Liquid crystalline resin composition

Abstract

Provided is a liquid crystalline resin which has favorable fluidity and from which a molded article having a low dielectric constant is obtained.　This liquid crystalline resin comprises 70-98 mass% of (A) a liquid crystalline resin and 2-30 mass% of (B) inorganic spherical hollow bodies, wherein: the (A) component exhibits optical anisotropy when melted, contains constitutional units (I)-(III), and contains or does not contain a constitutional unit (IV); the contents of the constitutional units (I)-(IV) with respect to the all constitutional units are 1-40 mol%, 20-98 mol%, 1-40%, and 0-39 mol%, respectively; and in the constitutional unit (I), the difference between a maximum value and a minimum value of rotational energy around a central atom C1, as calculated by a PM6 method, which is a semi-empirical molecular orbital method, is 0.42-0.82 kcal / mol. In the formulae, R1 and R2 independently represent a hydrogen atom or the like, Xs independently represent a hydrogen atom or the like, Ar1-Ar3 independently represent a phenylene group or the like, and Y and Z independently represent an oxygen atom or an imino group.

Description

Liquid crystalline resin composition

[0001] The present invention relates to 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] Japanese Patent Application Laid-Open No. 2004-27021

[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 increase the viscosity of the liquid crystalline resin composition. Therefore, it is believed that by improving the dielectric properties of the liquid crystalline resin itself, the dielectric properties of a molded article containing the liquid crystalline resin are likely to be improved even if it does not contain inorganic hollow spheres, while the increase in viscosity of a liquid crystalline resin composition containing the liquid crystalline resin is likely to be suppressed.

[0006] In view of the above problems, an object of the present invention is to provide a liquid crystalline resin composition having good flowability which can give a molded article having a low dielectric constant.

[0007] 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 composition containing a liquid crystalline resin containing structural units derived from a specific bisphenol, structural units derived from a hydroxyarenecarboxylic acid, and structural units derived from an arylenedicarboxylic acid, and which may or may not contain structural units derived from an arenediol, arenediamine, or hydroxyarylamine, and in which the contents of each structural unit are within specific ranges, and inorganic hollow spherical objects in a predetermined content, and have completed the present invention. More specifically, the present invention provides the following.

[0008] (1) A liquid crystalline resin composition containing (A) a liquid crystalline resin and (B) inorganic hollow spheres, wherein the (A) liquid crystalline resin is a liquid crystalline resin that exhibits optical anisotropy when melted, and contains the following structural units (I), (II), and (III), and may or may not contain the following structural unit (IV), wherein 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, and the structural unit (I) has a central atom C calculated by the PM6 method, which is a semi-empirical molecular orbital method. １ a difference between the maximum and minimum values ​​of rotational energy around the liquid crystal molecule is 0.42 to 0.82 kcal / mol; a content of the liquid crystal resin (A) is 70 to 98 mass% with respect to the entire liquid crystal resin composition; and a content of the inorganic hollow spherical bodies (B) is 2 to 30 mass%.

[0009] (In the formula, R １ and R ２each 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.

[0010] (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.

[0011] (2) The liquid crystal resin composition according to (1), wherein the total content of the structural units (I) to (IV) in the liquid crystal resin (A) is 100 mol % based on all structural units.

[0012] (3) The liquid crystalline resin composition according to (1) or (2), wherein in the liquid crystalline resin (A), 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.

[0013] (4) The liquid crystalline resin according to any one of (1) to (3), wherein in the liquid crystalline resin (A), the structural unit (I) is a structural unit derived from one or more 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.

[0014] (5) The liquid crystalline resin composition according to any one of (1) to (4), wherein the inorganic hollow spheres (B) are glass balloons.

[0015] (6) A molded article made of the liquid crystal resin composition according to any one of (1) to (5).

[0016] According to the present invention, it is possible to provide a liquid crystalline resin composition having good fluidity which gives a molded article having a low dielectric constant.

[0017] FIG. 1 is a top view showing the cutting positions of test pieces for evaluating dielectric properties used in the Synthesis Examples, Comparative Synthesis Examples, Examples, and Comparative Examples.

[0018] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0019] <Liquid Crystalline Resin Composition> The liquid crystal resin composition according to the present invention contains (A) a liquid crystal resin and (B) inorganic hollow spheres. The components constituting the liquid crystal resin composition according to the present invention will be described below.

[0020] [(A) Liquid Crystalline Resin] The (A) liquid crystal resin is a liquid crystal resin that exhibits optical anisotropy when melted, and contains the following structural units (I), (II), and (III), and may or may not contain the following structural unit (IV). The component (A) may be used alone or in combination of two or more types.

[0021]

[0022] 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.

[0023] R １ and R ２From 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.

[0024] R １ and R ２ With 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] R １ and R ２ With 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 (A) liquid crystalline resin has both polymerizability and a low dielectric constant. More specifically, when the (A) liquid crystalline resin 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 (A) liquid crystalline resin and results in a low dielectric constant. On the other hand, when the (A) liquid crystalline resin is molten, the structural unit (I) approaches a linear shape under shear conditions due to the appropriate degree of rotational freedom. This makes it difficult for the (A) liquid crystalline resin as a whole to become entangled with each other, making it easier to suppress an increase in melt viscosity during polymerization, and as a result, it is presumed that polymerizability is maintained.

[0037] 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 １ The 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).

[0038]

[0039] 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 (A) liquid crystalline resin, the structural unit (I) may be used alone, or two or more members may be used in combination.

[0040] In the (A) liquid crystalline resin, the content of the structural unit (I) is 1 to 40 mol% relative to all structural units. If the content of the structural unit (I) 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 (I) is preferably 3 to 35 mol%, more preferably 4 to 30 mol%, and even more preferably 5 to 25 mol%.

[0041] 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, monomers that derive the structural unit (II), such as 2-HBA, 3-HBA, 4-HBA, and HNA, will also be referred to as "monomer (II)." In the (A) liquid crystalline resin, the structural unit (II) may be used alone, or two or more types may be used in combination.

[0042] In the (A) liquid crystalline resin, 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%.

[0043] 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-phenylene dicarboxylic acid (hereinafter also referred to as "IA"), 1,4-phenylene dicarboxylic 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-phenylene dicarboxylic acid. Hereinafter, monomers that derive the structural unit (III), such as IA, TA, and NDA, are also referred to as monomer (III). In the (A) liquid crystal resin, the structural unit (III) may be used alone or in combination of two or more types.

[0044] In the (A) liquid crystal resin, 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%.

[0045] 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 crystal resin (A), the structural unit (IV) may be used alone, or two or more types may be used in combination.

[0046] In the (A) liquid crystalline resin, 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 the polymerizability and the 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%.

[0047] As described above, the (A) liquid crystalline resin 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.

[0048] In the (A) liquid crystalline resin, 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 (A) liquid crystalline resin may contain a structural unit other than the structural units (I) to (IV) (hereinafter also referred to as "structural unit (Z)"). In the (A) liquid crystalline resin, 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.

[0049] 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 (A) liquid crystal resin, the structural unit (Z) may be used alone or in combination of two or more types.

[0050] Next, a method for producing the (A) liquid crystalline resin will be described. The (A) liquid crystalline resin 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.

[0051] 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.

[0052] 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).

[0053] 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).

[0054] 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.

[0055] 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).

[0056] Next, the properties of the liquid crystalline resin will be described. (A) The liquid crystalline resin exhibits liquid crystallinity, that is, optical anisotropy when melted.

[0057] In the present invention, the liquid crystalline resin (A) exhibiting liquid crystallinity is an essential element for the resin (A) 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 (A) is limited to resins that exhibit optical anisotropy when melted.

[0058] 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.

[0059] 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.

[0060] (A) A temperature 10 to 40°C higher than the melting point of the liquid crystal resin and a shear rate of 1000 sec －１ The melt viscosity of the (A) liquid crystalline resin in the above 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 (A) liquid crystalline resin itself or a composition containing the (A) 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.

[0061] The content of the component (A) is 70 to 98% by mass, preferably 73 to 96% by mass, and more preferably 75 to 95% by mass, based on the total mass of the liquid crystal resin composition. The content of the component (A) within the above range is preferred in terms of fluidity, dielectric properties, etc.

[0062] [(B) Inorganic Hollow Spherical Body] (B) Inorganic hollow spherical bodies are generally called balloons, and examples of materials for the inorganic hollow spherical bodies include inorganic materials such as alumina, silica, glass, and shirasu. Among these, glass and silica are preferred from the viewpoint of heat resistance and strength, and glass is more preferred. That is, glass balloons and silica balloons are preferably used as inorganic hollow spherical bodies, and glass balloons are more preferably used. The (B) component may be used alone or in combination of two or more types.

[0063] The aspect ratio of the (B) inorganic hollow spherical objects is preferably 1.15 or more, more preferably 1.20 or more and 2.00 or less, even more preferably 1.22 or more and 1.50 or less, and even more preferably 1.25 or more and less than 1.30, from the viewpoints of suppressing an increase in melt viscosity and a deterioration in fluidity, as well as moldability, etc. In this specification, the aspect ratio is determined by measuring the maximum length L, which is the length of the longest part in the particle projection plane, and the maximum perpendicular length S, which is the length of the longest part in the particle projection plane in the direction perpendicular to the maximum length L, for 3,000 particles using a dynamic image analysis method / particle state analyzer, and repeating the measurement several times to obtain the average value of the ratio L / S calculated for each particle.

[0064] From the viewpoint of moldability, the median diameter of component (B) is preferably 5 μm or more, more preferably 10 μm or more, and from the viewpoint of suppressing breakage of component (B) and moldability, it is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. In this specification, the median diameter refers to the volume-based median value measured by a laser diffraction / scattering particle size distribution measurement method. The median diameter can be measured, for example, using a laser diffraction / scattering particle size distribution measurement device LA-920 manufactured by Horiba, Ltd. The median diameter of component (B) in the liquid crystalline resin composition is measured by applying the above method to the remaining component (B) after heating the liquid crystalline resin composition to incinerate it at 600°C for 2 hours.

[0065] The content of the (B) component is 2 to 30% by mass, preferably 4 to 27% by mass, and more preferably 5 to 25% by mass, based on the total mass of the liquid crystal resin composition. When the (B) component content is 2% by mass or more, a liquid crystal resin composition with excellent dielectric properties is easily obtained. When the (B) component content is 30% by mass or less, a liquid crystal resin composition with good fluidity is easily obtained.

[0066] [Other Components] The liquid crystalline resin composition according to the present invention may contain other polymers, other fillers, and known substances generally added to synthetic resins, i.e., stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, flame retardants, colorants such as dyes and pigments, lubricants, mold release agents, crystallization accelerators, crystal nucleating agents, etc., as appropriate depending on the required performance, within the range not impairing the effects of the present invention.

[0067] The other polymer refers to a polymer other than the (A) liquid crystalline resin, for example, an epoxy group-containing copolymer. The other filler refers to a filler other than the (B) inorganic hollow spheres, for example, a granular filler such as silica; a plate-like filler such as mica; a fibrous filler such as glass fiber; carbon black, etc. In terms of fluidity, dielectric properties, etc., the content of the other filler is preferably 0 to 15% by mass, more preferably 0 to 12% by mass, and even more preferably 0 to 10% by mass, based on the entire liquid crystalline resin composition.

[0068] [Preparation of Liquid Crystalline Resin Composition] The preparation of the liquid crystal resin composition according to the present invention is not particularly limited. For example, the liquid crystal resin composition is prepared by blending the component (A), the component (B), and optionally other components, and melt-kneading the mixture using a single-screw or twin-screw extruder.

[0069] [Liquid Crystalline Resin Composition] From the viewpoint of fluidity, the melt viscosity of the liquid crystal resin composition according to the present invention obtained as described above is preferably 68 Pa·s or less, more preferably 66 Pa·s or less, and even more preferably 65 Pa·s or less. The lower limit of the melt viscosity is not particularly limited, and may be 5 Pa·s or more, 10 Pa·s or more, or 20 Pa·s or more. In this specification, the melt viscosity is defined as the melt viscosity at a cylinder temperature 10 to 40°C higher than the melting point of the liquid crystal resin, a shear rate of 1000 sec －１ The value obtained by the measurement method in accordance with ISO 11443 under the above conditions is adopted.

[0070] <Molded Article> The molded article of the present invention is made from 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 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.

[0071] The relative dielectric constant of the molded article of the present invention at a measurement frequency of 5 GHz is preferably 3.04 or less, more preferably 3.02 or less, and even more preferably 3.00 or less, from the viewpoint of dielectric properties. The lower limit of the relative dielectric constant is not particularly limited, and may be more than 1.0, 1.5 or more, or 2.0 or more.

[0072] The dielectric loss tangent of the molded article of the present invention at a measurement frequency of 5 GHz is preferably 0.008 or less, more preferably 0.007 or less, and even more preferably 0.006 or less, from the viewpoint of dielectric properties. The lower limit of the dielectric loss tangent is not particularly limited, and may be 0.001 or more, 0.0015 or more, or 0.0017 or more.

[0073] The molded article of the present invention has a low dielectric constant. Preferred applications of the molded article of the present invention having such properties include electronic components for use in high frequency ranges such as microwaves and millimeter waves.

[0074] 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.

[0075] Synthesis 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 filter, and nitrogen purge was initiated: (I) 67 g (15 mol %) of 1,1-bis(4-hydroxyphenyl)ethane (bisphenol E) (II) 145 g (50 mol %) of 4-hydroxybenzoic acid (HBA) (III) 87 g (25 mol %) of 1,4-phenylenedicarboxylic acid (TA) (IV) 39 g (10 mol %) of 4,4'-dihydroxybiphenyl (BP) 45 mg of a fatty acid metal salt catalyst (potassium acetate catalyst) 222 g of an acylating agent (acetic anhydride) 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.

[0076] <Synthesis Examples 2 to 12, Comparative Synthesis Examples 1 to 7> Resins were obtained in the same manner as in Synthesis Example 1, except that the types and charging ratios (mol%) of raw material monomers were as shown in Tables 2 to 4. However, the final polymerization temperature was changed to 340°C in Synthesis Examples 2 to 10 and 12 and Comparative Synthesis Examples 2 to 7, and to 360°C in Synthesis Example 11 and Comparative Synthesis Example 1. 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.

[0077] 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.

[0078] <Evaluation> The resins of Synthesis Examples and Comparative Synthesis Examples were evaluated for liquid crystallinity, melting point, dielectric properties, and polymerizability by the following methods. The results are shown in Tables 2 to 4.

[0079] [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.

[0080] [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.

[0081] [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 (Synthesis Example 1) 330°C (Synthesis Examples 2 to 4, 6 to 10, and 12 and Comparative Synthesis Examples 3 to 7) 350°C (Synthesis Examples 5 and 11 and Comparative Synthesis Example 2) 370°C (Comparative Synthesis Example 1) Mold temperature: 80°C Injection speed: 33 mm / sec Holding pressure: 60 MPa

[0082] [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.

[0083]

[0084]

[0085] *In Comparative Synthesis Example 3, no endothermic peak appeared within the range of measurement by DSC, so the melting point could not be measured.

[0086] As is clear from the results shown in Tables 2 to 4, it was confirmed that the liquid crystal resins of the synthesis examples had a low dielectric constant while maintaining good polymerizability.

[0087] Examples 1 to 8 and Comparative Examples 1 to 5 [Liquid Crystalline Resins] Liquid Crystalline Resin A: Liquid Crystalline Resin Obtained in Synthesis Example 10 Liquid Crystalline Resin B: Liquid Crystalline Resin Obtained in Synthesis Example 2 Liquid Crystalline Resin C: Liquid Crystalline Resin Obtained in Synthesis Example 11 Liquid Crystalline Resin D: Liquid Crystalline Resin Obtained in Synthesis Example 12

[0088] Liquid Crystalline Resin E: The following raw materials were charged into a polymerization vessel, and the temperature of the reaction system was raised to 140°C and allowed to react 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. 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 heat-treated at 300°C for 2 hours under a nitrogen stream to obtain the target polymer. The melting point of the obtained polymer was 336°C. The melting point of the above polymer was measured according to the melting point measurement method described above. 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

[0089] Liquid Crystalline Resin F: The following raw materials were charged into a polymerization vessel, and the temperature of the reaction system was raised to 140°C and allowed to react 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. 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 heat-treated at 300°C for 3 hours under a nitrogen stream to obtain the target polymer. The melting point of the obtained polymer was 348°C. The melting point of the above polymer was measured according to the melting point measurement method described above. 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

[0090] [Materials other than liquid crystalline resin] Glass balloon: Y12000 (manufactured by Seishin Enterprise Co., Ltd., aspect ratio (average) 1.264, median diameter 35 μm, true specific gravity 0.6) Glass fiber: ECS03T-786H (manufactured by Nippon Electric Glass Co., Ltd., chopped strand, fiber diameter 10 μm, length 3 mm) Mica: AB-25S (manufactured by Yamaguchi Mica Co., Ltd., mica, median diameter 25.0 μm)

[0091] [Production of Liquid Crystalline Resin Composition] The above components were melt-kneaded in the proportions shown in Table 5 or Table 6 using a twin-screw extruder (TEX30α type, manufactured by The Japan Steel Works, Ltd.) at the following cylinder temperatures to obtain liquid crystal resin composition pellets. [Production conditions] Cylinder temperature: 330°C (Examples 1 to 6, and 8, and Comparative Example 5) 350°C (Example 7, and Comparative Examples 1, 3, and 4) 370°C (Comparative Example 2)

[0092] [Melt Viscosity] Using a Capillograph 1B model manufactured by Toyo Seiki Seisakusho Co., Ltd., the liquid crystal resin was melted at a temperature 10 to 40° C. higher than the melting point of the liquid crystal resin using an orifice having an inner diameter of 1 mm and a length of 20 mm at a shear rate of 1,000 sec. －１ The melt viscosity of the liquid crystalline resin composition was measured in accordance with ISO 11443 at 330°C (Examples 1 to 6, and 8, and Comparative Example 5) 350°C (Example 7, and Comparative Examples 1, 3, and 4) 380°C (Comparative Example 2)

[0093] [Dielectric properties] The relative permittivity and dielectric loss tangent at a measurement frequency of 5 GHz were measured in the same manner as in [Evaluation of dielectric properties] above, except that the pellets of the Examples and Comparative Examples were used instead of the resin and the molding conditions were changed as follows. The results are shown in Tables 5 and 6. [Molding conditions] Cylinder temperature: 330°C (Examples 1 to 6, and 8, and Comparative Example 5) 350°C (Example 7, and Comparative Examples 1, 3, and 4) 370°C (Comparative Example 2)

[0094]

[0095]

[0096] As is clear from the results shown in Tables 5 and 6, the liquid crystal resin compositions of the examples gave molded articles having low dielectric constants and good flowability.

Claims

1. A liquid crystalline resin composition comprising (A) a liquid crystalline resin and (B) inorganic hollow spheres, wherein the (A) liquid crystalline resin is a liquid crystalline resin that exhibits optical anisotropy when melted, and contains the following structural units (I), (II), and (III), and may or may not contain the following structural unit (IV), wherein the content of structural unit (I) is 1 to 40 mol% of all structural units, the content of structural unit (II) is 20 to 98 mol% of all structural units, the content of structural unit (III) is 1 to 40 mol% of all structural units, and the content of structural unit (IV) is 0 to 39 mol% of all structural units, and the structural unit (I) has a central atom C calculated by the PM6 method, which is a semi-empirical molecular orbital method. １ a difference between the maximum and minimum values ​​of rotational energy around the liquid crystal molecule is 0.42 to 0.82 kcal / mol; a content of the liquid crystal resin (A) is 70 to 98 mass% with respect to the entire liquid crystal resin composition; and a content of the inorganic hollow spherical bodies (B) is 2 to 30 mass%. (In the formula, 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. 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. (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 crystal resin composition according to claim 1, wherein the total content of the structural units (I) to (IV) in the liquid crystal resin (A) is 100 mol % based on all structural units.

3. The liquid crystalline resin composition according to claim 1 or 2, wherein in said (A) liquid crystalline resin, 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 composition according to claim 1 or 2, wherein in the (A) liquid crystalline resin, 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. The liquid crystalline resin composition according to claim 1 or 2, wherein the inorganic hollow spherical bodies (B) are glass balloons.

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

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