KR20130100068A - Liquid crystalline polyester composition - Google Patents

Abstract

PURPOSE: A liquid crystal polyester composition is provided to manufacture a molded product with excellent thermal conductivity and stiffness. CONSTITUTION: A liquid crystal polyester composition includes a liquid crystal polyester mixture, an alumina microparticle, and a plate-like filler formed of an electric insulating material, and a fibrous filler formed of electric insulating material. The content of the alumina microparticle is larger than the total content of the plate-like filler and the fibrous filler. The total content of the alumina microparticle, the plate-like filler, and the fibrous filler is 150 parts by weight or greater to 100.0 parts by weight of the liquid crystal polyester mixture. The particle diameter distribution of the alumina microparticle measured by laser diffraction scatterometry is bimodal. [Reference numerals] (AA) Intensity → (strong); (BB) Second maximum value; (CC) First maximum value; (DD) Diameter → (large)

Description

Liquid crystalline polyester composition {LIQUID CRYSTALLINE POLYESTER COMPOSITION}

The present invention relates to a molded article superior in its thermal conductivity and stiffness with balance, and a liquid crystal polyester composition for obtaining the molded article.

As a thermally conductive composition comprising liquid crystalline polyester, Japanese Patent Laid-Open No. 62-100577 discloses a composition consisting of a liquid crystal polyester and a filler having a thermal conductivity of 300 W or more and 10 W / m · K or more. Japanese Unexamined Patent Application Publication No. 3-7891 discloses a composition composed of a high thermal conductive filler having a thermal conductivity of 10 Pa / mh ° C or higher and a liquid crystal polyester.

However, the molded article made of the former composition has a problem of insufficient thermal conductivity and rigidity. Moreover, although the molded object which consists of said latter composition has favorable thermal conductivity, there exists a problem that rigidity is inadequate.

This invention is made | formed in view of the said situation, and makes it a subject to provide the molded object excellent in balance with thermal conductivity and rigidity, and the liquid crystal polyester composition for obtaining this molded object.

In order to solve the said subject, this invention contains following component (A), (B), (C) and (D), and content (mass) of component (B) is a component (C) and (D) It is more liquid-crystalline polyester composition than the sum total content (mass) of:

(A) mixture of following liquid crystalline polyester (1) and (2);

(B) alumina fine particles;

(C) the plate-shaped filler which consists of an electrically insulating material; And

(D) fibrous fillers made of an electrically insulating material;

The liquid crystalline polyester (1) is composed of 30 to 80 units of repeating unit (I) derived from p-hydroxybenzoic acid, hydroquinone and / or 4,4'-dihydrate. 10 to 35 units of repeating units (II) derived from oxybiphenyl and 10 to 35 units of repeating units (III) derived from terephthalic acid and / or isophthalic acid are included (repeating units (I) and (II) and ( The sum of III) is 100 units);

The liquid crystalline polyester (2) is composed of 40 to 74.8 units of the repeating unit (I ') derived from 6-hydroxy-2-naphthoic acid and a repeat derived from hydroquinone and / or 4,4'-dihydroxybiphenyl. Unit (II ') 12.5-30 unit, 12.5-30 units of repeating unit (III') derived from 2, 6- naphthalenedicarboxylic acid, and aromatic dicarboxyl other than 2, 6- naphthalenedicarboxylic acid Repeating units (IV ') derived from an acid containing 0.2 to 15 units (the total of repeating units (I') and (II ') and (III') and (IV ') is 100 units), and repeating units The content of (1 II ') and (IV') satisfies the following formula:

Content of repeating unit (III ') / {total content of repeating unit (III') and (IV ')} ≥0.5.

In the liquid-crystalline polyester composition of this invention, the total content of component (B), (C), and (D) becomes like this. Preferably it is 150 mass parts or more with respect to 100 mass parts of content of a component (A).

In the liquid crystal polyester composition of the present invention, the component (A) is preferably a mixture containing 100 parts by mass of the liquid crystal polyester (1) and 25 to 70 parts by mass of the liquid crystal polyester (2).

In the liquid-crystalline polyester composition of this invention, it is preferable that the particle size distribution calculated | required by the laser diffraction scattering measurement of component (B) is bimodal.

In the liquid-crystalline polyester composition of this invention, 2 whose particle size distribution calculated | required by the laser diffraction scattering measurement of component (B) has a local maximum in the range of the volume average particle diameter of 1-5 micrometers, and the range of the volume average particle diameter of 0.1-1 micrometer, respectively. It is preferable that it is sealing.

In the liquid-crystalline polyester composition of this invention, it is preferable that a component (C) is talc.

In the liquid crystalline polyester composition of this invention, it is preferable that the volume average particle diameter of the long axis of the said talc is 15 micrometers or more.

Moreover, this invention provides the molded object which consists of liquid crystal polyester composition of this invention.

It is preferable that the molded object is an electrical / electronic component.

It is preferable that this electrical / electronic component is a sealing material of an electronic element, an insulator, the reflecting plate for display apparatuses, an electronic element storage case, or a surface mounting component.

According to this invention, the molded object excellent in the balance of thermal conductivity and rigidity, and the liquid crystal polyester composition for obtaining this molded object are provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the outline (1st example) of bimodal particle size distribution calculated | required by the laser diffraction scattering measurement of component (B).
It is a schematic diagram which shows the outline (2nd example) of the binary particle size distribution calculated | required by the laser diffraction scattering measurement of component (B).
It is a perspective view which shows typically one plate-shaped filler.

<Liquid Crystal Polyester Composition>

The liquid crystal polyester composition of this invention contains components (A), (B), (C) and (D), and content (mass) of a component (B) is total content of a component (C) and (D) ( Mass).

Based on this feature, a molded article excellent in thermal conductivity and rigidity is obtained.

[Component (A)]

Liquid-crystalline polyester (1) is a repeating unit (I) 30-80 unit derived from p-hydroxybenzoic acid, and a repeating unit (II) 10 derived from hydroquinone and / or 4,4'- dihydroxybiphenyl. It contains-35 units and 10-35 units of repeating unit (III) derived from terephthalic acid and / or isophthalic acid (the total of repeating unit (I), (II), and (III) is made into 100 units).

Repeating unit (I) is a repeating unit derived from aromatic hydroxycarboxylic acid, repeating unit (II) is a repeating unit derived from aromatic diol, and repeating unit (III) is a repeating unit derived from aromatic dicarboxylic acid To each.

The liquid crystal polyester (1) may have a repeating unit other than the repeating units (I) to (III). The content makes the total amount of repeating units (I)-(III) 100 units, Preferably it is 10 units or less, More preferably, it is 5 units or less. It is especially preferable that liquid crystalline polyester (1) has only repeating units (I)-(III).

Liquid crystalline polyester (1) is liquid crystalline polyester which shows liquid crystallinity in a molten state, and is melted at 450 degrees C or less.

From the viewpoint of obtaining a molded article excellent in thermal conductivity, the liquid crystal polyester (1) does not contain a naphthalene skeleton, as apparent from the above definitions relating to the repeating units (I) to (III). From the same viewpoint, when liquid crystalline polyester (1) has repeating units other than repeating units (I)-(III), it is preferable that this repeating unit also does not contain a naphthalene skeleton.

The liquid crystalline polyester (2) is composed of 40 to 74.8 units of the repeating unit (I ') derived from 6-hydroxy-2-naphthoic acid and a repeat derived from hydroquinone and / or 4,4'-dihydroxybiphenyl. Unit (II ') 12.5-30 unit, 12.5-30 units of repeating unit (III') derived from 2, 6- naphthalenedicarboxylic acid, and aromatic dicarboxyl other than 2, 6- naphthalenedicarboxylic acid Repeating units (IV ') derived from an acid containing 0.2 to 15 units (the total of repeating units (I') and (II ') and (III') and (IV ') is 100 units), and repeating units The content of (III ') and (IV') satisfies the following formula:

Content of repeating unit (III ') / {total content of repeating unit (III') and (IV ')} ≥0.5.

The repeating unit (I ') is a repeating unit derived from an aromatic hydroxycarboxylic acid, the repeating unit (II') is a repeating unit derived from an aromatic diol, and the repeating units (III ') and (IV') are an aromatic dica It corresponds to the repeating unit derived from a carboxylic acid, respectively.

The repeating unit (IV ') is one kind or a combination of two or more kinds of repeating units derived from aromatic dicarboxylic acids other than 2,6-naphthalenedicarboxylic acid.

As preferable repeating unit (IV '), the repeating unit derived from terephthalic acid and the repeating unit derived from isophthalic acid can be illustrated.

Liquid crystal polyester (2) may have repeating units other than repeating unit (I ')-(IV'). The content makes the total amount of repeating units (I ')-(IV') 100 units, Preferably it is 10 units or less, More preferably, it is 5 units or less. It is especially preferable that liquid crystalline polyester (2) has only repeating units (I ')-(IV').

Liquid crystalline polyester (2) is liquid crystalline polyester which shows liquid crystallinity in a molten state, and is melted at 450 degrees C or less.

As the liquid crystal polyester (2) contains a naphthalene skeleton, as apparent from the above definitions relating to the repeating unit (I ') and the repeating unit (III'), a molded article having excellent rigidity is obtained.

As a manufacturing method of liquid crystalline polyester (1) and (2), the method which consists of the following processes as described in Unexamined-Japanese-Patent No. 2002-146003 can be illustrated.

(1) The above-mentioned aromatic hydroxycarboxylic acid, aromatic diol, and aromatic dicarboxylic acid which are raw material monomers are melt-polymerized (polycondensation), and the aromatic polyester having a relatively low molecular weight (hereinafter referred to as "prepolymer") Obtaining process;

(2) powdering the prepolymer; And

(3) A step of heating and solidifying the powdered prepolymer to obtain a high molecular weight liquid crystal polyester (1) or (2).

Some or all of the above-mentioned raw material monomers may be derivatives which can be polymerized.

Melt polymerization of the step (1) may be performed in the presence of a catalyst. Metal compounds such as magnesium acetate, first tin acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate and antimony trioxide as catalysts; And nitrogen-containing heterocyclic compounds such as 4- (dimethylamino) pyridine and 1-methylimidazole. Especially, a nitrogen-containing heterocyclic compound is preferable.

As a derivative which can superpose | polymerize the raw material monomer described in process (1), about the compound which has a carboxyl group, such as aromatic hydroxycarboxylic acid and aromatic dicarboxylic acid, the ester and carboxyl group which converted the carboxyl group into the alkoxycarbonyl group or the aryloxycarbonyl group halo The acid halide which converted into the formyl group, and the acid anhydride which converted the carboxyl group into the acyloxycarbonyl group can be illustrated.

About the compound which has hydroxyl groups, such as an aromatic hydroxycarboxylic acid and aromatic diol, the acyl compound which acylated the hydroxyl group and converted into the acyloxyl group can be illustrated.

From the viewpoint of improving the heat resistance of the liquid crystal polyester composition of the present invention, the flow start temperature of the liquid crystal polyester (1) is preferably 280 to 420 ° C, more preferably 280 to 390 ° C.

From the viewpoint of improving the heat resistance of the liquid crystal polyester composition of the present invention, the flow start temperature of the liquid crystal polyester (2) is preferably 300 to 400 ° C, more preferably 320 to 380 ° C, still more preferably 330 to 360 ° C. to be.

Said flow start temperature is liquid crystalline polyester at a temperature increase rate of 4 degree-C / min under the load of 9.8 Mpa (100 kg / cm <2>) using the capillary type | mold rheometer equipped with the die | dye of internal diameter 1mm and length 10mm. When extruding from a nozzle, it means the temperature which melt viscosity shows 4,800 Pa.s (48,000 poise). The flow start temperature is an index of the molecular weight of the liquid crystalline polyester (see Koide Naoyuki, "Liquid Crystalline Polymer-Synthesis, Molding, Application-", pages 95 to 105, CMC, issued June 5, 1987).

Content of liquid crystal polyester (1) and (2) in a component (A) makes liquid crystal polyester (1) the sum total of both to 100 mass parts from the thermal conductivity of the molded object which consists of liquid crystal polyester composition of this invention. ) Is preferably 10 to 95 parts by mass, more preferably 50 to 90 parts by mass, and the liquid crystalline polyester (2) is preferably 5 to 90 parts by mass, more preferably 10 to 50 parts by mass. In particular, the component (A) containing 100 mass parts of liquid crystal polyester (1) and 25-70 mass parts of liquid crystal polyester (2) further improves the thermal conductivity of a liquid crystal polyester composition.

The liquid crystalline polyesters (1) and (2) are used in combination of one kind or two or more kinds, respectively.

As a preferred method of mixing the liquid crystal polyester (1) and (2), (1) the liquid crystal polyester (1) and (2) are mixed with a known mixer such as a Henschel mixer and a tumbler, and then the obtained mixture is extruded. Melt kneading in a furnace, and pelletizing the kneaded product obtained as necessary, and (2) simultaneously exposing the liquid crystal polyesters (1) and (2) with the components (B), (C) and (D) with an extruder. The method (later) of melt kneading can be illustrated. Method (2) is a method of simultaneously performing production of component (A) by mixing liquid crystal polyesters (1) and (2) and mixing of components (B), (C) and (D).

[Component (B)]

The alumina fine particles of the component (B) are preferably fine particles composed of α alumina. Among them, the content of aluminum oxide (A1 ₂ O ₃ ) is 95% by mass or more, preferably 99% by mass or more, and more preferably 99.5% by mass or more, from the viewpoint of increasing the electrical insulation and thermal conductivity of the molded article of the present invention. As microparticles | fine-particles whose volume average particle diameter is 0.1-50 micrometers is more preferable.

The volume average particle diameter of the alumina fine particles is preferably 0.1 to 30 µm, more preferably 0.1 to 20 µm, and particularly preferably 0.1 to 10 µm. This volume average particle diameter is measured by the method which consists of the following procedures using a microtrack particle size analyzer (for example, "HRA" by Nikkiso Corporation): (1) Hexametha which is 2 mass% of alumina microparticles | fine-particles. The procedure of adding to the sodium phosphate aqueous solution, (2) order to disperse | distribute it by the ultrasonic cleaning apparatus sufficiently, and (3) the procedure to irradiate a laser beam to the obtained dispersion liquid, and to measure the diffraction (scattering) (by the laser diffraction scattering measurement Particle size distribution measurement).

Alumina microparticles | fine-particles may be a commercial item. As commercially available alumina microparticles | fine-particles which can be easily obtained, the alumina microparticles by Sumitomo Chemical Co., Ltd. make, Nippon Light Metal Co., Ltd. make can be illustrated.

The particle size distribution of the alumina microparticles | fine-particles calculated | required by said measuring method becomes like this. Preferably it is 2 rod shape, More preferably, it is 2 which has a local maximum in each of the range of the volume average particle diameters 1-5 micrometers, and the range of the volume average particle diameters 0.1-1 micrometer. It is sewing. By using bimodal alumina microparticles | fine-particles, the liquid crystal polyester composition with high content of alumina microparticles | fine-particles can be obtained, As a result, the molded object excellent in thermal conductivity can be obtained.

1 and 2 are schematic diagrams showing an outline of the "seal particle size distribution" of alumina microparticles | fine-particles. Fig. 1 shows a typical bimodal particle size distribution, and there are two local maxima which are the first local maxima and the second local maxima. In this invention, the 1st local maximum as shown in FIG. 2 means the particle size distribution of 2 particle size distribution degree which exists as a shoulder peak of the peak which has a 2nd local maximum. Said "the range of volume average particle diameters 0.1-1 micrometer" means the range in which a 1st local maximum exists in FIGS. 1 and 2, and said "range of the volume average particle diameters 1-5 micrometers" is FIG. 1 and In 2, the range in which a 2nd maximum value exists is meant.

[Component (C)]

The plate-like filler of component (C) preferably has an aspect ratio of 5 or more, more preferably 15 or more.

The "aspect ratio" in this invention has the definition described in 10th-16th page and 23rd-30th page of filler research meeting "filler utilization dictionary". 3 is a perspective view schematically showing one plate-like filler. An aspect ratio is calculated | required by ratio (D / T) of the average diameter D and the average thickness T of the planar part of this figure. In this invention, D / T value of 100 or more plate-shaped filler is calculated | required, for example, and those average values are called aspect ratio.

The volume resistivity of the plate-shaped filler is preferably 1 × 10 ¹⁰ Ωm or more from the viewpoint of improving the electrical insulation of the molded article of the present invention. The volume resistivity value is measured according to ASTM D257.

The volume average particle diameter of the long axis of a plate-shaped filler becomes like this. Preferably it is 15 micrometers or more, More preferably, it is 15-50 micrometers, More preferably, it is 15-30 micrometers. When a volume average particle diameter is less than 15 micrometers, it exists in the tendency for a component (C) to become difficult to mix with a component (A). As a result, manufacture of a liquid crystal polyester composition is difficult, or a component (C) exists nonuniformly in the molded object which consists of this composition, and thermal conductivity falls. When a volume average particle diameter exceeds 50 micrometers, there exists a tendency for the mechanical characteristic of a molded object to fall easily. This volume average particle diameter is measured by the method which consists of the following procedures using the microtrack particle size analyzer (for example, "SRA" by Nikkiso Corporation): (1) The procedure of adding a plate filler to ethanol, (2) It ultrasonically The procedure to fully disperse | distribute with a washing | cleaning apparatus, and (3) The procedure which irradiates a laser beam to the obtained dispersion liquid, and measures the diffraction (scattering).

Kaolinite as a component (C); Talc; Micas such as mica, biotite (serisite), dolomite (muskerbite) and gold mica (flogofite); Layered clay minerals such as chlorite, montmorillonite and halosite; And glass flakes can be illustrated. Among them, talc is preferable from the viewpoint of performance such as electrical insulation and thermal conductivity of component (C) and from the viewpoint of being inexpensive. Component (C) is used by the 1 type or the combination of 2 or more types.

Talc is generally obtained by roughly crushing ore produced in nature, then pulverizing and classifying. As an apparatus used for coarse grinding | pulverization, a jaw crusher, a hammer grinder, and a roll grinder can be illustrated. As a device used for pulverization, a jet mill, a screen mill, a roller mill, and a vibration mill can be illustrated. As a device used for classification, a cyclone air separator, a micro separator, and a sharp cut separator can be illustrated.

As a commercially available talc which can be used in the present invention, talc having an aspect ratio of 5 or more manufactured by Nippon Talc Co., Ltd. or Asada Milling Co., Ltd. can be exemplified.

Commercially available talc is used as it is, or surface treated with a coupling agent (for example, a silane coupling agent and a titanium coupling agent) or a surfactant in order to improve dispersibility and adhesion to the component (A).

As the silane coupling agent, methacrylsilane, vinylsilane, epoxysilane and aminosilane can be exemplified. Titanic acid can be illustrated as a titanium coupling agent. As the surfactant, higher fatty acids, higher fatty acid esters, higher fatty acid amides and higher fatty acid salts can be exemplified.

[Component (D)]

The fibrous filler of component (D) is an inorganic fibrous filler, an organic fibrous filler or a combination thereof. As the component (D), glass fibers, carbon fibers and alumina fibers can be exemplified. Especially, from a viewpoint of improving the mechanical strength of the molded object of this invention, an inorganic fibrous filler is preferable and glass fiber is more preferable. Component (D) is used by the 1 type or the combination of 2 or more types.

The number average fiber diameter of the fibrous filler is preferably 0.1 to 20 µm, more preferably 0.5 to 15 µm. When number average fiber diameter is 0.1 micrometer or more, the curvature amount of the molded object of this invention is reduced and heat resistance improves. When number average fiber diameter is 20 micrometers or less, the fluidity | liquidity of a liquid-crystal polyester composition improves and the curvature amount of a molded object is reduced.

The number average fiber length of the fibrous filler is preferably 1 to 300 µm, more preferably 2 to 300 µm. When the number average fiber length is 1 µm or more, the heat resistance and the mechanical strength of the molded body are improved. When the number average fiber length is 300 µm or less, the fluidity of the liquid crystal polyester composition is improved.

The volume specific resistance measured in accordance with ASTM D257 of the fibrous filler is preferably 1 × 10 ¹⁰ Ωm or more in order to improve the electrical insulation of the molded article of the present invention.

[Other Ingredients]

In this invention, you may use other components other than components (A)-(D). Mold release improvers, such as a fluororesin, as another component; Coloring agents such as dyes and pigments; Antioxidants; Thermal stabilizer; UV absorber; An antistatic agent; And conventional additives such as surfactants.

Content of another component makes the whole quantity of the liquid crystal polyester composition of this invention 100 mass%, Preferably it is 5 mass% or less.

The content (mass) of the component (B) in the liquid crystal polyester composition of the present invention is more than the total content (mass) of the components (C) and (D) from the viewpoint of thermal conductivity and rigidity of the molded article of the present invention, and the total It is preferable that it is 2 times or more of content, and it is more preferable that it is 3 times or more.

In the liquid crystal polyester composition of the present invention, the total content of the components (B), (C) and (D) is preferably 150 parts by mass or more, more preferably relative to 100 parts by mass of the content of the component (A). It is 170 mass parts or more.

The liquid crystal polyester composition of this invention can be manufactured by mix | blending component (A)-(D) and other components which are arbitrary components in the compounding quantity which said quantitative relationship is satisfied, and then mixing. As a preferable manufacturing method, the manufacturing method which consists of the process (1) of mixing these components with mixers, such as a Henschel mixer and a tumbler, and the process (2) of melt-kneading the obtained mixture with an extruder can be illustrated. The kneaded material obtained in a process (2) is pelletized suitably. Instead of performing the step (1), the liquid crystal polyesters (1) and (2) constituting the component (A) and all remaining components may be thrown into the extruder of the step (2) at the same time and melt kneaded.

<Molded body>

By molding the liquid-crystalline polyester composition of the present invention, the molded article of the present invention having excellent heat conductivity and rigidity in a balanced manner is obtained.

The molding method is preferably a melt molding method, more preferably an injection molding method. Especially, the injection molding method is suitable for molding the molded article having a thin imposing complex shape. The molded article obtained by the injection molding method is useful as a member which requires particularly high thermal conductivity, such as an electrical and electronic component.

The molded article of the present invention is excellent in thermal conductivity, and a molded article having a thermal conductivity of, for example, 0.9 W / m · K or more can be obtained. The thermal conductivity can be obtained by multiplying the thermal diffusivity, specific heat and specific gravity of the molded body. Moreover, the molded object of this invention is excellent in rigidity, and can obtain the molded object of bending elastic modulus more than 12.0 GPa, for example. In addition, the molded article of the present invention is excellent in mechanical strength, and a molded article having a bending strength of, for example, 100 MPa or more can be obtained. Bending elastic modulus and bending strength can be measured based on ASTMD790, for example.

The molded article of the present invention can be applied to various applications, and in particular, since the thermal conductivity and rigidity are excellent in balance, the sealing material, the insulator, the reflecting plate for the display device, the electronic device storage case, and the surface mounting component (connector) of the electronic device (connector) It is especially preferable as an electrical / electronic component like the above. Insufficient heat dissipation of heat generated during operation of the electric / electronic device provided with these electric / electronic parts causes problems such as malfunction, and the reliability of the device tends to be lowered. Since the molded article of the present invention is excellent in balance between thermal conductivity and rigidity, when used as an electrical / electronic component, heat dissipation and deformation are difficult. Therefore, stable operation of the electrical / electronic device can be realized.

Example

Hereinafter, the present invention will be described by way of examples.

The following components (B), (C) and (D) were used.

Component (B): Fine low soda alumina ALM-41-01 by Sumitomo Chemical Co., Ltd. which satisfies following (1)-(3).

(1) The volume average particle diameter measured using Nikkiso Co., Ltd. microtrack particle size analyzer "HRA" is 1.7 micrometers.

(2) The particle size distribution determined by laser diffraction scattering measurement is a bimodal particle size distribution having one local maximum in the range of the volume average particle diameter of 1.0 to 2.0 µm and the range of the volume average particle diameter of 0.2 to 0.4 µm.

(3) Content of aluminum oxide is 99.9 mass% (alpha) alumina.

Component (C): Talc X50 manufactured by Nippon Talc Co., Ltd. which satisfies the following (1) and (2).

(1) The volume average particle diameter of the long axis measured using the microtrack particle size analyzer "SRA" by Nikkiso Corporation is 17.4 micrometers;

(2) The aspect ratio measured in the following procedure is 21.2;

(i) Select the particles whose thickness can be checked by electron microscopy (i.e. their cross-sections can be identified):

(ii) the particle diameter and thickness of the particle were measured;

(iii) It is computed based on the formula whose aspect ratio = particle diameter / thickness.

Component (D): The glass fiber CS03 JAPX-1 by Asahi Fiber Glass Co., Ltd. whose number average fiber diameter measured by the electron microscope based on JISR3420 is 10 micrometers, and the number average fiber length is 3 mm.

<Production of Liquid Crystal Polyester>

[Production Example 1]

(Production of Liquid Crystal Polyester (1))

994.5 g (7.2 mol) of p-hydroxybenzoic acid, 446.9 g (2.4 mol) of 4,4'-dihydroxybiphenyl, terephthalic acid in a reactor equipped with a stirring device, a torque meter, a nitrogen gas introduction tube, a thermometer and a reflux condenser 239.2 g (1.44 moles), 159.5 g (0.96 moles) of isophthalic acid and 1,347.6 g (13.2 moles) of acetic anhydride were introduced, the reactor was sufficiently replaced with nitrogen gas, and then stirred for 30 minutes while stirring under a nitrogen gas stream. It heated up to ° C and refluxed at 150 ° C for 1 hour.

Subsequently, while distilling off the acetic acid and the unreacted acetic anhydride which were distilled by-products, it heated up to 320 degreeC over 2 hours and 50 minutes, and obtained the prepolymer at the time when the torque rise was confirmed as a reaction end point.

After cooling the obtained prepolymer to room temperature and grinding | pulverizing with a coarse grinder, it heated up from room temperature to 250 degreeC over 1 hour under nitrogen gas atmosphere, and it heated up over 250 hours from 250 degreeC to 285 degreeC, and 3 hours at 285 degreeC. Solid phase superposition | polymerization was performed by hold | maintaining, and liquid crystal polyester (1) (henceforth "LCP1") of the fluidization start temperature 327 degreeC was obtained.

Flow start temperature was measured by the following procedure using the flow tester CFT-500 type | mold by Shimadzu Corporation:

(1) About 2 g of liquid crystalline polyester is filled in the cylinder equipped with the die which has a nozzle of internal diameter 1mm and length 10mm;

(2) Melting the liquid crystalline polyester while raising the temperature at a rate of 4 ° C / min under a load of 9.8 MPa (100 kg / cm 2);

(3) Extrude from a nozzle and let the temperature which shows the viscosity of 4,800 Pa.s (48,000 poise) be a flow start temperature.

[Production Example 2]

(Production of Liquid Crystal Polyester (2))

940.9 g (5.0 mol) of 6-hydroxy-2-naphthoic acid, 512.1 g of 4,4'-dihydroxybiphenyl (2.75) in a reactor equipped with a stirring device, a torque meter, a nitrogen gas introduction tube, a thermometer and a reflux condenser Mole), 497.2 g (2.3 mole) of 2,6-naphthalenedicarboxylic acid, 33.2 g (0.2 mole) of terephthalic acid, 1179.1 (11.5 mole) of acetic anhydride and 0.198 g of 1-methylimidazole as a catalyst are added thereto, and room temperature After stirring for 15 minutes, the temperature was raised while stirring. When internal temperature became 145 degreeC, it stirred at 145 degreeC for 1 hour, and 5.94g of 1-methylimidazole which is a catalyst was further added.

Subsequently, while acetic acid and unreacted acetic anhydride of the by-product discharged by distillation were distilled off, it heated up to 310 degreeC over 3 hours and 30 minutes, it hold | maintained at 310 degreeC for 2 hours and 10 minutes, and obtained the prepolymer.

After cooling the obtained prepolymer to room temperature and grinding | pulverizing with a coarse grinder, it heated up from room temperature to 250 degreeC over 1 hour in nitrogen gas atmosphere, and it heated up from 250 degreeC to 325 degreeC over 10 hours, and 12 hours at 325 degreeC. Solid phase superposition | polymerization was performed by hold | maintaining, and liquid crystal polyester (2) (henceforth "LCP2") of the flow start temperature 335 degreeC was obtained.

<Production of Liquid Crystal Polyester Composition and Molded Body>

[Examples 1-4, Comparative Examples 1-2]

(Production of Liquid Crystal Polyester Composition)

LCP1, LCP2, component (B), component (C) and component (D) were supplied to the coaxial twin screw extruder PCM-30HS manufactured by Ikegai Iron Works at a ratio shown in Table 1, and melt kneaded at 330 ° C. And pelletized.

(Production of molded body)

The pellet was injected into a cylinder temperature of 320 ° C. (Examples 1 to 4 and Comparative Example 1) or 340 ° C. (Comparative Example 2), mold temperature 120 ° C., using an injection molding machine UH-1000 manufactured by Nissei Resin Co., Ltd. Injection molding was carried out under the condition of a rate of 100 cm 3 / s to obtain a square plate-shaped molded body having a size of 64 mm × 64 mm × 1 mm (thickness).

Separately, the pellet was injected with a cylinder temperature of 320 ° C. (Examples 1 and 2 and Comparative Example 1) or 340 ° C. (Comparative Example 2), a mold temperature of 120 ° C., using an injection molding machine PS40E5ASE manufactured by Nissei Resin Co., Ltd. Injection molding was carried out under the condition of a rate of 30 cm 3 / s to obtain a molded article of ASTM No. 4 dumbbell or a rectangular plate-shaped molded article having a size of 126 mm × 12 mm × 6 mm (thickness).

<Evaluation of molded body>

Using each said molded object, thermal conductivity, bending strength, and bending elastic modulus were measured by the following measuring methods. The results are shown in Table 1.

(Measurement of thermal conductivity)

Thermal conductivity was measured by the following procedure:

(1) The thermal diffusivity in the thickness direction of the square plate-shaped molded body is measured by using a laser flash method thermal constant measuring device TC-7000 manufactured by Albak Co., Ltd .;

(2) The specific heat of the pellets is measured using DSC DSC7 manufactured by PERKIN ELMER (since the specific heat of the pellets and the specific heat of the molded body are the same, the specific heat of the pellet is defined as the specific heat of the molded body);

(3) The specific gravity of the molded object of ASTM No. 4 dumbbell was measured based on ASTM D792 using the automatic specific gravity measuring apparatus ASG-320K by Canto Major Co., Ltd .;

(4) The thermal conductivity in the thickness direction of the square plate-shaped molded body is obtained from the equation of thermal conductivity = thermal diffusivity x specific heat x specific gravity.

(Measurement of bending strength and bending elastic modulus)

The bending strength and the bending elastic modulus of the rectangular plate-shaped molded body were measured in accordance with ASTM D790.

As is clear from Table 1, the molded articles of Examples 1 to 4 have a thermal conductivity of 0.9 W / m · K or more and a bending elastic modulus of 12.0 Pa or more, so that the thermal conductivity and the rigidity are excellent in balance.

In contrast, the molded article of Comparative Example 1 using only LCP1 as the liquid crystalline polyester has a thermal conductivity of 1.2 W / m · K, but has a bending elastic modulus of 11.2 GPa, and thus cannot be said to have excellent thermal conductivity and rigidity in balance. Moreover, the molded object of the comparative example 2 using only LCP2 as liquid crystalline polyester is neither excellent in thermal conductivity (0.8 W / m * K) nor bending elastic modulus (11.9 kPa).

The liquid crystal polyester composition and the molded article of the present invention are particularly suitable for electrical and electronic components requiring high heat dissipation.

Claims (10)

Liquid crystal poly which contains following component (A), (B), (C) and (D), and content (mass) of a component (B) is more than the total content (mass) of components (C) and (D). Ester composition:
(A) mixture of following liquid crystalline polyester (1) and (2);
(B) alumina fine particles;
(C) the plate-shaped filler which consists of an electrically insulating material; And
(D) fibrous fillers made of an electrically insulating material;
Liquid-crystalline polyester (1) is a repeating unit (I) 30-80 unit derived from p-hydroxybenzoic acid, and a repeating unit (II) 10 derived from hydroquinone and / or 4,4'- dihydroxybiphenyl. To 35 units and 10 to 35 units of repeating unit (III) derived from terephthalic acid and / or isophthalic acid (the total of repeating units (I), (II) and (III) is 100 units);
The liquid crystalline polyester (2) is composed of 40 to 74.8 units of the repeating unit (I ') derived from 6-hydroxy-2-naphthoic acid and a repeat derived from hydroquinone and / or 4,4'-dihydroxybiphenyl. Unit (II ') 12.5-30 unit, 12.5-30 units of repeating unit (III') derived from 2, 6- naphthalenedicarboxylic acid, and aromatic dicarboxyl other than 2, 6- naphthalenedicarboxylic acid Repeating units (IV ') derived from an acid containing 0.2 to 15 units (the total of repeating units (I') and (II ') and (III') and (IV ') is 100 units), and repeating units The content of (III ') and (IV') satisfies the following formula:
Content of repeating unit (III ') / {total content of repeating unit (III') and (IV ')} ≥0.5. The method of claim 1,
Liquid crystal polyester composition whose total content of component (B), (C), and (D) is 150 mass parts or more with respect to 100 mass parts of content of component (A). The method of claim 1,
Liquid crystal polyester composition whose component (A) is a mixture containing 100 mass parts of liquid crystal polyester (1) and 25-70 mass parts of liquid crystal polyester (2). The method of claim 1,
The liquid crystal polyester composition whose particle size distribution calculated | required by the laser diffraction scattering measurement of component (B) is bimodal. 5. The method of claim 4,
The liquid crystal polyester composition which is bimodal having a maximum value in each of particle size distribution in the range of the volume average particle diameter of 1-5 micrometers, and the range of the volume average particle diameter of 0.1-1 micrometer. The method of claim 1,
Liquid crystal polyester composition whose component (C) is talc. The method according to claim 6,
The liquid crystal polyester composition whose volume average particle diameter of the long axis of talc is 15 micrometers or more. A molded article comprising the liquid crystal polyester composition according to claim 1. The method of claim 8,
A molded article in which the molded article is an electrical / electronic component. The method of claim 9,
A molded article in which the electric and electronic parts are sealing materials for electronic elements, insulators, reflecting plates for display devices, cases for storing electronic elements, or surface mount parts.

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