TW202344562A - Method for producing liquid crystalline resin - Google Patents

Abstract

The present invention provides a method which is for producing a liquid crystal resin and from which a liquid crystal resin with a low amount of bonding of ketone can be obtained. This method for producing a liquid crystal resin, through the reaction of raw monomers containing at least one selected from the group consisting of an aromatic hydroxycarboxylic acid and a polymerizable derivative thereof, comprises conducting a polycondensation reaction of the raw monomers in the presence of at least one onium salt having at least one phosphorus atom. The method may further comprise acylating the raw monomers in the presence of at least one onium salt having one or more phosphorus atoms before conducting the polycondensation reaction.

Description

Method for manufacturing liquid crystalline resin

The present invention relates to a method for producing liquid crystalline resin.

Liquid crystalline resins, such as liquid crystal polyester resin and liquid crystal polyester amide resin, have a good balance in excellent fluidity, mechanical strength, heat resistance, chemical resistance and electrical properties, so they are suitable and widely used. Make high-performance engineering plastics. As a method for producing a liquid crystalline resin, there is known a method of obtaining a liquid crystalline resin by melt-polymerizing raw material monomers and further solid-phase polymerizing them if necessary. After melt-polymerizing the raw material monomers to generate oligomers, Methods such as solid-phase polymerization of oligomers to obtain liquid crystalline resins. Among them, in the former method, the raw material monomer needs to be melt-polymerized at a high temperature exceeding the melting point of the liquid crystal resin. When the raw material monomers are melt-polymerized at high temperatures, various side reactions tend to occur. One patent document describes a fully aromatic polyester in which the amount of ketone bonds generated by side reactions during polymerization reaction is within a prescribed range. On the other hand, Patent Document 2 describes a method for producing polyester, which includes mixing a diester containing divalent phenols and a predetermined aliphatic monoacid, an aromatic dicarboxylic acid, and a catalytic amount of an organic cation-containing diester. The step of heating the salt reaction mixture at a temperature above the melting temperature of the diester.

Patent Document 1: International Publication No. 2020/204125 Patent Document 2: Japanese Patent Publication No. 2001-516374

During melt polymerization of raw material monomers, if ketone-type bonds instead of ester bonds are formed in the main chain skeleton through side reactions, a branched chain structure will be easily formed. A liquid crystalline resin having a branched chain structure may have various physical properties such as toughness lowered than a liquid crystalline resin having a linear chain structure. Therefore, a liquid crystal resin with a small amount of ketone bonds is required.

An object of the present invention is to provide a method for producing a liquid crystalline resin that can obtain a liquid crystalline resin with a small amount of ketone bonds.

The present invention has the following aspects. [1] A method for producing a liquid crystalline resin by reacting one or more raw material monomers selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof to produce a liquid crystalline resin. Method, containing: In the presence of at least one onium salt having one or more phosphorus atoms, the raw material monomer is subjected to a polycondensation reaction. [2] The method for producing a liquid crystalline resin as described in [1], further comprising: before performing the aforementioned polycondensation reaction, in the presence of at least one onium salt having one or more phosphorus atoms, the aforementioned raw material monomer is chelated change. [3] The method for producing a liquid crystalline resin according to [1] or [2], wherein the onium salt has one or more aryl groups. [4] The method for producing a liquid crystalline resin according to any one of [1] to [3], wherein the onium salt contains a compound selected from the group consisting of a phosphonium salt and a phosphazenium salt. More than 1 species. [5] The method for producing a liquid crystalline resin according to any one of [1] to [4], wherein the final polymerization temperature at which the polycondensation reaction is performed is 200°C or higher. [6] The method for producing a liquid crystalline resin according to any one of [1] to [5], wherein the final polymerization temperature at which the polycondensation reaction is performed is 330°C or higher.

According to the present invention, a method for producing a liquid crystalline resin can be provided, which can obtain a liquid crystalline resin with a small amount of ketone bonds.

Hereinafter, one embodiment of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be implemented with appropriate changes within a range that does not inhibit the effects of the present invention. When a specific description describing one embodiment also applies to another embodiment, the description may be omitted in the other embodiment. In the present disclosure, the expression "X~Y" for the numerical range means "above X and below Y". In addition, when a plurality of upper limit values and lower limit values are described for a specific parameter, any upper limit value and lower limit value can be combined within these upper limit values and lower limit values to form an appropriate numerical range. .

[Method for manufacturing liquid crystalline resin] The method for producing a liquid crystalline resin according to this embodiment is a method for producing a liquid crystalline resin by reacting one or more raw material monomers selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof. The raw material monomer is subjected to a polycondensation reaction in the presence of at least one onium salt having one or more phosphorus atoms. Conventionally, attempts have been made to reduce the amount of ketone bonds by lowering the final polymerization temperature of the polycondensation reaction (for example, Patent Document 1). According to the research of the present inventor, it was found that by adding a compound selected from the group consisting of aromatic hydroxycarboxylic acids and their polymerizable derivatives in the presence of at least one onium salt having one or more phosphorus atoms, By performing a condensation polymerization reaction on one or more raw material monomers, the amount of ketone bonds in the resulting liquid crystalline resin can be reduced regardless of the final polymerization temperature of the condensation polymerization reaction. Since a liquid crystalline resin with a small number of ketone bonds has a small branched structure, a liquid crystalline resin excellent in various physical properties (especially toughness) can be obtained.

"Liquid crystallinity" refers to the property of forming an optically anisotropic melt phase. The nature of the anisotropic melt phase can be identified by conventional polarization inspection using crossed polarizers. More specifically, the confirmation of the anisotropic melt phase can be carried out by observing the melted sample placed on the Leitz hot stage under a nitrogen atmosphere at a magnification of 40 times using a Leitz polarizing microscope. When a resin with liquid crystallinity is inspected between crossed polarizers, polarized light is still transmitted even in a molten and static state, showing optical anisotropy.

(raw material monomer) The raw material monomer includes one or more compounds selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof. In the present disclosure, a "polymerizable derivative" refers to a compound that can be polymerized by melt polymerization among compounds in which a part of the molecular structure is changed. Examples include chelates in which phenolic hydroxyl groups and/or amino groups are chelated with a chelating agent, halides in which one or more hydrogen atoms of an aromatic hydrocarbon group are substituted with halogen atoms, and halides in which a carboxyl group is halogenated with a halogenating agent. (acid halide), acid anhydride, alkyl ester (about 1 to 4 carbon atoms), etc.

The aromatic hydroxycarboxylic acid and its polymerizable derivatives are not particularly limited, and examples thereof include 4-hydroxybenzoic acid (HBA) and 6-hydroxy-2-naphthoic acid (6-hydroxy-2-naphthoic acid). naphthoic acid (HNA), 3-hydroxybenzoic acid, 6-hydroxy-3-naphthoic acid, 6-hydroxy-4-naphthoic acid, 4-hydroxy-4'-carboxydiphenyl ether), 2,6-dichloroparahydroxybenzoic acid, 2-chloroparahydroxybenzoic acid, 2,6-dimethylparahydroxybenzoic acid, 2,6-difluoroparahydroxybenzoic acid, 4-hydroxy-4 '-Biphenylcarboxylic acid (4'-hydroxy-4-biphenylcarboxylic acid), vanillic acid, etc. At least one compound selected from these can be used. Among them, from the viewpoint of easy availability, it is preferred to use at least one selected from 4-hydroxybenzoic acid (HBA) and 6-hydroxy-2-naphthoic acid (HNA).

In one embodiment, one or more types of raw material monomers may be chelates in which phenolic hydroxyl groups and/or amino groups are chelated with a chelating agent. The chelation reaction will be described later.

The raw material monomer preferably satisfies the following (1) or (2). (1) Containing at least one compound selected from the group consisting of aromatic or alicyclic dicarboxylic acids and their polymerizable derivatives, or (2) Containing at least one compound selected from the group consisting of aromatic or alicyclic dicarboxylic acids and their polymerizable derivatives, and a compound selected from the group consisting of aromatic or alicyclic diols, aromatic or aliphatic diols At least one compound from the group consisting of cyclic hydroxylamine, aromatic or alicyclic diamine, and polymerizable derivatives thereof.

The aromatic dicarboxylic acid is not particularly limited, and examples thereof include 1,4-phenylenedicarboxylic acid (TA), 1,3-phenylenedicarboxylic acid (IA), 4,4' -diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, compounds represented by the following general formula (I), etc. General formula (I): (Y: a group selected from -(CH ₂ ) _n -(n=1~4) and -O(CH ₂ ) _n O-(n=1~4))

The alicyclic dicarboxylic acid is not particularly limited, and examples thereof include 1,4-cyclohexanedicarboxylic acid (cyclohexanedicarboxylic aAcid), 1,3-cyclopentanedicarboxylic acid, and the like. The polymerizable derivative is not particularly limited, and examples thereof include alkyl esters (about 1 to 4 carbon atoms) and halides of the above compounds.

The aromatic diol is not particularly limited, and examples thereof include 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl (BP), and 1,4-dihydroxynaphthalene. Dihydroxybenzene (HQ), 1,3-dihydroxybenzene (RES), a compound represented by the following general formula (II), a compound represented by the following general formula (III), and the like.

General formula (II): (X: a group selected from alkylene group (C ₁ ~ C ₄ ), alkylidene group (alkylidene), -O-, -SO-, -SO ₂ -, -S- and -CO-)

General formula (III):

The alicyclic diol is not particularly limited, and examples thereof include 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, and the like. The polymerizable derivative is not particularly limited, and examples thereof include alkyl esters (about 1 to 4 carbon atoms), halides, and the like of the above compounds.

The aromatic hydroxylamine is not particularly limited, and examples thereof include 4-aminophenol (aminophnol), 3-aminophenol, N-acetyl-para-aminophenol (APAP), and the like. The alicyclic hydroxylamine is not particularly limited, and examples thereof include 4-aminocyclohexanol, 3-aminocyclopentanol, and the like. The polymerizable derivative is not particularly limited, and examples thereof include alkyl esters (about 1 to 4 carbon atoms), halides, and the like of the above compounds.

Examples of aromatic diamines include 1,4-phenylenediamine (phenylenediamine) and the like. The alicyclic diamine is not particularly limited, and examples thereof include 1,4-cyclohexanediamine, 1,3-cyclopentanediamine, and the like. The polymerizable derivative is not particularly limited, and examples thereof include alkyl esters (about 1 to 4 carbon atoms), halides, and the like of the above compounds.

As a specific combination of raw material monomers, for example, a combination selected from the following can be used: (I) Containing (a) at least one compound selected from the group consisting of aromatic hydroxycarboxylic acid and its polymerizable derivatives (preferably, it is selected from the group consisting of aromatic hydroxycarboxylic acid and its polymerizable derivatives) consisting of at least 1 compound in the group); (II) Containing (a) at least one compound selected from the group consisting of aromatic hydroxycarboxylic acids and their polymerizable derivatives, (b) selected from the group consisting of aromatic or alicyclic dicarboxylic acids and their polymerizable derivatives At least one compound in the group consisting of derivatives, (c) is selected from the group consisting of aromatic or ester cyclic diols, aromatic hydroxylamines, aromatic diamines, and polymerizable derivatives thereof At least one compound (preferably composed of the above-mentioned compound (a), compound (b) and compound (c)). In addition, a molecular weight regulator may be used in combination with the above-mentioned constituent components as necessary.

(Onium salt with one or more phosphorus atoms) In the polycondensation reaction step, the above-mentioned raw material monomer is subjected to a polycondensation reaction in the presence of at least one onium salt having one or more phosphorus atoms (abbreviated as “onium salt”). By subjecting the raw material monomers to a polycondensation reaction in the presence of at least one onium salt having one or more phosphorus atoms, the amount of ketone bonds in the resulting liquid crystalline resin can be reduced.

In one embodiment, the onium salt having one or more phosphorus atoms is preferably composed of an organic cation, inorganic or organic anion having one or more phosphorus atoms. In one embodiment, the onium salt having one or more phosphorus atoms preferably has one or more, more preferably two or more, more preferably three or more, particularly preferably four or more aryl groups which may have substituents. (Preferably phenyl). In one embodiment, the onium salt having one or more phosphorus atoms preferably has one or more organic cations, more preferably two or more, still more preferably three or more, particularly preferably four or more, and may be substituted. Aryl group (preferably phenyl).

In one embodiment, the onium salt having one or more phosphorus atoms preferably has a cation represented by the following formula (IV) or formula (V): (In the formula, R ¹ , R ² , R ³ and R ⁴ each independently represent an alkyl group or aryl group having 1 to 20 carbon atoms (preferably a phenyl group) which may have a substituent); (In the formula, R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represent an alkyl group or aryl group having 1 to 20 carbon atoms (preferably a phenyl group) which may have a substituent. ).

In the formula (IV), preferably 1 or more of R ¹ , R ² , R ³ and R ⁴ are used, more preferably 2 or more are more preferably 3 or more, and particularly preferably 4 are aryl groups which may have substituents. (Preferably phenyl).

In formula (V), preferably 1 or more of R ⁵ , R ⁶ and R ⁷ , more preferably 2 or more, and still more preferably 3 are aryl groups (preferably phenyl) which may have a substituent. In formula (V), preferably 1 or more of R ⁸ , R ⁹ and R ¹⁰ , more preferably 2 or more, and still more preferably 3 are aryl groups (preferably phenyl groups) which may have a substituent.

The anion of the onium salt having one or more phosphorus atoms may be an inorganic anion or an organic anion. In one embodiment, the anion may be a halide ion such as Cl ^- , Br ^- , or I ^- . In another embodiment, the anion may have a structure represented by the following formula (VI): (In the formula, R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each independently represent an alkyl group or aryl group having 1 to 20 carbon atoms (preferably a phenyl group) which may have a substituent).

In one embodiment, at least one onium salt having one or more phosphorus atoms is preferably at least one selected from the group consisting of phosphonium salts and phosphazenium salts.

Specific examples of onium salts having one or more phosphorus atoms include methyltriphenylphosphonium chloride, tetraphenylphosphonium chloride, triphenylphosphoranylidene chloride, benzyl benzyltriphenylphosphonium chloride, naphthylmethyl triphenylphosphonium chloride, tetraphenylphosphonium bromide, tetraphenylphosphonium tetraphenylborate, tetraphenyl Phosphonium iodide (tetraphenylphosphonium iodide), etc. Preferably, one or more types selected from these are included. One type of onium salt having at least one phosphorus atom may be used alone, or two or more types may be used in combination.

The usage amount of the onium salt having one or more phosphorus atoms is preferably 0.001~0.2 mol%, more preferably 0.005~0.05 mol% relative to the raw material monomer. In one embodiment, an onium salt having one or more phosphorus atoms can function as a catalyst in the polycondensation reaction of the raw material monomer and/or the chelation reaction described below. In one embodiment, the usage amount of the onium salt having one or more phosphorus atoms can be set as the catalyst amount.

(Condensation polymerization reaction step (melt polymerization step)) In the polycondensation reaction step, a polycondensation reaction is performed on one or more raw material monomers selected from the group consisting of aromatic hydroxycarboxylic acids and polymerizable derivatives thereof. The polycondensation reaction proceeds by melt polymerization. Liquid crystalline resin is obtained by subjecting raw material monomers to a polycondensation reaction. As will be described later, depending on the requirements, there may be a chelation step of the raw material monomer before the polycondensation reaction step, or a solid-phase polymerization step after the polycondensation reaction step.

The polycondensation temperature is, for example, preferably 200 to 400°C, more preferably 240 to 380°C. According to the method for producing a liquid crystalline resin of this embodiment, the amount of ketone bonds can be reduced even when the final polymerization temperature is high. In one embodiment, the final polymerization temperature may be 330°C or higher, may be a temperature exceeding 330°C, may be 340°C or higher, may be 350°C or higher.

The time of the polycondensation reaction is preferably 2 to 12 hours, more preferably 3 to 10 hours, and still more preferably 4 to 7 hours.

In one embodiment, the polycondensation reaction is preferably performed after the reaction system reaches a predetermined temperature and then starts to be depressurized to a predetermined degree of pressure reduction.

The above-mentioned onium salt having one or more phosphorus atoms has a function as a catalyst in addition to the function of preventing the amount of ketone bonds. In one embodiment, a catalyst is preferably used in the polycondensation reaction step, and the catalyst preferably contains at least one onium salt having one or more phosphorus atoms. The usage amount of the onium salt having one or more phosphorus atoms is as described above.

Organic compound-based catalysts such as N-methylimidazole and 4-dimethylaminopyridine can be used. However, the above-mentioned onium salt having one or more phosphorus atoms functions as a catalyst and therefore does not need to be included. The above-mentioned organic compound is a catalyst.

In one embodiment, from the viewpoint of reducing the amount of ketone bonds in the liquid crystal resin, the content of ammonium cations in the polycondensation reaction mixture is preferably less than 0.05 mol% relative to the raw material monomers, and more preferably does not contain ammonium cations. . Examples of salts containing ammonium cations include pentafluorophenylammonium trifluoromethanesulfonate (PFPAT), pentafluorophenylammonium bistrifluoromethanesulfonylimide, and diphenylammonium trifluoromethanesulfonylimide. Sulfonic acid (diphenylammonium trifluoromethanesulfonate, DPAT), etc.

The molecular weight of the liquid crystalline resin obtained by the polycondensation reaction can be further increased by solid phase polymerization. Solid phase polymerization will be described later.

In one embodiment, the number average degree of polymerization of the liquid crystalline resin obtained by the polycondensation reaction step is preferably 40 or more, more preferably 50 or more. The number average degree of polymerization is a value calculated based on the distillation amount of acetic acid by-produced during the polycondensation reaction.

(enzyme step) In the production method of this embodiment, a step of chelating the raw material monomer using a chelating agent may be provided before the polycondensation reaction. From the viewpoint of producing the liquid crystalline resin in a shorter time and improving the chelation rate, it is preferable to carry out the chelation in the presence of at least one onium salt having one or more phosphorus atoms. That is, in one embodiment, the method for producing a liquid crystalline resin preferably further includes: before performing the polycondensation reaction, the raw material monomer is chelated in the presence of at least one onium salt having one or more phosphorus atoms. The onium salt having one or more phosphorus atoms used here may be the same type as the onium salt having one or more phosphorus atoms used in the polycondensation reaction step, or may be a different type. In one embodiment, when the polycondensation reaction step is performed after the chelation step, at least one onium salt having one or more phosphorus atoms used in the chelation step can be used continuously in the polycondensation reaction step. Specific examples and usage amounts of onium salts having one or more phosphorus atoms are as described above, so they are omitted here.

Examples of the chelating agent include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, tertiary valeric anhydride (pivalic anhydride), 2-ethylhexanoic anhydride, monochloroacetic anhydride, dichloroacetic anhydride, and trichloroacetic anhydride. Acetic anhydride, monobromoacetic anhydride, dibromoacetic anhydride, tribromoacetic anhydride, monofluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, glutaric anhydride, maleic anhydride, succinic anhydride, β-bromopropionic anhydride, etc. , no special restrictions. At least one selected from these can be used. From the viewpoint of price and workability, carboxylic anhydrides such as acetic anhydride, propionic anhydride, butyric anhydride and isobutyric anhydride are preferably used. Among them, acetic anhydride is preferred from the viewpoint of easy availability. From the viewpoint of easy control of the reaction, the usage amount of the chelating agent is preferably 1.0 to 1.1 equivalents, more preferably 1.01 to 1.05 equivalents in the total amount of hydroxyl groups of the substances used for the reaction.

The chelation can be performed by a known method. For example, the raw material monomers and the chelating agent are mixed and heated in a temperature range of 120 to 160° C. for about 0.5 to 5 hours to perform a chelating reaction to obtain a reaction product containing a chelating compound.

(Solid phase polymerization step) The manufacturing method of this embodiment may include the step of further solid-phase polymerizing the resin obtained in the polycondensation reaction step. By solid-state polymerization, the molecular weight of the raw material resin can be increased, and a liquid crystalline resin excellent in strength, heat resistance, etc. can be obtained.

A conventionally known method can be used for solid phase polymerization. For example, it can be performed under reduced pressure or vacuum, in an inert gas flow such as nitrogen, by heating at a temperature 10 to 120° C. lower than the liquid crystal formation temperature of the raw resin (resin obtained in the polycondensation step). In addition, the melting point of the liquid crystalline resin increases as the solid-state polymerization proceeds, so the solid-state polymerization can be performed above the original melting point of the raw resin. Solid-state polymerization can be carried out at a certain temperature, or it can reach high temperatures in stages. The heating method is not particularly limited, and microwave heating, heater heating, etc. can be used.

[Liquid crystalline resin] The liquid crystalline resin obtained by the method for producing a liquid crystalline resin of this embodiment preferably contains at least one selected from the group consisting of liquid crystalline polyester and liquid crystalline polyesteramide. The liquid crystalline polyester and liquid crystalline polyesteramide are not particularly limited, but aromatic polyester or aromatic polyesteramide is preferred. In addition, a polyester partially containing aromatic polyester or aromatic polyesteramide in the same molecular chain may be used. In one embodiment, the liquid crystalline resin obtained preferably contains one or more types selected from the group consisting of a fully aromatic polyester and a fully aromatic polyesteramide. "Fully aromatic" means that all raw material monomers have aromatic rings.

The aromatic polyester or aromatic polyesteramide contains at least a structural unit derived from an aromatic hydroxycarboxylic acid and its polymerizable derivatives. More specifically, examples include: (1) Polyester mainly composed of (a) one or more types of aromatic hydroxycarboxylic acid and its derivatives; (2) Mainly composed of (a) 1 or more types of aromatic hydroxycarboxylic acid and its derivatives, and (b) 1 type of aromatic dicarboxylic acid, alicyclic dicarboxylic acid, and their derivatives Or polyester composed of 2 or more types; (3) Mainly composed of (a) one or more aromatic hydroxycarboxylic acids and their derivatives, (b) one or more aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives Polyester composed of 2 or more kinds, and (c) 1 or 2 or more kinds of aromatic diols, alicyclic diols, aliphatic diols, and their derivatives; (4) Mainly composed of (a) 1 or more kinds of aromatic hydroxycarboxylic acids and their derivatives, (c1) 1 or more kinds of aromatic hydroxylamine, aromatic diamine, and their derivatives, and (c2) polyesteramides composed of one or more types of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives; (5) Mainly composed of (a) one or more aromatic hydroxycarboxylic acids and their derivatives, (b) one or more aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives 2 or more types, (c1) 1 or more types of aromatic hydroxylamine, aromatic diamine, and their derivatives, and (c2) aromatic diol, alicyclic diol, and their derivatives Polyesteramides composed of one or more than two types.

The molecular weight (number average molecular weight Mn) of the liquid crystalline resin is not particularly limited, but as the resin obtained in the polycondensation reaction (melt polymerization) step, it is preferably 10,000 to 100,000, more preferably 15,000 to 80,000. As for the resin obtained in the solid phase polymerization step, 12,000 to 120,000 is preferred, and 15,000 to 100,000 is more preferred. In addition, the number average molecular weight Mn can be measured by gel permeation chromatography. The molecular weight (weight average molecular weight Mw) of the liquid crystalline resin is not particularly limited, but as the resin obtained in the polycondensation reaction (melt polymerization) step, it is preferably 50,000 to 500,000, more preferably 75,000 to 400,000. As for the resin obtained in the solid phase polymerization step, 60,000 to 600,000 is preferred, and 75,000 to 550,000 is more preferred. In addition, the weight average molecular weight Mw can be measured by gel permeation chromatography.

The melting point of the liquid crystal resin is not particularly limited, but may be 250 to 380°C. The melt viscosity of the liquid crystal resin is not particularly limited. As a resin obtained in the polycondensation reaction (melt polymerization) step, the melt viscosity is measured at a tube temperature 10 to 30°C higher than the melting point of the liquid crystal resin and a shear speed of 1000 sec ^-1 It 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. When the solid-state polymerization step is further performed, the melt viscosity of the resin measured at a tube temperature 10 to 30°C higher than the melting point of the liquid crystal resin and a shear speed of 1000 sec ^-1 is preferably 5 Pa·s or more and 200 Pa·s or less. , more preferably 10Pa·s or more and 150Pa·s or less. The so-called "tube temperature that is 10 to 30°C higher than the melting point of the liquid crystal resin" refers to the tube temperature at which the liquid crystal resin can melt to the extent that the melt viscosity can be measured. The tube temperature is set to how many degrees Celsius higher than the melting point. The range of 10~30℃ varies depending on the type of raw resin. The liquid crystalline resin may be in the form of a mixture of powder and granules, or may be in the form of a molten mixture (melt-kneaded product) of particles or the like. In this disclosure, melt viscosity refers to melt viscosity measured according to ISO11443.

The liquid crystalline resin obtained by the method for producing a liquid crystalline resin according to this embodiment has few branched structures based on ketone-type bonds. In one embodiment, the ketone bond amount of the obtained liquid crystalline resin calculated by the following method is preferably 0.12 mol% or less, more preferably 0.10 mol% or less, more preferably 0.08 mol% or less, particularly preferably 0.05 mol% or less. . The calculation method of the ketone bond amount is as follows. Using a thermal decomposition device, the liquid crystal resin is heated in the coexistence of tetramethylammonium hydroxide (TMAH) to generate gas through thermal decomposition/methylation. The gas is analyzed with a gas chromatograph, and the amount of ketone bonds is calculated from the ratio of the peak area from the ketone bond to the peak area from the ester bond. [Example]

The present invention will be explained more specifically by the following Examples, but the interpretation of the present invention is not limited to these Examples.

[Example 1] After the following raw materials were put into the polymerization vessel, the temperature of the reaction system was raised to 140°C, and the reaction was carried out at 140°C for 3 hours (gelation step). Thereafter, the temperature was raised to 360° C. again over 4.5 hours, and then the pressure was reduced to 10 Torr (i.e., 1330 Pa) over 15 minutes, and polycondensation was performed while distilling off acetic acid, excess acetic anhydride and other low-boiling components (polycondensation reaction step). After the stirring torque reaches a predetermined value, nitrogen gas is introduced to change the pressure from a reduced pressure state to a normal pressure state to a pressurized state, and the polymer is discharged from the lower part of the polymerization vessel. After that, the strand is granulated to obtain liquid crystalline resin particles. (raw material) 4-hydroxybenzoic acid (HBA): 183.7g (60 mol%) 1,4-phenylenedicarboxylic acid (TA): 51.56g (14 mol%) 1,3-phenylenedicarboxylic acid (IA): 22.10g (6 mol%) 4,4-dihydroxybiphenyl (BP): 82.56g (20 mol%) Methyltriphenylphosphonium chloride: 191.2mg (0.02mol%) Chelating agent (acetic anhydride): 233.1g

[Examples 2~8]. Liquid crystalline resin particles were obtained in the same manner as in Example 1, except that the onium salt-substituted methyltriphenylphosphonium chloride shown in Table 1 was used.

[Comparative example 1] Liquid crystalline resin particles were obtained in the same manner as in Example 1, except that at least one onium salt having one or more phosphorus atoms and other catalysts were not used.

[Comparative example 2] Liquid crystalline resin particles were obtained in the same manner as in Example 1, except that pentafluorophenylammonium trifluoromethanesulfonate (PFPAT) was used instead of methyltriphenylphosphonium chloride.

[Example 9] After the following raw materials were put into the polymerization vessel, the temperature of the reaction system was raised to 140°C, and the reaction was carried out at 140°C for 3 hours (gelation step). Thereafter, the temperature was raised to 320°C again over 3.5 hours, and polycondensation (polycondensation reaction step) was performed for 45 minutes while distilling out acetic acid, excess acetic anhydride, and other low-boiling components. Thereafter, while introducing nitrogen gas, the oligomer was discharged from the lower part of the polymerization container. Thereafter, the strands were crushed using a Wiley-type crusher and classified using a sieve with a mesh size of 2.0 mm and a sieve with a mesh size of 1.4 mm to obtain a liquid crystalline resin with an average particle diameter of 1.4 to 2.0 mm. The weight average molecular weight (Mw) of the liquid crystalline resin was calculated as follows and was 44,000 (oligomer). (raw material) 4-Hydroxybenzoic acid (HBA): 188.3g (60 mol%) 6-hydroxy-2-naphthoic acid (HNA): 21.4g (5 mol%) 1,4-phenylenedicarboxylic acid (TA): 66.0g (17.5 mol%) 4,4-Dihydroxybiphenyl (BP): 52.9g (12.5 mol%) N-acetyl-para-aminophenol (APAP): 17.2 g (5 mol%) Tetraphenylphosphonium chloride: 56.2 mg (0.0068 mol%) 10 g of liquid crystalline resin (oligomer) with an average particle diameter of 1.4 to 2.0 mm obtained above was put into a solid-phase polymerization container equipped with a nitrogen inlet/outlet, and placed under a nitrogen atmosphere. The reaction system was heated to 140°C and then dried for 3 hours. Furthermore, the temperature was raised to 280°C over 1.5 hours, followed by reaction for 4 hours (solid phase polymerization step). Thereafter, the temperature was lowered to normal temperature to obtain a liquid crystalline resin. The weight average molecular weight (Mw) of the liquid crystalline resin was calculated as follows and was 536,000. [Weight average molecular weight (Mw)] The obtained liquid crystalline resin was dissolved by stirring at normal temperature for 6 hours using 3,5-bis(trifluoromethyl)phenol as a solvent. This solution was analyzed using gel permeation chromatography (manufactured by Tosoh Corporation, "HLC-8320GPC", differential refractometer detector), and the weight average molecular weight (Mw) was calculated in terms of standard polystyrene.

[Comparative example 3] A liquid crystalline resin with an average particle diameter of 1.4 to 2.0 mm was obtained in the same manner as in Example 9, except that at least one onium salt having one or more phosphorus atoms and other catalysts were not used. The weight average molecular weight (Mw) of the liquid crystalline resin was calculated and found to be 32,000 (oligomer). The obtained liquid crystalline resin (oligomer) with an average particle diameter of 1.4 to 2.0 mm was solid-state polymerized in the same manner as in Example 9 to obtain a liquid crystalline resin. The weight average molecular weight (Mw) of the liquid crystalline resin was calculated and found to be 60,000.

[keto bond amount] The ketone bond amount of the obtained liquid crystalline resin was calculated by the thermal decomposition gas chromatography method described in Polymer Degradation and Stability 76 (2002) 85-94. Specifically, a thermal decomposition device ("PY2020iD" manufactured by Frontier Labs Co., Ltd.) is used to heat the fully aromatic polyester in the coexistence of tetramethylammonium hydroxide (TMAH), and thermal decomposition/methylation Generate gas. This gas was analyzed with a gas chromatograph ("GC-6890N" manufactured by Agilent Technologies, Co., Ltd.), and the amount of ketone bonds was calculated from the ratio of the peak area derived from ketone bonds and the peak area derived from ester bonds. The results are shown in Table 1 and Table 2.

[Solid phase polymerization speed] In Example 9 and Comparative Example 3, the difference in weight average molecular weight of the liquid crystalline resin obtained before and after solid phase polymerization was calculated as the solid phase polymerization time divided by the solid phase polymerization time. The results are shown in Table 2.

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative example 1 Comparative example 2 onium salt - Methyltriphenylphosphonium chloride Tetraphenylphosphonium chloride triphenylphosphine chloride Benzyltriphenylphosphonium chloride Naphthylmethyltriphenylphosphonium chloride Tetraphenylphosphonium bromide Tetraphenylborontetraphenylphosphonium Tetraphenylphosphonium iodide without Pentafluoroanilinium trifluoromethanesulfonic acid - Onium salt content mol% 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 - 0.02 final polymerization temperature ℃ 360 360 360 360 360 360 360 360 360 360 Amount of ketone bonds mol% 0.12 0.02 0.04 0.06 0.07 0.02 0.01 0.02 0.13 0.20

[Table 2] Example Comparative example 9 3 onium salt - Tetraphenylphosphonium chloride without - Onium salt content mol% 0.0068 - final polymerization temperature ℃ 320 320 solid phase polymerization rate Mw/h 123000 7000 Amount of ketone bonds mol% 0.02 0.08

As shown in Table 1, the ketone bond amount of the liquid crystalline resin obtained by the manufacturing method of Examples 1 to 8 is 0.12 mol% or less, and the ketone bond amount is less than that of Comparative Example 1 (without catalyst) and Comparative Example 2 ( PFPAT) liquid crystal resin obtained by the manufacturing method. Liquid crystalline resin with a small number of ketone bonds has a small branched chain structure and is particularly excellent in toughness. As shown in Table 2, the same is true when a solid-state polymerization step is performed after a polycondensation step. The amount of ketone bonds in the liquid crystalline resin obtained by the production method of Example 9 is less than that of Comparative Example 3 (without catalyst). Liquid crystalline resin obtained by manufacturing method. Liquid crystalline resin with a small number of ketone bonds has a small branched chain structure and is particularly excellent in toughness. In addition, in the manufacturing method of Example 9, the solid-phase polymerization rate is improved compared to the manufacturing method of Comparative Example 3. [Industrial availability]

According to the method for producing a liquid crystalline resin of this embodiment, a liquid crystalline resin having a small amount of ketone bonds and excellent physical properties can be obtained, and therefore has industrial applicability.

without

without

Claims (6)

A method for producing a liquid crystalline resin, which is a method for producing a liquid crystalline resin by reacting one or more raw material monomers selected from the group consisting of aromatic hydroxycarboxylic acids and their polymerizable derivatives, including : In the presence of at least one onium salt having one or more phosphorus atoms, the raw material monomer is subjected to a polycondensation reaction. The method for producing a liquid crystalline resin according to claim 1, further comprising: before performing the polycondensation reaction, the raw material monomer is chelated in the presence of at least one onium salt having one or more phosphorus atoms. The method for producing a liquid crystalline resin according to claim 1 or 2, wherein the onium salt has one or more aryl groups. The method for producing a liquid crystalline resin according to claim 1 or 2, wherein the onium salt contains at least one selected from the group consisting of phosphonium salts and phosphazenium salts. The method for producing a liquid crystalline resin according to claim 1 or 2, wherein the final polymerization temperature for carrying out the polycondensation reaction is 200°C or higher. The method for producing a liquid crystalline resin according to claim 1 or 2, wherein the final polymerization temperature for carrying out the polycondensation reaction is 330°C or higher.