Method for producing liquid crystalline resin

Abstract

To provide a method for producing a liquid crystalline resin that achieves higher reaction speed than conventional methods.SOLUTION: A method for producing a liquid crystalline resin, comprising polycondensing a raw monomer including at least one selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof, in the presence of at least one first metal compound containing potassium and at least one second metal compound containing one or more metal atoms selected from the group consisting of calcium, iron, and sodium. The polycondensation preferably involves only melt polymerization, or both melt polymerization and solid-phase polymerization.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing a liquid crystalline resin. [Background technology]

[0002] Liquid crystalline resins, typified by liquid crystalline polyester resins and liquid crystalline polyesteramide resins, have a good balance of excellent fluidity, mechanical strength, heat resistance, chemical resistance, electrical properties, etc., and are therefore widely used as high-performance engineering plastics.

[0003] Known methods for producing liquid crystalline resins include melt-polymerizing raw material monomers and, if necessary, further solid-phase polymerizing them to obtain a liquid crystalline resin, and melt-polymerizing raw material monomers to form oligomers, and then solid-phase polymerizing the oligomers to obtain a liquid crystalline resin. For example, Patent Document 1 proposes a method for obtaining a liquid crystalline polyester by two-stage polymerization of prepolymer melt polymerization and solid-phase polymerization. Before melt polymerization, the phenolic hydroxyl groups or amino groups of the raw material monomers may be acylated as necessary. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-139674 Summary of the Invention [Problem to be solved by the invention]

[0005] In the polycondensation step of raw material monomers, if the reaction rates of acylation of the raw material monomers, melt polymerization, and the subsequent solid-state polymerization are slow, productivity will decrease.

[0006] An object of the present disclosure is to provide a method for producing a liquid crystalline resin with a reaction rate that is improved compared to conventional methods. [Means for solving the problem]

[0007] As a result of extensive research, the inventors of the present application have found that the above-mentioned problems can be solved by a method for producing a liquid crystalline resin, which comprises polycondensing raw material monomers containing one or more elements selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof in the presence of at least one first metal compound containing potassium and at least one second metal compound containing one or more metal atoms selected from the group consisting of calcium, iron, and sodium. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a method for producing a liquid crystalline resin with a reaction rate that is improved compared to conventional methods. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present disclosure will be described in detail below, but the scope of the present disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the present disclosure. Furthermore, when multiple numerical ranges are described for a specific parameter, any of the numerical values ​​described therein can be combined to form a suitable numerical range. Furthermore, the lower and / or upper limits of a numerical range described in this disclosure are numerical values ​​within that range and may be replaced with numerical values ​​shown in the examples. The expression "X to Y" indicating a numerical range means "X or more and Y or less." When a specific description given for one embodiment also applies to other embodiments, that description may be omitted in other embodiments.

[0010] [Method for producing liquid crystal resin] The method for producing a liquid crystalline resin according to this embodiment involves polycondensing raw material monomers containing one or more compounds selected from the group consisting of aromatic hydroxycarboxylic acids and their polymerizable derivatives in the presence of at least one first metal compound containing potassium and at least one second metal compound containing one or more metal atoms selected from the group consisting of calcium, iron, and sodium. Polycondensing the raw material monomers in the presence of the first metal compound and the second metal compound can shorten the time required to reach a predetermined final torque. It can also increase the polymerization rate in solid-state polymerization.

[0011] "Liquid crystallinity" refers to the ability to form an optically anisotropic melt phase. The properties of an anisotropic melt phase can be confirmed by a conventional polarization examination method using crossed polarizers. More specifically, the anisotropic melt phase can be confirmed by observing a molten sample placed on a Leitz hot stage at 40x magnification using a Leitz polarizing microscope under a nitrogen atmosphere. When a resin with liquid crystallinity is examined between crossed polarizers, polarized light usually passes through, even when the resin is in a molten, stationary state, demonstrating optical anisotropy.

[0012] <Raw material monomer> The raw material monomer includes one or more compounds selected from the group consisting of aromatic hydroxycarboxylic acids and their polymerizable derivatives. In the present disclosure, "polymerizable derivative" refers to a compound whose molecular structure has been partially changed and which can be polymerized by a polycondensation reaction. Examples include acylated compounds in which a phenolic hydroxyl group and / or an amino group is acylated with an acylating agent, halides in which one or more hydrogen atoms of an aromatic hydrocarbon group are substituted with a halogen atom, acid halides in which a carboxyl group is halogenated with a halogenating agent, acid anhydrides, and alkyl esters (having approximately 1 to 4 carbon atoms).

[0013] (aromatic hydroxycarboxylic acid) Examples of aromatic hydroxycarboxylic acids include 4-hydroxybenzoic acid (HBA), 6-hydroxy-2-naphthoic acid (HNA), 3-hydroxybenzoic acid, 6-hydroxy-3-naphthoic acid, 6-hydroxy-4-naphthoic acid, 4-hydroxy-4'-carboxydiphenyl ether, 2,6-dichloro-p-hydroxybenzoic acid, 2-chloro-p-hydroxybenzoic acid, 2,6-dimethyl-p-hydroxybenzoic acid, 2,6-difluoro-p-hydroxybenzoic acid, 4-hydroxy-4'-biphenylcarboxylic acid, and vanillic acid. At least one compound selected from these can be used as the raw material monomer. Among these, at least one compound selected from 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid is preferred in terms of availability.

[0014] (Polymerizable derivatives of aromatic hydroxycarboxylic acids) The polymerizable derivative of aromatic hydroxycarboxylic acid that can be contained in the raw material monomer preferably includes an acylated product obtained by acylating the phenolic hydroxyl group of aromatic hydroxycarboxylic acid with an acylating agent. In a particularly preferred embodiment, the polymerizable derivative includes an acylated product of 4-hydroxybenzoic acid (HBA) and / or an acylated product of 6-hydroxy-2-naphthoic acid (HNA).

[0015] In one embodiment, the content of the aromatic hydroxycarboxylic acid and its polymerizable derivative in the raw material monomers may be 40 to 100 mol %, 40 to 70 mol %, or 65 to 100 mol % relative to the total amount of the raw material monomers.

[0016] (Other monomers) The raw material monomers may contain polycondensable monomers (other monomers) other than one or more compounds selected from the group consisting of aromatic hydroxycarboxylic acids and their polymerizable derivatives. When other monomers are contained, it is preferable that the following (1) or (2) is satisfied:

[0017] (1) containing at least one compound selected from the group consisting of aromatic or alicyclic dicarboxylic acids and polymerizable derivatives thereof, or (2) Contains at least one compound selected from the group consisting of aromatic or alicyclic dicarboxylic acids and polymerizable derivatives thereof, and at least one compound selected from the group consisting of aromatic or alicyclic diols, aromatic or alicyclic hydroxyamines, aromatic or alicyclic diamines, and polymerizable derivatives thereof.

[0018] The aromatic dicarboxylic acid is not particularly limited, and examples thereof include terephthalic acid (TA), isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and compounds represented by the following general formula (I).

[0019] General formula (I): TIFF2025134299000001.tif20170(Y:-(CH2) n -(n=1 to 4) and -O(CH2) n O-(n=1 to 4).

[0020] The polymerizable derivative of the aromatic dicarboxylic acid is not particularly limited, and examples thereof include alkyl esters (having about 1 to 4 carbon atoms) of the above compounds, halides of the above compounds, and the like.

[0021] The alicyclic dicarboxylic acid is not particularly limited, and examples thereof include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, etc. Polymerizable derivatives thereof include alkyl esters (having about 1 to 4 carbon atoms) of the above compounds, halides of the above compounds, etc.

[0022] The total content of at least one compound selected from the group consisting of aromatic or alicyclic dicarboxylic acids and polymerizable derivatives thereof is preferably 5 to 50 mol %, more preferably 15 to 25 mol %, and even more preferably 15 to 20 mol %, based on the total amount of raw material monomers.

[0023] The aromatic diol is not particularly limited, and examples thereof include 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl (BP), hydroquinone, resorcinol, a compound represented by the following general formula (II), and a compound represented by the following general formula (III).

[0024] General formula (II): TIFF2025134299000002.tif21170 (X: alkylene (C1-C4), alkylidene (C1-C 10 ), —O—, —SO—, —SO2—, —S—, and —CO—.

[0025] General formula (III): TIFF2025134299000003.tif21170 The alicyclic diol is not particularly limited, and examples thereof include 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, etc. Polymerizable derivatives thereof include acylated products of the above compounds, alkyl esters (having about 1 to 4 carbon atoms) of the above compounds, and halides of the above compounds.

[0026] The aromatic hydroxyamine is not particularly limited, and examples thereof include N-acetyl-p-aminophenol (APAP), 4-aminophenol, 3-aminophenol, etc. The alicyclic hydroxyamine is not particularly limited, and examples thereof include 4-aminocyclohexanol, 3-aminocyclopentanol, etc. The polymerizable derivatives include acylated products of the above compounds, alkyl esters (having about 1 to 4 carbon atoms) of the above compounds, and / or halides of the above compounds.

[0027] Examples of aromatic diamines include 1,4-phenylenediamine, etc. Examples of alicyclic diamines include, but are not limited to, 1,4-cyclohexanediamine, 1,3-cyclopentanediamine, etc. Examples of polymerizable derivatives include acylated compounds of the above compounds, alkyl esters (having about 1 to 4 carbon atoms) of the above compounds, and / or halides of the above compounds.

[0028] The total content of at least one compound selected from the group consisting of aromatic or alicyclic diols, aromatic or alicyclic hydroxyamines, aromatic or alicyclic diamines, and polymerizable derivatives thereof is preferably 5 to 50 mol %, more preferably 15 to 25 mol %, and even more preferably 15 to 20 mol %, based on the total amount of raw material monomers.

[0029] Specific combinations of raw material monomers include, for example: (I) (Ia) contains at least one compound selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof (preferably contains only at least one compound selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof, more preferably contains only aromatic hydroxycarboxylic acids and / or acylated aromatic hydroxycarboxylic acids); (II) (IIa) at least one compound selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof, (IIb) at least one compound selected from the group consisting of aromatic or alicyclic dicarboxylic acids and polymerizable derivatives thereof, and (IIc) at least one compound selected from the group consisting of aromatic or alicyclic diols, aromatic hydroxyamines, aromatic diamines, and polymerizable derivatives thereof (preferably, the composition contains only the compounds (IIa), (IIb), and (IIc), more preferably, the compound (IIa) contains only aromatic hydroxycarboxylic acids and / or acylated aromatic hydroxycarboxylic acids); The combination may be selected from the following: Furthermore, a molecular weight modifier may be used in combination with the above-mentioned components, if necessary.

[0030] <First metal compound> The first metal compound is a compound containing potassium. The first metal compound may be one type, or two or more types may be used in combination.

[0031] In one embodiment, from the viewpoint of easily achieving the effects of the present disclosure, the first metal compound preferably includes one or more selected from the group consisting of acetates, carbonates, oxides, hydroxides, and chlorides containing potassium. In a preferred embodiment, the first metal compound includes one or more selected from the group consisting of potassium acetate, potassium carbonate, potassium oxide, potassium hydroxide, and potassium chloride. In a more preferred embodiment, the first metal compound includes potassium acetate. Note that when the first metal compound is a compound that forms a hydrate, the first metal compound may be an anhydride or a hydrate.

[0032] In one embodiment, the amount of the first metal compound used in the polycondensation step is preferably 5 to 150 ppm by mass, more preferably 5 to 50 ppm by mass, and even more preferably 15 to 40 ppm by mass, relative to the total amount of raw material monomers. The aforementioned amount is the total amount used in the entire polycondensation step. In the present disclosure, the amount of the first metal compound used is the amount of metal (potassium amount) contained in the first metal compound relative to the total amount of raw material monomers. In the production method of the present disclosure, the reaction rate of the polycondensation step can be improved by using the first metal compound and the second metal compound in combination as polymerization catalysts. Furthermore, the above effects can be achieved with a relatively small amount of catalyst.

[0033] <Second metal compound> The second metal compound is a compound containing one or more metal atoms selected from the group consisting of calcium, iron, and sodium. The second metal compound may be one type, or two or more types may be used in combination.

[0034] In one embodiment, the second metal compound is preferably a compound containing one metal atom selected from the group consisting of calcium, iron, and sodium. From the viewpoint of easily achieving the effects of the present disclosure, the second metal compound preferably contains calcium or iron as the metal atom, and more preferably contains calcium.

[0035] In one embodiment, the second metal compound preferably comprises one or more selected from the group consisting of acetates, carbonates, oxides, hydroxides, and chlorides containing the one or more metal atoms, more preferably comprises one or more selected from the group consisting of acetates and carbonates containing the one or more metal atoms, and even more preferably comprises an acetate of calcium, iron, or sodium. When the second metal compound is a compound that forms a hydrate, the second metal compound may be anhydrous or hydrated.

[0036] Preferred examples of the second metal compound include calcium acetate, iron acetate, sodium acetate, calcium carbonate, iron carbonate, sodium carbonate, calcium oxide, iron oxide, sodium oxide, calcium hydroxide, iron hydroxide, sodium hydroxide, calcium chloride, iron chloride, and sodium chloride, and it is preferred to use one or more of these in combination.

[0037] In one embodiment, the amount of the second metal compound used in the polycondensation step is preferably 1 to 30 ppm by mass, more preferably 1 to 20 ppm by mass, and particularly preferably 2 to 10 ppm by mass, relative to the total amount of raw material monomers. The aforementioned amount refers to the total amount used in the entire polycondensation step. In the present disclosure, the amount of the second metal compound used refers to the amount of metal contained in the second metal compound (the total amount of one or more metals selected from the group consisting of calcium, iron, and sodium) relative to the total amount of raw material monomers. As described above, in the production method of the present disclosure, the reaction rate of the polycondensation step can be improved by using the first metal compound and the second metal compound in combination as polymerization catalysts. Furthermore, the above effects can be achieved with a relatively small amount of catalyst.

[0038] <Combination of First Metal Compound and Second Metal Compound> As a combination of the first metal compound and the second metal compound, when the polycondensation step includes melt polymerization and solid-state polymerization, from the viewpoint of easily improving the reaction rates in both polymerization steps, a combination in which the first metal compound is potassium acetate and the second metal compound includes one or more acetates of calcium, iron, or sodium is preferred. In a more preferred embodiment, the combination may be potassium acetate and calcium acetate.

[0039] The total amount of the first metal compound and the second metal compound used in the polycondensation step is preferably 5 to 150 ppm by mass, more preferably 10 to 75 ppm by mass, and even more preferably 10 to 50 ppm by mass, relative to the total amount of raw material monomers. The total amount is the sum of the amount of the first metal compound (potassium amount) and the amount of the second metal compound (total amount of one or more metals selected from the group consisting of calcium, iron, and sodium) used relative to the total amount of raw material monomers.

[0040] In one embodiment, the ratio of the amounts of the first metal compound and the second metal compound used (amount of the first metal compound used / amount of the second metal compound used) is preferably 1 to 50, more preferably 1 to 20, and even more preferably 2 to 16. From the viewpoint of easily achieving the effect of improving the reaction rate, it is more preferable that the amount of the first metal compound used is greater than the amount of the second metal compound used. Furthermore, it is particularly preferable that the amount of the first metal compound used is 1.5 times or more the amount of the second metal compound used.

[0041] <Other ingredients> In the production method according to the present embodiment, it is possible to carry out polymerization by adding stabilizers, colorants, fillers, etc., within a range that does not inhibit or reduce the effects of the present disclosure. Furthermore, a polymerization catalyst other than the first metal compound and the second metal compound may also be used in combination. From the viewpoint of easily achieving the effects of the present disclosure, it is preferable that the polymerization catalyst contains only the first metal compound and the second metal compound.

[0042] <Polycondensation process> In the production method according to this embodiment, raw material monomers containing one or more selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof are polycondensed in the presence of the first metal compound and the second metal compound. The polycondensation step may include only melt polymerization, or may include melt polymerization and solid-state polymerization. When the polycondensation step includes melt polymerization and solid-state polymerization, it is preferable to carry out solid-state polymerization after melt polymerization. By polycondensing the raw material monomers, a desired liquid crystalline resin can be obtained.

[0043] (melt polymerization) The polycondensation step preferably includes melt polymerization. The polycondensation temperature during melt polymerization is preferably 200 to 400°C, more preferably 240 to 380°C, and even more preferably 300 to 360°C.

[0044] In the production method according to this embodiment, the reaction rate during polycondensation can be improved by using the first metal compound and the second metal compound together as catalysts. In particular, the time required to reach the final torque can be shortened. In one embodiment, the time required to reach the final torque in melt polymerization can be 0.5 to 0.9 times the time required to reach the final torque when only the first metal compound or only the second metal compound is used as a catalyst.

[0045] In one embodiment, it is preferable that the melt polymerization is carried out by starting the decompression after the reaction system has reached a predetermined temperature, and then maintaining the decompression at a predetermined level. In one embodiment, the polycondensation reaction is preferably carried out by melt polymerization under a reduced pressure of 10,000 to 133 Pa (preferably 5,000 to 1,330 Pa). In another embodiment, the melt polymerization is carried out under normal pressure (1.013 × 10 5The melt polymerization may be carried out at a pressure of 1000 Pa or less. When the melt polymerization is carried out under normal pressure, an oligomer (having a weight-average molecular weight of less than 50,000) of the raw material monomer is obtained. That is, when the production method according to this embodiment includes only melt polymerization, the finally obtained liquid crystalline resin may contain an oligomer having a weight-average molecular weight of less than 50,000. Note that, from the viewpoint of making the finally obtained liquid crystalline resin have a weight-average molecular weight of 50,000 or more, more preferably 70,000 or more, the melt polymerization is preferably carried out under reduced pressure. Furthermore, from the viewpoint of further increasing the molecular weight, it is preferable to carry out solid-phase polymerization after the melt polymerization. The solid-phase polymerization will be described later.

[0046] When the production method according to the present embodiment includes melt polymerization and solid-state polymerization, the resin obtained by melt polymerization and used as the raw material for solid-state polymerization will be referred to as a "prepolymer" for convenience. Furthermore, in the present disclosure, the weight-average molecular weight is a value calculated by analysis using gel permeation chromatography.

[0047] In a preferred embodiment, the polycondensation step is carried out using a raw material monomer containing an acylated product of the aromatic hydroxycarboxylic acid. In this case, it is preferable to prepare the raw material monomer containing the acylated product and then carry out melt polymerization. Hereinafter, the preparation of the raw material monomer containing the acylated product will be described as the "acylation step."

[0048] (Acylation step) The acylation step involves reacting a raw material monomer containing one or more compounds selected from the group consisting of aromatic hydroxycarboxylic acids and their polymerizable derivatives with an acylating agent. The acylation step is carried out in the presence of a first metal compound and a second metal compound. By carrying out the acylation step in the presence of the first metal compound and the second metal compound, the acylation rate can be increased in a shorter time than in conventional methods. As a result, a method for producing a liquid crystalline resin with a faster reaction rate than conventional methods can be achieved.

[0049] The first metal compound and the second metal compound used in the acylation step can be a combination of the preferred compounds exemplified in the polycondensation step. That is, in a preferred embodiment of the production method of this embodiment, raw material monomers, an acylating agent, and a first metal compound and a second metal compound (preferably a combination of potassium acetate and a second metal compound containing one or more acetates of calcium, iron, or sodium) are charged into a polymerization vessel and reacted at a temperature below the polycondensation initiation temperature of the raw material monomers to prepare raw material monomers containing an acylated product, and then the temperature is raised to the polymerization initiation temperature of the raw material monomers containing the acylated product to perform melt polymerization. After preparing the raw material monomers containing an acylated product, additional first metal compounds and second metal compounds may be added to perform melt polymerization. When additional first metal compounds and second metal compounds are added, first metal compounds and / or second metal compounds different from those used in the acylation step may also be added.

[0050] The reaction temperature during the acylation step can be adjusted arbitrarily within the range of 120 to 160°C. The reaction time is not particularly limited as long as it is a time that results in an acylation rate of 90% or more, and can be set within the range of 0.5 to 5 hours, for example. In the production method according to this embodiment, the acylation step is performed in the presence of the first metal compound and the second metal compound, so that the time required to achieve an acylation rate of 90% or more can be shortened.

[0051] Examples of acylating agents include, but are not limited to, acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, pivalic anhydride, 2-ethylhexanoic anhydride, monochloroacetic anhydride, dichloroacetic anhydride, trichloroacetic anhydride, monobromoacetic anhydride, dibromoacetic anhydride, tribromoacetic anhydride, monofluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, glutaric anhydride, maleic anhydride, succinic anhydride, and β-bromopropionic anhydride. At least one selected from these can be used. Preferred acylating agents from the standpoint of cost and ease of handling include carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, butyric anhydride, and isobutyric anhydride. Among these, acetic anhydride is preferred from the standpoint of ease of availability. The amount of acylating agent used is preferably 1.0 to 1.1 equivalents, more preferably 1.01 to 1.05 equivalents, based on the total amount of hydroxyl groups in the substances used in the reaction, from the standpoint of ease of reaction control.

[0052] As described above, carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, butyric anhydride, and isobutyric anhydride can be preferably used as the acylating agent, and in this case, the polycondensation step of the liquid crystalline resin is carried out under acidic conditions. In the production method according to this embodiment, since a specific first metal compound and a specific second metal compound are used as polymerization catalysts, a certain catalytic effect (i.e., an improvement in the reaction rate in the polycondensation step) can be obtained even if the pH of the aqueous solution in the polycondensation step fluctuates slightly.

[0053] (solid-state polymerization) In one embodiment, solid-state polymerization may be carried out after melt polymerization. By carrying out solid-state polymerization after melt polymerization, it is possible to increase the molecular weight and obtain a liquid crystalline resin with superior strength and heat resistance. The solid-state polymerization is also carried out in the presence of a first metal compound and a second metal compound. By carrying out solid-state polymerization in the presence of a first metal compound and a second metal compound, it is possible to increase the molecular weight in a short time. As a result, the solid-state polymerization rate can be increased compared to conventional methods.

[0054] When solid-state polymerization is carried out after melt polymerization, the prepolymer is pelletized, and the pellets are then charged into a solid-state polymerization vessel to carry out solid-state polymerization.

[0055] Solid-state polymerization can be carried out by a conventionally known method. For example, it can be carried out by heating the prepolymer at a temperature 10 to 120°C lower than the liquid crystal formation temperature under reduced pressure or vacuum in a stream of inert gas such as nitrogen gas. Since the melting point of the liquid crystalline resin increases as the solid-state polymerization proceeds, it is also possible to carry out solid-state polymerization at a temperature higher than the original melting point of the prepolymer. Solid-state polymerization can be carried out at a constant temperature or by gradually increasing the temperature. The heating method is not particularly limited, and microwave heating, heater heating, etc. can be used.

[0056] In one embodiment, the solid-state polymerization may be carried out preferably at 250 to 320° C., more preferably at 260 to 300° C., for preferably 2 to 10 hours, more preferably 2 to 5 hours.

[0057] The production method according to this embodiment may include deactivating the first metal compound and the second metal compound after the polycondensation step.

[0058] The desired liquid crystalline resin can be obtained through the above-mentioned polycondensation step. In a preferred embodiment, the acylation step, melt polymerization, and solid-state polymerization do not include the additional addition of the first metal compound and the second metal compound. That is, in the production method according to this embodiment, predetermined amounts of the first metal compound and the second metal compound are charged together with the raw material monomers at the start of polymerization, and then the desired liquid crystalline resin can be produced by melt polymerization alone or by a combination of melt polymerization and solid-state polymerization.

[0059] [Liquid Crystalline Resin] The liquid crystalline resin obtained by the method for producing a liquid crystalline resin according to this embodiment preferably contains at least one selected from liquid crystalline polyesters and liquid crystalline polyesteramides. The liquid crystalline polyesters and liquid crystalline polyesteramides are not particularly limited, but are preferably aromatic polyesters or aromatic polyesteramides. Furthermore, polyesters that partially contain aromatic polyesters or aromatic polyesteramides in the same molecular chain may also be used. In one embodiment, the liquid crystalline resin obtained preferably contains one or more selected from wholly aromatic polyesters and wholly aromatic polyesteramides. "Wholely aromatic" means that all raw material monomers have aromatic rings.

[0060] The aromatic polyester or aromatic polyester amide contains at least a structural unit derived from an aromatic hydroxycarboxylic acid and a polymerizable derivative thereof, and more specifically, (1) Polyesters consisting essentially of (1a) one or more aromatic hydroxycarboxylic acids and their derivatives; (2) Polyesters consisting essentially of (2a) one or more aromatic hydroxycarboxylic acids and their derivatives, and (2b) one or more aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives; (3) polyesters consisting essentially of (3a) one or more aromatic hydroxycarboxylic acids and their derivatives, (3b) one or more aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives, and (3c) one or more aromatic diols, alicyclic diols, aliphatic diols, and their derivatives; (4) polyesteramides consisting essentially of (4a) one or more aromatic hydroxycarboxylic acids and their derivatives, (4c1) one or more aromatic hydroxyamines, aromatic diamines, and their derivatives, and (4c2) one or more aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives; (5) Examples include polyesteramides mainly composed of (5a) one or more aromatic hydroxycarboxylic acids and their derivatives, (5b) one or more aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives, (5c1) one or more aromatic hydroxyamines, aromatic diamines, and their derivatives, and (5c2) one or more aromatic diols, alicyclic diols, and their derivatives.

[0061] The molecular weight (weight average molecular weight Mw) of the liquid crystalline resin is not particularly limited. When the aforementioned production method includes only melt polymerization, or includes melt polymerization and solid-state polymerization, the Mw of the liquid crystalline resin (or prepolymer) after melt polymerization is preferably 50,000 to 500,000, more preferably 75,000 to 400,000. When the aforementioned production method includes melt polymerization and solid-state polymerization, the Mw of the liquid crystalline resin obtained after solid-state polymerization is preferably 60,000 to 600,000, more preferably 75,000 to 500,000.

[0062] The melting point of the liquid crystal resin is not particularly limited and can be set to 250 to 380°C.

[0063] The melt viscosity of the liquid crystalline resin is also not particularly limited. When the above-mentioned production method includes only melt polymerization, or includes melt polymerization and solid-state polymerization, the liquid crystalline resin (or prepolymer) after melt polymerization is melted at a cylinder temperature 10 to 30°C higher than the melting point of the liquid crystalline resin and a shear rate of 1000 sec -1 The melt viscosity measured by is preferably 5 Pa·s or more and 150 Pa·s or less, more preferably 10 Pa·s or more and 100 Pa·s or less, and even more preferably 20 Pa·s or more and 50 Pa·s or less.

[0064] When the above-mentioned production method includes melt polymerization and solid-state polymerization, the liquid crystalline resin obtained after solid-state polymerization is subjected to a cylinder temperature 10 to 30°C higher than the melting point of the liquid crystalline resin and a shear rate of 1000 sec -1The melt viscosity measured by is preferably 5 Pa·s or more and 200 Pa·s or less, more preferably 10 Pa·s or more and 150 Pa·s or less, and even more preferably more than 50 Pa·s and 100 Pa·s or less.

[0065] The term "cylinder temperature 10 to 30°C higher than the melting point of the liquid crystalline resin" refers to the cylinder temperature at which the liquid crystalline resin can be melted to an extent that allows measurement of the melt viscosity. The cylinder temperature higher than the melting point varies within the range of 10 to 30°C depending on the type of raw material resin. The liquid crystalline resin can be in the form of a powder or granular mixture, or in the form of a molten mixture (melt-kneaded product) such as pellets. In the present disclosure, melt viscosity refers to the melt viscosity measured in accordance with ISO 11443.

[0066] Another embodiment of the present disclosure is a use of at least one first metal compound containing potassium and at least one second metal compound containing one or more metal atoms selected from the group consisting of calcium, iron, and sodium as a catalyst for polycondensation of raw material monomers containing one or more selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof, or a method of using the same. The first metal compound is preferably potassium acetate, and the second metal compound is preferably calcium acetate, iron acetate, or sodium acetate.

[0067] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of the present disclosure are set forth below.

[0068] [1] A method for producing a liquid crystalline resin, comprising polycondensing raw material monomers containing one or more compounds selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof in the presence of at least one first metal compound containing potassium and at least one second metal compound containing one or more metal atoms selected from the group consisting of calcium, iron, and sodium.

[0069] [2] The method for producing a liquid crystalline resin according to [1], wherein the polycondensation includes only melt polymerization, or includes melt polymerization and solid-state polymerization.

[0070] [3] The method for producing a liquid crystalline resin according to [1] or [2], wherein the raw material monomer contains an acylated product of the aromatic hydroxycarboxylic acid.

[0071] [4] the raw material monomer includes an acylated product of the aromatic hydroxycarboxylic acid, The method for producing a liquid crystalline resin according to any one of [1] to [3], wherein the polycondensation comprises preparing the raw material monomer containing the acylated product and then melt-polymerizing the raw material monomer.

[0072] [5] The method for producing a liquid crystalline resin according to [4], wherein the polycondensation further comprises solid-state polymerization after the melt polymerization.

[0073] [6] The method for producing a liquid crystalline resin according to any one of [1] to [5], wherein the first metal compound comprises one or more selected from the group consisting of acetates, carbonates, oxides, hydroxides, and chlorides, including potassium.

[0074] [7] The method for producing a liquid crystalline resin according to any one of [1] to [6], wherein the second metal compound comprises one or more selected from the group consisting of acetates, carbonates, oxides, hydroxides, and chlorides containing the one or more metal atoms. [Example]

[0075] The present disclosure will be explained in more detail below by showing examples, but interpretation of the present disclosure is not limited to these examples.

[0076] [Example 1] The following raw materials were charged into a polymerization vessel, and then the temperature of the reaction system was raised to 140°C and the reaction was carried out at 140°C for 3 hours to prepare raw material monomers containing acylated products (acylation step).

[0077] Thereafter, the temperature was further increased to 325°C over 4.5 hours, and the pressure was then reduced to 10 Torr (i.e., 1330 Pa) over 15 minutes, and melt polymerization was carried out while distilling off acetic acid, excess acetic anhydride, and other low boiling points.

[0078] After the stirring torque reached a predetermined value (0.7 V), nitrogen was introduced to change the pressure from reduced pressure to normal pressure and then to pressurized state, and the polymer was discharged from the bottom of the polymerization vessel. The strands were then pelletized to obtain prepolymer pellets. The time required from the start of pressure reduction until the stirring torque reached the predetermined value (0.7 V) (time to reach final torque) was measured. The results are shown in Table 1. The obtained prepolymer was subjected to a shear rate of 1000 sec. -1 The melt viscosity measured at a cylinder temperature of 300°C was 23 Pa·s.

[0079] The prepolymer pellets were then solid-state polymerized under the following conditions:

[0080] 10 g of the prepolymer pellets obtained above were charged into a solid-state polymerization vessel equipped with a nitrogen inlet / outlet and placed under a nitrogen atmosphere. The reaction system was heated to 270°C and reacted for 3 hours. The temperature was then lowered to room temperature, and the liquid crystalline resin pellets were taken out. The obtained liquid crystalline resin was subjected to a shear rate of 1000 sec. -1 The melt viscosity measured at a cylinder temperature of 300°C was 73.6 Pa·s. The solid-state polymerization rate was calculated as follows. The results are shown in Table 1.

[0081] [Solid phase polymerization rate] The difference between the melt viscosity of the prepolymer and the melt viscosity of the liquid crystalline resin was divided by the solid phase polymerization time to calculate the solid phase polymerization rate.

[0082] [Raw materials] <Raw material monomer> 4-Hydroxybenzoic acid (HBA): 226 g (73 mol%) 6-Hydroxy-2-naphthoic acid (HNA): 114 g (27 mol%) <First metal compound> Potassium acetate (KOAc): 22.5 g (30 ppm by mass as potassium relative to the total amount of raw material monomers) <Second metal compound> Calcium acetate (Ca(OAc)2): 0.6 mg (2 ppm by mass as calcium relative to the total amount of raw material monomers) <Acylating agent> Acetic anhydride: 234g

[0083] [Example 2] A liquid crystalline resin was produced in the same manner as in Example 1, except that the second metal compound was changed to iron acetate (Fe(OAc)2). The time to reach final torque, the melt viscosity of the prepolymer, the melt viscosity of the liquid crystalline resin, and the solid-state polymerization rate were measured in the same manner as in Example 1. The results are shown in Table 1.

[0084] [Example 3] A liquid crystalline resin was produced in the same manner as in Example 1, except that the second metal compound was changed to sodium acetate (NaOAc). The time to reach final torque, the melt viscosity of the prepolymer, the melt viscosity of the liquid crystalline resin, and the solid-state polymerization rate were measured in the same manner as in Example 1. The results are shown in Table 1.

[0085] [Example 4] A liquid crystalline resin was produced in the same manner as in Example 1, except that the amount of calcium acetate in the second metal compound was changed to 8 ppm by mass in terms of calcium. The time to reach final torque, the melt viscosity of the prepolymer, the melt viscosity of the liquid crystalline resin, and the solid-state polymerization rate were measured in the same manner as in Example 1. The results are shown in Table 1.

[0086] [Example 5] A liquid crystalline resin was produced in the same manner as in Example 2, except that the amount of iron acetate in the second metal compound was changed to 8 ppm by mass in terms of iron. The time to reach final torque, the melt viscosity of the prepolymer, the melt viscosity of the liquid crystalline resin, and the solid-state polymerization rate were measured in the same manner as in Example 2. The results are shown in Table 1.

[0087] [Example 6] A liquid crystalline resin was produced in the same manner as in Example 3, except that the amount of sodium acetate in the second metal compound was changed to 8 ppm by mass in terms of sodium. The time to reach final torque, the melt viscosity of the prepolymer, the melt viscosity of the liquid crystalline resin, and the solid-state polymerization rate were measured in the same manner as in Example 3. The results are shown in Table 1.

[0088] [Comparative Examples 1 to 3] A liquid crystalline resin was produced in the same manner as in Example 1, except that the amount of potassium acetate in the first metal compound (as a potassium amount) was as shown in Table 1 and no second metal compound was added. The time to reach final torque, the melt viscosity of the prepolymer, the melt viscosity of the liquid crystalline resin, and the solid-state polymerization rate were measured in the same manner as in Example 1. The results are shown in Table 1.

[0089] [Example 7] The following raw materials were charged into a polymerization vessel, and the temperature of the reaction system was raised to 140°C. The reaction was carried out at 140°C for 1 hour to prepare raw material monomers containing acylated products (acylation step). The acylation rate was calculated in the same manner as in Example 1. The results are shown in Table 2.

[0090] Thereafter, the temperature was further increased to 340°C over 4.5 hours, and the pressure was then reduced to 10 Torr (i.e., 1330 Pa) over 15 minutes, and melt polymerization was carried out while distilling off acetic acid, excess acetic anhydride, and other low boiling points.

[0091] After the stirring torque reached a predetermined value (0.7 V), nitrogen was introduced to change the pressure from reduced pressure to normal pressure and then to pressurized state, and the polymer was discharged from the bottom of the polymerization vessel. The strands were then pelletized to obtain prepolymer pellets. The time required from the start of pressure reduction until the stirring torque reached the predetermined value (0.7 V) (time to reach final torque) was measured. The results are shown in Table 2. The obtained prepolymer was subjected to a shear rate of 1000 sec. -1 The melt viscosity measured at a cylinder temperature of 360°C was 16.2 Pa·s.

[0092] The prepolymer pellets were then solid-state polymerized under the following conditions:

[0093] 10 g of the prepolymer pellets obtained above were charged into a solid-state polymerization vessel equipped with a nitrogen inlet / outlet and placed under a nitrogen atmosphere. The reaction system was heated to 295°C and reacted for 4 hours. The temperature was then lowered to room temperature, and the liquid crystalline resin pellets were taken out. The obtained liquid crystalline resin was subjected to a shear rate of 1000 sec. -1 The melt viscosity measured at a cylinder temperature of 360°C was 60.8 Pa·s. The solid-state polymerization rate was calculated under the same conditions as in Example 1. The results are shown in Table 2.

[0094] [Raw materials] <Raw material monomer> 4-Hydroxybenzoic acid (HBA): 188 g (60 mol%) 6-Hydroxy-2-naphthoic acid (HNA): 21 g (5 mol%) Terephthalic acid (TA): 66 g (17.5 mol%) 4,4'-dihydroxybiphenyl (BP): 53 g (12.5 mol%) N-acetyl-p-aminophenol (APAP): 17 g (5 mol%) <First metal compound> Potassium acetate: 15 mg (20 ppm by mass as potassium relative to the total amount of raw material monomers) <Second metal compound> Calcium acetate: 3 mg (10 ppm by mass as calcium relative to the total amount of raw material monomers) <Acylating agent> Acetic anhydride: 225g

[0095] Comparative Example 4 A liquid crystalline resin was produced in the same manner as in Example 7, except that the second metal compound was not added. The time to reach final torque, the melt viscosity of the prepolymer, the melt viscosity of the liquid crystalline resin, and the solid-state polymerization rate were measured in the same manner as in Example 7. The results are shown in Table 2.

[0096] Comparative Example 5 A liquid crystalline resin was produced in the same manner as in Example 7, except that the amount of potassium acetate in the first metal compound was changed to 30 ppm by mass in terms of potassium, and no second metal compound was added. The time to reach final torque, the melt viscosity of the prepolymer, the melt viscosity of the liquid crystalline resin, and the solid-state polymerization rate were measured in the same manner as in Example 7. The results are shown in Table 2.

[0097] Comparative Example 6 A liquid crystalline resin was produced in the same manner as in Example 7, except that no first metal compound was added and calcium acetate was added as the second metal compound in an amount of 30 ppm by mass in terms of calcium. The time to reach final torque, the melt viscosity of the prepolymer, the melt viscosity of the liquid crystalline resin, and the solid-state polymerization rate were measured in the same manner as in Example 7. The results are shown in Table 2.

[0098] [Table 1]

[0099] [Table 2]

[0100] In Table 1, the decrease in the time to reach final torque in Examples 1 to 6 and Comparative Examples 2 to 3 is a relative value to Comparative Example 1 in which the first metal compound was used alone. Similarly, the increase in the solid-state polymerization rate is also a relative value to Comparative Example 1. In Table 2, the decrease in the time to reach final torque and the increase in the solid-state polymerization rate in Example 7 and Comparative Examples 5 to 6 are relative values ​​to Comparative Example 4.

[0101] As shown in Examples 1 to 7 in Tables 1 and 2, by polycondensing raw material monomers in the presence of the first metal compound and the second metal compound, the time to reach the final torque in melt polymerization could be shortened compared to Comparative Examples 1 to 6. Also, in solid-state polymerization, the solid-state polymerization rate could be increased compared to Comparative Examples 1 to 7. [Industrial Applicability]

[0102] The method for producing a liquid crystalline resin according to the present embodiment has an improved reaction rate compared to conventional methods, and therefore can produce a liquid crystalline resin efficiently, and has industrial applicability.

Claims

1. A method for producing a liquid crystalline resin, comprising polycondensing raw material monomers containing one or more compounds selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof, in the presence of at least one first metal compound containing potassium and at least one second metal compound containing one or more metal atoms selected from the group consisting of calcium, iron, and sodium.

2. The method for producing a liquid crystalline resin according to claim 1 , wherein the polycondensation comprises only melt polymerization, or comprises melt polymerization and solid-state polymerization.

3. The method for producing a liquid crystalline resin according to claim 1 or 2, wherein the raw material monomer comprises an acylated product of the aromatic hydroxycarboxylic acid.

4. the raw material monomer includes an acylated product of the aromatic hydroxycarboxylic acid, The method for producing a liquid crystalline resin according to claim 1 or 2, wherein the polycondensation comprises preparing the raw material monomer containing the acylated product and then melt-polymerizing the raw material monomer.

5. The method for producing a liquid crystalline resin according to claim 4 , wherein the polycondensation further comprises solid-state polymerization after the melt polymerization.

6. 3. The method for producing a liquid crystalline resin according to claim 1, wherein the first metal compound comprises one or more selected from the group consisting of acetates, carbonates, oxides, hydroxides, and chlorides containing potassium.

7. 3. The method for producing a liquid crystalline resin according to claim 1, wherein the second metal compound comprises one or more selected from the group consisting of acetates, carbonates, oxides, hydroxides, and chlorides containing the one or more metal atoms.

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