Liquid crystalline resin and liquid crystalline resin composition

Abstract

The present invention provides: a liquid crystalline resin which has a low dielectric constant, while maintaining good polymerizability; and a liquid crystalline resin composition which contains the same.　A liquid crystalline resin according to the present invention exhibits optical anisotropy when melted, contains constituent units (I) to (III), and contains or does not contain a constituent unit (IV). Relative to all constituent units, the content of the constituent unit (I) is 1-40 mol%, the content of the constituent unit (II) is 20-98 mol%, the content of the constituent unit (III) is 1-40%, and the content of the constituent unit (IV) is 0-39 mol%. With respect to the constituent unit (I), the difference between the maximum value and the minimum value of the rotational energy around a central atom C1 as calculated by a PM6 method, which is a semiempirical molecular orbital method, is 0.42-0.82 kcal / mol. In the formula, each of R1 and R2 independently represents a hydrogen atom or the like, each X independently represents a hydrogen atom or the like, Ar1 to Ar3 each independently represent a phenylene group or the like, and Y and Z each independently represent an oxygen atom or an imino group.

Description

Liquid crystal resin and liquid crystal resin composition

[0001] The present invention relates to a liquid crystalline resin and a liquid crystalline resin composition.

[0002] Liquid crystalline resins have a good balance of excellent mechanical strength, heat resistance, chemical resistance, electrical properties, etc., and also have excellent dimensional stability, and are therefore widely used as high-performance engineering plastics. Meanwhile, in recent years, remarkable technological developments have been made in the information and communications field, including mobile phones; wireless LANs; and ITS technologies such as GPS, VICS (registered trademark), and ETC. Accordingly, there is a growing need for high-performance high-frequency electronic components that can be used in high-frequency regions such as microwaves and millimeter waves. Materials constituting such electronic components are required to have appropriate dielectric properties depending on the design of each electronic component.

[0003] For example, Patent Document 1 discloses that a molded article of a wholly aromatic liquid crystalline polyester resin composition having a relative dielectric constant of 3.0 or less and a dielectric dissipation factor of 0.04 or less, which is obtained by injection molding a composition containing 90 to 45% by weight of a wholly aromatic liquid crystalline polyester having a melting point of 320°C or more, 10 to 40% by weight of inorganic hollow spheres having an aspect ratio of 2 or less, and 0 to 15% by weight of an inorganic filler having an aspect ratio of 4 or more, has heat resistance such as resistance to solder reflow, is excellent in dielectric properties, and is used as a fixing or holding member for transmitting and receiving parts of information and communication devices used in high frequency bands such as microwaves and millimeter waves.

[0004] JP 2004-27021 A JP 2017-095625 A

[0005] However, according to the investigations of the present inventors, it has been found that increasing the amount of inorganic hollow spheres added to improve the dielectric properties tends to decrease the strength of the molded article. Therefore, it is believed that by improving the dielectric properties of the liquid crystalline resin itself, a molded article containing the liquid crystalline resin will be able to easily maintain its strength while improving its dielectric properties, even if it does not contain inorganic hollow spheres.

[0006] For example, Patent Document 2 discloses a liquid crystal polymer that is a copolymer composed of a polymerizable monomer selected from the group consisting of specific biphenylfluorene compounds and their reactive derivatives and other polymerizable monomers, as a liquid crystal polymer in which the resin itself has a low dielectric constant and is excellent in dielectric properties. However, conventional liquid crystal resins in which the resin itself has a low dielectric constant and is excellent in dielectric properties tend to have a rapid increase in melt viscosity during polymerization, and as a result, polymerizability tends to decrease.

[0007] In view of the above problems, an object of the present invention is to provide a liquid crystalline resin having a low dielectric constant while maintaining good polymerizability, and a liquid crystalline resin composition containing the same.

[0008] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, they have found that the above-mentioned problems can be solved by a liquid crystalline resin containing a structural unit derived from a specific bisphenol, a structural unit derived from a hydroxyarenecarboxylic acid, and a structural unit derived from an arylenedicarboxylic acid, and containing or not containing a structural unit derived from an arenediol, arenediamine, or hydroxyarylamine, and the content of each structural unit being within a specific range, thereby completing the present invention. More specifically, the present invention provides the following.

[0009] (1) A liquid crystalline resin that exhibits optical anisotropy when melted, the liquid crystalline resin contains the following structural units (I), (II), and (III), and may or may not contain the following structural unit (IV), the content of structural unit (I) is 1 to 40 mol% based on all structural units, the content of structural unit (II) is 20 to 98 mol% based on all structural units, the content of structural unit (III) is 1 to 40 mol% based on all structural units, and the content of structural unit (IV) is 0 to 39 mol% based on all structural units, the structural unit (I) has a central atom C calculated by the PM6 method, which is a semi-empirical molecular orbital method. １ A liquid crystalline resin, wherein the difference between the maximum and minimum values ​​of rotational energy around the molecule is 0.42 to 0.82 kcal / mol.

[0010] (In the formula, R １ and R２ each independently represents a hydrogen atom, an aliphatic chain hydrocarbon group having from 1 to 6 carbon atoms, an alicyclic hydrocarbon group having from 3 to 8 carbon atoms, or an aromatic hydrocarbon group having from 6 to 10 carbon atoms. Each X independently represents a hydrogen atom, an aliphatic chain hydrocarbon group having from 1 to 6 carbon atoms, an alicyclic hydrocarbon group having from 3 to 8 carbon atoms, an aromatic hydrocarbon group having from 6 to 10 carbon atoms, or a halogen atom.

[0011] (In the formula, Ar １ , Ar ２ , and Ar ３ each independently represents a phenylene group, a naphthylene group, or a biphenylylene group; and Y and Z each independently represent an oxygen atom or an imino group.

[0012] (2) The liquid crystal resin according to (1), wherein the total content of the structural units (I) to (IV) is 100 mol % based on all the structural units.

[0013] (3) The liquid crystal resin according to (1) or (2), wherein the content of the structural unit (I) is 3 to 35 mol % relative to all structural units, the content of the structural unit (II) is 30 to 90 mol % relative to all structural units, the content of the structural unit (III) is 5 to 35 mol % relative to all structural units, and the content of the structural unit (IV) is 0 to 30 mol % relative to all structural units.

[0014] (4) The liquid crystal resin according to any one of (1) to (3), wherein the structural unit (I) is a structural unit derived from one or more members selected from the group consisting of 1,1-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)cyclohexylmethane, 1,1-bis(4-hydroxyphenyl)-1-phenylpropane, 1,1-bis(4-hydroxyphenyl)-1-phenylbutane, and derivatives thereof.

[0015] (5) A liquid crystal resin composition comprising the liquid crystal resin according to any one of (1) to (4).

[0016] (6) A molded article made of the liquid crystalline resin according to any one of (1) to (4).

[0017] (7) A molded article made of the liquid crystal resin composition according to (5).

[0018] According to the present invention, it is possible to provide a liquid crystalline resin having a low dielectric constant while maintaining good polymerizability, and a liquid crystalline resin composition containing the same.

[0019] FIG. 1 is a top view showing the cutting positions of the test pieces for evaluating dielectric characteristics used in the examples and comparative examples.

[0020] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0021] <Liquid Crystalline Resin> The liquid crystal resin of the present invention contains the following structural units (I), (II), and (III), and may or may not contain the following structural unit (IV).

[0022]

[0023] In the formula representing the structural unit (I), R １ and R ２ each independently represents a hydrogen atom, an aliphatic chain hydrocarbon group having from 1 to 6 carbon atoms, an alicyclic hydrocarbon group having from 3 to 8 carbon atoms, or an aromatic hydrocarbon group having from 6 to 10 carbon atoms.

[0024] R １ and R ２ From the viewpoint of achieving both polymerizability and a low dielectric constant, the aliphatic chain hydrocarbon group having 1 to 6 carbon atoms represented by is preferably an aliphatic chain hydrocarbon group having 1 to 4 carbon atoms, and more preferably an aliphatic chain hydrocarbon group having 1 to 3 carbon atoms. Examples of the aliphatic chain hydrocarbon group having 1 to 6 carbon atoms include alkyl groups having 1 to 6 carbon atoms, alkenyl groups having 2 to 6 carbon atoms, and alkynyl groups having 2 to 6 carbon atoms.

[0025] R １ and R ２With regard to the above, from the viewpoint of achieving both polymerizability and a low dielectric constant, the alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. From the viewpoint of achieving both polymerizability and a low dielectric constant, a methyl group, an ethyl group, a propyl group, and a butyl group are preferred, and a methyl group, an ethyl group, and a propyl group are more preferred.

[0026] R １ and R ２ With regard to the above, from the viewpoint of achieving both polymerizability and a low dielectric constant, the alkenyl group having from 2 to 6 carbon atoms is preferably an alkenyl group having from 2 to 4 carbon atoms, and more preferably an alkenyl group having from 2 to 3 carbon atoms. Examples of the alkenyl group include an ethylene group, a propylene group, and a butylene group, and from the viewpoint of achieving both polymerizability and a low dielectric constant, an ethylene group and a propylene group are preferred.

[0027] R １ and R ２ With regard to the above, from the viewpoint of achieving both polymerizability and a low dielectric constant, the alkynyl group having from 2 to 6 carbon atoms is preferably an alkynyl group having from 2 to 4 carbon atoms, and more preferably an alkynyl group having from 2 to 3 carbon atoms. Examples of the alkynyl group include an ethynyl group and a propargyl group, and from the viewpoint of achieving both polymerizability and a low dielectric constant, an ethynyl group is preferred.

[0028] R １ and R ２ From the viewpoint of achieving both polymerizability and a low dielectric constant, the alicyclic hydrocarbon group having 3 to 8 carbon atoms represented by the formula (I) is preferably an alicyclic hydrocarbon group having 4 to 7 carbon atoms, and more preferably an alicyclic hydrocarbon group having 5 to 6 carbon atoms. Examples of alicyclic hydrocarbon groups having 3 to 8 carbon atoms include cycloalkyl groups having 3 to 8 carbon atoms.

[0029] R １ and R ２With regard to the above, from the viewpoint of achieving both polymerizability and a low dielectric constant, the cycloalkyl group having 3 to 8 carbon atoms is preferably a cycloalkyl group having 4 to 7 carbon atoms, and more preferably a cycloalkyl group having 5 to 6 carbon atoms. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. From the viewpoint of achieving both polymerizability and a low dielectric constant, a cyclopentyl group and a cyclohexyl group are preferred, and a cyclohexyl group is more preferred.

[0030] R １ and R ２ Examples of the aromatic hydrocarbon group having 6 to 10 carbon atoms represented by include a phenyl group and a naphthyl group, and from the viewpoint of achieving both polymerizability and a low dielectric constant, a phenyl group is preferred.

[0031] R １ and R ２ From the viewpoint of achieving both polymerizability and a low dielectric constant, a hydrogen atom, a methyl group, an ethyl group, a propyl group, a cyclohexyl group, and a phenyl group are preferred, and a hydrogen atom and a methyl group are more preferred.

[0032] In the formula representing the structural unit (I), each X independently represents a hydrogen atom, an aliphatic chain hydrocarbon group having from 1 to 6 carbon atoms, an alicyclic hydrocarbon group having from 3 to 8 carbon atoms, an aromatic hydrocarbon group having from 6 to 10 carbon atoms, or a halogen atom.

[0033] Regarding X, an aliphatic chain hydrocarbon group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 8 carbon atoms, and an aromatic hydrocarbon group having 6 to 10 carbon atoms are R １ and R ２ This is similar to what was previously described for

[0034] Examples of the halogen atom represented by X include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. From the viewpoint of achieving both polymerizability and a low dielectric constant, a fluorine atom and a chlorine atom are preferred, and a fluorine atom is more preferred.

[0035] From the viewpoint of achieving both polymerizability and a low dielectric constant, X is preferably a hydrogen atom, a methyl group, an isopropyl group, or a phenyl group, and more preferably a hydrogen atom.

[0036] The structural unit (I) has a central atom C calculated by the PM6 method, which is a semi-empirical molecular orbital method. １ The difference between the maximum and minimum values ​​of the rotational energy around the molecule is 0.42 to 0.82 kcal / mol. If the difference between the maximum and minimum values ​​is less than 0.42 kcal / mol, it is difficult to obtain a liquid crystalline resin having a low dielectric constant. If the difference between the maximum and minimum values ​​is more than 0.82 kcal / mol, it is difficult to obtain a liquid crystalline resin that maintains good polymerizability. From the viewpoint of achieving both polymerizability and a low dielectric constant, the difference between the maximum and minimum values ​​is preferably 0.46 to 0.77 kcal / mol, more preferably 0.49 to 0.72 kcal / mol, even more preferably 0.50 to 0.60 kcal / mol, and particularly preferably 0.51 to 0.55 kcal / mol.

[0037] The difference between the maximum and minimum values ​​of the structural unit (I) is 0.42 to 0.82 kcal / mol, and therefore the structural unit (I) has an appropriate degree of rotational freedom. As a result, it is presumed that the liquid crystalline resin of the present invention has both polymerizability and a low dielectric constant. More specifically, when the liquid crystalline resin of the present invention is solidified, the structural unit (I) maintains a bent structure due to the appropriate degree of rotational freedom, which reduces the specific gravity of the liquid crystalline resin and results in a low dielectric constant. On the other hand, when the liquid crystalline resin of the present invention is molten, the structural unit (I) approaches a linear shape under shear conditions due to the appropriate degree of rotational freedom, which makes the liquid crystalline resin as a whole less likely to entangle with each other. This makes it easier to suppress an increase in melt viscosity during polymerization, and as a result, it is presumed that polymerizability is maintained.

[0038] The difference between the maximum and minimum values ​​was calculated using MOPAC, an integrated program for implementing semi-empirical molecular orbital methods, and the central atom C １The rotational energy around the nucleus is calculated, the maximum and minimum values ​​of the energy are determined, and the difference between the maximum and minimum values ​​is calculated. An example of a commercially available MOPAC product is SCIGRESS MO Compact ver. 1 (manufactured by Fujitsu Ltd.). Table 1 shows examples of the results of determining the difference between the maximum and minimum values ​​for structural units satisfying the formula representing structural unit (I).

[0039]

[0040] Examples of the structural unit (I) include structural units in which the difference between the maximum and minimum values ​​mentioned above in Table 1 is 0.42 to 0.82 kcal / mol. Specific examples include structural units derived from one or more members selected from the group consisting of 1,1-bis(4-hydroxyphenyl)ethane (i.e., bisphenol E), bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)cyclohexylmethane, 1,1-bis(4-hydroxyphenyl)-1-phenylpropane, 1,1-bis(4-hydroxyphenyl)-1-phenylbutane, and derivatives thereof. Hereinafter, a monomer that derives the structural unit (I), such as bisphenol E, will also be referred to as "monomer (I)." In the liquid crystalline resin of the present invention, the structural unit (I) may be used alone or in combination of two or more members.

[0041] In the liquid crystalline resin of the present invention, the content of the structural unit (I) is 1 to 40 mol% relative to all structural units. If the content of the structural unit (II) is less than 1 mol% or more than 40 mol%, at least one of polymerizability and low dielectric constant tends to be insufficient. From the viewpoint of achieving both polymerizability and low dielectric constant, the content of the structural unit (I) is preferably 3 to 35 mol%, more preferably 4 to 30 mol%, and even more preferably 5 to 25 mol%.

[0042] In the formula representing the structural unit (II), Ar １Examples of the structural unit (II) include a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a 2,6-naphthylene group, and a 4,4'-biphenylylene group, and from the viewpoint of achieving both polymerizability and a low dielectric constant, a 1,4-phenylene group and a 2,6-naphthylene group are preferred. Therefore, the structural unit (II) is derived from, for example, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, or 6-hydroxy-2-naphthoic acid (hereinafter also referred to as "2-HBA," "3-HBA," "4-HBA," or "HNA," respectively), and from the viewpoint of achieving both polymerizability and a low dielectric constant, it is preferably derived from 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, or a combination of 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid. Hereinafter, a monomer from which the structural unit (II) is derived, such as 2-HBA, 3-HBA, 4-HBA, or HNA, will also be referred to as "monomer (II)." In the liquid crystal resin of the present invention, the structural unit (II) may be used alone or in combination of two or more types.

[0043] In the liquid crystalline resin of the present invention, the content of the structural unit (II) is 20 to 98 mol% relative to all structural units. If the content of the structural unit (II) is less than 20 mol% or more than 98 mol%, at least one of polymerizability and low dielectric constant tends to be insufficient. From the viewpoint of achieving both polymerizability and a low dielectric constant, the content of the structural unit (II) is preferably 30 to 90 mol%, more preferably 35 to 80 mol%, and even more preferably 40 to 70 mol%.

[0044] In the formula representing the structural unit (III), Ar ２Examples of the structural unit (III) include a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a 2,6-naphthylene group, and a 4,4'-biphenylylene group. From the viewpoint of achieving both polymerizability and a low dielectric constant, a 1,4-phenylene group is preferred. Therefore, the structural unit (III) is derived from, for example, 1,3-phenylenedicarboxylic acid (hereinafter also referred to as "IA"), 1,4-phenylenedicarboxylic acid (hereinafter also referred to as "TA"), or 2,6-naphthalenedicarboxylic acid (hereinafter also referred to as "NDA"), and from the viewpoint of achieving both polymerizability and a low dielectric constant, it is preferably derived from 1,4-phenylenedicarboxylic acid. Hereinafter, monomers that derive the structural unit (III), such as IA, TA, and NDA, are also referred to as monomer (III). In the liquid crystal resin of the present invention, the structural unit (III) may be used alone or in combination of two or more types.

[0045] In the liquid crystal resin of the present invention, the content of the structural unit (III) is 1 to 40 mol% relative to all structural units. If the content of the structural unit (III) is less than 1 mol% or more than 40 mol%, at least one of polymerizability and low dielectric constant tends to be insufficient. From the viewpoint of achieving both polymerizability and a low dielectric constant, the content of the structural unit (III) is preferably 5 to 35 mol%, more preferably 10 to 32 mol%, and even more preferably 15 to 30 mol%.

[0046] In the formula representing the structural unit (IV), Ar ３Examples of the structural unit (IV) include a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a 2,6-naphthylene group, and a 4,4'-biphenylylene group. From the viewpoint of achieving both polymerizability and a low dielectric constant, a 4,4'-biphenyl group and a 1,4-phenylene group are preferred. Therefore, structural unit (IV) is derived from, for example, hydroquinone (hereinafter also referred to as "HQ"), 2,6-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl (hereinafter also referred to as "BP"), or N-acetyl-p-aminophenol (hereinafter also referred to as "APAP"), and from the viewpoint of achieving both polymerizability and a low dielectric constant, structural unit (IV) is preferably derived from 4,4'-dihydroxybiphenyl or N-acetyl-p-aminophenol. Hereinafter, monomers that derive structural unit (IV), such as HQ, BP, and APAP, are also referred to as monomer (IV). In the liquid crystalline resin of the present invention, the structural unit (IV) may be used alone or in combination of two or more types.

[0047] In the liquid crystalline resin of the present invention, the content of the structural unit (IV) is 0 to 39 mol% relative to all structural units. If the content of the structural unit (IV) exceeds 39 mol%, at least one of polymerizability and low dielectric constant tends to be insufficient. From the viewpoint of achieving both polymerizability and a low dielectric constant, the content of the structural unit (IV) is preferably 0 to 30 mol%, more preferably 0 to 25 mol%, and even more preferably 0 to 20 mol%.

[0048] As described above, the liquid crystalline resin of the present invention contains the structural units (I), (II), and (III), and may or may not contain the structural unit (IV). The content of each of the structural units (I) to (IV) is within a specific range relative to all the structural units. The structural unit (I) has a central atom C calculated by the PM6 method, which is a semi-empirical molecular orbital method. １ The difference between the maximum and minimum values ​​of the rotational energy around the molecule is 0.42 to 0.82 kcal / mol, so that the molecule has a low dielectric constant while maintaining good polymerizability.

[0049] In the liquid crystalline resin of the present invention, from the viewpoint of achieving both polymerizability and a low dielectric constant, the total content of the structural units (I) to (IV) is preferably 80 to 100 mol%, more preferably 90 to 100 mol%, even more preferably 95 to 100 mol%, and most preferably 100 mol%, based on all structural units. Therefore, the liquid crystalline resin of the present invention may contain a structural unit other than the structural units (I) to (IV) (hereinafter also referred to as "structural unit (Z)"). In the liquid crystalline resin of the present invention, from the viewpoint of achieving both polymerizability and a low dielectric constant, the content of the structural unit (Z) is preferably 0 to 20 mol%, more preferably 0 to 10 mol%, even more preferably 0 to 5 mol%, and most preferably 0 mol%, based on all structural units.

[0050] Examples of the structural unit (Z) include structural units derived from one or more selected from the group consisting of aliphatic chain dicarboxylic acids, alicyclic dicarboxylic acids, aliphatic chain diols, alicyclic diols, and derivatives thereof. Hereinafter, a monomer that derives the structural unit (Z) is also referred to as monomer (Z). In the liquid crystalline resin of the present invention, the structural unit (Z) may be used alone or in combination of two or more types.

[0051] Next, a method for producing the liquid crystalline resin of the present invention will be described. The liquid crystalline resin of the present invention is polymerized using a direct polymerization method, a transesterification method, etc. For the polymerization, a melt polymerization method, a solution polymerization method, a slurry polymerization method, a solid phase polymerization method, etc., or a combination of two or more of these methods is used, and a melt polymerization method or a combination of a melt polymerization method and a solid phase polymerization method is preferably used.

[0052] Various catalysts can be used in these polymerizations, and examples thereof include metal salt catalysts such as fatty acid metal salt catalysts and organic compound catalysts. Typical examples include metal salt catalysts such as potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, antimony trioxide, and tris(2,4-pentanedionato)cobalt(III), and organic compound catalysts such as 1-methylimidazole and 4-dimethylaminopyridine.

[0053] The reaction conditions are, for example, a reaction temperature of 200 to 380°C and a final pressure of 0.1 to 760 Torr (i.e., 13 to 101,080 Pa). In particular, in the case of a melting reaction, the reaction temperature is, for example, 260 to 380°C, preferably 300 to 360°C, and the final pressure is, for example, 1 to 100 Torr (i.e., 133 to 13,300 Pa), preferably 1 to 50 Torr (i.e., 133 to 6,670 Pa).

[0054] The reaction can be initiated by charging all raw material monomers (monomers (I) to (III), optionally monomer (IV), and optionally monomer (Z)), an acylating agent, and a catalyst into the same reaction vessel (single-stage system), or by acylating the hydroxyl groups of monomer (I), monomer (II), optionally monomer (IV) having a hydroxyl group, and optionally monomer (Z) having a hydroxyl group with an acylating agent, followed by reacting them with the carboxyl groups of monomer (II), monomer (III), and optionally monomer (Z) having a carboxyl group (two-stage system).

[0055] The melt polymerization is carried out by starting pressure reduction and setting the pressure to a predetermined level after the reaction system has reached a predetermined temperature. After the torque of the stirrer has reached a predetermined value, an inert gas is introduced, and the pressure is increased from a reduced pressure state to normal pressure and then to a predetermined pressurized state, and the liquid crystalline resin is discharged from the reaction system.

[0056] The liquid crystalline resin produced by the above polymerization method can be further subjected to solid-state polymerization by heating in an inert gas at normal or reduced pressure to increase the molecular weight. Preferred conditions for the solid-state polymerization reaction are a reaction temperature of 230 to 350°C, preferably 260 to 330°C, and a final pressure of 10 to 760 Torr (i.e., 1,330 to 101,080 Pa).

[0057] Next, the properties of the liquid crystalline resin will be described. The liquid crystalline resin of the present invention exhibits liquid crystallinity, that is, optical anisotropy when melted.

[0058] In the present invention, the liquid crystalline resin exhibiting liquid crystallinity is an essential element for the liquid crystalline resin to have both thermal stability and easy processability. Although some resins containing the structural units (I), (II), and (III) and containing or not containing the structural unit (IV) do not form an anisotropic molten phase depending on the structural components and the sequence distribution in the resin, the liquid crystalline resin of the present invention is limited to resins that exhibit optical anisotropy when melted.

[0059] The melt anisotropy can be confirmed by a conventional polarization inspection method using crossed polarizers. More specifically, melt anisotropy can be confirmed by melting a sample placed on a Linkam hot stage using an Olympus polarizing microscope and observing it at 150x magnification under a nitrogen atmosphere. Liquid crystal resins are optically anisotropic and transmit light when inserted between crossed polarizers. If a sample is optically anisotropic, polarized light will transmit even when it is in a molten, static liquid state, for example.

[0060] Nematic liquid crystalline resins experience a significant drop in viscosity above their melting point, and therefore, the fact that they exhibit liquid crystallinity at or above their melting point is generally an indicator of processability. From the standpoint of heat resistance, a melting point that is as high as possible is preferable, but considering factors such as thermal degradation during melt processing of the liquid crystalline resin and the heating capacity of the molding machine, a melting point of 275°C or higher is a preferable guideline. The melting point is more preferably 280 to 400°C, and even more preferably 285 to 380°C.

[0061] A temperature 10 to 30°C higher than the melting point of the liquid crystal resin of the present invention and a shear rate of 1000 sec －１ The melt viscosity of the liquid crystalline resin in the above range is preferably 500 Pa·s or less, more preferably 0.5 to 300 Pa·s, and even more preferably 1 to 100 Pa·s. When the melt viscosity is within the above range, the liquid crystalline resin itself or a composition containing the liquid crystalline resin is likely to have sufficient fluidity during molding, and the filling pressure is unlikely to become excessive. In this specification, the melt viscosity refers to the melt viscosity measured in accordance with ISO 11443.

[0062] <Polyester Resin Composition> The liquid crystalline resin of the present invention may be blended with various fibrous, granular, or plate-like inorganic and organic fillers depending on the intended use.

[0063] The inorganic filler to be blended in the liquid crystal resin composition of the present invention may be in the form of fiber, granules or plates.

[0064] Examples of fibrous inorganic fillers include inorganic fibrous materials such as glass fiber, milled glass fiber, carbon fiber, asbestos fiber, silica fiber, silica-alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, silicate fibers such as wollastonite, magnesium sulfate fiber, aluminum borate fiber, and metal fibers such as stainless steel, aluminum, titanium, copper, brass, etc. A particularly representative fibrous filler is glass fiber.

[0065] Further, examples of granular inorganic fillers include carbon black, graphite, silica, quartz powder, glass beads, glass balloons, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, silicates such as wollastonite, metal oxides such as iron oxide, titanium oxide, zinc oxide, antimony trioxide, and alumina, metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, as well as ferrite, silicon carbide, silicon nitride, boron nitride, and various metal powders.

[0066] Examples of the plate-like inorganic filler include mica, glass flakes, talc, and various metal foils.

[0067] Examples of organic fillers include heat-resistant, high-strength synthetic fibers such as aromatic polyester fibers, liquid crystal polymer fibers, aromatic polyamide fibers, and polyimide fibers.

[0068] These inorganic and organic fillers can be used alone or in combination of two or more. The combination of a fibrous inorganic filler with a granular or plate-like inorganic filler is a preferred combination in terms of simultaneously providing mechanical strength, dimensional accuracy, electrical properties, etc. Particularly preferred are glass fiber as the fibrous filler and mica and talc as the plate-like filler, and the total blending amount of these is preferably 120 parts by mass or less, more preferably 20 to 80 parts by mass, per 100 parts by mass of the liquid crystal resin. By combining glass fiber with mica or talc, the liquid crystal resin composition exhibits particularly significant improvements in heat distortion temperature, mechanical properties, etc.

[0069] When using these fillers, a sizing agent or a surface treatment agent may be used, if necessary.

[0070] As described above, the liquid crystalline resin composition of the present invention contains the liquid crystalline resin of the present invention as an essential component, and optionally contains an inorganic or organic filler, but may contain other components as long as the effects of the present invention are not impaired. Here, the other components may be any components, and examples thereof include additives such as other resins, antioxidants, stabilizers, pigments, and crystal nucleating agents.

[0071] The method for producing the liquid crystal resin composition of the present invention is not particularly limited, and the liquid crystal resin composition of the present invention can be prepared by a conventionally known method.

[0072] <Molded Article> The molded article of the present invention is made from the liquid crystalline resin of the present invention or the liquid crystalline resin composition of the present invention. The molded article of the present invention can be obtained by molding the liquid crystalline resin of the present invention or the liquid crystalline resin composition of the present invention. The molding method is not particularly limited, and a general molding method can be used. Examples of general molding methods include injection molding, extrusion molding, compression molding, blow molding, vacuum molding, foam molding, rotational molding, gas injection molding, and inflation molding. The shape of the molded article is not particularly limited, and may be any desired shape.

[0073] The liquid crystalline resin or liquid crystalline resin composition of the present invention has excellent moldability and can be easily processed into various three-dimensional molded articles, fibers, films, etc. Examples of applications include connectors, CPU sockets, relay switch parts, bobbins, actuators, noise reduction filter cases, electronic circuit boards, and heat fixing rolls for office automation equipment.

[0074] A molded article made of the liquid crystalline resin of the present invention has a low dielectric constant. In addition, a molded article made of the liquid crystalline resin composition of the present invention has a low dielectric constant and, when containing an inorganic or organic filler, further improves mechanical strength and the like.

[0075] Preferred applications of the molded article of the present invention having the above-mentioned properties include electronic parts for use in high frequency ranges such as microwaves and millimeter waves.

[0076] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0077] Example 1 The following raw materials were charged into a polymerization vessel equipped with a stirrer, a reflux column, a monomer inlet, a nitrogen inlet, and a pressure reduction / outlet line, and nitrogen purge was initiated. (I) 490 g (15 mol %) of 1,1-bis(4-hydroxyphenyl)ethane (bisphenol E) (II) 1,011 g (50 mol %) of 4-hydroxybenzoic acid (HBA) (III) 633 g (25 mol %) of 1,4-phenylenedicarboxylic acid (TA) (IV) 284 g (10 mol %) of 4,4'-dihydroxybiphenyl (BP) Fatty acid metal salt catalyst (potassium acetate catalyst): 165 mg Acylating agent (acetic anhydride): 1,587 g After the raw materials were charged, the atmosphere inside the polymerization vessel was purged with nitrogen, and the temperature of the reaction system was raised to 200°C. Thereafter, the temperature was further increased to a final polymerization temperature of 380°C over 6 hours, and then the pressure was reduced to 10 Torr (i.e., 1330 Pa) over 20 minutes, and melt polymerization was carried out while distilling off acetic acid and other low-boiling components. After the stirring torque reached a predetermined value, nitrogen was introduced to change the pressure from a reduced pressure state to normal pressure and then to a pressurized state, and the polymer was discharged from the bottom of the polymerization vessel and pelletized to obtain a pellet-shaped resin.

[0078] Examples 2 to 9, Comparative Examples 3 to 7 Resins were obtained in the same manner as in Example 1, except that the types and charging ratios (mol%) of raw material monomers were as shown in Table 2 or Table 3. However, the final polymerization temperature was changed to 340°C in Examples 2 to 9 and Comparative Examples 3 to 7. In the tables, bisphenol A represents 2,2-bis(4-hydroxyphenyl)propane, bisphenol FL represents 9,9-bis(4-hydroxyphenyl)fluorene, bisphenol F represents bis(4-hydroxyphenyl)methane, HNA represents 6-hydroxy-2-naphthoic acid, and APAP represents N-acetyl-p-aminophenol.

[0079] Comparative Example 1: After the following raw materials were charged into a polymerization vessel, the temperature of the reaction system was raised to 140°C and the reaction was carried out at 140°C for 1 hour. The temperature was then further raised to 360°C over 5.5 hours, and the pressure was then reduced to 5 Torr (i.e., 667 Pa) over 30 minutes, during which melt polymerization was carried out while distilling off acetic acid, excess acetic anhydride, and other low-boiling components. After the stirring torque reached a predetermined value, nitrogen was introduced to change the pressure from reduced pressure to normal pressure and then to pressurized pressure. The polymer was discharged from the bottom of the polymerization vessel, and the strands were pelletized to obtain pellets. The obtained pellets were subjected to a heat treatment at 300°C for 3 hours under a nitrogen stream to obtain the target polymer. 6-Hydroxy-2-naphthoic acid (HNA): 1218 g (48 mol%), 4-hydroxybenzoic acid (HBA): 37 g (2 mol%), 1,4-phenylenedicarboxylic acid: 560 g (TA): (25 mol%), 4,4'-dihydroxybiphenyl (BP): 628 g (25 mol%), fatty acid metal salt catalyst (potassium acetate catalyst): 165 mg, acylating agent (acetic anhydride): 1432 g

[0080] Comparative Example 2: After the following raw materials were charged into a polymerization vessel, the temperature of the reaction system was raised to 140°C and the reaction was carried out at 140°C for 1 hour. The temperature was then further raised to 340°C over 4.5 hours, and the pressure was then reduced to 10 Torr (i.e., 1330 Pa) over 15 minutes, during which melt polymerization was carried out while distilling off acetic acid, excess acetic anhydride, and other low-boiling components. After the stirring torque reached a predetermined value, nitrogen was introduced to change the pressure from reduced pressure to normal pressure and then to pressurized pressure. The polymer was discharged from the bottom of the polymerization vessel, and the strands were pelletized to obtain pellets. The obtained pellets were subjected to heat treatment at 300°C for 2 hours under a nitrogen stream to obtain the target polymer. 4-Hydroxybenzoic acid (HBA): 1,380 g (60 mol%), 6-hydroxy-2-naphthoic acid (HNA): 157 g (5 mol%), 1,4-phenylenedicarboxylic acid (TA): 484 g (17.5 mol%), 4,4'-dihydroxybiphenyl (BP): 388 g (12.5 mol%), N-acetyl-p-aminophenol (APAP): 126 g (5 mol%), fatty acid metal salt catalyst (potassium acetate catalyst): 110 mg, acylating agent (acetic anhydride): 1,659 g

[0081] As described above, for the structural unit satisfying the formula representing the structural unit (I), the central atom C calculated by the PM6 method, which is a semi-empirical molecular orbital method, １ The difference between the maximum and minimum rotational energies around the central atom C1 is as follows: Structural unit derived from bisphenol E: 0.520 kcal / mol Structural unit derived from bisphenol A: 0.829 kcal / mol Structural unit derived from bisphenol F: 0.412 kcal / mol Note that, because the structural unit derived from bisphenol FL does not rotate around the central atom C1 due to its structure, the rotational energy could not be calculated, and the difference between the maximum and minimum values ​​could not be calculated.

[0082] <Evaluation> The resins of the Examples and Comparative Examples were evaluated for liquid crystallinity, melting point, dielectric properties, and polymerizability by the following methods. The results are shown in Table 2 or Table 3.

[0083] [Evaluation of Liquid Crystallinity] Using a polarizing microscope manufactured by Olympus Corporation, the resin was placed on a hot stage manufactured by Linkam Corporation and melted. The resin was observed under a nitrogen atmosphere at a magnification of 150 times under crossed Nicols, and the liquid crystallinity was evaluated according to the following criteria: ∘ (Good): An optically anisotropic molten phase was formed in the molten resin. × (Poor): An optically anisotropic molten phase was not formed in the molten resin.

[0084] [Measurement of melting point] Using a DSC (manufactured by PerkinElmer), the endothermic peak temperature (Tm1) observed when the resin was heated from room temperature at a temperature increase rate of 20°C / min was measured, and the resin was then held at a temperature of (Tm1+40)°C for 2 minutes, cooled to room temperature at a temperature decrease rate of 20°C / min, and then heated again at a temperature increase rate of 20°C / min to measure the endothermic peak temperature (Tm2), which was taken as the melting point of the resin.

[0085] [Evaluation of Dielectric Properties] The resin was molded under the following molding conditions using a molding machine ("SE-100DU" manufactured by Sumitomo Heavy Industries, Ltd.) to prepare a flat plate-shaped test piece measuring 80 mm x 80 mm x 1 mm. As shown in FIG. 1 , a test piece measuring 80 mm x 1 mm x 1 mm was cut out from the center of the flat plate-shaped test piece in the flow direction, and this was used as a test piece for evaluating dielectric properties. The relative permittivity and dielectric loss tangent of this test piece at a measurement frequency of 5 GHz were measured using a cavity resonator perturbation method complex permittivity evaluation device manufactured by Kanto Electronics Application Development Co., Ltd. and having the following configuration. Scalar network analyzer: Agilent Technology 8757D Frequency synthesizer: Agilent Technology 83650L Sweep CW Generator Fixed attenuator: Agilent Technology 85025D Detector Cavity resonator: Kanto Electronics Application Development CP431 Measurement program: Kanto Electronics Application Development CPMA-S2 / V2 [Molding conditions] Cylinder temperature: 380°C (Example 1) 330°C (Examples 2 to 4, 6 to 8 and Comparative Examples 3 to 7) 350°C (Example 5 and Comparative Example 2) 370°C (Comparative Example 1) Mold temperature: 80°C Injection speed: 33 mm / sec Holding pressure: 60 MPa

[0086] [Evaluation of Polymerization] During the resin polymerization process, the polymerization was evaluated according to the following criteria: ∘ (Good): The predetermined torque serving as the criterion for polymer discharge was not reached before depressurization, and the depressurization process was carried out normally. × (Poor): The predetermined torque serving as the criterion for polymer discharge was reached before depressurization, and the depressurization process could not be carried out normally.

[0087]

[0088] *In Comparative Example 3, no endothermic peak appeared within the range of measurement by DSC, so the melting point could not be measured.

[0089] As is clear from the results shown in Tables 2 and 3, it was confirmed that the liquid crystal resins of the examples had a low dielectric constant while maintaining good polymerizability.

Claims

1. A liquid crystalline resin exhibiting optical anisotropy when melted, the liquid crystalline resin containing the following structural units (I), (II), and (III), and containing or not containing the following structural unit (IV), the content of the structural unit (I) is 1 to 40 mol % based on all structural units, the content of the structural unit (II) is 20 to 98 mol % based on all structural units, the content of the structural unit (III) is 1 to 40 mol % based on all structural units, and the content of the structural unit (IV) is 0 to 39 mol % based on all structural units, the structural unit (I) has a central atom C calculated by the PM6 method, which is a semi-empirical molecular orbital method. １ A liquid crystal resin, the difference between the maximum and minimum values ​​of the rotational energy around the molecule being 0.42 to 0.82 kcal / mol. (In the formula, R １ and R ２ each independently represents a hydrogen atom, an aliphatic chain hydrocarbon group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. each X independently represents a hydrogen atom, an aliphatic chain hydrocarbon group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 8 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a halogen atom. (In the formula, Ar １ , Ar ２ , and Ar ３ each independently represents a phenylene group, a naphthylene group, or a biphenylylene group; Y and Z each independently represent an oxygen atom or an imino group.

2. The liquid crystalline resin according to claim 1, wherein the total content of the structural units (I) to (IV) is 100 mol % based on all the structural units.

3. The liquid crystal resin according to claim 1 or 2, wherein the content of structural unit (I) is 3 to 35 mol % relative to all structural units, the content of structural unit (II) is 30 to 90 mol % relative to all structural units, the content of structural unit (III) is 5 to 35 mol % relative to all structural units, and the content of structural unit (IV) is 0 to 30 mol % relative to all structural units.

4. The liquid crystalline resin according to claim 1 or 2, wherein the structural unit (I) is a structural unit derived from one or more members selected from the group consisting of 1,1-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)cyclohexylmethane, 1,1-bis(4-hydroxyphenyl)-1-phenylpropane, 1,1-bis(4-hydroxyphenyl)-1-phenylbutane, and derivatives thereof.

5. A liquid crystal resin composition comprising the liquid crystal resin according to claim 1 or 2.

6. A molded article made of the liquid crystalline resin according to claim 1 or 2.

7. A molded article made of the liquid crystal resin composition according to claim 5.

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