Liquid crystal polyester composition and molded body

Abstract

This liquid crystal polyester composition comprises a liquid crystal polyester and a release agent including pentaerythritol tetrastearate, wherein the release agent satisfies (a) and (b). (a): The 1% weight loss temperature in a nitrogen atmosphere is 270°C-360°C. (b): The amount of high-boiling components generated during heating at 120°C for 20 hours is 15 ppm or less.

Description

Liquid crystal polyester composition and molded article

[0001] This disclosure relates to a liquid crystal polyester composition and a molded article. This application claims priority to Japanese Patent Application No. 2024-112602, filed on July 12, 2024, the contents of which are incorporated herein by reference.

[0002] Liquid crystal polyesters have high heat resistance, strength, and excellent melt fluidity, and are therefore used as molding materials for producing various products and parts, such as electrical and electronic components. Taking advantage of their particularly excellent melt fluidity, liquid crystal polyesters are ideally used as molding materials for producing molded articles with thin walls or complex shapes. However, when producing such molded articles, ease of removal of the molded article from the mold, i.e., mold releasability from the mold, is important. In this regard, molding materials containing liquid crystal polyesters blended with mold release agents have been investigated. Patent Document 1 discloses a liquid crystal polyester composition containing a liquid crystal polyester blended with a fatty acid ester having a specific acid value and hydroxyl value as a mold release agent.

[0003] JP 2009-114224 A

[0004] In recent years, as electrical and electronic components have become more powerful or more compact or lightweight, their operating environments have become more severe, and molding materials are increasingly required to have higher heat resistance and strength. However, conventional liquid crystal polyester compositions and molded articles thereof have poor heat resistance, and suffer from gas generation during kneading of the composition or during production of a molded article, or color changes in the molded article before and after high-temperature heating, making them insufficient in terms of required performance. The present disclosure has been made in view of the above circumstances, and aims to provide a liquid crystal polyester composition that has good mold releasability, suppresses gas generation during molding, and can produce a molded article that is less susceptible to color changes due to high-temperature heating, and a molded article containing the same.

[0005] In order to solve the above problems, the present disclosure includes the following aspects.

[0006] [1] A liquid crystal polyester composition containing a liquid crystal polyester and a release agent containing pentaerythritol tetrastearate, wherein the release agent satisfies the following (a) and (b): (a) a 1% weight loss temperature in a nitrogen atmosphere of 270°C or higher and 360°C or lower, and (b) the amount of high boiling components generated during heating at 120°C for 20 hours is 15 ppm or lower.

[0007] [2] The liquid crystal polyester composition according to [1], wherein the release agent further satisfies the following (c): (c) the color tone SCI L* after heating at 350°C for 15 minutes in an air atmosphere is 40 or more.

[0008] [3] The liquid crystal polyester composition according to [1] or [2], wherein the release agent satisfies the following (a') and (b): (a') the 1% weight loss temperature in a nitrogen atmosphere is 280°C or higher and 350°C or lower, and (b) the amount of high boiling components generated during heating at 120°C for 20 hours is 15 ppm or lower.

[0009] [4] The liquid crystal polyester composition according to [1] or [2], wherein the release agent satisfies the following (a) and (b'): (a) the 1% weight loss temperature in a nitrogen atmosphere is 270°C or higher and 360°C or lower, and (b') the amount of high boiling components generated during heating at 120°C for 20 hours is 13 ppm or lower.

[0010] [5] The liquid crystal polyester composition according to [1] or [2], wherein the release agent satisfies the following (a') and (b'): (a') the 1% weight loss temperature in a nitrogen atmosphere is 280°C or higher and 350°C or lower, and (b') the amount of high boiling components generated during heating at 120°C for 20 hours is 13 ppm or lower.

[0011] [6] The liquid crystal polyester composition according to any one of [2] to [5], wherein the release agent further satisfies the following (c'): (c') the color tone SCI L* after heating at 350°C for 15 minutes in an air atmosphere is 45 or more.

[0012] [7] The liquid crystal polyester composition according to any one of [1] to [6], wherein the content of the release agent is 0.01 parts by mass or more relative to 100 parts by mass of the liquid crystal polyester. [8] The liquid crystal polyester composition according to [7], wherein the content of the release agent is 0.01 parts by mass or more and 1 part by mass or less relative to 100 parts by mass of the liquid crystal polyester.

[0013] [9] The liquid crystal polyester composition according to any one of [1] to [8], further comprising a fibrous filler.

[10] The liquid crystal polyester composition according to [9], wherein the content of the fibrous filler is 5 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of the liquid crystal polyester.

[0014]

[11] A molded article comprising the liquid crystal polyester composition according to any one of [1] to

[10] .

[12] The molded article according to

[11] , wherein the amount of high boiling components generated during heating at 120°C for 20 hours is 0.1 ppm or less.

[0015] According to the present disclosure, it is possible to provide a liquid crystal polyester composition that has good releasability from a mold, suppresses gas generation during molding, and can produce a molded article that is less likely to undergo color change due to high-temperature heating, and a molded article containing the same.

[0016] (Liquid Crystal Polyester Composition) One embodiment of the liquid crystal polyester composition is a liquid crystal polyester composition containing a liquid crystal polyester and a release agent containing pentaerythritol tetrastearate, wherein the release agent satisfies the following (a) and (b): (a) the 1% weight loss temperature in a nitrogen atmosphere is 270°C or higher and 360°C or lower, and (b) the amount of high boiling components generated during heating at 120°C for 20 hours is 15 ppm or lower.

[0017] The components other than the release agent in the liquid crystal polyester composition of the present embodiment may be components contained in known liquid crystal polyester compositions. The term "liquid crystal polyester composition" as used herein refers to a mixture obtained by mixing a liquid crystal polyester, the release agent, and any other components, and includes a mixture in the form of pellets.

[0018] As used herein, the term "high boiling point component" refers primarily to a volatile component having a large molecular weight, such as a volatile component having a large molecular weight contained in the release agent or a volatile component having a large molecular weight and a benzene ring produced by decomposition of the liquid crystal polyester (excluding phenyl acetate and phenol). The high boiling point component in the release agent is measured by headspace gas chromatography under the "measurement condition X" described below and is defined as a component detected after a retention time of 19 minutes. The high boiling point component in the molded article is measured by headspace gas chromatography under the "measurement condition X" described below and is defined as a component detected after a retention time of 16 minutes, excluding phenyl acetate and phenol.

[0019] <Liquid Crystal Polyester> The liquid crystal polyester in this embodiment is not particularly limited as long as it is a polyester resin that exhibits liquid crystallinity in a molten state. The liquid crystal polyester is preferably one that melts at a temperature of 450° C. or less.

[0020] The flow initiation temperature of the liquid crystal polyester is preferably 250° C. or higher, more preferably 270° C. or higher, and even more preferably 280° C. or higher. The flow initiation temperature of the liquid crystal polyester is preferably 410° C. or lower, more preferably 400° C. or lower, and even more preferably 390° C. or lower. For example, the flow initiation temperature of the liquid crystal polyester is preferably 250° C. or higher and 410° C. or lower, more preferably 270° C. or higher and 400° C. or lower, and even more preferably 280° C. or higher and 390° C. or lower.

[0021] In this specification, the flow initiation temperature of the liquid crystalline polyester is measured by subjecting the liquid crystalline polyester to a pressure of 9.8 MPa (100 kg / cm) using a flow tester. ２ When the liquid crystal polyester is melted under a load of 1000 kJ / min while being heated at a rate of 4° C. / min and extruded through a nozzle having an inner diameter of 1 mm and a length of 10 mm, the liquid crystal polyester exhibits a viscosity of 4800 Pa·s (48,000 poise).

[0022] The liquid crystal polyester is preferably a wholly aromatic liquid crystal polyester having only repeating units derived from aromatic compounds.

[0023] In this specification, the term "derived from" means that during polymerization of the raw material monomer, the chemical structure of the functional group that contributes to polymerization changes, but other chemical structures do not change. The term "derived from" as used herein is a concept that also encompasses cases where the raw material monomer is derived from a polymerizable derivative thereof.

[0024] Examples of polymerizable derivatives of compounds having a carboxy group, such as aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids, include esters in which the carboxy group is converted to an alkoxycarbonyl group or an aryloxycarbonyl group; acid halides in which the carboxy group is converted to a haloformyl group; and acid anhydrides in which the carboxy group is converted to an acyloxycarbonyl group.

[0025] Examples of polymerizable derivatives of compounds having a hydroxy group, such as aromatic hydroxycarboxylic acids, aromatic diols, and aromatic hydroxyamines, include acylated products in which the hydroxy group is acylated to convert it into an acyloxyl group, etc. Examples of polymerizable derivatives of compounds having an amino group, such as aromatic hydroxyamines and aromatic diamines, include acylated products in which the amino group is acylated to convert it into an acylamino group, etc.

[0026] The liquid crystal polyester preferably has a repeating unit represented by the following formula (1) (hereinafter also referred to as "repeating unit (1)"), and more preferably has the 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)").

[0027] (1) -O-Ar １ -CO- (2) -CO-Ar ２ -CO- (3)-X-Ar ３ -Y- [In formulas (1) to (3), Ar １ represents a phenylene group, a naphthylene group, or a biphenylylene group; Ar ２ and Ar ３each independently represents a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by the following formula (4), and X and Y each independently represent an oxygen atom or an imino group (—NH—). １ , Ar ２ or Ar ３ One or more hydrogen atoms in the group represented by the formula (I) may be substituted, independently of one another, with a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.]

[0028] (4)-Ar ４ -Z-Ar ５ - [In formula (4), Ar ４ and Ar ５ each independently represents a phenylene group or a naphthylene group, and Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group having 1 to 10 carbon atoms. ４ or Ar ５ One or more hydrogen atoms in the group represented by the formula (I) may be substituted, independently of one another, with a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.]

[0029] Ar １ , Ar ２ , Ar ３ , Ar ４ or Ar ５ Examples of halogen atoms that can substitute for hydrogen atoms in include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0030] Ar １ , Ar ２ , Ar ３ , Ar ４ or Ar ５ The alkyl group that can substitute for a hydrogen atom in is an alkyl group having 1 to 10 carbon atoms, and examples thereof 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. The alkyl group may be linear or branched.

[0031] Ar １ , Ar ２ , Ar３ , Ar ４ or Ar ５ The aryl group capable of substituting a hydrogen atom in is an aryl group having 6 to 20 carbon atoms, such as 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 monocyclic group or a condensed ring. The aryl group may also be a group in which a hydrogen atom in an aromatic ring is substituted with an alkyl group, such as a tolyl group.

[0032] Ar １ , Ar ２ , Ar ３ , Ar ４ or Ar ５ When a hydrogen atom of is substituted with the above-mentioned group, the number of substitutions is preferably one or two, and more preferably one.

[0033] The alkylidene group for Z in formula (4) is an alkylidene group having 1 to 10 carbon atoms, and examples thereof include a methylene group, an ethylidene group, an isopropylidene group, an n-butylidene group, and a 2-ethylhexylidene group.

[0034] The repeating unit (1) may be Ar １ A repeating unit in which is a 1,4-phenylene group or a repeating unit in which is a 2,6-naphthylene group is preferred.

[0035] The repeating unit (2) may be Ar ２ is preferably a repeating unit in which Ar is a 1,4-phenylene group, a 1,3-phenylene group, a 2,6-naphthylene group, a 2,7-naphthylene group, a 4,4'-biphenylylene group, or a diphenylether-4,4'-diyl group, ２ More preferred are repeating units in which R is a 1,4-phenylene group, a 1,3-phenylene group, or a 2,6-naphthylene group.

[0036] The repeating unit (3) is Ar ３ A repeating unit in which R is a 1,4-phenylene group or a repeating unit in which R is a 4,4'-biphenylylene group is preferred.

[0037] The repeating unit (3) preferably has a repeating unit in which X and Y are each an oxygen atom, since this tends to reduce the melt viscosity of the liquid crystal polyester. It is more preferable that the repeating unit (3) contains only repeating units in which X and Y are each an oxygen atom.

[0038] More specifically, the liquid crystal polyester having the repeating units (1) to (3) preferably has a repeating unit represented by the following formula (11) (hereinafter also referred to as "repeating unit (11)"), a repeating unit represented by the following formula (12) (hereinafter also referred to as "repeating unit (12)"), and a repeating unit represented by the following formula (13) (hereinafter also referred to as "repeating unit (13)").

[0039] (11) -O-Ar １１ -CO- (12)-CO-Ar １２ -CO- (13)-O-Ar １３ -O- [In formulas (11) to (13), Ar １１ represents a 2,6-naphthylene group or a 1,4-phenylene group. １２ represents a 2,6-naphthylene group, a 2,7-naphthylene group, a 1,4-phenylene group, a 1,3-phenylene group, a 4,4'-biphenylylene group, or a diphenylether-4,4'-diyl group. １３ represents a 1,4-phenylene group or a 4,4'-biphenylylene group. １１ , Ar １２ or Ar １３ One or more hydrogen atoms in the group represented by the formula (I) may be substituted, independently of one another, with a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.]

[0040] Preferred liquid crystal polyesters having the repeating units (11) to (13) include Ar １１ A repeating unit (11) in which Ar is a 1,4-phenylene group, and １２ A repeating unit (12) in which Ar is a 1,4-phenylene group, and １２ A repeating unit (12) in which Ar is a 1,3-phenylene group, and １３ and a repeating unit (13) in which is a 4,4'-biphenylylene group.

[0041] The number of repeating units (1) is preferably 30% or more and 80% or less, more preferably 40% or more and 70% or less, and even more preferably 45% or more and 70% or less, of the total number (100%) of all repeating units constituting the liquid crystal polyester (hereinafter referred to as the "total number of all repeating units").

[0042] The number of repeating units (2) is preferably 10% to 35%, more preferably 15% to 30%, and even more preferably 15% to 27.5%, of the total number of all repeating units.

[0043] The number of repeating units (3) is more preferably 10% to 35%, more preferably 15% to 30%, and even more preferably 15% to 27.5%, of the total number of all repeating units.

[0044] The liquid crystal polyester having repeating units (1) to (3) is preferably one in which the number of repeating units (1) is 30% or more and 80% or less of the total number of all repeating units, and the number of repeating units (2) and the number of repeating units (3) are both 10% or more and 35% or less of the total number of all repeating units.

[0045] Furthermore, it is more preferable that the number of repeating units (1) is 40% or more and 70% or less of the total number of all repeating units, and the number of repeating units (2) and the number of repeating units (3) are both 15% or more and 30% or less of the total number of all repeating units.

[0046] Furthermore, it is particularly preferred that the liquid crystal polyester has a number of repeating units (1) of 45% or more and 70% or less of the total number of all repeating units, and that the number of repeating units (2) and the number of repeating units (3) are both 15% or more and 27.5% or less of the total number of all repeating units.

[0047] The ratio of the content of repeating units (2) to the content of repeating units (3), expressed as [number of repeating units (2)] / [number of repeating units (3)], is preferably 0.9 / 1 to 1 / 0.9, more preferably 0.95 / 1 to 1 / 0.95, and even more preferably 0.98 / 1 to 1 / 0.98.

[0048] The liquid crystal polyester may have two or more types of each of the repeating units (1), (2), and (3). The liquid crystal polyester may also have repeating units other than the repeating units (1), (2), and (3), but the number of such repeating units is preferably 10% or less, more preferably 5% or less, of the total number of all repeating units.

[0049] In the liquid crystal polyester having repeating units (1), (2), and (3), the sum of the content of repeating unit (1), the content of repeating unit (2), and the content of repeating unit (3) does not exceed 100%.

[0050] In this specification, the number of each repeating unit constituting 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 depolymerized product (monomers that derive each repeating unit) is quantified by liquid chromatography, whereby the number of each repeating unit relative to the total number of repeating units can be calculated.

[0051] The liquid crystal polyester composition of the present embodiment may contain one liquid crystal polyester or two or more liquid crystal polyesters. The content of the liquid crystal polyester relative to the total mass (100 mass%) of the liquid crystal polyester composition of the present embodiment may be 45 mass% or more and 75 mass% or less, 50 mass% or more and 70 mass% or less, or 55 mass% or more and 65 mass% or less.

[0052] [Method for producing liquid crystal polyester] Liquid crystal polyester can be produced by melt-polymerizing raw material monomers corresponding to the repeating units constituting the liquid crystal polyester, and then solid-phase polymerizing the obtained polymer. For example, as in the method described in Japanese Patent No. 6439027, it can be produced by a production method including the following acylation step and polymerization step. Note that the method for producing liquid crystal polyester is not limited to the above method, and it can also be produced by melt polymerization alone.

[0053] Acylation step: A step of obtaining an acylated product by acylating the phenolic hydroxy group of the raw material monomer with a fatty acid anhydride (e.g., acetic anhydride, etc.). Polymerization step: A step of obtaining a liquid crystal polyester by polymerizing the acyl group of the acylated product with the carboxyl group of the acylated product of an aromatic dicarboxylic acid and an aromatic hydroxycarboxylic acid so as to cause transesterification.

[0054] <Release Agent> The release agent in this embodiment contains pentaerythritol tetrastearate and satisfies the following (a) and (b): (a) the 1% weight loss temperature under a nitrogen atmosphere (hereinafter sometimes referred to as "TGA (1)") is 270°C or higher and 360°C or lower, and (b) the amount of high boiling components generated during heating at 120°C for 20 hours (hereinafter sometimes referred to as "amount of high boiling components (b)") is 15 ppm or lower.

[0055] In addition to pentaerythritol tetrastearate, the release agent may contain, for example, triesters having a different number of fatty acid residues (i.e., pentaerythritol tristearate), diesters (i.e., pentaerythritol distearate), monoesters (i.e., pentaerythritol monostearate); esters having a different number of carbon atoms in the fatty acid residues (i.e., esters of pentaerythritol with a fatty acid having a different number of carbon atoms from stearic acid); or impurities other than these. Examples of the release agent include those containing pentaerythritol tetrastearate as a main component, and the content of pentaerythritol tetrastearate relative to the total mass (100 mass%) of the release agent is preferably 50 mass% or more, more preferably 75 mass% or more, and even more preferably 90 mass% or more. The remainder of the content of pentaerythritol tetrastearate relative to the total mass (100 mass%) of the release agent may be pentaerythritol tristearate, pentaerythritol distearate, pentaerythritol monostearate, esters of pentaerythritol with a fatty acid having a carbon number different from that of stearic acid, or other impurities.

[0056] [(a) 1% Weight Loss Temperature in Nitrogen Atmosphere] In the release agent, TGA (1) is 270°C or higher and 360°C or lower, preferably 280°C or higher and 350°C or lower, more preferably 300°C or higher and 350°C or lower, even more preferably 310°C or higher and 350°C or lower, and particularly preferably 320°C or higher and 350°C or lower. When TGA (1) is within the above range, gas generation during molding is suppressed, and color changes of molded articles due to high-temperature heating are unlikely to occur. Furthermore, when TGA (1) is equal to or higher than the lower limit of the above range, color changes of molded articles due to high-temperature heating are particularly unlikely to occur. When TGA (1) is equal to or lower than the upper limit of the above range, gas generation during molding is particularly likely to be suppressed.

[0057] In this specification, TGA (1) means the temperature at which the mass of 1% by mass is reduced when 10 mg of the release agent is heated in a nitrogen atmosphere from room temperature (25° C.) to 600° C. at a rate of 10° C. / min.

[0058] [(b) Amount of high boiling components generated during heating at 120°C for 20 hours] In the release agent, the amount of high boiling components (b) is 15 ppm or less, preferably 13 ppm or less, and more preferably 11 ppm or less. The smaller the amount of high boiling components (b), the better. If the amount of high boiling components (b) is within the above range, the color tone of the molded product is unlikely to change due to high-temperature heating, and the mold is unlikely to be contaminated due to the adhesion of high boiling components to the mold.

[0059] In this specification, the amount of high boiling components (b) means the amount obtained by heating 8 mg of the release agent at 120° C. for 20 hours in a helium atmosphere, measuring the generated gas by headspace gas chromatography under the following <<Measurement Condition X>>, and calculating the amount of components detected from the measurement results after a retention time of 19 minutes according to the following <<Calculation Method X>>.

[0060] <<Measurement Condition X>> Column: polyethylene glycol column (for example, "TC-WAX" (length 30 m, inner diameter 0.25 mm) manufactured by GL Sciences Inc.) Oven temperature: 130°C Incubation time: 50 minutes Split ratio: 0 Heating program: After holding for 5 minutes, increase the temperature from 60°C to 240°C at 10°C / min, and hold at 240°C for 15 minutes Detector: FID Peak detection threshold: 3000

[0061] <Calculation Method X> A calibration curve is prepared in advance using phenol as a standard. The sum of the peak areas of the detected components is regarded as the area of ​​phenol, and the weight of the high boiling components converted into phenol is calculated. Assuming that the high boiling components are produced from 4 g of a molded product containing 8 mg of a mold release agent, the weight ratio (ppm) of the high boiling components to the molded product is calculated.

[0062] [(c) Color Tone SCI L* After Heating in an Air Atmosphere at 350° C. for 15 Minutes] Furthermore, the release agent preferably has a color tone SCI L* (hereinafter sometimes referred to as "color tone (c)") after heating in an air atmosphere at 350° C. for 15 minutes of 40 or more, more preferably 45 or more, and the higher the value of color tone (c), the better. If the color tone (c) is within the above range, the color tone of the molded article is less likely to change due to high-temperature heating.

[0063] In this specification, the color tone (c) refers to the color tone SCI L* obtained by heating 5 g of the release agent in an air atmosphere at 350° C. for 15 minutes and measuring it with a spectrophotometer.

[0064] Furthermore, the release agent preferably has a 5% weight loss temperature (hereinafter sometimes referred to as "TGA (5)") under a nitrogen atmosphere of 380° C. or higher and 400° C. or lower, more preferably 385° C. or higher and 395° C. or lower. In this specification, TGA (5) means the temperature at which a 5% weight loss occurs when 10 mg of the release agent is heated under a nitrogen atmosphere from room temperature (25° C.) to 600° C. at a rate of 10° C. / min.

[0065] Furthermore, in the release agent, the difference between TGA (5) and TGA (1) (TGA (5) - TGA (1)) is preferably 100°C or less, more preferably 40°C or more and 100°C or less, even more preferably 45°C or more and 90°C or less, particularly preferably 50°C or more and 80°C or less, and most preferably 60°C or more and 70°C or less. If the difference between TGA (5) and TGA (1) is within the above range, gas generation during molding is suppressed, and the molded product is less likely to change in color due to high-temperature heating. Furthermore, if the difference between TGA (5) and TGA (1) is equal to or greater than the lower limit of the above range, gas generation during molding is particularly easily suppressed. If the difference between TGA (5) and TGA (1) is equal to or less than the upper limit of the above range, the molded product is particularly less likely to change in color due to high-temperature heating.

[0066] The TGA (1), the amount of high boiling components (b), the color tone (c), and the TGA (5) of the above-described release agent can be controlled, for example, by selecting the raw materials for esterification (carboxylic acids, alcohols), the method for producing the ester, the degree of purification, etc. in the production of the release agent. The acid value of such a release agent is preferably more than 0.5 (mgKOH / g) and not more than 2 (mgKOH / g), and more preferably 1 (mgKOH / g) or more and 2 (mgKOH / g) or less. The hydroxyl value of such a release agent is preferably more than 5 (mgKOH / g) and not more than 15 (mgKOH / g), and more preferably 5.5 (mgKOH / g) or more and 10 (mgKOH / g) or less.

[0067] In this specification, the acid value of a release agent is determined by dissolving the release agent in a benzene-ethanol mixed solvent and titrating the solution with a potassium hydroxide solution of known potency. The hydroxyl value of the release agent is determined by heating the release agent together with acetic anhydride to acetylate it, measuring the saponification value of the acetylated product produced, and then calculating according to the following formula: Hydroxyl value = A / (1-0.00075 x A)-B Here, A is the saponification value after acetylation, and B is the saponification value before acetylation.

[0068] The release agent used in this embodiment may be a preparation produced by a known method, or a commercially available product. An example of a commercially available product that can be used as a release agent is "EW-480" manufactured by Riken Vitamin Co., Ltd.

[0069] "EW-480" manufactured by Riken Vitamin Co., Ltd. Main component: pentaerythritol tetrastearate (PETS) TGA (1): 324°C High boiling point component (b): 10.8 ppm Color tone (c): 49 TGA (5): 390°C Acid value: 1.6 mg KOH / g, Hydroxyl value: 6 mg KOH / g

[0070] The liquid crystal polyester composition of this embodiment may contain one type of release agent, or may contain two or more types of release agents. The release agent in this embodiment contains pentaerythritol tetrastearate and satisfies the above (a) and (b), and preferably contains pentaerythritol tetrastearate and satisfies the above (a), (b), and (c). More preferred release agents contain pentaerythritol tetrastearate and satisfy the following (a') and (b), or satisfy the following (a) and (b'), or satisfy the following (a') and (b'). Further preferred release agents include those which contain pentaerythritol tetrastearate and which satisfy the following (a'), (b), and (c): those which satisfy the following (a'), (b), and (c'): those which satisfy the following (a'), (b'), and (c): those which satisfy the following (a'), (b'), and (c'): those which satisfy the following (a'), (b'), and (c'): those which satisfy the above (a), (b), and (c'): those which satisfy the above (a), (b'), and (c'):

[0071] (a') The 1% weight loss temperature in a nitrogen atmosphere is 280°C or higher and 350°C or lower. (b') The amount of high boiling components generated during heating at 120°C for 20 hours is 13 ppm or lower. (c') The color tone SCI L* after heating at 350°C for 15 minutes in an air atmosphere is 45 or higher.

[0072] In the liquid crystal polyester composition of the present embodiment, the content of the release agent is preferably 0.01 parts by mass or more, more preferably 0.01 parts by mass or more and 1 part by mass or less, still more preferably 0.025 parts by mass or more and 0.75 parts by mass or less, and particularly preferably 0.05 parts by mass or more and 0.5 parts by mass or less, relative to 100 parts by mass of the liquid crystal polyester.

[0073] The content of the release agent relative to the total mass (100 mass%) of the liquid crystal polyester composition of the present embodiment is preferably 0.01 mass% or more, more preferably 0.01 mass% or more and 1 mass% or less, even more preferably 0.025 mass% or more and 0.5 mass% or less, still more preferably 0.05 mass% or more and 0.4 mass% or less, and particularly preferably 0.05 mass% or more and 0.25 mass% or less.

[0074] <Other Components> The liquid crystal polyester composition of the present embodiment may contain any other components in addition to the liquid crystal polyester and the release agent described above.

[0075] The liquid crystal polyester composition of this embodiment may further contain a fibrous filler. The inclusion of a fibrous filler improves the mechanical properties of the molded article. The fibrous filler may be an inorganic filler or an organic filler. Examples of fibrous inorganic fillers include glass fibers, irregular cross-section glass fibers, carbon fibers, silica fibers, alumina fibers, ceramic fibers, metal fibers, silicon carbide fibers, and whiskers. Examples of fibrous organic fillers include polyester fibers; para- or meta-aramid fibers; and polyparaphenylene benzobisoxazole (PBO) fibers. Among fibrous fillers, fibrous inorganic fillers are preferred, and glass fibers are more preferred. The cross section perpendicular to the length direction of the fibrous filler may be a perfect circle or a non-circular shape such as an ellipse.

[0076] The number average fiber length of the glass fibers is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more. On the other hand, the number average fiber length of the glass fibers is preferably 700 μm or less, more preferably 650 μm or less, and even more preferably 600 μm or less. An example of the numerical range of the number average fiber length of the glass fibers is preferably 20 μm or more and 700 μm or less, more preferably 30 μm or more and 650 μm or less, and even more preferably 40 μm or more and 600 μm or less. In this specification, "number average fiber length of glass fibers" refers to a value measured by the method described below in "Measurement Method Y." "Measurement Method Y": 4 g of a liquid crystal polyester composition is heated at 600°C for 4 hours to obtain ash. The obtained ash is dispersed in ethylene glycol to prepare a preparation, which is then photographed at a 100x magnification using an optical microscope. Images taken at 100x magnification in multiple fields of view are combined to form a single combined image, and the fiber lengths of fibers that fall within the field of view of the single image (i.e., fibers with both ends within the field of view) and have a length equal to or greater than the fiber diameter are measured. The fiber lengths of 500 or more (e.g., 500) fibers are measured, and the number average fiber length is calculated.

[0077] The liquid crystal polyester composition of this embodiment may contain one type of fibrous filler or two or more types of fibrous fillers. In the liquid crystal polyester composition of this embodiment, the content of the fibrous filler is preferably 5 parts by mass or more and 100 parts by mass or less, more preferably 25 parts by mass or more and 80 parts by mass or less, and particularly preferably 50 parts by mass or more and 75 parts by mass or less, relative to 100 parts by mass of the liquid crystal polyester.

[0078] The content of the fibrous filler relative to the total mass (100 mass%) of the liquid crystal polyester composition of this embodiment may be 25 mass% or more and 55 mass% or less, 30 mass% or more and 50 mass% or less, or 35 mass% or more and 45 mass% or less.

[0079] The liquid crystal polyester composition of the present embodiment may further contain an external additive such as a metal salt of a higher fatty acid, etc. The liquid crystal polyester composition of the present embodiment may further contain, as other components, other resins other than the liquid crystal polyester, fillers other than fibrous fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration dampers, antibacterial agents, insect repellents, deodorizing agents, coloration inhibitors, heat stabilizers, antistatic agents, plasticizers, lubricants, dyes, foaming agents, antifoaming agents, viscosity modifiers, surfactants, etc.

[0080] Examples of resins other than the liquid crystal polyester include fluororesins, polyolefin resins, vinyl resins, polystyrene resins, polyamide resins, polyester resins, polysulfone resins, polyphenylene sulfide, polyether ketone, polycarbonate, polyphenylene ether, and polyimide resins. For example, the liquid crystal polyester composition of the present embodiment may not contain a fluororesin as a release agent, or may not contain polytetrafluoroethylene.

[0081] Fillers other than fibrous fillers include plate-like fillers, spherical fillers, and powder fillers. Examples of plate-like fillers include talc, mica, glass flakes, and graphite. The plate-like fillers may be surface-treated or untreated. Examples of mica include natural mica such as muscovite, phlogopite, fluorphlogopite, and tetrasilicic mica, as well as artificially produced synthetic mica. Examples of spherical fillers include glass beads and glass balloons. Examples of powder fillers include calcium carbonate, dolomite, clay barium sulfate, titanium oxide, carbon black, conductive carbon, and fine silica.

[0082] [Method for Producing Liquid Crystal Polyester Composition] The liquid crystal polyester composition of this embodiment can be produced by mixing the above-mentioned liquid crystal polyester, a release agent containing pentaerythritol tetrastearate, and other components used as needed, all at once or in a suitable order. That is, the liquid crystal polyester composition of this embodiment is a composition containing the above-mentioned liquid crystal polyester, a release agent containing pentaerythritol tetrastearate, and other components used as needed. The mixing is preferably melt-kneading. The liquid crystal polyester composition of this embodiment can be provided as a pelletized product obtained by melt-kneading the liquid crystal polyester, the release agent containing pentaerythritol tetrastearate, and other components used as needed using an extruder. Alternatively, the liquid crystal polyester composition can be provided by adding any other components (e.g., external additives or other components) to pellets obtained by melt-kneading at least the liquid crystal polyester and the release agent containing pentaerythritol tetrastearate using an extruder and adhering them to the pellet surface.

[0083] As described above, the liquid crystal polyester composition of this embodiment contains pentaerythritol tetrastearate and a release agent that satisfies the following conditions together with the liquid crystal polyester: (a) the 1% weight loss temperature in a nitrogen atmosphere is 270°C or higher and 360°C or lower, and (b) the amount of high boiling components generated during heating at 120°C for 20 hours is 15 ppm or lower.

[0084] The release agent contained in this liquid crystal polyester composition contains pentaerythritol tetrastearate, which has a good release effect. Furthermore, in addition to the low content of high-boiling components in the release agent alone (condition (b)), the 1% weight loss temperature is not too low compared to conventional products, but is not too high, and is within an appropriate temperature range (condition (a)). This is thought to suppress the effects of shear stress and other factors applied during molding. Because the liquid crystal polyester composition of this embodiment contains a release agent with these specific physical properties, it is thought that the liquid crystal polyester composition of this embodiment has good releasability from a mold, suppresses gas generation during molding, and enables the production of molded articles that are less susceptible to color change due to high-temperature heating.

[0085] The liquid crystal polyester composition of the present embodiment preferably further contains a release agent that satisfies the condition (c): (c) the color tone SCI L* after heating at 350°C for 15 minutes in an air atmosphere is 40 or more.

[0086] In this way, by using a release agent that also has a high SCI L* after heating at high temperatures, oxidative degradation is suppressed when a molded product is formed. Therefore, by using a liquid crystal polyester composition containing a release agent that satisfies not only condition (a) and condition (b) but also condition (c), the color change of the molded product due to high-temperature heating (heating at 350 ° C for 15 minutes in an air atmosphere) can be made less likely to occur. In addition, a molded product that is less likely to deteriorate even after repeated regrind (grinding and regeneration) can be obtained.

[0087] Another aspect of the present disclosure includes the following.

[0088] [1] A liquid crystal polyester composition containing a liquid crystal polyester and a release agent containing pentaerythritol tetrastearate, wherein the release agent satisfies the following (a) and (b): (a) the 1% weight loss temperature in a nitrogen atmosphere is 270°C or higher and 360°C or lower, and (b) the amount of high boiling components generated during heating at 120°C for 20 hours is 15 ppm or lower.

[0089]

[21] A liquid crystal polyester composition comprising a liquid crystal polyester and a release agent containing pentaerythritol tetrastearate, wherein the release agent satisfies the following (a) and (b): (a) a 1% weight loss temperature in a nitrogen atmosphere of 270°C or higher and 360°C or lower, and (b) the amount of high boiling components generated during heating at 120°C for 20 hours is 15 ppm or lower.

[0090]

[22] The liquid crystal polyester composition according to [1] or

[21] , wherein the release agent further satisfies the following (c): (c) the color tone SCI L* after heating at 350°C for 15 minutes in an air atmosphere is 40 or more.

[0091]

[23] The liquid crystal polyester composition according to [1],

[21] or

[22] , wherein the release agent has a 5% weight loss temperature (TGA(5)) under a nitrogen atmosphere and a 1% weight loss temperature (TGA(1)) under a nitrogen atmosphere, and the following relationship holds: TGA(5)-TGA(1)≦100°C.

[0092]

[24] The liquid crystal polyester composition according to any one of [1] and

[21] to

[23] , wherein the acid value of the release agent is greater than 0.5 (mgKOH / g) and not more than 2 (mgKOH / g).

[0093]

[25] The liquid crystal polyester composition according to any one of [1] and

[21] to

[24] , wherein the hydroxyl value of the release agent is more than 5 (mgKOH / g) and 15 (mgKOH / g) or less.

[0094]

[26] The liquid crystal polyester composition according to any one of [1] and

[21] to

[25] , wherein the liquid crystal polyester has a repeating unit represented by the following formula (1): (1) -O-Ar １ -CO- In formula (1), Ar １ represents a phenylene group, a naphthylene group, or a biphenylylene group. １ One or more hydrogen atoms in the group represented by the formula (I) may be substituted, independently of one another, with a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0095]

[27] The liquid crystal polyester composition according to

[26] , wherein the liquid crystal polyester has a repeating unit represented by the following formula (1), a repeating unit represented by the following formula (2), and a repeating unit represented by the following formula (3): (1) -O-Ar １ -CO- (2) -CO-Ar ２ -CO- (3)-X-Ar ３ -Y- In formulas (1) to (3), Ar １ represents a phenylene group, a naphthylene group, or a biphenylylene group; Ar ２ and Ar ３ each independently represents a phenylene group, a naphthylene group, a biphenylylene group, or a group represented by the following formula (4), and X and Y each independently represent an oxygen atom or an imino group (—NH—). １ , Ar ２ or Ar ３ One or more hydrogen atoms in the group represented by the formula (4) may be substituted, independently of one another, with a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms. ４ -Z-Ar ５ - In formula (4), Ar ４ and Ar ５ each independently represents a phenylene group or a naphthylene group, and Z represents an oxygen atom, a sulfur atom, a carbonyl group, a sulfonyl group, or an alkylidene group having 1 to 10 carbon atoms. ４ or Ar ５ One or more hydrogen atoms in the group represented by the formula (I) may be substituted, independently of one another, with a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0096]

[28] The liquid crystal polyester composition according to any one of [1] and

[21] to

[27] , wherein the release agent satisfies the following (a') and (b): (a') the 1% weight loss temperature in a nitrogen atmosphere is 280°C or higher and 350°C or lower, and (b) the amount of high boiling components generated during heating at 120°C for 20 hours is 15 ppm or lower.

[0097]

[29] The liquid crystal polyester composition according to any one of [1] and

[21] to

[27] , wherein the release agent satisfies the following (a) and (b'): (a) the 1% weight loss temperature under a nitrogen atmosphere is 270°C or higher and 360°C or lower, and (b') the amount of high boiling components generated during heating at 120°C for 20 hours is 13 ppm or lower.

[0098]

[30] The liquid crystal polyester composition according to any one of [1] and

[21] to

[27] , wherein the release agent satisfies the following (a') and (b'): (a') the 1% weight loss temperature in a nitrogen atmosphere is 280°C or higher and 350°C or lower, and (b') the amount of high boiling components generated during heating at 120°C for 20 hours is 13 ppm or lower.

[0099]

[31] The liquid crystal polyester composition according to any one of

[22] to

[30] , wherein the release agent further satisfies the following (c'): (c') the color tone SCI L* after heating at 350°C for 15 minutes in an air atmosphere is 45 or more.

[0100]

[32] The liquid crystal polyester composition according to any one of [1] and

[21] to

[31] , wherein the content of the release agent is 0.01 parts by mass or more relative to 100 parts by mass of the liquid crystal polyester.

[33] The liquid crystal polyester composition according to

[32] , wherein the content of the release agent is 0.01 parts by mass or more and 1 part by mass or less relative to 100 parts by mass of the liquid crystal polyester.

[0101]

[34] The liquid crystal polyester composition according to any one of [1] and

[21] to

[33] , further comprising a fibrous filler.

[35] The liquid crystal polyester composition according to

[34] , wherein the content of the fibrous filler is 5 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of the liquid crystal polyester.

[36] The liquid crystal polyester composition according to

[34] or

[35] , wherein the content of the liquid crystal polyester is 55% by mass or more and 65% by mass or less, the content of the fibrous filler is 35% by mass or more and 45% by mass or less, and the content of the release agent is 0.05% by mass or more and 0.25% by mass or less, relative to the total mass (100% by mass) of the liquid crystal polyester composition (provided that the sum of the contents of the liquid crystal polyester, the fibrous filler, and the release agent does not exceed 100% by mass).

[37] The liquid crystal polyester composition according to any one of

[34] to

[36] , wherein the fibrous filler is glass fiber.

[0102]

[38] A molded article comprising the liquid crystal polyester composition according to any one of [1] and

[21] to

[37] .

[39] The molded article according to

[38] , wherein the amount of high boiling components generated during heating at 120°C for 20 hours is 0.1 ppm or less.

[0103]

[40] A method for producing a liquid crystal polyester composition, comprising a step of mixing a liquid crystal polyester with a release agent, wherein the release agent contains pentaerythritol tetrastearate and satisfies the following (a) and (b): (a) the 1% weight loss temperature in a nitrogen atmosphere is 270°C or higher and 360°C or lower, and (b) the amount of high boiling components generated during heating at 120°C for 20 hours is 15 ppm or lower.

[0104]

[41] The method for producing a liquid crystal polyester composition according to

[40] , wherein the release agent further satisfies the following (c): (c) the color tone SCI L* after heating at 350°C for 15 minutes in an air atmosphere is 40 or more.

[0105] (Molded article) One embodiment of the molded article is a molded article containing the liquid crystal polyester composition of the above-mentioned embodiment. The molded article of this embodiment can be obtained by a known molding method using the liquid crystal polyester composition. As a molding method using the liquid crystal polyester composition of the above-mentioned embodiment, a melt molding method is preferred, and examples thereof include extrusion molding methods such as injection molding, T-die method, inflation method, compression molding, blow molding, vacuum molding, and press molding. Among them, injection molding is preferred.

[0106] For example, a molded article can be obtained by melting the liquid crystal polyester composition of the above-described embodiment using a known injection molding machine and injecting the molten liquid crystal polyester composition into a mold. Examples of known injection molding machines include TR450EH3 manufactured by Sodick Co., Ltd. and PS40E5ASE, ES400, and NEX50IV manufactured by Nissei Plastic Industrial Co., Ltd.

[0107] Regarding the temperature conditions for injection molding, the cylinder temperature of the injection molding machine is preferably set to a temperature 10 to 80°C higher than the flow initiation temperature of the liquid crystal polyester composition used. The mold temperature is preferably set in the range of 25°C to 180°C from the viewpoint of the time required to cool the liquid crystal polyester composition and productivity. Other injection conditions such as the screw rotation speed, back pressure, injection speed, dwell pressure, and dwell pressure time may be appropriately adjusted.

[0108] Since the molded article of this embodiment uses the liquid crystal polyester composition described above, it has good mold releasability and is less likely to undergo color change due to high-temperature heating. The molded article of this embodiment contains the liquid crystal polyester composition of the embodiment described above, and preferably has a high-boiling point component generation amount of 0.1 ppm or less when heated at 120°C for 20 hours. Thus, a liquid crystal polyester composition capable of producing a molded article with a low generation amount of high-boiling points suppresses gas generation during molding, such as kneading, thereby preventing mold contamination, for example. Furthermore, the molded article of this embodiment also has good mechanical properties such as heat resistance, strength, and dimensional stability. The molded article of this embodiment is suitable for consumer applications, and is particularly useful for electrical and electronic components such as connectors and bobbins.

[0109] The present disclosure will be described in more detail below using examples, but the present disclosure is not limited to the following examples.

[0110] <Release Agents> The release agents shown below were measured for (a) the 1% weight loss temperature in a nitrogen atmosphere, (b) the amount of high-boiling components generated during heating at 120°C for 20 hours, (c) the color tone SCI L* after heating at 350°C for 15 minutes in an air atmosphere, and the 5% weight loss temperature in a nitrogen atmosphere. These results are shown in Table 1. The acid value and hydroxyl value of each release agent were also measured, and the results are shown below.

[0111] MR-A: Release agent containing pentaerythritol tetrastearate as the main component, "EW-480" manufactured by Riken Vitamin Co., Ltd.; acid value 1.6 mg KOH / g, hydroxyl value 6 mg KOH / g

[0112] MR-B: Release agent containing pentaerythritol tetrastearate as the main component, "EW-440A" manufactured by Riken Vitamin Co., Ltd.; acid value 2.3 mg KOH / g, hydroxyl value 17 mg KOH / g. MR-C: Release agent containing pentaerythritol tetrastearate as the main component, "WE-6" manufactured by NOF Corporation; acid value 0 mg KOH / g, hydroxyl value 2 mg KOH / g. MR-D: Release agent containing pentaerythritol tetrabehenate as the main component, "WE-5" manufactured by NOF Corporation; acid value 0 mg KOH / g, hydroxyl value 2 mg KOH / g.

[0113] MR-E: A release agent containing pentaerythritol tetrastearate as the main component, "VPG861" manufactured by Emery Oleochemicals Japan; acid value 1.6 mg KOH / g, hydroxyl value 7 mg KOH / g. MR-F: A release agent containing pentaerythritol tetrastearate as the main component, "H-476" manufactured by NOF Corporation; acid value 2.8 mg KOH / g, hydroxyl value 20 mg KOH / g.

[0114] MR-G: Mold release agent containing dipentaerythritol hexastearate as the main component, "VPG2571" manufactured by Emery Oleochemicals Japan; acid value 1.9 mg KOH / g, hydroxyl value 7 mg KOH / g. MR-H: Mold release agent containing dipentaerythritol hexastearate as the main component, "HL-01" manufactured by Riken Vitamin Co., Ltd.; acid value 3.2 mg KOH / g, hydroxyl value 2 mg KOH / g.

[0115] [(a) 1% Weight Loss Temperature in a Nitrogen Atmosphere] Using a thermogravimetric analyzer ("DTG-60A" manufactured by Shimadzu Corporation), 10 mg of the release agent precisely weighed out on a platinum pan was heated in a nitrogen atmosphere from room temperature (25° C.) to 600° C. at a rate of 10° C. / min., and the temperature at which the mass had decreased by 1% by mass was measured. This measured temperature was defined as the 1% weight loss temperature in a nitrogen atmosphere.

[0116] [(b) Amount of high boiling components generated during heating at 120°C for 20 hours] 8 mg of the release agent was placed in a vial, the vial was filled with helium gas, and then sealed with a septum. The sealed vial was placed in a hot air circulation dryer and heated at 120°C for 20 hours. Thereafter, the gas in the vial was measured using a headspace gas chromatograph (Gas Chromatograph "GC-2014" manufactured by Shimadzu Corporation) under the following <<Measurement Condition X>>. From the measurement results, the amount of components detected after a retention time of 19 minutes was calculated according to the following <<Calculation Method X>>, and this was taken as the amount of high boiling components generated during heating at 120°C for 20 hours.

[0117] <<Measurement Condition X>> Column: polyethylene glycol column (for example, "TC-WAX" (length 30 m, inner diameter 0.25 mm) manufactured by GL Sciences Inc.) Oven temperature: 130°C Heating time: 50 minutes Split ratio: 0 Heating program: After holding for 5 minutes, increase the temperature from 60°C to 240°C at 10°C / min, and hold at 240°C for 15 minutes Detector: FID Peak detection threshold: 3000

[0118] <Calculation Method X> A calibration curve was prepared in advance using phenol as a standard. The sum of the peak areas of the detected components was considered to be the area of ​​phenol, and the weight of the high boiling components converted into phenol was calculated. Assuming that the high boiling components were produced from 4 g of a molded product containing 8 mg of a release agent, the weight ratio (ppm) of the high boiling components to the molded product was calculated.

[0119] [(c) Color Tone SCI L* After Heating in an Air Atmosphere at 350°C for 15 Minutes] A crucible containing 5 g of release agent was heated in a muffle furnace at 350°C for 15 minutes. After cooling to room temperature, the solid in the crucible was heated at 90°C for 2 minutes to melt it. A plate having a thickness of 3 mm was prepared from the melt to obtain a test specimen. The color tone (SCI L*) of the test specimen was measured using a spectrophotometer ("CM-3600A" manufactured by Konica Minolta Japan, Inc., light source D65, and measuring diameter φ4.0 mm).

[0120] [5% Weight Loss Temperature in Nitrogen Atmosphere] Using a thermogravimetric analyzer ("DTG-60A" manufactured by Shimadzu Corporation), 10 mg of the release agent precisely weighed out on a platinum pan was heated in a nitrogen atmosphere from room temperature (25° C.) to 600° C. at a rate of 10° C. / min., and the temperature at which the mass had decreased by 5% by mass was measured. This measured temperature was defined as the 5% weight loss temperature in a nitrogen atmosphere.

[0121] [Acid value and hydroxyl value] The release agent was dissolved in a benzene-ethanol mixed solvent and titrated with a potassium hydroxide solution of known potency to determine the acid value. The release agent was heated together with acetic anhydride to perform acetylation, and the saponification value of the acetylated product was measured. The hydroxyl value was then determined by calculation according to the following formula: Hydroxyl value = A / (1 - 0.00075 x A) - B Here, A represents the saponification value after acetylation, and B represents the saponification value before acetylation.

[0122]

[0123] <Production Example of Liquid Crystal Polyester (LCP-A)> p-Hydroxybenzoic acid (994.5 g, 7.2 mol), 4,4'-dihydroxybiphenyl (446.9 g, 2.4 mol), terephthalic acid (358.8 g, 2.16 mol), isophthalic acid (39.9 g, 0.24 mol), acetic anhydride (1347.6 g, 13.2 mol), and 0.194 g of 1-methylimidazole as a catalyst were added to a reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser. After thoroughly purging the atmosphere inside the reactor with nitrogen gas, the temperature was raised with stirring, and the mixture was stirred at an internal temperature of 145°C for 1 hour. Thereafter, the temperature was raised over 2 hours and 50 minutes while distilling off the by-product acetic acid and unreacted acetic anhydride, and the mixture was maintained at 320°C until an increase in torque was observed. The contents were removed from the reactor and cooled to room temperature. The resulting solid was pulverized in a pulverizer to a particle size of approximately 0.1 to 1 mm, yielding a powdered prepolymer. The prepolymer was then heated in a nitrogen atmosphere from room temperature to 250°C over 1 hour, then from 250°C to 300°C over 5 hours, and held at 300°C for 3 hours to allow solid-phase polymerization to proceed, yielding a liquid crystal polyester (LCP-A). The flow initiation temperature of the resulting LCP-A was 361°C.

[0124] The fibrous fillers, release agents, and external additives used in the production of the liquid crystal polyester composition are shown below.

[0125] Fibrous filler Fibrous filler A: "EFH75-01" manufactured by Nitto Boseki Co., Ltd. (milled glass fiber, number average fiber length 75 μm)

[0126] Release agent: MR-A, MR-B, MR-C, MR-D

[0127] External additive: Lithium laurate, "LS-3" manufactured by Nitto Kasei Kogyo Co., Ltd.

[0128] <Production Examples of Liquid Crystal Polyester Composition> (Example 1) 60 parts by mass of LCP-A, 40 parts by mass of fibrous filler A, 0.10 parts by mass of MR-A, and 0.02 parts by mass of an external additive were charged into a twin-screw extruder equipped with a side feeder ("PCM-30HS" manufactured by Ikegai Iron Works Co., Ltd.), and melt-kneaded at a cylinder temperature of 360° C. The extruded strand was cut to obtain pellets of the liquid crystal polyester composition of Example 1.

[0129] Example 2 Pellets of a liquid crystal polyester composition of Example 2 were obtained in the same manner as in Example 1, except that the blending amount of MR-A was changed to 0.20 parts by mass.

[0130] Comparative Examples 1 to 3 Pellets of liquid crystal polyester compositions of Comparative Examples 1 to 3 were obtained in the same manner as in Example 2, except that 0.20 parts by mass of MR-A was changed to 0.20 parts by mass of MR-B to MR-D, respectively.

[0131] <Evaluation of Molded Articles> Using pellets of the liquid crystal polyester composition of each example, test pieces for each evaluation were molded, and the gas generation during molding, releasability from the mold, color change of the molded article due to high-temperature heating, and mechanical properties of the molded article were evaluated.

[0132] [Gas Generation During Molding] Pellets of the liquid crystal polyester composition were placed in an injection molding machine and injection molded under the following <<Injection Condition Z>> to obtain a molded body (JIS K7139-A12 dumbbell test piece, thickness 0.8 mm). This molded body was cut to obtain a test piece measuring 5 mm in length, 5 mm in width, and 0.8 mm in thickness. <<Injection Condition Z>> Injection molding machine: NEX50IV (manufactured by Nissei Plastic Industrial Co., Ltd.) Cylinder temperature: 380°C Injection speed: 50 mm / s Screw rotation speed: 100 rpm Back pressure: 4 MPa Holding pressure: 40 MPa Mold temperature: 130°C

[0133] A 4 g sample was placed in a vial, filled with helium gas, and then sealed with a septum. The sealed vial was placed in a hot air circulating oven and heated at 120°C for 20 hours. The gas in the vial was then measured under the above-mentioned "Measurement Condition X" using a headspace gas chromatograph (Gas Chromatography "GC-2014" manufactured by Shimadzu Corporation). From the measurement results, the amount of components detected after a retention time of 16 minutes was calculated according to the above-mentioned "Calculation Method X." The calculated amount of gas generated is shown in Table 2 as the amount of high-boiling components generated during 20 hours of heating at 120°C. It can be said that the smaller the amount of high-boiling components generated during 20 hours of heating at 120°C, the more suppressed gas generation during molding.

[0134] [Mold Releasability] Pellets of the liquid crystal polyester composition were placed in an injection molding machine ("NEX50IV" manufactured by Nissei Plastic Industrial Co., Ltd.) and injected into a mold having the same configuration as that shown in FIG. 1 described in JP 2017-75339 A under conditions of a cylinder temperature of 380°C, a mold temperature of 130°C, a holding pressure of 170 MPa, and an injection speed of 100 mm / sec. Thereafter, a test piece (φ11 × φ15 × 20 mm, with a draft angle of 0° on the core side and the cavity side) was removed from the mold. The ejector ejection torque required to remove the test piece was measured, and the mold releasability was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 2. Evaluation criteria A: The test piece was released from the mold before the ejector ejection torque reached near its upper limit. B: The test piece was released from the mold after the ejector ejection torque reached near its upper limit. C: The test piece was not released from the mold even when the ejector ejection torque reached the upper limit.

[0135] [Color Tone Change of Molded Article Due to High-Temperature Heating] Pellets of the liquid crystal polyester composition were loaded into an injection molding machine ("NEX50IV" manufactured by Nissei Plastic Industrial Co., Ltd.) and injection molded under the above-mentioned "Injection Condition Z" to obtain a test piece measuring 64 mm in length, 64 mm in width, and 3 mm in thickness. The color tone (SCI L*) of the obtained test piece was measured using a spectrophotometer ("CM-3600A" manufactured by Konica Minolta Japan Inc., light source D65, and measuring diameter φ25.4 mm). The obtained test piece was then heated in a muffle furnace at 350°C for 15 minutes. Thereafter, the test piece was cooled to room temperature, and the color tone (SCI L*) of the test piece was measured using the spectrophotometer. The color tone change of the molded article was evaluated based on the difference in the color tone (SCI L*) of the test piece before and after heating at 350°C for 15 minutes, using the following evaluation criteria. The evaluation results are shown in Table 2. Evaluation criteria A: The difference in color tone (SCI L*) of the test piece before and after heating was less than 5. B: The difference in color tone (SCI L*) of the test piece before and after heating was 5 or more.

[0136] [Mechanical Properties of Molded Article] The mechanical properties of the molded article were evaluated by measuring the solder heat resistance temperature, flexural strength and flexural modulus, and deflection temperature under load.

[0137] <<Solder Heat Resistance Temperature>> Pellets of the liquid crystal polyester composition were placed in an injection molding machine ("NEX50IV" manufactured by Nissei Plastic Industrial Co., Ltd.) and injection molded under the above-mentioned <<Injection Condition Z>> to obtain test pieces (JIS K7139-A12 dumbbell test pieces, thickness 0.8 mm). The test pieces were immersed in a solder bath heated to a predetermined temperature for 1 minute, removed, and then visually inspected for the presence of blisters or warping on the surface of the test pieces. The temperature of the solder bath was increased by 10°C increments, and the same visual inspection was performed. The highest temperature at which neither blisters nor warping was visually observed was measured as the solder heat resistance temperature of the liquid crystal polyester composition.

[0138] Pellets of the liquid crystal polyester composition were placed in an injection molding machine (NEX50IV manufactured by Nissei Plastic Industrial Co., Ltd.) and injection molded under the above-mentioned injection condition Z to obtain ASTM strip test pieces (length 127 mm, width 12.7 mm, thickness 6.4 mm). The flexural strength and flexural modulus of the test pieces were measured in accordance with ASTM D790.

[0139] <<Deflection temperature under load>> Pellets of the liquid crystal polyester composition were placed in an injection molding machine (NEX50IV manufactured by Nissei Plastic Industrial Co., Ltd.) and injection molded under the above-mentioned <<Injection condition Z>> to obtain ASTM strip test pieces (length 127 mm, width 12.7 mm, thickness 6.4 mm). The deflection temperature under load of the test pieces was measured at a heating rate of 2°C / min under a load of 1.82 MPa in accordance with ASTM D648.

[0140]

[0141] When the liquid crystal polyester compositions of Examples 1 and 2 were used, the amount of gas generated during molding was zero, and gas generation was suppressed. In addition, the molded articles containing the liquid crystal polyester compositions of Examples 1 and 2 had good releasability from the mold, and the color change of the molded articles due to high-temperature heating was small. When the liquid crystal polyester compositions of Comparative Examples 1 to 3 were used, gas was generated during molding. Furthermore, the molded articles containing the liquid crystal polyester compositions of Comparative Examples 1 and 2 showed a large color change due to high-temperature heating. The measured mechanical properties of the molded articles containing the liquid crystal polyester compositions of Examples 1 and 2 and the molded articles containing the liquid crystal polyester compositions of Comparative Examples 1 to 3 were comparable.

[0142] The configurations and combinations thereof in each embodiment are merely examples, and modifications such as addition, omission, and substitution of configurations are possible within the scope of the spirit of this disclosure. Furthermore, this disclosure is not limited to each embodiment, but is limited only by the claims.

Claims

1. A liquid crystal polyester composition comprising a liquid crystal polyester and a release agent containing pentaerythritol tetrastearate, wherein the release agent satisfies the following (a) and (b): (a) the 1% weight loss temperature in a nitrogen atmosphere is 270°C or higher and 360°C or lower, and (b) the amount of high boiling components generated during heating at 120°C for 20 hours is 15 ppm or less.

2. The liquid crystal polyester composition according to claim 1, wherein the release agent further satisfies the following requirement (c): (c) the color tone SCI L* after heating at 350°C for 15 minutes in an air atmosphere is 40 or more.

3. The liquid crystal polyester composition according to claim 1, wherein the release agent satisfies the following (a') and (b): (a') the 1% weight loss temperature in a nitrogen atmosphere is 280°C or higher and 350°C or lower, and (b) the amount of high boiling components generated during heating at 120°C for 20 hours is 15 ppm or lower.

4. The liquid crystal polyester composition according to claim 1, wherein the release agent satisfies the following (a) and (b'): (a) the 1% weight loss temperature in a nitrogen atmosphere is 270°C or higher and 360°C or lower, and (b') the amount of high boiling components generated during heating at 120°C for 20 hours is 13 ppm or lower.

5. The liquid crystal polyester composition according to claim 1, wherein the release agent satisfies the following (a') and (b'): (a') the 1% weight loss temperature in a nitrogen atmosphere is 280°C or higher and 350°C or lower, and (b') the amount of high boiling components generated during heating at 120°C for 20 hours is 13 ppm or lower.

6. The liquid crystal polyester composition according to claim 2, wherein the release agent further satisfies the following (c'): (c') the color tone SCI L* after heating at 350°C for 15 minutes in an air atmosphere is 45 or more.

7. The liquid crystal polyester composition according to claim 1, wherein the content of the release agent is 0.01 parts by mass or more based on 100 parts by mass of the liquid crystal polyester.

8. The liquid crystal polyester composition according to claim 7, wherein the content of the release agent is 0.01 part by mass or more and 1 part by mass or less per 100 parts by mass of the liquid crystal polyester.

9. The liquid crystal polyester composition according to claim 1, further comprising a fibrous filler.

10. The liquid crystal polyester composition according to claim 9, wherein the content of the fibrous filler is 5 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the liquid crystal polyester.

11. A molded article comprising the liquid crystal polyester composition according to any one of claims 1 to 10.

12. The molded product according to claim 11, wherein the amount of high boiling components generated when the molded product is heated at 120°C for 20 hours is 0.1 ppm or less.

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