JP2019189737A - Liquid crystal polyester resin having excellent mechanical strength and dielectric properties - Google Patents

Abstract

To provide a liquid crystal polyester resin having excellent mechanical strength, and having excellent dielectric properties in which the resin itself has reduced dielectric constants.SOLUTION: A liquid crystal polyester resin contains repeating units represented by formulae (I)-(III), and has a dielectric constant of 3.50 or less as measured at 10GHz with a test piece of 85 mm×1.7 mm×1.7 mm by a cavity resonator perturbation method in accordance with JIS C2565.SELECTED DRAWING: None

Description

  The present invention relates to a liquid crystal polyester resin excellent in mechanical strength and dielectric properties.

  Thermotropic liquid crystalline polyester resin (hereinafter abbreviated as liquid crystalline polyester resin or LCP) is excellent in mechanical properties, moldability, chemical resistance, gas barrier properties, moisture resistance, electrical properties, etc. It is used. In particular, since it is excellent in heat resistance, thin-wall formability, and insulation, its use for electronic parts and the like is expanding.

  In recent years, with the development of a highly information-oriented society, the amount of information transmitted and the transmission speed of information communication devices have increased explosively in the field of information and communication such as personal computers and mobile phones. In particular, the need for high-performance high-frequency electronic components that can be applied in the high-frequency region of microwaves and millimeter waves is becoming stronger.

  However, when a liquid crystal polyester resin having a high dielectric constant is used as a substrate such as an electrical connector, the high-frequency signal is attenuated, resulting in a problem that the signal propagation speed is reduced. Therefore, the liquid crystal polyester resin used for these electronic components is required to have a low dielectric constant.

  In general, it is known that a liquid crystalline polyester resin composition (Patent Document 1) in which glass fibers and glass balloons are blended with a liquid crystal polyester resin has a low dielectric constant. Moreover, in order to reduce the dielectric constant of liquid crystal polyester resin, a liquid crystal polyester resin composition in which a fibrous filler having an aspect ratio of 4 or more and an inorganic spherical hollow body having a specific particle diameter are blended has been proposed (Patent Document 2). ).

JP 2004-323705 A JP 2004-143270 A

  However, the liquid crystal polyester resin composition has a problem that the physical properties of the composition are deteriorated or the physical properties are uneven because the glass balloon or the inorganic spherical hollow body is damaged or not uniformly dispersed in the liquid crystal polyester resin. There was a problem such as.

  Therefore, there has been a demand for a liquid crystal polyester resin that does not deteriorate the physical properties of the liquid crystal polyester resin, has a low dielectric constant, and has excellent dielectric properties.

  An object of the present invention is to provide a liquid crystal polyester resin that is excellent in mechanical strength and excellent in dielectric properties in which the resin itself has a low dielectric constant.

  As a result of intensive studies, the present inventors have found that a liquid crystal polyester resin having excellent mechanical strength such as impact strength and tensile strength and excellent dielectric properties in a high frequency band by using a specific repeating unit as a constituent component. As a result, the present invention was completed.

［式中、
ｐ、ｑおよびｒは、それぞれ、液晶ポリエステル樹脂中での各繰返し単位の組成比（モル％）であり、以下の条件を満たす：
０．０１≦ｐ≦７、
０．１≦ｑ／（ｑ＋ｒ）≦０．９、
８≦ｒ≦３４］
で表される繰返し単位を含み、ＪＩＳ Ｃ２５６５に準拠した空洞共振器摂動法で８５ｍｍ×１．７ｍｍ×１．７ｍｍの試験片を用いて１０ＧＨｚにて測定した誘電率が３．５０以下である、液晶ポリエステル樹脂に関する。 That is, the present invention relates to the formulas (I) to (III)

[Where:
p, q, and r are the composition ratio (mol%) of each repeating unit in the liquid crystal polyester resin, respectively, and satisfy the following conditions:
0.01 ≦ p ≦ 7,
0.1 ≦ q / (q + r) ≦ 0.9,
8 ≦ r ≦ 34]
The dielectric constant measured at 10 GHz using a test piece of 85 mm × 1.7 mm × 1.7 mm by a cavity resonator perturbation method in accordance with JIS C2565 is 3.50 or less. The present invention relates to a liquid crystal polyester resin.

  The liquid crystalline polyester resin of the present invention has good mechanical strength such as impact strength and tensile strength, and excellent dielectric properties in the high frequency band, so that electrical and electronic devices such as thin layers, highly integrated connectors, antennas and printed wiring boards, etc. It can be suitably used as a material for parts.

  The liquid crystal polyester resin of the present invention is a liquid crystal polyester resin that forms an anisotropic molten phase, called a thermotropic liquid crystal polyester resin by those skilled in the art.

  The property of the anisotropic molten phase of the liquid crystal polyester resin can be confirmed by a normal deflection inspection method using an orthogonal deflector, that is, by observing a sample placed on a hot stage in a nitrogen atmosphere.

［式中、
ｐ、ｑおよびｒは、それぞれ、液晶ポリエステル樹脂中での各繰返し単位の組成比（モル％）であり、以下の条件を満たす：
０．０１≦ｐ≦７、
０．１≦ｑ／（ｑ＋ｒ）≦０．９、
８≦ｒ≦３４］
で表される繰返し単位を含む。 The liquid crystal polyester resin of the present invention has the formulas (I) to (III).

[Where:
p, q, and r are the composition ratio (mol%) of each repeating unit in the liquid crystal polyester resin, respectively, and satisfy the following conditions:
0.01 ≦ p ≦ 7,
0.1 ≦ q / (q + r) ≦ 0.9,
8 ≦ r ≦ 34]
The repeating unit represented by

  The composition ratio p according to the formula (I) is preferably 0.05 to 6 mol%, more preferably 0.1 to 5 mol%.

  When the repeating unit represented by the formula (I) is less than 0.01 mol%, it is difficult to obtain an improvement effect on the dielectric properties, and when it exceeds 7 mol%, the mechanical strength tends to decrease.

  Specific examples of the monomer that gives the repeating unit represented by the formula (I) include 3-hydroxybenzoic acid and ester-forming derivatives such as acylated products, ester derivatives, and acid halides.

  The composition ratio q according to the formula (II) and the composition ratio r according to the formula (III) preferably satisfy 0.3 ≦ q / (q + r) ≦ 0.8, more preferably 0.5 ≦ q / (q + r ) ≦ 0.75.

  10-32 mol% is preferable and, as for the composition ratio r concerning Formula (III), 12-30 mol% is more preferable.

  Specific examples of the monomer that gives the repeating unit represented by the formula (II) include 4-hydroxybenzoic acid and ester-forming derivatives such as acylated products, ester derivatives, and acid halides.

  Specific examples of the monomer that gives the repeating unit represented by the formula (III) include 6-hydroxy-2-naphthoic acid and ester-forming derivatives such as acylated products, ester derivatives, and acid halides. .

  A preferred first embodiment of the liquid crystal polyester resin of the present invention includes a liquid crystal polyester resin composed of repeating units represented by the formulas (I) to (III).

［式中、
Ａｒ_１およびＡｒ_２は、それぞれ１種または２種以上の２価の芳香族基を表し、ｐ、ｑ、ｒ、ｓおよびｔは、それぞれ、液晶ポリエステル樹脂中での各繰返し単位の組成比（モル％）であり、以下の条件を満たす：
０．０１≦ｐ≦７、
０．１≦ｑ／（ｑ＋ｒ）≦０．９、
８≦ｒ≦３４、
１０≦ｓ≦２５、および
１０≦ｔ≦２５］
で表される繰返し単位から構成される液晶ポリエステル樹脂が挙げられる。 Further, as a second preferred embodiment of the liquid crystal polyester resin of the present invention, the formulas (I) to (V)

[Where:
Ar ₁ and Ar ₂ each represent one or more divalent aromatic groups, and p, q, r, s, and t are the composition ratios of the respective repeating units in the liquid crystal polyester resin ( Mol%) and satisfy the following conditions:
0.01 ≦ p ≦ 7,
0.1 ≦ q / (q + r) ≦ 0.9,
8 ≦ r ≦ 34,
10 ≦ s ≦ 25, and 10 ≦ t ≦ 25]
And a liquid crystal polyester resin composed of repeating units represented by the formula:

  In the second embodiment, the composition ratio p according to the formula (I), the composition ratio q according to the formula (II), and the composition ratio r according to the formula (III) are the same as those described above regarding the first embodiment. And the preferred conditions are satisfied.

  The composition ratio s according to the formula (IV) and the composition ratio t according to the formula (V) are each preferably 12 to 24 mol%, more preferably 14 to 22 mol%. s and t are preferably equimolar amounts.

In the above repeating unit, for example, Ar ₁ (or Ar ₂ ) represents two or more divalent aromatic groups. The repeating unit represented by the formula (IV) (or (V)) is a liquid crystal polyester resin. It means that two or more kinds are contained depending on the kind of the divalent aromatic group. In this case, the composition ratio s according to the formula (IV) (or the composition ratio t according to the formula (V)) represents a composition ratio obtained by summing two or more kinds of repeating units.

  Specific examples of the monomer that gives the repeating unit represented by the formula (IV) include, for example, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, and 2,7-naphthalene. Dicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 4,4′-dicarboxybiphenyl, and the like, and alkyl, alkoxy, or halogen-substituted products thereof, and ester-forming derivatives such as ester derivatives and acid halides thereof .

  Specific examples of the monomer that gives the repeating unit represented by the formula (V) include, for example, hydroquinone, resorcin, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1, 4-dihydroxynaphthalene, 4,4′-dihydroxybiphenyl, 3,3′-dihydroxybiphenyl, 3,4′-dihydroxybiphenyl, 4,4′-dihydroxybiphenyl ether and the like, and alkyl, alkoxy or halogen substituents thereof, And ester-forming derivatives such as acylated products thereof.

Among them, Ar ₁ and Ar ₂ related to the repeating units represented by the formulas (IV) and (V) are each independently a group consisting of an aromatic group represented by the formulas (1) to (4). A liquid crystal polyester resin containing one or more selected from is preferred.

Among these, as Ar ₁ related to the repeating unit represented by the formula (IV), the aromatic group represented by the formula (1) and the formula (4) is a mechanical property and heat resistance of the obtained liquid crystal polyester resin. It is more preferable because the crystal melting temperature and the moldability are easily adjusted to an appropriate level.

  Monomers that give these repeating units include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and ester-forming derivatives thereof.

As the Ar ₂ according to the repeating unit represented by formula (V), formula (1) and / or Formula aromatic group represented by (3), at the time of polymerization reactivity and the obtained liquid crystal polyester resin It is more preferable because the mechanical strength, heat resistance, crystal melting temperature, and molding processability are easily adjusted to appropriate levels.

  Monomers that give these repeating units include hydroquinone and 4,4'-dihydroxybiphenyl, and ester-forming derivatives thereof.

  The sum [p + q + r] of the composition ratio of repeating units in the liquid crystal polyester resin of the first embodiment and the sum [p + q + r + s + t] of the composition ratio of repeating units in the liquid crystal polyester resin of the second embodiment are both 100 mol%. Although it is preferable, it may further contain other repeating units as long as the object of the present invention is not impaired.

  Other monomers that give repeating units include other aromatic hydroxycarboxylic acids, aromatic hydroxyamines, aromatic diamines, aromatic aminocarboxylic acids, aromatic hydroxydicarboxylic acids, aliphatic diols, aliphatic dicarboxylic acids, Aromatic mercaptocarboxylic acids, aromatic dithiols, aromatic mercaptophenols, combinations thereof and the like.

  Specific examples of other aromatic hydroxycarboxylic acids include, for example, 2-hydroxybenzoic acid, 5-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 4′-hydroxyphenyl-4-benzoic acid, 3'-Hydroxyphenyl-4-benzoic acid, 4'-hydroxyphenyl-3-benzoic acid and their alkyl, alkoxy or halogen-substituted products, and their ester-forming derivatives such as acylated products, ester derivatives, acid halides, etc. Is mentioned.

  The total composition ratio of repeating units given from these other monomer components is preferably 10 mol% or less in the entire repeating units.

Hereinafter, the manufacturing method of the liquid crystalline polyester resin of this invention is demonstrated.
The method for producing the liquid crystalline polyester resin of the present invention is not particularly limited, and a known polycondensation method for forming an ester bond with the above monomer components, for example, a melt acidolysis method or a slurry polymerization method can be used.

  The melt acidosis method is a method suitable for producing the liquid crystalline polyester resin of the present invention, and this method involves first heating a monomer to form a molten liquid of a reactant and continuing the reaction. Thus, a molten polyester is obtained. A vacuum may be applied to facilitate removal of volatiles (for example, acetic acid, water, etc.) by-produced in the final stage of the condensation.

  The slurry polymerization method is a method of reacting in the presence of a heat exchange fluid, and the solid product is obtained in a state suspended in a heat exchange medium.

  In both the melt acidification method and the slurry polymerization method, the polymerizable monomer component used in producing the liquid crystal polyester resin reacts at room temperature as a modified form in which the hydroxyl group is acylated, that is, a lower acylated product. It can also be used. The lower acyl group preferably has 2 to 5 carbon atoms, more preferably 2 or 3 carbon atoms. Particularly preferred is a method using an acetylated product of the monomer component in the reaction.

  The lower acylated product of the monomer may be separately acylated and synthesized in advance, or may be produced in the reaction system by adding an acylating agent such as acetic anhydride to the monomer during the production of the liquid crystalline polyester resin. it can.

  In either case of the melt acidolysis method or the slurry polymerization method, a catalyst may be used as needed during the reaction.

Specific examples of the catalyst include, for example, organotin compounds (dialkyltin oxide such as dibutyltin oxide, diaryltin oxide), titanium dioxide, antimony trioxide, organic titanium compounds (alkoxytitanium silicate, titanium alkoxide, etc.), carboxylic acid Examples thereof include alkali and alkaline earth metal salts (such as potassium acetate and sodium acetate), Lewis acids (such as BF ₃ ), and gaseous acid catalysts (such as HCl) such as hydrogen halide.

  10-1000 ppm is preferable with respect to the monomer mass, and, as for the usage-amount of a catalyst, 20-200 ppm is more preferable.

  The liquid crystalline polyester resin obtained by such a polycondensation reaction is extracted from the polymerization reaction tank in a molten state, and then processed into pellets, flakes, or powders for use in molding or melt kneading. .

  The liquid crystal polyester resin in the form of pellets, flakes, or powders is substantially a solid phase under reduced pressure, vacuum, or an inert gas atmosphere such as nitrogen or helium for the purpose of increasing the molecular weight and improving heat resistance. You may heat-process in a state.

  The temperature of the heat treatment is not particularly limited as long as the liquid crystal polyester resin is not melted, but is preferably 260 to 350 ° C, more preferably 280 to 320 ° C.

  The liquid crystal polyester resin of the present invention thus obtained has a dielectric constant of 3 measured at 10 GHz using a test piece of 85 mm × 1.7 mm × 1.7 mm by a cavity resonator perturbation method according to JIS C2565. .50 or less, and has excellent dielectric properties. The dielectric constant is preferably 3.49 or less, more preferably 3.48 or less. The dielectric constant of the liquid crystal polyester resin of the present invention is usually 3.0 or more.

  The liquid crystal polyester resin of the present invention obtained as described above can be a liquid crystal polyester resin composition containing an inorganic filler and / or an organic filler, additives, other resin components, and the like.

  Specific examples of the inorganic filler and / or organic filler that may be contained in the liquid crystal polyester resin composition of the present invention include, for example, glass fiber, silica alumina fiber, alumina fiber, carbon fiber, potassium titanate fiber, boron Examples include aluminum oxide fiber, aramid fiber, talc, mica, graphite, wollastonite, dolomite, clay, glass flake, glass beads, glass balloon, calcium carbonate, barium sulfate, and titanium oxide. These fillers may be used alone or in combination of two or more.

  Among these, talc and glass fiber are preferable in that the balance between mechanical properties and cost is excellent.

  When the inorganic filler and / or the organic filler are contained, the content thereof is preferably 1 to 150 parts by mass and more preferably 10 to 100 parts by mass with respect to 100 parts by mass of the liquid crystal polyester resin. preferable.

  When the content of the inorganic filler and / or the organic filler is 1 part by mass or more, the effect of improving the mechanical strength of the liquid crystal polyester resin composition is easily obtained. When the content of the inorganic filler and / or the organic filler exceeds 150 parts by mass, the fluidity tends to decrease and the effect of improving the dielectric characteristics tends to be insufficient.

  Specific examples of other additives that may be contained in the liquid crystal polyester resin composition of the present invention include, for example, higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty acid metal salts (where higher fatty acids are carbon Lubricants such as polysiloxane and fluororesin, dyes, pigments, colorants such as carbon black, flame retardants, antistatic agents, surfactants, phosphorous oxidation Examples thereof include antioxidants, phenolic antioxidants, antioxidants such as sulfur antioxidants, weathering agents, heat stabilizers, and neutralizing agents. These additives may be used alone or in combination of two or more.

  When these additives are contained, the content is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 3 parts by mass as the total amount with respect to 100 parts by mass of the total amount of the liquid crystal polyester resin.

  When the content of the additive is less than 0.01 parts by mass, the function of the additive tends to be difficult to achieve. When the content exceeds 10 parts by mass, the thermal stability during the molding process of the liquid crystal polyester resin composition is increased. Tend to get worse.

  Moreover, when using additives, such as a lubricant and a mold release agent, among these other additives, it may be added when preparing a liquid crystal polyester resin composition, or a liquid crystal polyester resin during molding processing. It may be attached to the surface of the pellet.

  Specific examples of other resin components that may be contained in the liquid crystal polyester resin composition of the present invention include, for example, polyamide, polyester, polyacetal, polyphenylene ether and modified products thereof, polysulfone, polyethersulfone, polyetherimide, polyamide Thermosetting resins such as thermoplastic resins such as imides, phenol resins, epoxy resins, and polyimide resins can be used. These resin components may be used alone or in combination of two or more.

  0.1-100 mass parts is preferable with respect to 100 mass parts of liquid crystal polyester resins, and, as for content of the said other resin component, 0.5-80 mass parts is more preferable.

  The liquid crystal polyester resin composition is prepared by mixing a liquid crystal polyester resin and inorganic fillers and / or fillers, additives or other resin components, and using a Banbury mixer, a kneader, a single screw or a twin screw extruder, etc. It can be obtained by melt-kneading from near the crystal melting temperature of the polyester resin under the temperature condition of crystal melting temperature + 50 ° C.

  The liquid crystal polyester resin or liquid crystal polyester resin composition of the present invention thus obtained can be processed into a molded product by a known molding method such as injection molding, compression molding, extrusion molding or blow molding.

  Since the liquid crystal polyester resin or the liquid crystal polyester resin composition of the present invention has excellent dielectric properties such as a low dielectric constant, it can be suitably used as an electric / electronic component.

  Examples of such electrical and electronic parts include, but are not limited to, connectors, switches, relays, capacitors, coils, transformers, camera modules, antennas, chip antennas, and electronic circuit boards, especially printed circuit boards. . Among these, it can be particularly suitably used for a connector, an antenna or a substrate.

  The liquid crystal polyester resin or liquid crystal polyester resin composition of the present invention may be formed into a film (or sheet) by a known method such as inflation molding or T-die molding. The film may have a single layer structure or a multilayer structure with different materials.

Hereinafter, although an example explains the present invention in detail, the present invention is not limited to this.
The melt viscosity, tensile strength, Izod impact strength and dielectric constant in the examples were measured by the methods described below.

(1) Melt Viscosity Examples 1 to 3 and Comparative Example 1 using a melt viscosity measuring apparatus (Capillograph 1D manufactured by Toyo Seiki Co., Ltd.) using a 0.7 mmφ × 10 mm capillary under a shear rate of 1000 sec ^−1. -3 was measured at 320 ° C, and Examples 4-6 and Comparative Examples 4-6 were measured at 350 ° C.

(2) Tensile strength Using an injection molding machine (UH1000-110 manufactured by Nissei Plastic Industry Co., Ltd.), the cylinder set temperature was 320 ° C. for Examples 1 to 3 and Comparative Examples 1 to 3, and Examples 4 to 6 and For Comparative Examples 4 to 6, an ASTM No. 4 dumbbell test piece was molded at 350 ° C. and a mold temperature of 70 ° C., and measured according to ASTM D638.

(3) Izod Impact Strength Using an injection molding machine (UH1000-110 manufactured by Nissei Plastic Industry Co., Ltd.), cylinder setting temperature 350 ° C., mold temperature 70 ° C., length 127.0 mm, width 12.7 mm, thickness A strip-shaped test piece having a thickness of 3.2 mm was formed. The center of the test piece was cut perpendicular to the length direction to obtain a strip-shaped test piece having a length of 63.5 mm, a width of 12.7 mm, and a thickness of 3.2 mm, and was measured in accordance with ASTM D256.

(4) Dielectric constant Using an injection molding machine (Nissei Plastic Industry Co., Ltd. NEX-15-1E), the cylinder set temperature was 320 ° C. for Examples 1 to 3 and Comparative Examples 1 to 3, and Examples 4 to 6 were used. And about Comparative Examples 4-6, it shape | molded into the stick-shaped test piece of length 85mm, width 1.7mm, and thickness 1.7mm at 350 degreeC and die temperature 80 degreeC.
Using this test piece, a dielectric constant (10 GHz) was measured using a network analyzer (PNA series E8316A manufactured by Agilent Technologies) by a cavity resonator perturbation method based on JIS C2565.

In the examples, the following abbreviations represent the following compounds:
3HBA: 3-hydroxybenzoic acid POB: 4-hydroxybenzoic acid BON6: 6-hydroxy-2-naphthoic acid TPA: terephthalic acid HQ: hydroquinone

[Example 1]
In a reaction vessel equipped with a stirrer with a torque meter and a distillation tube, 3HBA: 4.5 g (0.5 mol%), POB: 651.8 g (72.6 mol%) and BON 6: 329.0 g (26. 9 mol%) and 1.03 times moles of acetic anhydride relative to the amount of hydroxyl groups (moles) of all monomers were further charged, and deacetic acid polymerization was carried out under the following conditions.

  The temperature was raised from room temperature to 150 ° C. over 1 hour in a nitrogen gas atmosphere, and the temperature was maintained for 30 minutes. Next, while acetic acid produced as a by-product was distilled off, the temperature was quickly raised to 210 ° C. and held at that temperature for 30 minutes. Then, after heating up to 325 degreeC over 5 hours, it pressure-reduced to 20 mmHg over 90 minutes. When a predetermined torque was applied, the polymerization reaction was terminated, the reaction vessel contents were taken out, and liquid crystal polyester resin pellets were obtained using a pulverizer. The amount of acetic acid distilled during the polymerization was almost as theoretical. Evaluation was performed by the above method using the obtained pellets. The results are shown in Table 1.

[Examples 2 and 3, Comparative Examples 1 to 3]
Liquid crystal polyester resin pellets were obtained in the same manner as in Example 1 except that 3HBA, POB and BON6 were used in the proportions (mol%) shown in Table 1. Using the obtained pellets, melt viscosity, tensile strength, Izod impact strength and dielectric constant were measured by the above methods. The results are shown in Table 1.

[Example 4]
In a reaction vessel equipped with a stirrer with a torque meter and a distillation pipe, 3HBA: 4.5 g (0.5 mol%), POB: 393.2 g (43.8 mol%), BON 6: 194.5 g (15. 9 mol%), TPA: 214.9 g (19.9 mol%) and HQ: 142.4 g (19.9 mol%), and 1.03 with respect to the amount of hydroxyl groups (mol) of all monomers. A double mole of acetic anhydride was charged, and deacetic acid polymerization was performed under the following conditions.

  The temperature was raised from room temperature to 150 ° C. over 1 hour in a nitrogen gas atmosphere, and the temperature was maintained for 30 minutes. Next, while acetic acid produced as a by-product was distilled off, the temperature was quickly raised to 210 ° C. and held at that temperature for 30 minutes. Then, after heating up to 345 degreeC over 5 hours, it pressure-reduced to 20 mmHg over 90 minutes. When a predetermined torque was applied, the polymerization reaction was terminated, the reaction vessel contents were taken out, and liquid crystal polyester resin pellets were obtained using a pulverizer. The amount of acetic acid distilled during the polymerization was almost as theoretical. Evaluation was performed by the above method using the obtained pellets. The results are shown in Table 2.

[Examples 5 and 6, Comparative Examples 4 to 6]
Liquid crystal polyester resin pellets were obtained in the same manner as in Example 4 except that 3HBA, POB, BON6, TPA, and HQ were used in the proportions (mol%) shown in Table 2. Using the obtained pellets, melt viscosity, tensile strength, Izod impact strength and dielectric constant were measured by the above methods. The results are shown in Table 2.

  The liquid crystal polyester resins (Examples 1 to 6) in each example had a sufficiently low dielectric constant and excellent dielectric characteristics. In contrast, the liquid crystal polyester resins (Comparative Examples 1 to 6) in which the content of repeating units given by 3HBA is outside the scope of the present invention were inferior in dielectric properties.

Claims (7)

Formulas (I) to (III)

[Where:
p, q, and r are the composition ratio (mol%) of each repeating unit in the liquid crystal polyester resin, respectively, and satisfy the following conditions:
0.01 ≦ p ≦ 7,
0.1 ≦ q / (q + r) ≦ 0.9,
8 ≦ r ≦ 34]
Including a repeating unit represented by
A liquid crystal polyester resin having a dielectric constant of 3.50 or less measured at 10 GHz using a test piece of 85 mm × 1.7 mm × 1.7 mm by a cavity resonator perturbation method according to JIS C2565.   The liquid crystal polyester resin according to claim 1, wherein the liquid crystal polyester resin is composed of repeating units represented by formulas (I) to (III). Liquid crystalline polyester resins are represented by the formulas (I) to (V)

[Where:
Ar ₁ and Ar ₂ each represent one or more divalent aromatic groups, and p, q, r, s, and t are the composition ratios of the respective repeating units in the liquid crystal polyester resin ( Mol%) and satisfy the following conditions:
0.01 ≦ p ≦ 7,
0.1 ≦ q / (q + r) ≦ 0.9,
8 ≦ r ≦ 34,
10 ≦ s ≦ 25, and 10 ≦ t ≦ 25]
The liquid crystalline polyester resin of Claim 1 comprised from the repeating unit represented by these. Ar ₁ and Ar ₂ are independently of each other represented by the formulas (1) to (4)

The liquid crystalline polyester resin according to claim 3, which represents one or more selected from the group consisting of aromatic groups represented by:   A liquid crystal polyester resin composition comprising the liquid crystal polyester resin according to claim 1 and an inorganic filler and / or an organic filler.   Inorganic filler and / or organic filler is glass fiber, silica alumina fiber, alumina fiber, carbon fiber, potassium titanate fiber, aluminum borate fiber, aramid fiber, talc, mica, graphite, wollastonite, dolomite, clay The liquid crystal polyester resin composition according to claim 5, which is at least one selected from the group consisting of glass flakes, glass beads, glass balloons, calcium carbonate, barium sulfate, and titanium oxide.   The molded article or film comprised from the liquid crystalline polyester resin in any one of Claims 1-4, or the liquid crystalline polyester resin composition in any one of Claims 5-6.