WO2024204593A1 - Liquid-crystalline resin composition - Google Patents

Abstract

Provided is a liquid-crystalline resin composition that has a low dielectric constant, a low dielectric loss tangent, and excellent blackness.　This liquid-crystalline resin composition contains (A) a liquid-crystalline resin, (B) a hollow filler, and (C) carbon black. There are 5–85 parts by mass of the (B) hollow filler and 0.1–7 parts by mass of the (C) carbon black per 100 parts by mass of the (A) liquid-crystalline resin, and the number average particle diameter of the (C) carbon black is 20–100 nm. The (A) liquid-crystalline resin is preferably an aromatic polyester or an aromatic polyesteramide that includes, as a constituent component, a constituent unit derived from at least one compound selected from the group that consists of aromatic hydroxycarboxylic acids and derivatives thereof. The (B) hollow filler is preferably glass balloons. The dielectric loss tangent of the liquid-crystalline resin composition at a measurement frequency of 5 GHz is preferably no more than 0.0067.

Description

Liquid crystal resin composition

The present invention relates to a liquid crystalline resin composition.

Liquid crystal resins have a good balance of excellent mechanical strength, heat resistance, chemical resistance, and electrical properties, as well as excellent dimensional stability, and are therefore widely used as high-performance engineering plastics. Meanwhile, in recent years, there has been remarkable technological development in the field of information and communications, including mobile phones; wireless LANs; and ITS technologies such as GPS, VICS (registered trademark), and ETC. In response to this, there is a growing need for high-performance electronic components that can be used in high-frequency ranges such as microwaves and millimeter waves. The materials that make up such electronic components are required to have appropriate dielectric properties according to the design of each electronic component.

For example, Patent Document 1 discloses a molded article of a wholly aromatic liquid crystal 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 crystal polyester with a melting point of 320°C or more, 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, excellent 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.

JP 2004-27021 A

Packages for electronic components, including the above-mentioned high-frequency compatible electronic components, are often colored black so that discoloration due to aging is less noticeable. To produce the above-mentioned packages colored black, for example, a liquid crystalline resin composition containing carbon black is preferably used. However, according to the studies of the present inventors, it was found that conventional liquid crystalline resin compositions containing carbon black have a significantly high dielectric tangent, and there is room for improvement in the dielectric properties.

The present invention has been made to solve the above problems, and its purpose is to provide a liquid crystalline resin composition that has a low dielectric constant, a low dielectric tangent, and excellent blackness.

The inventors have conducted extensive research to solve the above problems. As a result, they have discovered that a liquid crystalline resin composition containing a liquid crystalline resin, hollow filler, and carbon black in a specified content, in which the carbon black has a number average particle size of 20 to 100 nm, has a low dielectric constant and a low dielectric tangent, and is excellent in blackness, leading to the completion of the present invention. More specifically, the present invention provides the following.

(1) A liquid crystal resin composition containing (A) a liquid crystal resin, (B) a hollow filler, and (C) carbon black, in which the content of the (B) hollow filler is 5 to 85 parts by mass, the content of the (C) carbon black is 0.1 to 7 parts by mass, and the number average particle diameter of the (C) carbon black is 20 to 100 nm, relative to 100 parts by mass of the (A) liquid crystal resin.

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

(3) The liquid crystal resin composition according to (1) or (2), wherein the hollow filler (B) contains glass balloons.

(4) A liquid crystal resin composition according to any one of (1) to (3), in which the dielectric tangent at a measurement frequency of 5 GHz is 0.0067 or less.

The present invention provides a liquid crystal resin composition that has a low dielectric constant, a low dielectric tangent, and excellent blackness.

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

The following describes an embodiment of the present invention. Note that the present invention is not limited to the following embodiment.

<Liquid crystal resin composition>
The liquid crystal resin composition according to the present invention contains (A) a liquid crystal resin, (B) a hollow filler, and (C) carbon black, and the number average particle diameter of the carbon black is 20 to 100 nm. It is.

[(A) Liquid crystalline resin]
The liquid crystal resin (A) used in the present invention refers to a melt-processable polymer having a property capable of forming an optically anisotropic molten phase. More specifically, the anisotropic molten phase can be confirmed by a polarized light inspection method using a Leitz polarizing microscope, and a molten sample placed on a Leitz hot stage is observed at a magnification of 40 times under a nitrogen atmosphere. When the liquid crystal polymer applicable to the present invention is examined between crossed polarizers, it usually transmits polarized light even in a molten and stationary state, and exhibits optical anisotropy. .

The type of liquid crystal resin (A) as 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 are also included in this range. As the liquid crystal resin (A), one that has an inherent viscosity (I.V.) of preferably at least about 2.0 dl/g, and more preferably 2.0 to 10.0 dl/g when dissolved in pentafluorophenol at a concentration of 0.1% by mass at 60°C is preferably used.

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 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 composed of (a) at least one constituent unit selected from the group consisting of aromatic hydroxycarboxylic acids and their derivatives, (b) at least one constituent unit selected from the group consisting of aromatic hydroxyamines, aromatic diamines and their derivatives, (c) at least one constituent unit selected from the group consisting of aromatic dicarboxylic acids, alicyclic dicarboxylic acids and their derivatives, and (d) at least one constituent unit selected from the group consisting of aromatic diols, alicyclic diols, aliphatic diols and their derivatives. If necessary, a molecular weight modifier may be used in combination with the above constituents.

In (A) liquid crystal resin, the content of the constituent units derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and their derivatives is preferably 45 mol% or more, more preferably 50 mol% or more, even more preferably 55 mol% or more, even more preferably 60 mol% or more, and particularly preferably 62 mol% or more, based on all the constituent units, from the viewpoint of suppressing fluctuations in the molecular structure of (A) liquid crystal resin. The upper limit of the content is not particularly limited, and may be 100 mol% or less, 90 mol% or less, 80 mol% or less, 75 mol% or less, or 70 mol% or less, based on all the constituent units.

（Ｘ：アルキレン（Ｃ_１～Ｃ_４）、アルキリデン、－Ｏ－、－ＳＯ－、－ＳＯ_２－、－Ｓ－、及び－ＣＯ－より選ばれる基である。）

（Ｙ：－（ＣＨ_２）_ｎ－（ｎ＝１～４）及び－Ｏ（ＣＨ_２）_ｎＯ－（ｎ＝１～４）より選ばれる基である。） Preferable examples of specific compounds constituting the liquid crystal resin (A) applicable to the present invention include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid; aromatic diols such as 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, hydroquinone, resorcin, 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); aromatic amines such as p-aminophenol, p-phenylenediamine and N-acetyl-p-aminophenol. As the aromatic hydroxycarboxylic acid and its derivatives, 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, or a combination thereof are preferred from the viewpoints of reactivity and stability of the molecular structure of the liquid crystal resin (A).

(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 -( _CH2 ) _n- (n = 1 to 4) and -O( _CH2 ) _nO- (n = 1 to 4).)

The liquid crystal resin (A) used in the present invention can be prepared by a known method using direct polymerization or transesterification from the above monomer compound (or mixture of monomers). Usually, melt polymerization, solution polymerization, slurry polymerization, solid-phase polymerization, or a combination of two or more of these methods is used, and melt polymerization or a combination of melt polymerization and solid-phase polymerization is preferably used. The above compounds capable of forming esters may be used in the polymerization in their original form, or may be modified from a precursor to a derivative capable of forming the ester at a stage prior to polymerization. Various catalysts can be used in these polymerizations, and 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), and organic compound catalysts such as 1-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 the polymer produced by these polymerization methods can be further increased by solid-phase polymerization, in which the polymer is heated under reduced pressure or in an inert gas.

The melt viscosity of the liquid crystal resin (A) obtained by the above method is not particularly limited. In general, 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 crystal resin (A) may be a mixture of two or more kinds of liquid crystal resins.

[(B) Hollow filler]
(B) hollow filler is generally called balloon, and examples of the material of the hollow filler include inorganic materials such as alumina, silica, glass, and shirasu. Among them, 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 the hollow filler, and glass balloons are more preferably used. (B) component may be used alone or in combination of two or more kinds.

(B) From the viewpoint of suppressing an increase in melt viscosity and deterioration of fluidity, as well as moldability, the aspect ratio of the hollow filler is preferably 1.15 or more, 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 on the particle projection plane, and the maximum perpendicular length S, which is the length of the longest part in the direction perpendicular to the maximum length L on the particle projection plane, 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.

The median diameter of component (B) is preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of moldability, and is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less, from the viewpoint of suppressing breakage of component (B) and moldability. 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 content of the (B) component is 5 to 85 parts by mass, preferably 7 to 65 parts by mass, and more preferably 10 to 45 parts by mass, per 100 parts by mass of the (A) liquid crystal resin. When the content of the (B) component is 20 parts by mass or more, it is easy to obtain a liquid crystal resin composition with excellent dielectric properties. When the content of the (B) component is 75 parts by mass or less, it is easy to obtain a liquid crystal resin composition with good fluidity.

[(C) Carbon black]

The carbon black (C) used in the present invention may be any commonly available carbon black used for resin coloring, as long as it has a number average particle diameter of 20 to 100 nm, without any particular restrictions. The (C) component may be used alone or in combination of two or more types. In this specification, the number average particle diameter is determined by observing the carbon black with a transmission electron microscope in accordance with ASTM D3849-14a and measuring the particle diameter of 100 carbon black particles, and averaging the measured values.

The number average particle diameter of component (C) is 20 to 100 nm, preferably 22 to 92 nm, more preferably 24 to 84 nm, even more preferably 26 to 76 nm, even more preferably 28 to 68 nm, and particularly preferably 30 to 60 nm. When the number average particle diameter of component (C) is 20 nm or more, it is easy to obtain a liquid crystal resin composition having a low dielectric tangent. When the number average particle diameter of component (C) is 100 nm or less, it is easy to obtain a liquid crystal resin composition with good fluidity.

The content of the (C) component is 0.1 to 7 parts by mass, preferably 0.3 to 6.5 parts by mass, and more preferably 0.5 to 6 parts by mass, relative to 100 parts by mass of the (A) liquid crystal resin. When the content of the (C) component is 0.1 parts by mass or more, the blackness of the resulting resin composition is less likely to decrease. When the content of the (C) component is 7 parts by mass or less, it is easy to obtain a liquid crystal resin composition with good fluidity.

[(D) Fillers other than (B) hollow filler and (C) carbon black]
The liquid crystal resin composition according to the present invention may optionally contain (D) a filler other than (C) hollow filler and (C) carbon black. When the liquid crystal resin composition contains the (D) component, the molded article of the liquid crystal resin composition is likely to have improved mechanical strength such as bending modulus. The (D) component may be used alone or in combination of two or more kinds. The (D) component may be an inorganic filler or an organic filler. Examples of the (D) component 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 is likely to be suppressed from warping. 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 more likely to be ensured, and the molded body is more likely to have a high warping suppression effect. If the median diameter is 50 μm or less, the fluidity of the composition when melted is more likely to be improved. The preferred median diameter is 20 to 30 μm.

The plate-like filler is not particularly limited, and examples thereof include mica, talc, glass flakes, graphite, various metal foils (e.g., aluminum foil, iron foil, copper foil), etc. 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 filler 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 body made of the liquid crystal 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 crystal resin composition is likely to have sufficient fluidity. In this specification, the average fiber length of the fibrous filler is determined by importing 10 stereomicroscope images of the fibrous filler from a CCD camera into a PC, and measuring the fiber length of 100 fibrous fillers per stereomicroscope image, i.e., a total of 1,000 fibrous fillers, using an image processing method with an image measuring device. The average fiber length of the fibrous filler in the liquid crystal resin composition is measured by applying the above method to the fibrous filler remaining after heating the liquid crystal resin composition at 600° C. for 2 hours to incinerate it.

The 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 fiber diameter of the fibrous filler is determined by observing the fibrous filler with a scanning electron microscope and measuring the fiber diameter of 30 fibrous fillers. The fiber diameter of the fibrous filler in the liquid crystalline resin composition is measured by applying the above method to the fibrous filler remaining after the liquid crystalline resin composition is heated at 600°C for 2 hours to incinerate it.

Any fiber can be used as long as it satisfies the above shape requirements, but 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 fibrous materials made of metals 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 viewpoint 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 may be used alone or in combination of two or more kinds.

The median diameter of the granular filler is preferably 0.3 to 5.0 μm. If the median diameter is 0.3 μm or more, the impact resistance of the molded body is likely to be maintained. If 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 a value measured for the granular filler remaining after the liquid crystalline resin composition is incinerated by heating at 600°C for 2 hours.

Granular fillers include, for example, 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 reducing dust generation of the molded body, it is preferable to use one or more types selected from the group consisting of silica and barium sulfate as the granular filler, and it is more preferable to use silica.

The content of the (D) component is preferably 2 to 15 parts by mass, more preferably 5 to 12 parts by mass, and even more preferably 7 to 10 parts by mass, relative to 100 parts by mass of the (A) liquid crystal resin. When the content of the (D) component is within the above range, the flowability of the liquid crystal resin composition is sufficiently ensured, and the mechanical strength of the molded article made of the liquid crystal resin composition is likely to be improved.

[Other ingredients]
To the liquid crystal resin composition according to the present invention, other polymers 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, release agents, crystallization accelerators, crystal nucleating agents, etc., can be appropriately added according to the required performance, within the scope not impairing the effects of the present invention. The other polymers refer to polymers other than the (A) liquid crystal resin, and examples thereof include epoxy group-containing copolymers.

[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 (A) component, the (B) component, the (C) component, optionally the (D) component, and optionally other components, and melt-kneading the mixture using a single-screw or twin-screw extruder.

[Liquid crystal resin composition]
The melt viscosity of the liquid crystalline resin composition according to the present invention obtained as described above is preferably 100 Pa·sec or less, more preferably 90 Pa·sec or less, and further preferably 100 Pa·sec or less, from the viewpoint of flowability. The lower limit of the melt viscosity is not particularly limited, and may be 5 Pa·sec or more, 10 Pa·sec or more, or 20 Pa·sec or more. The value is measured at a cylinder temperature 10 to 30° C. higher than the melting point of the resin and at a shear rate of 1000 sec ⁻¹ in accordance with a measurement method in accordance with ISO 11443.

The relative dielectric constant of the liquid crystal resin composition according to the present invention at a measurement frequency of 5 GHz is preferably 4.0 or less, more preferably 3.9 or less, and even more preferably 3.8 or less, from the viewpoint of dielectric properties. The lower limit of the above relative dielectric constant is not particularly limited, and may be more than 1.0, 1.5 or more, or 2.0 or more.

The dielectric loss tangent of the liquid crystal resin composition according to the present invention at a measurement frequency of 5 GHz is preferably 0.0067 or less, more preferably 0.0065 or less, and even more preferably 0.0063 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.

The L value of the liquid crystal resin composition according to the present invention is preferably 60 or less, more preferably 50 or less, and even more preferably 45 or less, from the viewpoint of blackness. The lower limit of the L value is not particularly limited, and may be 0 or more, 5 or more, or 10 or more.

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

<Liquid Crystalline Resin>
Aromatic polyester After the following raw materials were charged into a polymerization vessel, the temperature of the reaction system was raised to 140°C and reacted at 140°C for 1 hour. Thereafter, the temperature was further raised to 360°C over 5.5 hours, and the pressure was reduced to 5 Torr (i.e., 667 Pa) over 30 minutes, and melt polymerization was carried out while distilling out acetic acid, excess acetic anhydride, and other low boiling points. After the stirring torque reached a predetermined value, nitrogen was introduced to change from a reduced pressure state to a pressurized state via normal pressure, and the polymer was discharged from the bottom of the polymerization vessel, and the strands were pelletized to obtain pellets. The obtained pellets were subjected to heat treatment at 300°C for 3 hours under a nitrogen stream to obtain the target polymer. The melting point of the obtained polymer was 348°C, and the melt viscosity at 370°C was 9 Pa·s. The melting point of the above polymer was measured according to the melting point measurement method described later, and the melt viscosity of the above polymer was measured in the same manner as the melt viscosity measurement method described later.
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%)
Metal catalyst (potassium acetate catalyst): 165 mg
Acylating agent (acetic anhydride): 1432 g

Aromatic polyester amide 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. Thereafter, the temperature was further raised to 340°C over 4.5 hours, and the pressure was reduced to 10 Torr (i.e., 1330 Pa) over 15 minutes, and melt polymerization was carried out while distilling out acetic acid, excess acetic anhydride, and other low boiling points. After the stirring torque reached a predetermined value, nitrogen was introduced to change from a reduced pressure state to a normal pressure state and then to a pressurized state, and the polymer was discharged from the bottom of the polymerization vessel, and the strands were pelletized to obtain pellets. The obtained pellets were subjected to heat treatment at 300°C for 2 hours under a nitrogen stream to obtain the target polymer. The melting point of the obtained polymer was 336°C, and the melt viscosity at 350°C was 19.0 Pa·s. The melting point of the above polymer was measured according to the melting point measurement method described later, and the melt viscosity of the above polymer was measured in the same manner as the melt viscosity measurement method described later.
4-Hydroxybenzoic acid (HBA): 1380 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%)
Metal catalyst (potassium acetate catalyst): 110 mg
Acylating agent (acetic anhydride): 1659 g

[Method of measuring melting point]
Using a DSC manufactured by TA Instruments, the endothermic peak temperature (Tm1) observed when the liquid crystalline resin was heated from room temperature at a temperature increase rate of 20°C/min was measured, and then the resin was 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 determined as the melting point of the polymer.

[Method of measuring melt viscosity]
The melt viscosity of the liquid crystal resin was measured in accordance with ISO 11443 using a Capillograph 1B model manufactured by Toyo Seiki Seisakusho Co., Ltd. at a temperature 10 to 30° C. higher than the melting point of the liquid crystal 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 370° C. for aromatic polyester and 350° C. for aromatic polyesteramide.

<Materials other than liquid crystal resin>
Glass balloon: Y12000 (manufactured by Seishin Enterprise Co., Ltd., aspect ratio (average) 1.264, median diameter 35 μm, true specific gravity 0.6)
Carbon black C1: Conductex 7054 Ultra (manufactured by Birla Carbon Korea Co., Ltd., number average particle size 54 nm)
Carbon black C2: BLACK PEARLS 4350 (manufactured by Cabot Japan Co., Ltd., number average particle size 25 nm)
Carbon black C3: MONARCH 4750 (manufactured by Cabot Japan Co., Ltd., number average particle size 18 nm)

<Production of Liquid Crystalline Resin Composition>
The above components were melt-kneaded in the ratio shown in Table 1 using a twin-screw extruder (TEX30α type, manufactured by The Japan Steel Works, Ltd.) at the cylinder temperature shown below to obtain liquid crystal resin composition pellets.
[Production conditions]
Cylinder Temperature:
370°C: In the case of a liquid crystal resin composition containing an aromatic polyester 350°C: In the case of a liquid crystal resin composition containing an aromatic polyester amide

<L value>
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 test pieces of 80 mm x 80 mm x 1 mm. The L value of these test pieces was measured using a spectrophotometer ("SE6000" manufactured by Nippon Denshoku Industries Co., Ltd.).
[Molding conditions]
Cylinder Temperature:
370°C (Examples 1 to 5 and Comparative Examples 1 to 4)
350° C. (Example 6)
Mold temperature: 80°C
Injection speed: 33mm/sec
Holding pressure: 60 MPa

<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 test pieces of 80 mm x 80 mm x 1 mm. As shown in FIG. 1, a test piece of 80 mm x 1 mm x 1 mm was cut out from the center of the flat test piece in the flow direction, and this was used as a test piece for evaluating dielectric properties. The relative dielectric constant and dielectric loss tangent of this test piece at a measurement frequency of 5 GHz were measured using a cavity resonator perturbation method complex dielectric constant 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:
370°C (Examples 1 to 5 and Comparative Examples 1 to 4)
350° C. (Example 6)
Mold temperature: 80°C
Injection speed: 33mm/sec
Holding pressure: 60 MPa

As is clear from the results shown in Table 1, the liquid crystal resin composition of the example had a low dielectric constant and a low dielectric tangent, and was excellent in blackness.

Claims (4)

(A) a liquid crystalline resin,
(B) a hollow filler; and (C) carbon black,
Relative to 100 parts by mass of the (A) liquid crystalline resin,
The content of the hollow filler (B) is 5 to 85 parts by mass,
The content of the (C) carbon black is 0.1 to 7 parts by mass,
The liquid crystalline resin composition, wherein the carbon black (C) has a number average particle size of 20 to 100 nm. The liquid crystal resin composition according to claim 1, wherein the (A) liquid crystal resin is an aromatic polyester or aromatic polyester amide having as a constituent a structural unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof. The liquid crystal resin composition according to claim 1 or 2, wherein the hollow filler (B) contains glass balloons. The liquid crystal resin composition according to claim 1 or 2, wherein the dielectric tangent at a measurement frequency of 5 GHz is 0.0067 or less.

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