystalline polyester having a first molecular weight distribution curve and a second liquid crystalline polyester having a second molecular weight distribution curve, wherein the log(M) value of a peak top of the first molecular weight distribution curve is smaller than the log(M) value of a peak top of the second molecular weight distribution curve.

[13] Pellets comprising the liquid crystalline polyester according to any one of [1] to

[10] .

[14] A molded article comprising the liquid crystalline polyester according to any one of [1] to

[10] , the molded article being a connector, a socket, a relay part, a coil bobbin, an optical pickup, an oscillator, a semiconductor package, an IC tray, a wafer carrier, a household electrical appliance part, a lighting fixture part, an audio product part, a ferrule for an optical cable, a telephone part, a facsimile part, a modem part, a separation claw, a heater holder, an impeller, a fan gear, a gear, a bearing, a motor part, a motor case, an engine part, an engine room part, an electrical component, an automobile interior part, a microwave cooking pot, a heat-resistant tableware, a flooring material, a wall material, a beam, a pillar, a roofing material, an aircraft part, a spacecraft part, a space equipment part, a nuclear reactor, a marine facility member, a cleaning tool, an optical equipment part, a valve, a pipe, a nozzle, a filter, a membrane, a medical equipment part, a medical material, a sensor part, a sanitary fixture, a sporting goods, or a leisure goods.

[0008] According to the present disclosure, it is possible to provide a liquid crystalline polyester that can achieve both good flowability in a melt and excellent mechanical properties of a molded article. Furthermore, according to the present disclosure, it is possible to provide a method for producing the polyester, and pellets and molded articles containing the liquid crystalline polyester.

[0009] FIG. 2 is a diagram showing a molecular weight distribution curve in Example 1.

[0010] Preferred embodiments of the present disclosure will be described in detail below.

[0011] The liquid crystal polyester of this embodiment (hereinafter also simply referred to as "liquid crystal polyester") is a liquid crystal polyester having a peak position (G) calculated by formula (1) of 4.50 or more and 4.87 or less, and a log(M) value of the peak top of the molecular weight distribution curve of 5.05 or more. [In formula (1), A １ , A ２ , μ １ and μ ２ The molecular weight distribution curve measured by GPC (vertical axis: differential molecular weight distribution, horizontal axis: logarithm of molecular weight in polystyrene equivalent with base 10) is calculated by the following formula (2): μ １ <μ ２ The values ​​shown are those obtained by fitting as follows.] [In formula (2), M represents the molecular weight, and log(M) represents the logarithm of the molecular weight.]

[0012] The liquid crystal polyester of the present embodiment has good fluidity when melted, and the molded articles have excellent mechanical properties (tensile strength, nominal tensile strain at break). In addition, the liquid crystal polyester of the present embodiment has a high deflection temperature under load, and can be said to be a molding raw material that combines moldability, mechanical properties, and heat resistance.

[0013] The present inventors have devised a peak position (G), which is a variable represented by formula (1), and have found that when the value of the peak position (G) and the value of the peak top are within a specific range, a liquid crystalline polyester can be obtained that has good mechanical properties and heat resistance while also having good fluidity when melted. The inclusion of high molecular weight molecular chains in the liquid crystalline polyester is considered to be preferable from the viewpoint of improving the mechanical properties and heat resistance of the liquid crystalline polyester. The inclusion of low molecular weight molecular chains in the liquid crystalline polyester is considered to be preferable from the viewpoint of improving the fluidity of the liquid crystalline polyester. The liquid crystalline polyester of this embodiment has a peak position (G) value and a peak top value within a specific range, and contains a balanced amount of high molecular weight molecular chains and low molecular weight molecular chains, and is therefore considered to exhibit the above-mentioned effects.

[0014] The molecular weight distribution curve is a polystyrene-equivalent molecular weight distribution curve measured using GPC, and is measured under the following conditions. <Preparation of Measurement Solution> 3.4 g of pentafluorophenol (PFP) is added to 4.86 mg of a sample powdered by freeze-pulverization, and the mixture is dissolved at 120 to 125°C for 2 hours while stirring with a stirrer. After cooling to 40 to 50°C, 6.3 g of chloroform is added, and after stirring, the mixture is filtered through a filter with a pore size of 0.45 μm to obtain a measurement solution. <Measurement Conditions> GPC Apparatus: HLC-8420GPC (Tosoh Corporation) Column: TSKgel Super HM-H (φ6.0 mm x 150 mm) (2 columns) Eluent: PFP / chloroform (weight ratio 35 / 65) Flow Rate: 0.4 mL / min Detector: RI detector Column Temperature: 40°C Injection Volume: 20 μL Molecular Weight Standard: Standard Polystyrene

[0015] The above formula (2) is a formula for fitting the molecular weight distribution curve as the sum of two normal distributions. In the fitting, the parameter (A １ , A ２ , μ １ , μ ２ , σ １ and σ ２ ) is determined. The parameters are determined using the solver function of Microsoft (registered trademark) Excel (registered trademark) under the following conditions. The initial values ​​of the parameters are changed appropriately so that the sum of squares is minimized. <Software used> Microsoft (registered trademark) Excel (registered trademark) for Microsoft 365 MSO (version 2209) <Solver conditions> - Solution method: GPG nonlinear - Convergence: 0.0001 - Differential coefficient: central

[0016] The peak position (G) is preferably 4.50 or more, more preferably 4.60 or more, and is preferably 4.87 or less, more preferably 4.85 or less.

[0017] The log(M) value of the peak top of the molecular weight distribution curve is 5.05 or more, preferably 5.06 or more, more preferably 5.07 or more. The log(M) value of the peak top of the molecular weight distribution curve may be, for example, 5.30 or less, or 5.20 or less. The log(M) value may be, for example, 5.05 or more and 5.30 or less, 5.06 or more and 5.20 or less, or 5.07 or more and 5.20 or less.

[0018] The liquid crystal polyester may be any polyester that exhibits liquid crystallinity in a molten state. The liquid crystal polyester may be one type of polymer or a mixture of two or more types of polymers.

[0019] The liquid crystal polyester has constituent units (also referred to as monomer units) derived from raw material monomers. The liquid crystal polyester may have a main monomer unit (for example, 90 mol% or more, 95 mol% or more, or 99 mol% or more of the monomer units relative to the total of all monomer units, preferably all monomer units) derived from an aromatic compound. A liquid crystal polyester in which all monomer units are derived from an aromatic compound is also referred to as a wholly aromatic liquid crystal polyester.

[0020] The liquid crystal polyester has a first monomer unit having a condensed aromatic ring and a monomer unit having a benzene ring. The liquid crystal polyester may have one or more types of first monomer units. The liquid crystal polyester may also have one or more types of second monomer units. The second monomer unit may be a monomer unit having a benzene ring but not having a condensed aromatic ring.

[0021] The first monomer unit may be a monomer unit derived from an aromatic compound (1) having a fused aromatic ring, and the second monomer unit may be a monomer unit derived from an aromatic compound (2) having a benzene ring.

[0022] In this specification, "derived" means that in the monomer units of the liquid crystal polyester formed by polymerization of the raw material monomers, the chemical structure of the functional group that contributes to polymerization of the raw material monomers has changed, but other structural changes have not occurred. Here, "derived" is a concept that also includes cases where the monomer unit is derived from a polymerizable derivative of the raw material monomer (for example, a compound obtained by converting the functional group that contributes to polymerization of the raw material monomers into another polymerizable group).

[0023] Examples of the first monomer unit include a monomer unit derived from an aromatic hydroxycarboxylic acid (1-1) having a fused aromatic ring (hereinafter also referred to as a monomer unit (1-1)), a monomer unit derived from an aromatic dicarboxylic acid (1-2) having a fused aromatic ring (hereinafter also referred to as a monomer unit (1-2)), and a monomer unit derived from an aromatic diol (1-3) having a fused aromatic ring (hereinafter also referred to as a monomer unit (1-3)).

[0024] Examples of the second monomer unit include a monomer unit derived from an aromatic hydroxycarboxylic acid (2-1) (hereinafter also referred to as a monomer unit (2-1)), a monomer unit derived from an aromatic dicarboxylic acid (2-2) (hereinafter also referred to as a monomer unit (2-2)), and a monomer unit derived from an aromatic diol (2-3) (hereinafter also referred to as a monomer unit (2-3)).

[0025] Examples of the fused aromatic ring contained in the first monomer unit include a naphthalene ring, an anthracene ring, a phenanthrene ring, a tetracene ring, a pyrene ring, a triphenylene ring, a perylene ring, and a fluorene ring. Of these, a naphthalene ring is preferred from the viewpoints of availability and cost.

[0026] Examples of the monomer unit contained in the liquid crystal polyester include a monomer unit represented by the following formula (I) (hereinafter also referred to as monomer unit (I)), a monomer unit represented by the following formula (II) (hereinafter also referred to as monomer unit (II)), and a monomer unit represented by the following formula (III) (hereinafter also referred to as monomer unit (III)). １ -CO- (I) -CO-Ar ２ -CO- (II) -X-Ar ３ -Y- (III) [wherein, Ar １ , Ar ２ and Ar ３ each independently represents a phenylene group, a biphenylene group, a condensed polycyclic aromatic hydrocarbon group, or a group represented by formula (IV). １ , Ar ２ and Ar ３ Some or all of the hydrogen atoms in -Ar may be substituted with halogen atoms, alkyl groups, or aryl groups. X and Y each independently represent an oxygen atom or an imino group (—NH—). ４ -Z-Ar ５ - (IV) [wherein, Ar ４ and Ar ５ each independently represents a phenylene group or a condensed polycyclic aromatic hydrocarbon group; Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkanediyl group.

[0027] The phenylene group may be a 1,4-phenylene group or a 1,3-phenylene group, and is preferably a 1,4-phenylene group.

[0028] The biphenylene group may be a 4,4'-biphenylylene group.

[0029] The condensed polycyclic aromatic hydrocarbon group is a group in which two hydrogen atoms have been removed from a condensed polycyclic aromatic hydrocarbon. Examples of the condensed polycyclic aromatic hydrocarbon include naphthalene, anthracene, phenanthrene, tetracene, pyrene, triphenylene, perylene, and fluorene. Among these, naphthalene is preferred from the viewpoints of availability and cost.

[0030] The condensed polycyclic aromatic hydrocarbon group may be a naphthylene group. The naphthylene group may be a 2,6-naphthylene group or a 2,7-naphthylene group, and is preferably a 2,6-naphthylene group.

[0031] Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0032] The alkyl group as a substituent may be linear, branched, or cyclic. The alkyl group may be, for example, an alkyl group having 1 to 10 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-hexyl group, a 2-ethylhexyl group, an n-octyl group, and an n-decyl group.

[0033] The aryl group as a substituent may be a monocyclic ring or a fused ring. The aryl group may be, for example, an aryl group having 6 to 20 carbon atoms. Examples of the aryl group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, and a 2-naphthyl group. The aryl group may be a group in which a hydrogen atom of an aromatic ring is substituted with an alkyl group, such as a tolyl group.

[0034] Ar １ , Ar ２ and Ar ３ The number of substituents that the has may be, for example, 0 to 2, or may be 0 or 1, or may be 0.

[0035] X and Y are preferably oxygen atoms.

[0036] The alkanediyl group in Z may be linear or branched. The alkanediyl group may be an alkanediyl group having 1 to 10 carbon atoms. Examples of the alkanediyl group include a methylene group, an ethanediyl group, a propanediyl group (e.g., a propane-2,2-diyl group), a butanediyl group, and an octanediyl group (e.g., an octane-3,3-diyl group).

[0037] Z is preferably an oxygen atom, a sulfur atom, a methylene group, an ethanediyl group, or a propanediyl group, and more preferably an oxygen atom.

[0038] The first monomer unit is a monomer unit represented by formula (I) (Ar １ is a condensed polycyclic aromatic hydrocarbon group, or Ar ４ and Ar ５ and a monomer unit represented by formula (II) (Ar ２ is a condensed polycyclic aromatic hydrocarbon group, or Ar ４ and Ar ５ and a monomer unit represented by formula (III) (Ar ２ is a condensed polycyclic aromatic hydrocarbon group, or Ar ４ and Ar ５ and at least one of which is a condensed polycyclic aromatic hydrocarbon group, may be a group represented by formula (IV).

[0039] The first monomer unit may be a monomer unit derived from an aromatic compound (1) having a fused aromatic ring. Examples of the aromatic compound (1) include 2-hydroxy-6-naphthoic acid, 2,6-naphthalenedicarboxylic acid, 2,6-dihydroxynaphthalene, 2-hydroxy-3-naphthoic acid, 1-hydroxy-5-naphthoic acid, and 2,7-naphthalenediol.

[0040] The second monomer unit is a monomer unit represented by formula (I) (Ar １is a phenylene group, a biphenylene group, or Ar ４ and Ar ５ is a phenylene group), and the monomer unit represented by formula (II) (Ar ２ is a phenylene group, a biphenylene group, or Ar ４ and Ar ５ is a phenylene group), and the monomer unit represented by formula (III) (Ar ３ is a phenylene group, a biphenylene group, or Ar ４ and Ar ５ is a phenylene group).

[0041] The second monomer unit may be a monomer unit derived from an aromatic compound (2) that does not have a fused aromatic ring but has a benzene ring. Examples of the aromatic compound (2) include p-hydroxybenzoic acid, terephthalic acid, hydroquinone, isophthalic acid, and 4,4'-biphenol.

[0042] In the liquid crystal polyester, the content of the first monomer unit may be, for example, 20 mol% or more, 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, or 70 mol% or more, based on the total of all monomer units constituting the liquid crystal polyester. A high content of the first monomer unit tends to further improve dielectric properties. Furthermore, the content of the first monomer unit may be, for example, 90 mol% or less, 85 mol% or less, or even 80 mol% or less, based on the total of all monomer units constituting the liquid crystal polyester. This tends to improve moldability and processability at low temperatures. That is, the content of the first monomer unit, relative to the total of all monomer units constituting the liquid crystal polyester, may be, for example, 20 mol% to 90 mol%, 20 mol% to 85 mol%, 20 mol% to 80 mol%, 30 mol% to 90 mol%, 30 mol% to 85 mol%, 30 mol% to 80 mol%, 40 mol% to 40 mol%, 40 mol% to 85 mol%, 40 mol% to 80 mol%, 50 mol% to 90 mol%, 50 mol% to 85 mol%, 50 mol% to 80 mol%, 60 mol% to 90 mol%, 60 mol% to 85 mol%, 60 mol% to 80 mol%, 70 mol% to 90 mol%, 70 mol% to 85 mol%, or 70 mol% to 80 mol%.

[0043] In the liquid crystal polyester, the content of the second monomer unit may be, for example, 10 mol% or more, 15 mol% or more, or 20 mol% or more, relative to the total of all monomer units constituting the liquid crystal polyester. This tends to be cost-effective. Furthermore, the content of the second monomer unit may be, for example, 80 mol% or less, 70 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, or 30 mol% or less, relative to the total of all monomer units constituting the liquid crystal polyester. That is, the content of the second monomer unit may be, for example, 10 mol% or more and 80 mol% or less, 10 mol% or more and 70 mol% or less, 10 mol% or more and 60 mol% or less, 10 mol% or more and 50 mol% or less, 10 mol% or more and 40 mol% or less, 10 mol% or more and 30 mol% or less, 15 mol% or more and 80 mol% or less, 15 mol% or more and 70 mol% or less, 15 mol% or more and 60 mol% or less, 15 mol% or more and 50 mol% or less, 15 mol% or more and 40 mol% or less, 15 mol% or more and 30 mol% or less, 20 mol% or more and 80 mol% or less, 20 mol% or more and 70 mol% or less, 20 mol% or more and 60 mol% or less, 20 mol% or more and 50 mol% or less, 20 mol% or more and 40 mol% or less, or 20 mol% or more and 30 mol% or less.

[0044] In the liquid crystal polyester, the total amount of the first monomer unit and the second monomer unit may be, for example, 90 mol% or more, 95 mol% or more, 99 mol% or more, or 100 mol% relative to the total of all monomer units constituting the liquid crystal polyester.

[0045] The liquid crystal polyester may be a polymer having two or more types of monomer unit (I), or may be a polymer having monomer unit (I), monomer unit (II) and monomer unit (III).

[0046] When the liquid crystal polyester has the monomer unit (I), the monomer unit (II) and the monomer unit (III), the content of the monomer unit (I) may be, for example, 30 mol% or more, 40 mol% or more, 45 mol% or more, 50 mol% or more, or 55 mol% or more, based on the total of all the monomer units of the liquid crystal polyester. Also, when the liquid crystal polyester has the monomer unit (I), the monomer unit (II) and the monomer unit (III), the content of the monomer unit (I) may be, for example, 80% or less, or 70% or less, based on the total of all the monomer units of the liquid crystal polyester. That is, when the liquid crystal polyester has the monomer unit (I), the monomer unit (II), and the monomer unit (III), the content of the monomer unit (I) may be, for example, 30 mol% or more and 80 mol% or less, 30 mol% or more and 70 mol% or less, 40 mol% or more and 80 mol% or less, 40 mol% or more and 70 mol% or less, 45 mol% or more and 80 mol% or less, 45 mol% or more and 70 mol% or less, 50 mol% or more and 80 mol% or less, 50 mol% or more and 70 mol% or less, 55 mol% or more and 80 mol% or less, or 55 mol% or more and 70 mol% or less, based on the total of all the monomer units of the liquid crystal polyester.

[0047] When the liquid crystal polyester has the monomer unit (I), the monomer unit (II), and the monomer unit (III), the content of the monomer unit (II) and the content of the monomer unit (III) may be, for example, 35 mol% or less, or 30 mol% or less, based on the total of all the monomer units of the liquid crystal polyester. When the liquid crystal polyester has the monomer unit (I), the monomer unit (II), and the monomer unit (III), the content of the monomer unit (II) and the content of the monomer unit (III) may be, for example, 5 mol% or more, 10 mol% or more, or 15 mol% or more, based on the total of all the monomer units of the liquid crystal polyester. That is, when the liquid crystal polyester has the monomer unit (I), the monomer unit (II), and the monomer unit (III), the content of the monomer unit (II) and the content of the monomer unit (III) may be, for example, 5 mol% or more and 35 mol% or less, 5 mol% or more and 30 mol% or less, 10 mol% or more and 35 mol% or less, 10 mol% or more and 30 mol% or less, 15 mol% or more and 35 mol% or less, or 15 mol% or more and 30 mol% or less, relative to the total of all the monomer units of the liquid crystal polyester.

[0048] The liquid crystal polyester may have monomer units other than the monomer unit (I), the monomer unit (II) and the monomer unit (III), and the number of such monomer units may be 10 mol % or less, 5 mol % or less, 2 mol % or less, 1 mol % or less, or even 0 mol %, based on the total of all the monomer units of the liquid crystal polyester.

[0049] In this specification, the number of each monomer unit contained in the liquid crystal polyester is determined by the analytical method described in JP 2000-19168 A. Specifically, the liquid crystal polyester is depolymerized by reacting it with a lower alcohol in a supercritical state, and the depolymerization product (monomers that derive each monomer unit) is quantified by liquid chromatography, whereby the number of each monomer unit relative to the total monomer units can be calculated.

[0050] The liquid crystal polyester can be produced by polymerizing raw material monomers corresponding to the monomer units that constitute the polyester, for example, according to the method described in Japanese Patent No. 6439027.

[0051] The liquid crystal polyester may have a dielectric loss tangent at 10 GHz of, for example, 0.002 or less, preferably 0.0015 or less, more preferably 0.001 or less. The liquid crystal polyester may have a dielectric loss tangent at 10 GHz of, for example, 0.0001 or more and 0.002 or less, 0.0001 or more and 0.0015 or less, or 0.0001 or more and 0.001 or less.

[0052] The dielectric constant of the liquid crystal polyester at 10 GHz may be, for example, 4.0 or less, or may be 3.8 or less. The dielectric constant of the liquid crystal polyester at 10 GHz may be, for example, 2.8 or more, or may be 3.0 or more. The dielectric constant of the liquid crystal polyester at 10 GHz may be, for example, 2.8 or more and 4.0 or less, or may be 3.0 or more and 3.8 or less.

[0053] In this specification, the dielectric loss tangent and relative permittivity of the liquid crystal polyester at 10 GHz are measured by the following method. Using an injection molding machine (ROBOSHOT S-2000i 30B, manufactured by FANUC Corporation), a test piece having a width of 50 mm, a length of 50 mm, and a thickness of 0.5 mm is obtained using a liquid crystal polyester pellet as the molding material under conditions of a mold temperature of 130°C and an injection speed of 50 mm / s. The cylinder temperature is set to a temperature (e.g., 300 to 350°C) at which the liquid crystal polyester melts and can be poured into the mold. The relative permittivity and dielectric loss tangent of the obtained test piece at 10 GHz are measured using a vector network analyzer (N5290A, manufactured by Keysight Technologies, Inc.) and a split cylinder resonator (CR710, manufactured by EM Lab Co., Ltd.). The measurement environment is 23°C and 50% RH.

[0054] The flow initiation temperature of the liquid crystal polyester may be, for example, 250° C. or higher, or 270° C. or higher. The flow initiation temperature of the liquid crystal polyester may be, for example, 400° C. or lower, 360° C. or lower, or 340° C. or lower. That is, the flow initiation temperature of the liquid crystal polyester may be, for example, 250° C. or higher and 400° C. or lower, 250° C. or higher and 360° C. or lower, 250° C. or higher and 340° C. or lower, 270° C. or higher and 400° C. or lower, 270° C. or higher and 360° C. or lower, or 270° C. or higher and 340° C. or lower.

[0055] In this specification, the flow initiation temperature of the liquid crystal polyester is measured using a flow tester, and the liquid crystal polyester is subjected to a pressure of 9.8 MPa (100 kg / cm ２ The liquid crystalline polyester is melted while being heated at a rate of 4°C / min under a load of 1000 kJ / min, and the molten liquid crystalline polyester is extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm, and the temperature is the temperature at which the viscosity of the extruded liquid crystalline polyester is 4800 Pa·s (48,000 poise).

[0056] The number average molecular weight (Mn) of the liquid crystal polyester may be, for example, 35,000 or more, and from the viewpoint of more excellent mechanical properties and heat resistance, it may be 37,000 or more, 39,000 or more, or 40,000 or more. Furthermore, the number average molecular weight (Mn) of the liquid crystal polyester may be, for example, 60,000 or less, and from the viewpoint of more excellent fluidity and flexibility, it may be 58,000 or less, 56,000 or less, or 55,000 or less. The number average molecular weight (Mn) of the liquid crystal polyester may be, for example, 35,000 or more and 60,000 or less, 37,000 or more and 58,000 or less, 39,000 or more and 56,000 or less, or 40,000 or more and 55,000 or less.

[0057] The weight average molecular weight (Mw) of the liquid crystal polyester may be, for example, 100,000 or more, and from the viewpoint of more excellent mechanical properties and heat resistance, it may be 120,000 or more, 130,000 or more, or 140,000 or more. The weight average molecular weight (Mw) of the liquid crystal polyester may be, for example, 250,000 or less, and from the viewpoint of more excellent fluidity and flexibility, it may be 230,000 or less, 220,000 or less, or 210,000 or less. The weight average molecular weight (Mw) of the liquid crystal polyester may be, for example, 100,000 or more and 250,000 or less, 120,000 or more and 230,000 or less, 130,000 or more and 220,000 or less, or 140,000 or more and 210,000 or less.

[0058] The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the liquid crystal polyester may be, for example, 3.20 or more, and from the viewpoint of more excellent heat resistance, may be 3.25 or more, 3.30 or more, or 3.35 or more. The ratio (Mw / Mn) may be, for example, 3.96 or less, and from the viewpoint of more excellent fluidity, may be 3.95 or less, 3.94 or less, or 3.93 or less. The ratio (Mw / Mn) may be, for example, 3.20 or more and 3.96 or less, 3.25 or more and 3.95 or less, 3.30 or more and 3.94 or less, or 3.35 or more and 3.93 or less.

[0059] In this specification, the number average molecular weight (Mn), weight average molecular weight (Mw) and ratio (Mw / Mn) of the liquid crystal polyester are values ​​determined from the above-mentioned molecular weight distribution curve.

[0060] The liquid crystal polyester may be one type of liquid crystal polyester or a mixture of two or more types of liquid crystal polyesters, for example, a mixture of two or more types of liquid crystal polyesters having different molecular weights.

[0061] The liquid crystal polyester may include, for example, a first liquid crystal polyester having a first molecular weight distribution curve and a second liquid crystal polyester having a second molecular weight distribution curve. In this case, the log(M) value of the peak top of the first molecular weight distribution curve may be smaller than the log(M) value of the peak top of the second molecular weight distribution curve. Furthermore, the content of the first liquid crystal polyester may be smaller than the content of the second liquid crystal polyester.

[0062] The liquid crystal polyester has good fluidity when melted and has excellent mechanical properties when molded. Therefore, the liquid crystal polyester can be suitably used as a molding material for obtaining molded articles. The liquid crystal polyester may be used, for example, as pellets.

[0063] The liquid crystal polyester may be mixed with other components to form a liquid crystal polyester composition.

[0064] The liquid crystal polyester composition may contain, for example, one or more resins other than the liquid crystal polyester, such as polyolefin, cyclic polyolefin, polyvinyl chloride, polysulfone, (meth)acrylic resin, polyphenylene ether resin, polyacetal resin, polyamide resin, imide resin, cellulose resin, polyether ether ketone resin, fluororesin, polycarbonate resin, styrene-based resin, and thermosetting resin.

[0065] The liquid crystal polyester composition may further contain an inorganic filler, a colorant, a dispersant, a plasticizer, an antioxidant, a curing agent, a flame retardant, a heat stabilizer, an ultraviolet absorber, an antistatic agent, a surfactant, a lubricant, a release agent, or the like.

[0066] The liquid crystal polyester composition has excellent fluidity when melted, and therefore can be suitably used as a molding material. The liquid crystal polyester composition may be used, for example, in the form of pellets.

[0067] The molded article of this embodiment may be the molded article comprising the above-mentioned liquid crystal polyester, or may be the molded article comprising the above-mentioned liquid crystal polyester composition.The molded article of this embodiment may be connector, socket, relay parts, coil bobbin, optical pickup, oscillator, semiconductor package, IC tray, wafer carrier, household electrical appliance parts, lighting fixture parts, audio product parts, ferrule for optical cable, telephone parts, facsimile parts, modem parts, separation claw, heater holder, impeller, fan gear, gear, bearing, motor parts, motor case, engine parts, engine room parts, electrical equipment parts, automobile interior parts, microwave cooking pot, heat-resistant tableware, flooring, wall materials, beams, pillars, roofing materials, aircraft parts, spacecraft parts, space equipment parts, nuclear reactors, marine facility parts, cleaning tools, optical equipment parts, valves, pipes, nozzles, filters, membranes, medical equipment parts, medical materials, sensor parts, sanitary equipment, sporting goods or leisure goods.

[0068] The molded article of the present embodiment can be obtained, for example, by molding the liquid crystal polyester or liquid crystal polyester composition described above into a desired shape and subjecting it to processing treatment as necessary.

[0069] The molding method for the molded article is preferably melt molding, and examples of the melt molding method include injection molding, extrusion molding, compression molding, blow molding, vacuum molding, foam molding, and press molding.

[0070] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments.

[0071] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Hereinafter, percentages and parts representing the content or amount used are based on mass unless otherwise specified.

[0072] (Production Example 1) Production of Liquid Crystal Polyester (LCP1) 1035.0 g (5.5 mol) of 2-hydroxy-6-naphthoic acid, 378.3 g (1.75 mol) of 2,6-naphthalenedicarboxylic acid, 83.1 g (0.5 mol) of terephthalic acid, 255.2 g of hydroquinone, 1226.87 g (12 mol) of acetic anhydride, and 0.17 g of 1-methylimidazole as a catalyst were placed in a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser. After thoroughly purging the reactor with nitrogen gas, the temperature was raised to 140°C over 30 minutes under a nitrogen gas stream, and the temperature was maintained while refluxing for 1 hour. Thereafter, the temperature was raised to 310°C over 4 hours and 35 minutes while distilling off the by-product acetic acid. The point at which an increase in torque was observed marked the end of the reaction, and the contents were removed. The flow initiation temperature of the resulting solids was 270°C. The resulting solid was cooled to room temperature and crushed in a coarse crusher. The temperature was then raised from room temperature to 250°C over 1 hour in a nitrogen atmosphere, then from 250°C to 280°C over 5 hours, and maintained at 280°C for 6 hours to allow the polymerization reaction to proceed in a solid phase. The flow initiation temperature of the resulting liquid crystal polyester (LCP1) was 301°C.

[0073] <Measurement of Flow Initiation Temperature> Using a flow tester (Shimadzu Corporation, CFT-500 model), approximately 2 g of liquid crystal polyester pellets were filled into a cylinder equipped with a die having a nozzle with an inner diameter of 1 mm and a length of 10 mm, and the temperature was measured under a pressure of 9.8 MPa (100 kg / cm ２ The liquid crystalline polyester was melted and extruded from a nozzle while increasing the temperature at a rate of 4°C / min under a load of 1000 kJ / min, and the temperature (FT) at which the viscosity reached 4800 Pa s (48000 P) was measured, and this temperature was defined as the flow initiation temperature. "About 2 g" can be estimated as 2 g ± 0.1 g.

[0074] The crystalline polyester (LCP1) had a relative permittivity of 3.5 and a dielectric loss tangent of 0.0010 at 10 GHz. The cylinder temperature during preparation of the test specimens was 320°C.

[0075] (Production Example 2) Production of Liquid Crystal Polyester (LCP2) 1035.0 g (5.5 mol) of 2-hydroxy-6-naphthoic acid, 378.3 g (1.75 mol) of 2,6-naphthalenedicarboxylic acid, 83.1 g (0.5 mol) of terephthalic acid, 255.2 g of hydroquinone, 1226.87 g (12 mol) of acetic anhydride, and 0.17 g of 1-methylimidazole as a catalyst were placed in a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser. After thoroughly purging the reactor with nitrogen gas, the temperature was raised to 140°C over 30 minutes under a nitrogen gas stream, and the temperature was maintained while refluxing for 1 hour. The temperature was then raised to 310°C over 4 hours and 35 minutes while distilling off the by-product acetic acid. The reaction was considered complete when an increase in torque was observed, and the contents were removed. The flow initiation temperature of the resulting solids was 264°C. The resulting solid was cooled to room temperature and crushed in a coarse crusher. The temperature was then raised from room temperature to 250°C over 1 hour in a nitrogen atmosphere, then from 250°C to 292°C over 7 hours, and maintained at 292°C for 6 hours to allow the polymerization reaction to proceed in a solid phase. The flow onset temperature of the resulting liquid crystal polyester (LCP2) was 319°C.

[0076] The liquid crystal polyester (LCP2) had a relative dielectric constant of 3.6 and a dielectric loss tangent of 0.00091 at 10 GHz. The cylinder temperature during preparation of the test specimen was 320°C.

[0077] (Production Example 3) Production of Liquid Crystal Polyester (LCP3) A reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser was charged with 1035.0 g (5.5 mol) of 2-hydroxy-6-naphthoic acid, 378.3 g (1.75 mol) of 2,6-naphthalenedicarboxylic acid, 83.1 g (0.5 mol) of terephthalic acid, 255.2 g of hydroquinone, 1226.87 g (12 mol) of acetic anhydride, and 0.17 g of 1-methylimidazole as a catalyst. After thoroughly purging the reactor with nitrogen gas, the temperature was raised to 140°C over 30 minutes under a nitrogen gas stream, and the temperature was maintained while refluxing for 1 hour. The temperature was then raised to 310°C over 4 hours and 35 minutes while distilling off the by-product acetic acid. The reaction was considered complete when an increase in torque was observed, and the contents were removed. The flow initiation temperature of the resulting solids was 270°C. The resulting solid was cooled to room temperature and crushed in a coarse crusher. The temperature was then raised from room temperature to 250°C over 1 hour in a nitrogen atmosphere, then from 250°C to 306°C over 9 hours and 20 minutes, and the temperature was maintained at 306°C for 6 hours, allowing the polymerization reaction to proceed in a solid phase. The flow initiation temperature of the resulting liquid crystal polyester (LCP3) was 330°C.

[0078] The liquid crystal polyester (LCP3) had a relative dielectric constant of 3.6 and a dielectric loss tangent of 0.00061 at 10 GHz. The cylinder temperature during preparation of the test specimen was 340°C.

[0079] (Production Example 4) Production of Liquid Crystal Polyester (LCP4) 1511.1 g (8.03 mol) of 2-hydroxy-6-naphthoic acid, 410.2 g (2.97 mol) of p-hydroxybenzoic acid, 1291.4 g (12.65 mol) of acetic anhydride, and 0.058 g of 1-methylimidazole as a catalyst were placed in a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser. After thoroughly purging the reactor with nitrogen gas, the temperature was raised to 140°C over 30 minutes under a nitrogen gas stream, and the temperature was maintained while refluxing for 1 hour. Thereafter, the temperature was raised to 275°C over 4 hours while distilling off the by-product acetic acid. The reaction was considered complete when an increase in torque was observed, and the contents were removed. The flow initiation temperature of the resulting solids was 217°C. The resulting solid was cooled to room temperature and crushed in a coarse crusher. The temperature was then raised from room temperature to 200°C over 1 hour in a nitrogen atmosphere, then from 200°C to 242°C over 7 hours, and maintained at 242°C for 10 hours to allow the polymerization reaction to proceed in a solid phase. The flow initiation temperature of the resulting liquid crystal polyester (LCP4) was 292°C.

[0080] The liquid crystal polyester (LCP4) had a relative dielectric constant of 3.5 and a dielectric loss tangent of 0.0011 at 10 GHz. The cylinder temperature during preparation of the test specimen was 310°C.

[0081] (Production Example 5) Production of Liquid Crystal Polyester (LCP5) 1511.1 g (8.03 mol) of 2-hydroxy-6-naphthoic acid, 410.2 g (2.97 mol) of p-hydroxybenzoic acid, 1291.4 g (12.65 mol) of acetic anhydride, and 0.058 g of 1-methylimidazole as a catalyst were placed in a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser. After thoroughly purging the reactor with nitrogen gas, the temperature was raised to 140°C over 30 minutes under a nitrogen gas stream, and the temperature was maintained while refluxing for 1 hour. Thereafter, the temperature was raised to 275°C over 4 hours while distilling off the by-product acetic acid. The point at which an increase in torque was observed marked the end of the reaction, and the contents were removed. The flow initiation temperature of the resulting solid content was 217°C. The resulting solid was cooled to room temperature and crushed in a coarse crusher. The temperature was then raised from room temperature to 200°C over 1 hour in a nitrogen atmosphere, then from 200°C to 247°C over 7 hours and 50 minutes, and the temperature was maintained at 247°C for 10 hours, allowing the polymerization reaction to proceed in a solid phase. The flow initiation temperature of the resulting liquid crystal polyester (LCP5) was 298°C.

[0082] The liquid crystal polyester (LCP5) had a relative dielectric constant of 3.5 and a dielectric loss tangent of 0.0011 at 10 GHz. The cylinder temperature during preparation of the test specimen was 330°C.

[0083] (Production Example 6) Production of Liquid Crystal Polyester (LCP6) 1511.1 g (8.03 mol) of 2-hydroxy-6-naphthoic acid, 410.2 g (2.97 mol) of p-hydroxybenzoic acid, 1291.4 g (12.65 mol) of acetic anhydride, and 0.058 g of 1-methylimidazole as a catalyst were placed in a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser. After thoroughly purging the reactor with nitrogen gas, the temperature was raised to 140°C over 30 minutes under a nitrogen gas stream, and the temperature was maintained while refluxing for 1 hour. Thereafter, the temperature was raised to 275°C over 4 hours while distilling off the by-product acetic acid. The point at which an increase in torque was observed marked the end of the reaction, and the contents were removed. The flow initiation temperature of the resulting solid content was 217°C. The resulting solid was cooled to room temperature and crushed in a coarse crusher. The temperature was then raised from room temperature to 200°C over 1 hour in a nitrogen atmosphere, then from 200°C to 259°C over 9 hours and 50 minutes, and the temperature was maintained at 259°C for 10 hours, allowing the polymerization reaction to proceed in a solid phase. The flow initiation temperature of the resulting liquid crystal polyester (LCP6) was 312°C.

[0084] The liquid crystal polyester (LCP6) had a relative dielectric constant of 3.6 and a dielectric loss tangent of 0.0010 at 10 GHz. The cylinder temperature during preparation of the test specimen was 345°C.

[0085] (Example 1) (1) Production of Liquid Crystal Polyester and Pellets Liquid crystal polyester (LCP1) and liquid crystal polyester (LCP5) were mixed in a mass ratio of 60:40 to obtain the liquid crystal polyester of Example 1. Next, the liquid crystal polyester was granulated at a cylinder temperature of 320°C using a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd., PCM-30) to obtain pellets of the liquid crystal polyester.

[0086] (2) Evaluation of Liquid Crystalline Polyester and Molded Article The number average molecular weight (Mn) of the obtained liquid crystal polyester was 43,500, the weight average molecular weight (Mw) was 147,000, and the ratio (Mw / Mn) was 3.38. The molecular weight distribution curve of the liquid crystal polyester was as shown in Table 1, and the peak top position was log(M) = 5.07. When the molecular weight distribution curve of the liquid crystal polyester was fitted with the above formula (2), A １ is 32.3, μ１ is 4.61, σ １ ２ is 0.247, A ２ is 63.4, μ ２ is 5.13, σ ２ ２ was 0.133 and the peak position (G) was 4.78.

[0087] The melt viscosity, tensile strength, nominal tensile strain at break, relative dielectric constant, dielectric loss tangent, and deflection temperature under load were determined by the following methods. The results are shown in Table 1.

[0088] <Evaluation of fluidity in melt> Using a capillary rheometer (Capillograph 1D, manufactured by Toyo Seiki Seisaku-sho, Ltd.), a capillary with an inner diameter of 0.5 mm and a length of 10 mm was attached to the tip of a cylinder, and pellets of the liquid crystalline polyester were melted in the cylinder heated to 340° C. and extruded from a nozzle. The viscosity of the extruded liquid crystalline polyester at a shear rate of 1000 / sec was measured, and this viscosity was evaluated as the melt viscosity of the liquid crystalline polyester.

[0089] <Measurement of Tensile Strength and Nominal Tensile Break Strain> Using an injection molding machine (Nissei Plastic Industrial Co., Ltd., PNX-40-5A), liquid crystal polyester pellets were injection molded into ASTM D638 dumbbell-shaped test pieces Type IV (thickness 2.5 mm) under conditions of a cylinder temperature of 330 ° C, a mold temperature of 130 ° C, and an injection speed of 75 mm / s. Five samples of the resulting dumbbell test pieces were subjected to a tensile test using a tensile tester (A & D Co., Ltd., Tensilon RTG-1310) at a chuck distance of 50 mm, a crosshead speed of 10 mm / min, and a test temperature of 25 ° C. The elongation at that time was measured, and the tensile strength (MPa) at break and the nominal tensile break strain (%) were averaged for the five samples. The nominal tensile break strain was calculated using the following formula. Nominal tensile fracture strain (%) = (L - Lo) / Lo x 100, where Lo is the distance between the chucks before the test (mm), and L is the distance between the chucks at fracture (mm).

[0090] <Evaluation of Dielectric Properties> Using an injection molding machine (ROBOSHOT S-2000i 30B, manufactured by FANUC Corporation), test pieces with a width of 50 mm, a length of 50 mm, and a thickness of 0.5 mm were obtained using liquid crystal polyester pellets as the molding material under conditions of a cylinder temperature of 325°C, a mold temperature of 130°C, and an injection speed of 50 mm / s. The relative permittivity and dielectric loss tangent at 10 GHz of the obtained test pieces were measured using a vector network analyzer (N5290A, manufactured by Keysight Technologies Inc.) and a split cylinder resonator (CR710, manufactured by EM Lab Co., Ltd.). Measurement environment: 23°C, 50% RH

[0091] <Evaluation of Deflection Temperature Under Load> Using an injection molding machine (PNX-40-5A, manufactured by Nissei Plastic Industrial Co., Ltd.), a rod-shaped molded body was produced in accordance with ASTM D648 using liquid crystal polyester pellets as the molding material under conditions of a cylinder temperature of 330°C, a mold temperature of 130°C, and an injection speed of 75 mm / s. The deflection temperature under load (DTUL (°C)) of the obtained rod-shaped molded body was measured in accordance with ASTM D648 at a load of 1.82 MPa and a heating rate of 2°C / min.

[0092] (Example 2) Liquid crystalline polyester (LCP1), liquid crystalline polyester (LCP3), and liquid crystalline polyester (LCP5) were mixed in a mass ratio of 50:10:40 to obtain a liquid crystalline polyester of Example 2. Using the obtained liquid crystalline polyester, pellets were prepared in the same manner as in Example 1, and the liquid crystalline polyester and molded articles were evaluated. The results are shown in Table 1.

[0093] In Example 2, the cylinder temperature during granulation was 320°C, the cylinder temperature in <Measurement of tensile strength and nominal tensile strain at break> was 330°C, the cylinder temperature in <Evaluation of dielectric properties> was 325°C, and the cylinder temperature in <Evaluation of deflection temperature under load> was 330°C.

[0094] (Example 3) Liquid crystalline polyester (LCP1) and liquid crystalline polyester (LCP6) were mixed in a mass ratio of 60:40 to obtain a liquid crystalline polyester of Example 3. Using the obtained liquid crystalline polyester, pellets were prepared in the same manner as in Example 1, and the liquid crystalline polyester and molded articles were evaluated. The results are shown in Table 1.

[0095] In Example 3, the cylinder temperature during granulation was 325°C, the cylinder temperature in <Measurement of tensile strength and nominal tensile strain at break> was 330°C, the cylinder temperature in <Evaluation of dielectric properties> was 325°C, and the cylinder temperature in <Evaluation of deflection temperature under load> was 330°C.

[0096] (Example 4) Liquid crystalline polyester (LCP1) and liquid crystalline polyester (LCP6) were mixed in a mass ratio of 80:20 to obtain a liquid crystalline polyester of Example 4. Using the obtained liquid crystalline polyester, pellets were prepared in the same manner as in Example 1, and the liquid crystalline polyester and molded articles were evaluated. The results are shown in Table 1.

[0097] In Example 4, the cylinder temperature during granulation was 325°C, the cylinder temperature in <Measurement of tensile strength and nominal tensile strain at break> was 330°C, the cylinder temperature in <Evaluation of dielectric properties> was 325°C, and the cylinder temperature in <Evaluation of deflection temperature under load> was 330°C.

[0098] (Comparative Example 1) Liquid crystalline polyester (LCP2) and liquid crystalline polyester (LCP4) were mixed in a mass ratio of 60:40 to obtain a liquid crystalline polyester of Comparative Example 1. Using the obtained liquid crystalline polyester, pellets were prepared in the same manner as in Example 1, and the liquid crystalline polyester and molded articles were evaluated. The results are shown in Table 2.

[0099] In Comparative Example 1, the cylinder temperature during granulation was 320°C, the cylinder temperature in <Measurement of tensile strength and nominal tensile strain at break> was 340°C, the cylinder temperature in <Evaluation of dielectric properties> was 330°C, and the cylinder temperature in <Evaluation of deflection temperature under load> was 340°C.

[0100] (Comparative Example 2) Liquid crystal polyester (LCP1) and liquid crystal polyester (LCP5) were mixed in a mass ratio of 80:20 to obtain a liquid crystal polyester of Comparative Example 2. Using the obtained liquid crystal polyester, pellets were prepared in the same manner as in Example 1, and the liquid crystal polyester and molded articles were evaluated. The results are shown in Table 2.

[0101] In Comparative Example 2, the cylinder temperature during granulation was 320°C, the cylinder temperature in <Measurement of tensile strength and nominal tensile strain at break> was 320°C, the cylinder temperature in <Evaluation of dielectric properties> was 330°C, and the cylinder temperature in <Evaluation of deflection temperature under load> was 320°C.

[0102] Comparative Example 3 Using only the liquid crystal polyester (LCP1), pellets were prepared, and the liquid crystal polyester and molded articles were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0103] In Comparative Example 3, the cylinder temperature during granulation was 320°C, the cylinder temperature in <Measurement of tensile strength and nominal tensile strain at break> was 330°C, the cylinder temperature in <Evaluation of dielectric properties> was 320°C, and the cylinder temperature in <Evaluation of deflection temperature under load> was 330°C.

[0104] (Comparative Example 4) Liquid crystalline polyester (LCP3) and liquid crystalline polyester (LCP5) were mixed in a mass ratio of 60:40 to obtain a liquid crystalline polyester of Comparative Example 4. Using the obtained liquid crystalline polyester, pellets were prepared in the same manner as in Example 1, and the liquid crystalline polyester and molded articles were evaluated. The results are shown in Table 2.

[0105] In Comparative Example 4, the cylinder temperature during granulation was 340°C, the cylinder temperature in <Measurement of tensile strength and nominal tensile strain at break> was 330°C, the cylinder temperature in <Evaluation of dielectric properties> was 330°C, and the cylinder temperature in <Evaluation of deflection temperature under load> was 330°C.

[0106]

[0107]

[0108] Fig. 1 is a diagram showing the molecular weight distribution curve of Example 1. In Fig. 1, 10 indicates the molecular weight distribution curve, and 1, 2, and 3 indicate the first normal distribution, the second normal distribution, and the sum of these. In the fitting described above, the molecular weight distribution curve 10 is fitted as the sum of the first normal distribution 1 and the second normal distribution 2.

Claims

1. A liquid crystal polyester having a peak position (G) calculated by formula (1) of 4.50 or more and 4.87 or less, and a peak top of a molecular weight distribution curve having a log(M) value of 5.05 or more. [In formula (1), A １ , A ２ , μ １ and μ ２ The molecular weight distribution curve measured by GPC (vertical axis: differential molecular weight distribution, horizontal axis: logarithm of molecular weight in polystyrene equivalent with base 10) is calculated by the following formula (2): １ <μ ２ The values ​​shown are those obtained by fitting as follows.] [In formula (2), M represents the molecular weight, and log(M) represents the logarithm of the molecular weight.] 2. The liquid crystal polyester according to claim 1, wherein the peak top in the molecular weight distribution curve has a log(M) value of 5.05 or more and 5.30 or less.

3. A １ <A ２ The liquid crystal polyester according to claim 1 , 4. The liquid crystal polyester according to claim 1, having a weight average molecular weight (Mw) of 100,000 or more and 250,000 or less.

5. The liquid crystal polyester according to claim 1, having a number average molecular weight (Mn) of 35,000 or more and 60,000 or less.

6. The liquid crystal polyester according to claim 1, wherein the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3.20 or more and 3.96 or less.

7. The liquid crystal polyester according to claim 1, which contains a first monomer unit having a condensed aromatic ring and a second monomer unit having a benzene ring.

8. The liquid crystal polyester according to claim 7, wherein the condensed aromatic ring is a naphthalene ring.

9. The liquid crystalline polyester according to claim 1, comprising two or more liquid crystalline polyesters.

10. The liquid crystal polyester according to claim 1, comprising: a first liquid crystal polyester having a first molecular weight distribution curve; and a second liquid crystal polyester having a second molecular weight distribution curve, wherein the log(M) value of a peak top of the first molecular weight distribution curve is smaller than the log(M) value of a peak top of the second molecular weight distribution curve.

11. A method for producing the liquid crystal polyester according to any one of claims 1 to 10, comprising the step of mixing two or more liquid crystal polyesters.

12. The method according to claim 11, wherein the step is a step of mixing a first liquid crystalline polyester having a first molecular weight distribution curve with a second liquid crystalline polyester having a second molecular weight distribution curve, and the log(M) value of a peak top of the first molecular weight distribution curve is smaller than the log(M) value of a peak top of the second molecular weight distribution curve.

13. A pellet comprising the liquid crystal polyester according to any one of claims 1 to 10.

14. A molded article comprising the liquid crystalline polyester according to any one of claims 1 to 10, the molded article being any one of connectors, sockets, relay parts, coil bobbins, optical pickups, oscillators, semiconductor packages, IC trays, wafer carriers, household electrical appliance parts, lighting fixture parts, audio product parts, ferrules for optical cables, telephone parts, facsimile parts, modem parts, separation claws, heater holders, impellers, fan gears, gears, bearings, motor parts, motor cases, engine parts, engine room parts, electrical parts, automobile interior parts, microwave cooking pots, heat-resistant tableware, flooring materials, wall materials, beams, columns, roofing materials, aircraft parts, spacecraft parts, space equipment parts, nuclear reactors, marine facility members, cleaning tools, optical equipment parts, valves, pipes, nozzles, filters, membranes, medical equipment parts, medical materials, sensor parts, sanitary equipment, sporting goods, and leisure goods.

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