JP7727445B2 - Liquid crystalline resin composition - Google Patents

Description

The present invention relates to a liquid crystalline resin composition.

Liquid crystalline resins, typified by liquid crystalline polyester resins, are widely used as high-performance engineering plastics because they have a good balance of excellent mechanical strength, heat resistance, chemical resistance, and electrical properties, as well as excellent dimensional stability. Meanwhile, in recent years, remarkable technological advances 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 ranges such as microwaves and millimeter waves. Materials that make up such electronic components are required to have appropriate dielectric properties depending on the design of each electronic component.

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

Japanese Patent Application Laid-Open No. 2004-27021

However, the inventors' investigations have revealed that conventional liquid crystalline resin compositions containing hollow fillers such as inorganic hollow spheres have extremely high melt viscosities, poor fluidity, and room for improvement in dielectric properties or heat resistance.

The present invention was made to solve the above problems, and its purpose is to provide a liquid crystalline resin composition that has excellent dielectric properties, heat resistance, and good fluidity.

The inventors of the present invention conducted extensive research to solve the above problems. As a result, they discovered that a liquid crystalline resin composition containing a liquid crystalline resin with a melting point of 300°C or higher and a cyclic olefin resin with a glass transition temperature of 100°C or higher in specified amounts has excellent dielectric properties and heat resistance, and good fluidity, leading to the completion of the present invention. More specifically, the present invention provides the following:

(1) A liquid crystalline resin composition containing (A) a liquid crystalline resin, (B) a cyclic olefin resin, and (C) a hollow filler, wherein the melting point of the (A) liquid crystalline resin is 300°C or higher, the glass transition temperature of the (B) cyclic olefin resin is 100°C or higher, and the content of the (A) liquid crystalline resin is 55 to 85 parts by volume, the content of the (B) cyclic olefin resin is 15 to 45 parts by volume, and the content of the (C) hollow filler is 20 to 75 parts by volume per 100 parts by volume of the total of the (A) liquid crystalline resin and the (B) cyclic olefin resin.

(2) The liquid crystalline resin composition according to (1), wherein (A) the liquid crystalline resin is an aromatic polyester or aromatic polyester amide having, as a constituent component, a structural unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof.

(3) The liquid crystalline resin composition according to (1) or (2), wherein (C) the hollow filler is a glass balloon.

(4) A liquid crystal resin composition according to any one of (1) to (3), wherein (B) the cyclic olefin resin is an addition polymer of a cyclic olefin monomer and an α-olefin.

(5) The liquid crystal resin composition according to any one of (1) to (4), further containing an inorganic filler.

The present invention makes it possible to provide a liquid crystalline resin composition that has excellent dielectric properties, heat resistance, and good fluidity.

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.

Embodiments of the present invention are described below. However, the present invention is not limited to the following embodiments. Furthermore, the value of parts by volume representing the content of a component in a liquid crystalline resin composition is a value calculated from the value of parts by mass of that component and the true specific gravity of that component. In this specification, the values of parts by volume and true specific gravity are those at room temperature (20 to 30°C).

<Liquid crystal resin composition>
The liquid crystalline resin composition according to the present invention contains (A) a liquid crystalline resin, (B) a cyclic olefin resin, and (C) a hollow filler, and the melting point of the (A) liquid crystalline resin is 300°C or higher, and the glass transition temperature of the (B) cyclic olefin resin is 100°C or higher.

[(A) Liquid Crystalline Resin]
The liquid crystalline resin (A) used in the present invention refers to a melt-processable polymer capable of forming an optically anisotropic melt phase. The properties of the anisotropic melt phase can be confirmed by a conventional polarization examination method using crossed polarizers. More specifically, the anisotropic melt phase can be confirmed by observing a molten sample placed on a Leitz hot stage at 40x magnification using a Leitz polarizing microscope under a nitrogen atmosphere. When examined between crossed polarizers, the liquid crystalline polymer applicable to the present invention normally transmits polarized light, even in a molten, stationary state, exhibiting optical anisotropy.

The melting point of the (A) liquid crystalline resin is 300°C or higher, preferably 300 to 360°C, and more preferably 315 to 345°C. When the melting point of the (A) liquid crystalline resin is 300°C or higher, it is easy to obtain a liquid crystalline resin composition with excellent heat resistance. When the melting point of the (A) liquid crystalline resin is 360°C or lower, it is easy to obtain a liquid crystalline resin composition with good fluidity.

The type of liquid crystalline resin (A) described above is not particularly limited, but is preferably an aromatic polyester and/or an aromatic polyester amide. Polyesters that partially contain aromatic polyesters and/or aromatic polyester amides in the same molecular chain also fall within this category. The liquid crystalline resin (A) preferably has an inherent viscosity (I.V.) of at least about 2.0 dl/g, and more preferably 2.0 to 10.0 dl/g, when dissolved in pentafluorophenol at 60°C at a concentration of 0.1% by mass.

The aromatic polyester or aromatic polyesteramide as the liquid crystal resin (A) applicable to the present invention is particularly preferably an aromatic polyester or aromatic polyesteramide having, as a constituent component, a constituent unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids, aromatic hydroxyamines, aromatic diamines, and derivatives thereof.

More specifically,
(1) A polyester mainly composed of structural units derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof;
(2) A polyester mainly composed of (a) a structural unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof, and (b) a structural unit derived from at least one selected from the group consisting of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and derivatives thereof;
(3) A polyester mainly composed of (a) a structural unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof, (b) a structural unit derived from at least one selected from the group consisting of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and derivatives thereof, and (c) a structural unit derived from at least one selected from the group consisting of aromatic diols, alicyclic diols, aliphatic diols, and derivatives thereof;
(4) A polyesteramide mainly composed of (a) a structural unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof, (b) a structural unit derived from at least one selected from the group consisting of aromatic hydroxyamines, aromatic diamines, and derivatives thereof, and (c) a structural unit derived from at least one selected from the group consisting of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and derivatives thereof;
(5) Polyesteramides mainly comprising (a) structural units derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and their derivatives, (b) structural units derived from at least one selected from the group consisting of aromatic hydroxyamines, aromatic diamines, and their derivatives, (c) structural units derived from at least one selected from the group consisting of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives, and (d) structural units derived from at least one selected from the group consisting of aromatic diols, alicyclic diols, aliphatic diols, and their derivatives. Furthermore, a molecular weight modifier may be used in combination with the above structural components, if necessary.

Preferred examples of the specific compound constituting the (A) liquid crystal resin applicable to the present invention include aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid; aromatic diols such as 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, hydroquinone, resorcinol, compounds represented by the following general formula (I) and compounds represented by the following general formula (II); aromatic dicarboxylic acids such as 1,4-phenylenedicarboxylic acid, 1,3-phenylenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid and compounds represented by the following general formula (III); and aromatic amines such as p-aminophenol, p-phenylenediamine and N-acetyl-p-aminophenol.
(X is a group selected from alkylene (C ₁ to C ₄ ), alkylidene, —O—, —SO—, —SO ₂ —, —S—, and —CO—.)
(Y is a group selected from —(CH ₂ ) _n — (n=1 to 4) and —O(CH ₂ ) _n O— (n=1 to 4).)

The liquid crystal resin (A) used in the present invention can be prepared from the above-mentioned monomer compound (or mixture of monomers) by known methods such as direct polymerization or transesterification. Typically, melt polymerization, solution polymerization, slurry polymerization, solid-state polymerization, or a combination of two or more of these methods is used. Melt polymerization or a combination of melt polymerization and solid-state polymerization is preferred. The above-mentioned compounds capable of forming esters may be used in the polymerization in their original form, or may be modified from precursors to derivatives capable of forming esters prior to polymerization. Various catalysts can be used in these polymerizations. Representative 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), as well as organic compound catalysts such as N-methylimidazole and 4-dimethylaminopyridine. The amount of catalyst used is generally about 0.001 to 1% by mass, and preferably about 0.01 to 0.2% by mass, based on the total mass of the monomers. If necessary, the molecular weight of polymers produced by these polymerization methods can be further increased by solid-state polymerization, in which the polymers are heated under reduced pressure or in an inert gas.

The melt viscosity of the liquid crystalline resin (A) obtained by the above method is not particularly limited. Generally, a resin having a melt viscosity at the molding temperature of 3 Pa·s to 500 Pa·s at a shear rate of 1000 sec ^-1 can be used. However, a resin having a viscosity that is too high is not preferred because it significantly deteriorates the flowability. The liquid crystalline resin (A) may be a mixture of two or more types of liquid crystalline resins.

The content of component (A) is 55 to 85 parts by volume, preferably 58 to 82 parts by volume, and more preferably 60 to 80 parts by volume, per 100 parts by volume of the total of the liquid crystal resin (A) and the cyclic olefin resin (B). When the content of component (A) is 55 parts by volume or more, a liquid crystal resin composition with excellent heat resistance is easily obtained. When the content of component (A) is 85 parts by volume or less, a liquid crystal resin composition with excellent dielectric properties is easily obtained.

[(B) Cyclic olefin resin]
The form of the cyclic olefin resin (B) in the present invention is not particularly limited, and examples thereof include the following.
(1) Addition polymers of a monomer having a ring structure and an olefin. (2) Ring-opening polymers of a monomer having a ring structure and a monomer having a monocyclic structure.

The type of cyclic olefin resin (B) blended into the liquid crystal resin composition of the present invention may be one type, or two or more types.

Whether the (B) cyclic olefin resin is an addition polymer or a ring-opening polymer, from the viewpoint of flexibility, etc., it is preferable that the monomers constituting the (B) cyclic olefin resin are selected so that the resulting (B) cyclic olefin resin contains an ethylene unit. Here, the ethylene unit refers to a structural unit derived from ethylene.
Examples of the monomers constituting the cyclic olefin resin (B) will be described below.

(Monomer having a ring structure)
(B) Examples of the monomer having a ring structure that constitutes the cyclic olefin resin include cyclic olefin monomers, such as norbornene and polycyclic cyclic monomers represented by the following general formula (IV):

In formula (I), R ¹ to R ¹² may be the same or different and are selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group, which may be a saturated or unsaturated hydrocarbon group.
An example of the unsaturated hydrocarbon group is a vinyl group. An example of a monomer having a ring structure containing a vinyl group is 5-vinyl-2-norbornene.

R ⁹ and R ¹⁰ , and R ¹¹ and R ¹² may combine together to form a divalent hydrocarbon group.
R ⁹ or R ¹⁰ and R ¹¹ or R ¹² may be joined together to form a ring.
n represents 0 or a positive integer, and when n is 2 or greater, R ⁵ to R ⁸ may be the same or different in each repeating unit, provided that when n=0, at least one of R ¹ to R ⁴ and R ⁹ to R ¹² is not a hydrogen atom.

Specific examples of when R ⁹ and R ¹⁰ , or R ¹¹ and R ¹² combine together to form a divalent hydrocarbon group include alkylidene groups such as an ethylidene group, a propylidene group, and an isopropylidene group.

When ^R9 or ^R10 and ^R11 or ^R12 together form a ring, the ring formed may be a monocyclic or polycyclic ring, a polycyclic ring having a bridge, a ring having a double bond, or a ring formed by a combination of these rings. In addition, these rings may have a substituent such as a methyl group.

The monomer having a ring structure may or may not have a side chain.

Specific examples of the monomer having a ring structure include norbornene and tetracyclododecene.
Norbornene is particularly preferred as the monomer having a ring structure from the viewpoint of high reactivity to a catalyst (such as a metallocene catalyst) in the reaction with an olefin.

In the (B) cyclic olefin resin, the content of structural units derived from monomers having a ring structure is not particularly limited. From the viewpoint of imparting heat resistance to the (B) cyclic olefin resin, the lower limit of the content of these structural units is preferably greater than 0 mol%, and more preferably 5 mol or more, relative to all structural units contained in the (B) cyclic olefin resin. From the viewpoint of easily imparting crosslinkability, the upper limit of the content of these structural units is preferably 55 mol% or less, more preferably 50 mol% or less, and even more preferably 40 mol% or less, relative to all structural units contained in the (B) cyclic olefin resin.

(B) The monomer having a ring structure that constitutes the cyclic olefin resin may be one type alone or two or more types in combination.

(olefin)
The olefin constituting the (B) cyclic olefin-based resin is not particularly limited, and examples thereof include α-olefins, preferably α-olefins having 2 to 10 carbon atoms.

Specific examples of α-olefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Of the above, ethylene is particularly preferred.

The olefin content in the (B) cyclic olefin resin is not particularly limited. From the viewpoint of easily imparting flexibility to the resulting crosslinked product, the lower limit of the olefin content is preferably 45 mol% or more, more preferably 50 mol% or more, and even more preferably 60 mol% or more, based on all structural units contained in the (B) cyclic olefin resin. From the viewpoint of easily obtaining a crosslinked product with an appropriate elastic modulus, the upper limit of the olefin content is preferably less than 100 mol%, more preferably 95 mol% or less, based on all structural units contained in the (B) cyclic olefin resin.

The olefins constituting (B) the cyclic olefin-based resin may be one type alone or a combination of two or more types.

(Monomer having a monocyclic structure)
The monomer having a monocyclic structure is not particularly limited as long as it is an olefin having only one cyclic structure, and the olefin is preferably an olefin having 3 to 10 carbon atoms.

Specific examples of monomers having a monocyclic structure include cyclic monoolefins (cyclopropene, cyclobutene, cyclopentene, methylcyclopentene, cyclohexene, methylcyclohexene, cycloheptene, cyclooctene, etc.) and cyclic diolefins (cyclohexadiene, methylcyclohexadiene, cyclooctadiene, methylcyclooctadiene, etc.). Of the above, cyclopentene is particularly preferred.

In the (B) cyclic olefin resin, the content of the monomer having a monocyclic structure is not particularly limited. The lower limit of the content of the monomer having a monocyclic structure is preferably 40 mol% or more, based on the total structural units contained in the (B) cyclic olefin resin, from the viewpoint of easily imparting flexibility to the resulting cross-linked product. The upper limit of the content of the monomer having a monocyclic structure is preferably less than 100 mol%, based on the total structural units contained in the (B) cyclic olefin resin, from the viewpoint of easily obtaining a cross-linked product with an appropriate elastic modulus. The monomer having a monocyclic structure that constitutes the (B) cyclic olefin resin may be one type alone or two or more types in combination.

(Addition type reaction)
When the (B) cyclic olefin resin is an addition polymer of a monomer having a ring structure and an olefin, the (B) cyclic olefin resin can be produced by employing any method known as a method for producing an addition polymer using the above-mentioned monomer having a ring structure and an olefin.

Metallocene catalysts are particularly suitable as addition polymerization catalysts. Specific examples of metallocene catalysts include (t-butylamido)dimethyl-9-fluorenylsilane titanium dimethyl, racemic ethylidene bis(indenyl)zirconium dichloride, racemic dimethylsilyl bis(2-methylbenzoindenyl)zirconium dichloride, racemic isopropylidene bis(tetrahydroindenyl)zirconium dichloride, isopropylidene(1-indenyl)(3-isopropylcyclopentadienyl)zirconium dichloride, and (t-butylamido)dimethyl-9-fluorenylsilane zirconium dichloride. dimethyl, (t-butylamido)dimethyl-9-fluorenylsilane zirconium dichloride, (t-butylamido)dimethyl-9-(3,6-dimethylfluorenyl)silane zirconium dimethyl, (t-butylamido)dimethyl-9-[3,6-di(i-propyl)fluorenyl]silane zirconium dimethyl, (t-butylamido)dimethyl-9-[3,6-di(t-butyl)fluorenyl]silane zirconium dimethyl, (t-butylamido)dimethyl-9-[2,7-di(t-butyl)fluorenyl]silane zirconium dimethyl, (t-butyl (t-butylamido)dimethyl-9-(2,3,6,7-tetramethylfluorenyl)silane zirconium dimethyl, racemic-ethylidene-bis(indenyl)titanium dichloride, racemic-dimethylsilyl-bis(2-methyl-benzoindenyl)titanium dichloride, racemic-isopropylidene-bis(tetrahydroindenyl)titanium dichloride, isopropylidene(1-indenyl)(3-isopropyl-cyclopentadienyl)titanium dichloride, (t-butylamido)dimethyl-9-fluorenylsilanetitanium dichloride, (t-butylamido)dimethyl Examples of the addition polymerization catalyst include, but are not limited to, methyl-9-(3,6-dimethylfluorenyl)silanetitanium dimethyl, (t-butylamido)dimethyl-9-[3,6-di(i-propyl)fluorenyl]silanetitanium dimethyl, (t-butylamido)dimethyl-9-[3,6-di(t-butyl)fluorenyl]silanetitanium dimethyl, (t-butylamido)dimethyl-9-[2,7-di(t-butyl)fluorenyl]silanetitanium dimethyl, and (t-butylamido)dimethyl-9-(2,3,6,7-tetramethylfluorenyl)silanetitanium dimethyl. The addition polymerization catalysts can be used alone or in combination of two or more.

(B) Cyclic olefin resins are more easily obtained by using a co-catalyst in addition to the polymerization catalyst. Co-catalysts can be used alone or in combination of two or more. Examples of co-catalysts include alkylaluminoxanes and alkylaluminums.

(Ring-opening reaction)
When the (B) cyclic olefin resin is a ring-opening polymer of a monomer having a ring structure and a monomer having a monocyclic structure, it can be obtained by ring-opening polymerization using the monomer having a ring structure, the monomer having a monocyclic structure, and a chain transfer agent in the presence of a ring-opening polymerization catalyst, followed by hydrogenation as needed.

There are no particular restrictions on chain transfer agents, as long as they can control the molecular weight and have one double bond between carbon atoms at the end, but examples include the above-mentioned α-olefins (1-hexene, etc.).

The ring-opening polymerization catalyst may be any catalyst capable of ring-opening copolymerization of a monocyclic olefin and a norbornene compound, with ruthenium carbene complexes being preferred. Specific examples of ruthenium carbene complexes include bis(tricyclohexylphosphine)benzylidene ruthenium dichloride, bis(triphenylphosphine)-3,3-diphenylpropenylidene ruthenium dichloride, bis(tricyclohexylphosphine)t-butylvinylidene ruthenium dichloride, dichloro-(3-phenyl-1H-inden-1-ylidene)bis(tricyclohexylphosphine)ruthenium, bis(1,3-diisopropylimidazolin-2-ylidene)benzylidene ruthenium dichloride, and bis(1,3-dicyclohexyl Examples of suitable ring-opening polymerization catalysts include (1,3-dimesitylimidazolin-2-ylidene)benzylideneruthenium dichloride, (1,3-dimesitylimidazolin-2-ylidene)(tricyclohexylphosphine)benzylideneruthenium dichloride, (1,3-dimesitylimidazolidin-2-ylidene)(tricyclohexylphosphine)benzylideneruthenium dichloride, bis(tricyclohexylphosphine)ethoxymethylideneruthenium dichloride, and (1,3-dimesitylimidazolidin-2-ylidene)(tricyclohexylphosphine)ethoxymethylideneruthenium dichloride. These ring-opening polymerization catalysts can be used alone or in combination.

In the present invention, after the ring-opening polymerization, if necessary, a hydrogenation catalyst and hydrogen may be added to the reaction system in the ring-opening polymerization step to hydrogenate the double bonds between carbon atoms in the ring-opening polymer. The hydrogenation catalyst may be any catalyst that is generally used in hydrogenation reactions of olefins and aromatic compounds. Specific examples of the hydrogenation catalyst include the following:
(1) Supported metal catalysts in which transition metals are supported on a support (carbon, alumina, silica, diatomaceous earth, etc.); (2) Homogeneous catalysts consisting of organic transition metal compounds (titanium, cobalt, nickel, etc.) and organic metal compounds (lithium, magnesium, aluminum, tin, etc.); and (3) Metal complex catalysts (rhodium, ruthenium, etc.).

((B) Glass Transition Temperature of Cyclic Olefin Resin)
The glass transition temperature (hereinafter also referred to as "Tg") of the (B) cyclic olefin resin is 100°C or higher. When the (B) cyclic olefin resin has a Tg of 100°C or higher, it is easy to obtain a liquid crystalline resin composition having excellent heat resistance while maintaining good fluidity. The lower limit of the Tg of the (B) cyclic olefin resin is preferably 120°C or higher, more preferably 140°C or higher. The upper limit of the Tg of the (B) cyclic olefin resin is not particularly limited, and may be 200°C or lower, or may be 170°C or lower.

In the present invention, the Tg is a value measured by the DSC method (method described in JIS K 7121) at a heating rate of 20°C/min.

The content of component (B) is 15 to 45 parts by volume, preferably 18 to 42 parts by volume, and more preferably 20 to 40 parts by volume, per 100 parts by volume of the total of the liquid crystal resin (A) and the cyclic olefin resin (B). When the content of component (B) is 15 parts by volume or more, it is easy to obtain a liquid crystal resin composition with excellent dielectric properties. When the content of component (A) is 45 parts by volume or less, it is easy to obtain a liquid crystal resin composition with excellent heat resistance.

[(C) Hollow filler]
The hollow filler (C) is generally called a balloon, and examples of materials for the hollow spheres include inorganic materials such as alumina, silica, and glass; and organic materials such as urea resin and phenolic resin. Among these, glass is preferred from the viewpoint of heat resistance and strength. That is, glass balloons are preferably used as the hollow filler. The component (C) may be used alone or in combination of two or more.

From the viewpoints of preventing an increase in melt viscosity and a deterioration in fluidity, as well as moldability, the aspect ratio of the (C) hollow filler is preferably 1.15 or greater, more preferably 1.20 to 2.00, even more preferably 1.22 to 1.50, and even more preferably 1.25 to less than 1.30. 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/particle state analyzer, and repeating the measurement several times to obtain the average value of the ratio L/S calculated for each particle.

From the viewpoint of moldability, the median diameter of component (C) is preferably 5 μm or more, more preferably 10 μm or more. From the viewpoint of suppressing breakage of component (C) 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, median diameter refers to the volume-based median value measured by a laser diffraction/scattering particle size distribution measurement method.

The content of component (C) is 20 to 75 parts by volume, preferably 25 to 73 parts by volume, and more preferably 30 to 70 parts by volume, per 100 parts by volume of the total of the liquid crystal resin (A) and the cyclic olefin resin (B). When the content of component (C) is 20 parts by volume or more, it is easy to obtain a liquid crystal resin composition with excellent dielectric properties. When the content of component (C) is 75 parts by volume or less, it is easy to obtain a liquid crystal resin composition with good fluidity.

[(D) (C) Inorganic fillers excluding hollow fillers]
The liquid crystalline resin composition according to the present invention may optionally contain (D) (C) an inorganic filler other than the hollow filler. When the liquid crystalline resin composition contains the component (D), the mechanical strength of a molded article of the liquid crystalline resin composition, such as the flexural modulus, is likely to be improved. The component (D) may be used alone or in combination of two or more. Examples of the component (D) include a plate-like filler, a fibrous filler, and a granular filler.

(Plate-like filler)
When the liquid crystalline resin composition according to the present invention contains a plate-like filler, the molded article made of the liquid crystalline resin composition is likely to have improved mechanical strength such as flexural modulus, and warpage is likely to be suppressed. The plate-like filler may be used alone or in combination of two or more kinds.

The plate-like filler preferably has a median diameter of 15 to 50 μm. If the median diameter is 15 μm or more, the necessary mechanical strength is likely to be ensured, and the molded article is likely to be more effective in suppressing warpage. If the median diameter is 50 μm or less, the fluidity of the composition when melted is likely to be improved. The preferred median diameter is 20 to 30 μm.

The plate-like filler is not particularly limited, and examples include mica, talc, glass flakes, graphite, and various metal foils (e.g., aluminum foil, iron foil, copper foil). In the present invention, it is preferable to use mica as the plate-like filler.

(fibrous filler)
When the liquid crystalline resin composition according to the present invention contains a fibrous filler, the molded article made of the liquid crystalline resin composition is likely to have improved mechanical strength such as flexural modulus. The fibrous fillers can be used alone or in combination of two or more.

The average fiber length of the fibrous filler is not particularly limited and may be, for example, 250 μm or more, preferably 350 to 600 μm, and more preferably 450 to 500 μm. When the average fiber length is 250 μm or more, the molded article made from the liquid crystalline resin composition of the present invention is likely to have improved mechanical strength and heat resistance. When the average fiber length is 600 μm or less, the liquid crystalline resin composition is likely to have sufficient fluidity. In this specification, the average fiber length of the fibrous filler is determined by capturing 10 stereomicroscope images of the fibrous filler from a CCD camera onto a PC and then processing the images using an image measuring device to measure the fiber lengths of 100 fibrous fillers per stereomicroscope image, i.e., a total of 1,000 fibrous fillers. The average fiber length of the fibrous filler in the liquid crystalline resin composition is measured by applying the above method to the remaining fibrous filler after heating the liquid crystalline resin composition to 600°C for 2 hours to incinerate it.

The average fiber diameter of the fibrous filler is not particularly limited and may be, for example, 20 μm or less, or 5 to 15 μm. In this specification, the average fiber diameter of the fibrous filler is determined by observing the fibrous filler with a scanning electron microscope and measuring the fiber diameters of 30 fibrous fillers. The average fiber diameter of the fibrous filler in the liquid crystalline resin composition is measured by the above-mentioned method on the remaining fibrous filler after heating the liquid crystalline resin composition to ash at 600°C for 2 hours.

Any fiber can be used as a fibrous filler as long as it satisfies the above-mentioned shape requirements. Examples of fibrous fillers include inorganic fibrous materials such as glass fiber, milled fiber, carbon fiber, asbestos fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, and metal fibers such as stainless steel, aluminum, titanium, copper, and brass. In the present invention, it is preferable to use glass fiber as the fibrous filler from the standpoint of mechanical strength.

(Granular filler)
When the liquid crystalline resin composition according to the present invention contains a granular filler, the molded article made of the liquid crystalline resin composition is likely to have improved mechanical strength such as flexural modulus and is likely to be inhibited from surface whitening. The granular filler can be used singly or in combination of two or more.

The median diameter of the granular filler is preferably 0.3 to 5.0 μm. When the median diameter is 0.3 μm or more, the impact resistance of the molded body is likely to be maintained. When the median diameter is 5.0 μm or less, the effect of suppressing surface whitening of the molded body is likely to be enhanced. The median diameter is more preferably 0.5 to 5.0 μm, and even more preferably 0.5 to 4.0 μm. The median diameter of the granular filler in the liquid crystalline resin composition is the value measured for the granular filler remaining after the liquid crystalline resin composition is incinerated by heating at 600°C for 2 hours.

Examples of granular fillers include metal oxides such as silica, quartz powder, glass beads, glass powder, potassium aluminum silicate, diatomaceous earth, iron oxide, titanium oxide, zinc oxide, and alumina; metal carbonates such as calcium carbonate and magnesium carbonate; metal sulfates such as calcium sulfate and barium sulfate; phosphates such as calcium pyrophosphate and anhydrous dicalcium phosphate; silicon carbide; silicon nitride; and boron nitride. In the present invention, from the viewpoints of suppressing surface whitening of the molded body and achieving low dust generation of the molded body, it is preferable to use one or more granular fillers selected from the group consisting of silica and barium sulfate, and it is more preferable to use silica.

The content of component (D) is preferably 2 to 15 parts by volume, more preferably 5 to 12 parts by volume, and even more preferably 7 to 10 parts by volume, per 100 parts by volume of the total of the liquid crystal resin (A) and the cyclic olefin resin (B). When the content of component (D) is within the above range, the fluidity of the liquid crystal resin composition is sufficiently ensured, while the mechanical strength of a molded article made from the liquid crystal resin composition is likely to be improved.

[Other ingredients]
To the liquid crystalline resin composition according to the present invention, 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., may be added as appropriate depending on the required performance, within the range not impairing the effects of the present invention.

Other polymers refer to polymers other than (A) liquid crystal resins and (B) cyclic olefin resins, such as epoxy group-containing copolymers. Other fillers refer to fillers other than (C) hollow fillers and (D) inorganic fillers, such as (C) organic fillers other than hollow fillers; carbon black.

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

[Liquid crystal resin composition]
The liquid crystalline resin composition according to the present invention obtained as described above preferably has a melt viscosity of 80 Pa sec or less, more preferably 75 Pa sec or less, and even more preferably 73 Pa sec or less, from the viewpoints of fluidity during melting and moldability. In this specification, the melt viscosity is a value obtained by a measurement method in accordance with ISO 11443 under conditions of a cylinder temperature 10 to 20°C higher than the melting point of the liquid crystalline resin and a shear rate of 1000 sec ^-1 .

The liquid crystal resin composition of the present invention preferably has a relative dielectric constant of 2.75 or less, more preferably 2.73 or less, and even more preferably 2.7 or less. The liquid crystal resin composition of the present invention preferably has a dielectric dissipation factor of 0.005 or less, more preferably 0.004 or less, and even more preferably 0.003 or less.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples.

<Liquid Crystalline Resin>
・Liquid crystal polyester amide resin (LCP1)
The following raw materials were charged into a polymerization vessel, and the temperature of the reaction system was raised to 140°C and reacted 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 melt viscosity at 350°C was 19.0 Pa s, and the true specific gravity was 1.4. The melt viscosity of the above polymer was measured using the same method for measuring melt viscosity as described below.
4-hydroxybenzoic acid (HBA): 1380 g (60 mol%)
2-Hydroxy-6-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%)
Metal catalyst (potassium acetate catalyst): 110 mg
Acylating agent (acetic anhydride): 1659 g

・Liquid crystal polyester resin (LCP2)
The following raw materials were charged into a polymerization vessel, and the temperature of the reaction system was raised to 140°C and reacted at 140°C for 1 hour. The temperature was then further raised to 330°C over 3.5 hours, and the pressure was then reduced to 10 Torr (i.e., 1,330 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 the target polymer as pellets. The melting point of the obtained polymer was 323°C, the melt viscosity at 340°C was 30 Pa s, and the true specific gravity was 1.4. The melt viscosity of the above polymer was measured in the same manner as the melt viscosity measurement method described below.
4-hydroxybenzoic acid (HBA): 2524 g (79.3 mol%)
6-Hydroxy-2-naphthoic acid (HNA): 867 g (20 mol%)
1,4-phenylenedicarboxylic acid (TA): 27 g (0.7 mol%)
Metal catalyst (potassium acetate catalyst): 150 mg
Acylating agent (acetic anhydride): 2336 g

<Cyclic olefin resin (COC)>
Toluene (4 liters) and a toluene solution (75 ml) of PMAO (manufactured by Tosoh Finechem Corporation) adjusted to a concentration of 2.2 mol/l were charged into a 5-liter autoclave equipped with a heater, a stirrer, and a nitrogen-inserting device. Then, norbornene (1,650 g) was poured into the autoclave, and the vessel was purged with nitrogen to reduce the pressure. Then, ethylene was injected from an ethylene cylinder to fill the vessel to a gauge pressure of 10 atm. The vessel was then heated to 70°C and stirred for 5 minutes. A toluene solution (5 ml) of isopyridene(9-fluorenyl)-(1-(3-methyl)cyclopentadienyl)zirconium dichloride adjusted to 1 μmol/ml in a glove box was added to the autoclave, and the vessel was left to react for 15 minutes. After the reaction, the contents were discharged, and 500 ml of distilled water and a filtering agent were added, followed by pressure filtration. The filtrate was poured into 10 liters of acetone, stirred, filtered, washed with the same amount of acetone, and then dried to obtain approximately 60 g of the target cyclic olefin resin, an addition polymer, as a white powder. The resulting cyclic olefin resin had a glass transition temperature of 155°C, an ethylene unit ratio of 40 mol%, and a true specific gravity of 1.02. The Tg and ethylene unit ratio of the cyclic olefin resin were measured as described below.

The above-mentioned cyclic olefin resin does not contain unsaturated bonds between carbon atoms in the main chain (i.e., the main chain contains only saturated bonds between carbon atoms). Furthermore, the above-mentioned cyclic olefin resin does not contain unsaturated bonds between carbon atoms in the side chain (i.e., the side chain contains only saturated bonds between carbon atoms).

(Glass transition temperature (Tg))
In accordance with JIS K 7121, the Tg (unit: ° C.) of the cyclic olefin resin was measured under the following conditions based on the DSC method.
DSC device: Differential scanning calorimeter "DSC-7000X" (Hitachi High-Tech Science Corporation)
Measurement atmosphere: nitrogen Temperature increase condition: 20°C/min

(Measurement of the ratio of ethylene units)
The ratio of ethylene units (unit: mol %) in the cycloolefin resin was measured by a method using ¹³ C-NMR, using the following apparatus and measurement conditions.

[ ¹³ C-NMR measurement conditions]
NMR device: "Bruker AVANCE 600" (manufactured by Bruker)
Measurement solvent: 1,1,2,2-tetrachloroethane- _d2
Measured nuclide: ^13C
Measurement temperature: 381K
Sample concentration: 80 mg/mL
Sample tube diameter: 10 mm
Accumulation count: 18,000 times Pulse repetition time: 3 seconds

[Method for calculating the ratio of ethylene units]
The norbornene ratio Nb (mol %) was calculated from the integral values of the signals derived from norbornene (C1 to C7) and the integral values of the signal derived from ethylene (E) using the following formula, and the ratio of ethylene units was calculated by subtracting this value from 100. The positions of C1 to C7 and E are as shown in formula (V) below.

<Materials other than 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, true specific gravity 2.6)
Mica: AB-25S (manufactured by Yamaguchi Mica Co., Ltd., mica, median diameter 25.0 μm, true specific gravity 2.8)

<Production of Liquid Crystalline Resin Composition>
The above components were melt-kneaded in the proportions shown in Table 1 or Table 2 using a twin-screw extruder (TEX30α type, manufactured by The Japan Steel Works, Ltd.) at the cylinder temperatures shown below to obtain liquid crystal resin composition pellets.
[Manufacturing conditions]
Cylinder temperature:
350°C: In the case of a liquid crystalline resin composition containing a liquid crystalline polyester amide resin (LCP1) 340°C: In the case of a liquid crystalline resin composition containing a liquid crystalline polyester resin (LCP2)

<Melt viscosity>
The melt viscosity of the liquid crystalline resin composition was measured in accordance with ISO 11443 using a Capillograph 1B model manufactured by Toyo Seiki Seisakusho, Ltd., at a temperature 10 to 20°C higher than the melting point of the liquid crystalline resin, using an orifice with an inner diameter of 1 mm and a length of 20 mm, at a shear rate of 1000/sec. The specific measurement temperatures were 350°C for the liquid crystalline resin composition containing the liquid crystalline polyesteramide resin (LCP1), and 340°C for the liquid crystalline resin composition containing the liquid crystalline polyester resin (LCP2). The results are shown in Tables 1 and 2.

<Bending test>
The liquid crystalline resin composition was injection molded under the following molding conditions to obtain a molded article having a thickness of 0.8 mm, and the flexural strength, flexural modulus, and flexural strain were measured in accordance with ASTM D790.
[Molding conditions]
Molding machine: Sumitomo Heavy Industries, Ltd., SE100DU
Cylinder temperature:
350°C (Examples 1 to 6 and 8 and Comparative Examples 1 to 7)
340°C (Example 7)
Mold temperature: 90°C
Injection speed: 33mm/sec

<Dielectric properties>
The pellets of the examples and comparative examples were molded under the following molding conditions using a molding machine ("SE-100DU" manufactured by Sumitomo Heavy Industries, Ltd.) to prepare flat plate-shaped test pieces 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 direction perpendicular to the flow, and this was used as a test piece for evaluating dielectric properties. The relative permittivity and dielectric loss tangent of this test piece at 1 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 Technologies 83650L Sweep CW Generator Fixed attenuator: Agilent Technologies 85025D Detector Cavity resonator: Kanto Electronics Application Development CP431
Measurement program: Kanto Electronics Application Development CPMA-S2/V2
[Molding conditions]
Cylinder temperature:
350°C (Examples 1 to 6 and 8 and Comparative Examples 1 to 7)
340°C (Example 7)
Mold temperature: 80°C
Injection speed: 33mm/sec
Holding pressure: 60 MPa

<Solder heat resistance>
The liquid crystal resin composition was injection molded under the following molding conditions to obtain 1/8 combustion test piece of 120 mm x 12.7 mm x 3.2 mm, which was subjected to reflow under the following conditions and evaluated according to the following criteria.
◯ (Good): There was no change in the appearance of the test piece before and after reflow.
Δ (bad): The test piece lost its surface gloss or its surface roughness worsened due to reflow.
× (very poor): The test piece was melted or significantly deformed by reflow.
[Molding conditions]
Molding machine: Sumitomo Heavy Industries, Ltd., SE100DU
Cylinder temperature:
350°C (Examples 1 to 6 and 8 and Comparative Examples 1 to 7)
340°C (Example 7)
Mold temperature: 90°C
Injection speed: 33mm/sec
[Reflow conditions]
Measuring instrument: Futaba Scientific Co., Ltd. conveyor-type hot air circulation dryer DFC-27-022S
Sample feed speed: 0.45 m/min
Time through reflow oven: 4 minutes 44 seconds Temperature condition of preheat zone: 185°C
Reflow zone temperature condition: 295°C
Peak temperature: 258°C
Time during which the temperature was 255°C or higher: 11 seconds

As is clear from the results shown in Table 1, the liquid crystalline resin compositions of the examples had excellent dielectric properties and heat resistance, and good fluidity.

Claims (6)

(A) a liquid crystalline resin,
(B) a cyclic olefin resin; and (C) a hollow filler,
(A) The melting point of the liquid crystal resin is 300°C or higher,
(B) The glass transition temperature of the cyclic olefin resin is 100°C or higher,
For a total of 100 parts by volume of the liquid crystal resin (A) and the cyclic olefin resin (B),
(A) The content of the liquid crystal resin is 55 to 85 parts by volume,
(B) The content of the cyclic olefin resin is 15 to 45 parts by volume,
(C) A liquid crystal resin composition having a hollow filler content of 20 to 75 parts by volume. The liquid crystal resin composition according to claim 1, which does not contain a fluororesin. 3. The liquid crystalline resin composition according to claim 1, wherein the liquid crystalline resin (A) is an aromatic polyester or aromatic polyester amide having, as a constituent component, a constituent unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof . 4. The liquid crystal resin composition according to claim 1, wherein the hollow filler (C) is a glass balloon. 5. The liquid crystal resin composition according to claim 1, wherein the cyclic olefin resin (B) is an addition polymer of a cyclic olefin monomer and an α-olefin. The liquid crystal resin composition according to any one of claims 1 to 5 , further comprising an inorganic filler.