JP4999285B2 - Liquid crystalline polyester resin composition - Google Patents

Description

  The present invention relates to a liquid crystal polyester resin composition that is excellent in mechanical properties, molding processability, plating processability, and dielectric properties, and gives a molded product having a smooth surface and an excellent appearance.

  In modern society, the use of ITS (Intelligent Transport Systems, Intelligent Transport Systems) typified by multimedia and ubiquitous daily life and ETC devices and GPS on toll roads is rapidly progressing. In order to cope with the explosive increase in information communication traffic accompanying this, the frequency of information transmission is increasing.

  Engineering plastic materials with excellent dielectric properties in the gigahertz band and excellent productivity and light weight are promising as materials for use in information communication devices with higher frequencies in this way. Various communication equipment, electronic devices, etc. Application as a housing, package, dielectric device, etc. is expected.

  Among the engineering plastics described above, the thermotropic liquid crystal polyester resin (hereinafter abbreviated as liquid crystal polyester resin or LCP) has a dielectric constant such that the relative dielectric constant (εr) is constant in the operating frequency band and the dielectric loss tangent (tan δ) is low. Excellent characteristics. In addition, it has excellent physical properties such as low expansion characteristics (environmental dimensional stability), heat resistance, flame retardancy, mechanical properties such as rigidity. Furthermore, it is excellent in fluidity during molding, and a molded product having a thin part and a fine part can be easily processed. Therefore, LCP is a material particularly expected in high frequency applications.

  Properties required for engineering plastic materials in high-frequency applications include plating characteristics such as surface smoothness and plating adhesion, as well as stability, productivity, and lightness of dielectric characteristics with respect to frequency, temperature, and humidity. . Various proposals have been made for liquid crystal polyester resin compositions having these characteristics.

  Liquid crystal polyester resin compositions with improved surface smoothness and plating characteristics include liquid crystal polyester resins blended with metal salts such as calcium pyrophosphate, barium sulfate, zinc oxide (see Patent Documents 1 and 2), phosphoric acid Ingredients containing alkaline earth metal carbonates such as calcium carbonate surface-treated with (see Patent Document 3), liquid crystal polyester resin having a melting point of 300 ° C. or more, and inorganic fillers such as titania and calcium carbonate (See Patent Document 4) and wholly aromatic liquid crystal polyester resin having a melting point of 320 ° C. or higher and an inorganic spherical hollow body having an aspect ratio of 2 or less and an inorganic filler having an aspect ratio of 4 or more (patent) Reference 5) is known.

  However, the liquid crystal polyester resins disclosed in Patent Documents 1 to 5 have the following problems.

  The liquid crystal polyester resin compositions disclosed in Patent Documents 1 and 2 can be plated by etching treatment, but their dielectric properties, surface smoothness, and mechanical properties are not sufficient for high frequency applications.

  Patent Document 3 has problems such as a decrease in mechanical properties of liquid crystal polyester resin composition produced when blending liquid crystal polyester resin with untreated calcium carbonate or a stable molding process (Comparison with Patent Document 1). In order to solve the problem, a liquid crystal polyester resin composition in which an alkaline earth metal carbonate such as calcium carbonate surface-treated with phosphoric acid is mixed with a liquid crystal polyester resin is proposed. However, since the liquid crystal polyester resin composition disclosed in Patent Document 3 requires a step of phosphoric acid treatment of an alkaline earth metal salt, the production cost of the liquid crystal polyester resin composition is increased. Moreover, it is necessary to process at a very high temperature, as in the example, at 380 ° C. The above-mentioned problems that occur when calcium carbonate or the like is blended can be improved somewhat by surface treatment of alkaline earth metal salts such as calcium carbonate with phosphoric acid, but there are still problems of poor mechanical properties and poor molding stability. is there.

  The liquid crystal polyester resin composition disclosed in Patent Document 4 is a composition in which calcium carbonate is blended with a liquid crystal polyester resin having a melting point of 300 ° C. or higher, and the above-described liquid crystal polyester resin blended with calcium carbonate is processed at a high temperature. Have a problem.

  In the liquid crystal polyester composition disclosed in Patent Document 5, the inorganic spherical hollow body is generally expensive, and the inorganic spherical hollow body is inevitably damaged during the production process and molding of the composition, and the dielectric properties are improved. There are problems such as it being difficult to obtain stable effects. In addition, there is room for improvement in the smoothness of the surface of the molded product.

As described above, liquid crystal polyester resin compositions that are all well balanced in terms of required properties in high frequency applications such as dielectric properties, productivity, light weight, surface smoothness and plating adhesion are not known, and their development has It is desired.
JP-A-1-92241 JP-A-1-98637 JP-A-4-4252 JP 2004-59702 A Japanese Patent Laid-Open No. 2004-27021

  An object of the present invention is to provide a liquid crystal polyester resin composition that is suitable for high-frequency applications, has excellent mechanical properties, molding processability, plating processability, and low dielectric properties, and gives a molded article having a smooth surface and excellent appearance. There is. Furthermore, the objective of this invention is providing the molded article suitable for a high frequency use which uses the said liquid crystal polyester resin composition.

The present invention relates to a liquid crystal polyester resin composition comprising 100 parts by weight of a liquid crystal polyester resin having a melting point of 200 to 260 ° C. measured by a differential scanning calorimeter and 5 to 100 parts by weight of particulate and / or fibrous calcium carbonate. Offer things.
Furthermore, this invention provides the molded article of the liquid crystal polyester resin which uses the said liquid crystal polyester resin composition.

  By blending 5 to 100 parts by weight of particulate and / or fibrous calcium carbonate with 100 parts by weight of a liquid crystalline polyester resin having a melting point measured by a differential scanning calorimeter of 200 to 260 ° C., mechanical properties and molding A liquid crystal polyester resin composition is obtained that is excellent in processability, plating processability, and dielectric properties, and gives a molded article having a smooth surface and an excellent appearance.

  The liquid crystal polyester resin used in the liquid crystal polyester resin composition of the present invention is a polyester resin that forms an anisotropic molten phase, and is called a thermotropic liquid crystal polyester resin by those skilled in the art, and includes a differential scanning calorimeter. If melting | fusing point measured by (200) shows 200-260 degreeC, it will not restrict | limit in particular.

  The property of the anisotropic molten phase 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.

  The liquid crystal polyester resin having a melting point of 200 to 260 ° C. measured by a differential scanning calorimeter used in the present invention is a semi-aromatic liquid crystal polyester resin having an aliphatic group in the molecular chain, or all the molecular chains are aromatic groups. Any of the wholly aromatic liquid crystal polyester resins constituted may be used. Among these liquid crystal polyester resins, wholly aromatic liquid crystal polyester resins are preferable because they have good flame retardancy and mechanical properties.

  As the repeating unit constituting the liquid crystal polyester resin used in the present invention, an aromatic oxycarbonyl repeating unit, an aromatic dicarbonyl repeating unit, an aromatic dioxy repeating unit, an aromatic oxydicarbonyl repeating unit, an aliphatic dioxy repeating unit, etc. Is mentioned. Liquid crystal polyester resins composed of these repeating units may or may not form an anisotropic molten phase depending on the constituent components, the composition ratio in the polyester resin, and the sequence distribution, but they are used in the present invention. The liquid crystal polyester resin is limited to those forming an anisotropic melt phase.

  Specific examples of the monomer that gives an aromatic oxycarbonyl repeating unit include, for example, parahydroxybenzoic acid, metahydroxybenzoic acid, orthohydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 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, their alkyl, alkoxy or halogen Substituents and ester-forming derivatives thereof such as acylated products, ester derivatives, acid halides and the like can be mentioned. Among these, it is preferable from the viewpoint of easily adjusting the characteristics and melting point of the liquid crystal polyester resin from which parahydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are obtained.

  Specific examples of the monomer giving the aromatic dicarbonyl repeating unit include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1, Aromatic dicarboxylic acids such as 4-naphthalenedicarboxylic acid, 4,4′-dicarboxybiphenyl, bis (4-carboxyphenyl) ether, bis (3-carboxyphenyl) ether, alkyl, alkoxy or halogen substituted products thereof And ester-forming derivatives thereof, such as ester derivatives and acid halides thereof. Among these, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferable because the liquid crystal polyester from which terephthalic acid and 2,6-naphthalenedicarboxylic acid are obtained can be easily adjusted to appropriate levels of mechanical properties, heat resistance, melting point temperature, and moldability.

  Specific examples of the monomer giving an aromatic dioxy repeating unit include, for example, hydroquinone, resorcin, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4 Aromatic diols such as 4,4'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl ether, alkyl, alkoxy or halogen substituents thereof, and Examples thereof include ester-forming derivatives such as acylated products. Among these, hydroquinone and 4,4'-dihydroxybiphenyl are preferable from the viewpoints of reactivity during polymerization, characteristics of the obtained liquid crystal polyester resin, and the like.

  Specific examples of monomers that give aromatic oxydicarbonyl repeating units include hydroxyaromatic dicarboxylic acids such as 3-hydroxy-2,7-naphthalenedicarboxylic acid, 4-hydroxyisophthalic acid, and 5-hydroxyisophthalic acid. And alkyl-substituted, alkoxy- or halogen-substituted products thereof, and ester-forming derivatives such as acylated products, ester derivatives, and acid halides thereof.

  Specific examples of the monomer giving the aliphatic dioxy repeating unit include aliphatic diols such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and acylated products thereof. In addition, polyesters containing aliphatic dioxy repeating units such as polyethylene terephthalate and polybutylene terephthalate are mixed with the above aromatic oxycarboxylic acids, aromatic dicarboxylic acids, aromatic diols and acylated products, ester derivatives, acid halides thereof. A liquid crystal polyester resin containing an aliphatic dioxy repeating unit can also be obtained by reacting with the above.

Among these combinations of repeating units, the following are examples of suitable combinations that exhibit a low melting point and good mechanical properties.

［繰返し単位の右下の数字は、液晶ポリエステル樹脂中における各繰返し単位のモル％を表す。］ Among these, combinations of repeating units shown below are particularly preferable.

[The number on the lower right of the repeating unit represents the mol% of each repeating unit in the liquid crystalline polyester resin. ]

  The liquid crystal polyester resin used in the present invention may contain an amide bond or a thioester bond as long as the object of the present invention is not impaired. Monomers that give such bonds include aromatic hydroxyamines, aromatic diamines, aromatic aminocarboxylic acids, mercaptoaromatic carboxylic acids, and aromatic dithiols and mercaptoaromatic phenols. The amount of these monomers used is that of the monomer giving the aromatic oxycarbonyl repeat unit, aromatic dicarbonyl repeat unit, aromatic dioxy repeat unit, aromatic oxydicarbonyl repeat unit, and aliphatic dioxy repeat unit. It is preferable that it is 10 mol% or less with respect to the total amount.

  In addition, the liquid crystalline polyester resin used in the present invention is used for the purpose of improving fluidity during molding, and for molding blisters (molded by generation of volatile components in the resin and gaseous by-products generated by thermal degradation of the resin. A blend of two or more liquid crystal polyester resins having a melting point of 200 to 260 ° C. measured by a differential scanning calorimeter may be used for the purpose of suppressing the occurrence of product surface swelling.

  The production method of the liquid crystal polyester resin used in the present invention is not particularly limited, and a known polyester polycondensation method for forming an ester bond comprising a combination of the above monomers, for example, a melt acidosis method, a slurry polymerization method, or the like is used. be able to.

  The melt acidolysis method is a preferable method for use in the method for producing the liquid crystal polyester resin used in the present invention, and this method first heats the monomer to form a melt of the reactant, and then reacts. To obtain a molten polymer. Note that 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 is reacted at room temperature as a modified form in which a hydroxyl group is esterified, that is, a lower acyl ester. Can also be provided. The lower acyl group preferably has 2 to 5 carbon atoms, more preferably 2 or 3 carbon atoms. Particularly preferred is a method in which the monomeric acetate is used for the reaction. The monomeric lower acyl ester 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. .

In any case of the melt acidification method or the slurry polymerization method, a catalyst may be used as needed during the reaction.
Specific examples of the catalyst include organic tin compounds such as dialkyltin oxide (for example, dibutyltin oxide) and diaryltin oxide; organic titanium compounds such as titanium dioxide, antimony trioxide, alkoxy titanium silicate, and titanium alkoxide; alkali and alkali of carboxylic acid Examples include earth metal salts (for example, potassium acetate); inorganic acid salts (for example, potassium sulfate); gaseous acid catalysts such as Lewis acids (for example, boron trifluoride) and hydrogen halides (for example, hydrogen chloride).

  The ratio of the catalyst used is usually 10 to 1000 ppm, preferably 20 to 200 ppm, based on the monomer.

  The thus obtained liquid crystal polyester resin has a melting point of 200 to 260 ° C., preferably 200 to 250 ° C., particularly preferably 200 to 240 ° C., measured by the following method using a differential scanning calorimeter (DSC). Can be suitably used in the liquid crystal polyester resin composition of the present invention.

<DSC measurement method>
Using an Exstar 6000 manufactured by Seiko Instruments Inc., an endothermic peak temperature (Tm1) observed when a sample of liquid crystal polyester resin was measured under a temperature rising condition from room temperature to 20 ° C./min, 20 to 20 from Tm1 Hold at 50 ° C elevated temperature for 10 minutes. Next, after the sample was cooled to room temperature under a temperature drop condition of 20 ° C./min, an endothermic peak was measured again when measured under a temperature rise condition of 20 ° C./min, and the temperature showing the peak top was the melting point of the liquid crystalline polyester resin. And

  Further, the liquid crystal polyester resin used in the liquid crystal polyester resin composition of the present invention is capable of measuring logarithmic viscosity in pentafluorophenol, and at that time, at a concentration of 0.1 g / dl at 60 ° C. The measured value is preferably 0.3 dl / g or more, preferably 0.5 to 10 dl / g, more preferably 1 to 8 dl / g.

  The melt viscosity of the liquid crystalline polyester resin used in the method of the present invention is 1 to 1000 Pa · S, preferably 5 to 300 Pa · S, as measured by a capillary rheometer.

  The liquid crystalline polyester resin thus obtained is extracted from the polymerization reaction tank in a molten state, and then processed into pellets, flakes, or powders, and then particulate and / or fibrous calcium carbonate. And processed into a liquid crystal polyester resin composition.

  The particulate and / or fibrous calcium carbonate used in the liquid crystal polyester resin composition of the present invention is not particularly limited as long as it is well dispersed in the composition. Even if it is heavy calcium carbonate, Light calcium carbonate (synthetic calcium carbonate) may be used. Among these, it is preferable to use light calcium carbonate. Examples of light calcium carbonate suitable for use in the liquid crystal polyester resin of the present invention include, for example, fibrous aragonite-type calcium carbonate having an average fiber diameter of 0.3 to 2 μm and an average fiber length of 10 to 35 μm, and / or an average Examples thereof include particulate calcite-type calcium carbonate having a particle diameter of 0.03 to 2 μm.

  The particulate and / or fibrous calcium carbonate used in the present invention may be a surface-treated calcium phosphate, fatty acid, fatty acid salt, fatty acid ester, polyacrylic acid, resin acid, various coupling agents, or the like. Good. However, the untreated surface is more preferably used because of the generation of volatiles during molding due to the surface treatment agent, and the surface treated calcium carbonate is expensive.

  The compounding amount of the particulate and / or fibrous calcium carbonate in the liquid crystal polyester resin composition of the present invention is 5 to 100 parts by weight, preferably 7 to 90 parts by weight, particularly preferably 100 parts by weight of the liquid crystal polyester resin. Is 10 to 80 parts by weight.

  The liquid crystal polyester resin composition of the present invention may further contain an inorganic filler and / or an organic filler in addition to calcium carbonate. Examples of the inorganic filler and / or organic filler that may be used in the liquid crystal polyester resin composition of the present invention include glass fiber, silica alumina fiber, alumina fiber, carbon fiber, aramid fiber, talc, mica, graphite, One or more types selected from the group consisting of lastite, dolomite, clay, glass flakes, glass beads, barium sulfate, and titanium oxide can be used. In these, glass fiber is preferable at the point which the balance of a physical property and cost is excellent.

  The blending amount of the inorganic filler and / or the organic filler in the liquid crystal polyester resin composition of the present invention is 50 parts by weight or less, preferably 30 parts by weight or less with respect to 100 parts by weight of the liquid crystal polyester resin. . When the blending amount of the inorganic filler and / or organic filler exceeds 50 parts by weight, both the dielectric properties and the surface smoothness tend to deteriorate, which is not preferable.

  In the liquid crystal polyester resin composition of the present invention, a mold release improver such as a higher fatty acid, a higher fatty acid ester, a higher fatty acid amide, a higher fatty acid metal salt, a polysiloxane, a fluororesin, and the like as long as the effects of the present invention are not impaired. Coloring agents such as dyes and pigments; antioxidants; heat stabilizers; ultraviolet absorbers; antistatic agents; surfactants and the like may be used alone or in combination.

  For those having an external lubricant effect such as higher fatty acid, higher fatty acid ester, higher fatty acid metal salt, and fluorocarbon surfactant, pellets of the liquid crystal polyester resin composition of the present invention are formed in advance when molding the liquid crystal polyester resin composition. It may be attached to the surface.

  In addition, the liquid crystal polyester resin composition of the present invention is blended with other resin components that can be molded and processed in the same temperature range as the liquid crystal polyester resin composition of the present invention as long as the object of the present invention is not impaired. May be. Examples of other resin components include polyamide, polyester, polyphenylene ether, and modified products thereof, acrylonitrile butadiene styrene copolymer resin (ABS), acrylonitrile ethylene propylene rubber styrene copolymer resin (AES), and acrylonitrile styrene copolymer resin (AS resin). ), Acrylonitrile styrene acrylate resin (ASA) resin), and thermosetting resins such as phenol resin, epoxy resin, and polyimide resin. Other resin components can be blended alone or in combination of two or more. The blending amount of the other resin components is not particularly limited, but may be determined so that the liquid crystal polyester resin composition is in a range suitable for high frequency applications. Typically, it is added in a range where the total blending amount of other resins with respect to 100 parts by weight of the liquid crystalline polyester resin is 0 to 100 parts by weight, particularly 0 to 80 parts by weight.

  The above-mentioned liquid crystalline polyester resin, fibrous and / or particulate calcium carbonate filler, inorganic filler and / or organic filler, and optionally various additives and other resin components, etc., with a predetermined composition, Banbury mixer The liquid crystal polyester resin composition of the present invention can be produced by melt-kneading using a kneader, a single screw or twin screw extruder or the like.

  The temperature at which the melt kneading is carried out when producing the liquid crystal polyester resin composition of the present invention is preferably 20 to 80 ° C. higher than the melting point of the liquid crystal polyester resin and preferably 280 ° C. or less. When the temperature during melt kneading exceeds 280 ° C., stable work is performed when the liquid crystal polyester resin composition is granulated into pellets after melt kneading or when the obtained liquid crystal polyester resin composition is molded. It may be difficult.

  In the liquid crystal polyester resin composition of the present invention, since a low melting point liquid crystal polyester resin is used, adverse effects caused by heating calcium carbonate during processing of the liquid crystal polyester resin composition can be suppressed. When calcium carbonate is blended to make a liquid crystal polyester resin composition or when molding, the operation can be performed stably.

  The liquid crystal polyester resin composition of the present invention thus obtained is processed into a molded product, a film, a sheet, a nonwoven fabric, and the like by a known molding method using an injection molding machine, an extruder, or the like.

  The molded product of the liquid crystal polyester resin composition of the present invention is not limited to a molded product composed only of the liquid crystal polyester resin composition of the present invention. For example, a metal material, a molded product using a molded product of another engineering plastic material as an insert material, a composite molded product molded by a method such as sandwich molding with another engineering plastic material, or another engineering plastic material, or A laminated material with a metal foil or a metal plate may be used.

  As described above, when the molded product is a material using a material different from the liquid crystal polyester resin composition of the present invention, a part or all of the surface of the molded product is formed of the liquid crystal polyester resin composition of the present invention. Is preferred.

  The molded product of the liquid crystalline polyester resin composition of the present invention is an article exhibiting excellent dielectric properties in the gigahertz band, and in particular, the dielectric loss tangent (tan δ) at 10 GHz measured by the cavity resonance method is 0.004 or less. Good low dielectric properties. The arithmetic average roughness (Ra) measured according to JIS B0601 is 1 μm or less, preferably 0.5 μm or less, particularly preferably 0.3 μm or less, and the maximum height (Rz) is 4 μm or less, preferably 3 μm or less. Particularly preferably, a molded article having excellent surface smoothness of 1 μm or less can be produced. Therefore, the liquid crystalline polyester resin composition of the present invention is suitably used for various molded products for high frequency applications.

  The molded product of the liquid crystal polyester resin composition of the present invention may be subjected to electroless plating treatment as desired. The electroless plating method is not particularly limited as long as it is a method conventionally used in engineering plastics, but as a pretreatment, an etching treatment with an alkaline solution such as a sodium hydroxide aqueous solution, an etching treatment with an acidic solution such as a sulfuric acid aqueous solution, or sulfuric acid Etching with an oxidizing agent solution such as an aqueous solution of chromic acid is preferably performed. The molded product of the liquid crystalline polyester resin composition of the present invention is formed with uniform unevenness on the surface of the molded product by the above-described etching treatment, which shows a high anchoring effect and excellent plating adhesion. .

  As described above, the liquid crystal polyester resin composition of the present invention and the molded product thereof are excellent in mechanical properties, molding processability, plating processability, surface smoothness and dielectric properties, for example, in the 5.8 GHz band. It is suitably used for high frequency applications such as an ETC antenna, a 2.4 GHz band wireless LAN antenna, or a 60 GHz band inter-vehicle collision prevention system antenna.

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

ＬＣＰ−ＩＩ（ＤＳＣにより測定された融点：３３０℃）

ＬＣＰ−ＩＩＩ（ＤＳＣにより測定された融点：２８２℃）

The liquid crystal polyester resins used in Examples and Comparative Examples are shown below.
The number on the lower right of the repeating unit represents the constituent ratio of each repeating unit in the liquid crystal polyester resin.
LCP-I (melting point measured by DSC: 210 ° C.)

LCP-II (melting point measured by DSC: 330 ° C.)

LCP-III (melting point measured by DSC: 282 ° C.)

Calcium carbonate used in Examples and Comparative Examples is shown below. Ca-I: Fibrous aragonite-type calcium carbonate (manufactured by Maruo Calcium Co., Ltd., Wiscal A), average fiber diameter of 0.5 to 1 μm, average fiber length of 20 to 30 μm.
Ca-II: particulate calcite-type calcium carbonate (manufactured by Maruo Calcium Co., Ltd., CUBE-18BH), average particle diameter 1.8 μm.
Ca-III: particulate light calcium carbonate (manufactured by Maruo Calcium Co., Ltd., Unigloss 1000), average particle size 0.05 μm.
Ca-IV: Surface treatment of particulate light calcium carbonate (Maruo Calcium Co., Ltd., Unigloss 1000) with phosphoric acid.

Examples 1-3
After blending Aragonite type fibrous calcium carbonate (Ca-I) as a calcium carbonate (B) with a composition shown in Table 1 with respect to 100 parts by weight of LCP-I as a liquid crystalline polyester resin (A) and mixing with a Henschel mixer Using a twin screw extruder (manufactured by Nippon Steel Works, TEX30α), the mixture was granulated into a pellet at a cylinder temperature of 260 ° C. to obtain a liquid crystal polyester resin composition.

  After the pellets of the obtained resin composition were dried at 130 ° C. for 4 hours, an injection molding machine (manufactured by FANUC CORPORATION, α-100iA) was used at a cylinder temperature of 260 ° C. and a mold temperature of 90 ° C. An 8 × 1.8 × 85 mm test piece was prepared, and dielectric characteristics at 10 GHz were measured by a cavity resonance method using a microwave device measurement system (manufactured by Agilent Technologies, 85070d).

In addition, a flat test piece of 55 × 90 × 0.8 mm was prepared using a mirror finish mold (# 8000) under the above-described injection molding conditions, and a surface roughness measuring machine (Co., Ltd.) according to JIS B0601. Surface roughness characteristics were measured using Mitutoyo, SV-3000).
The dielectric properties and surface roughness of the obtained resin composition are shown in Table 1.

Example 4
A test piece was obtained using LCP-I in the same manner as in Example 1 except that calcium carbonate (Ca-II) in the amount shown in Table 1 was blended, and dielectric properties and surface roughness properties were measured. . The dielectric properties and surface roughness of the obtained resin composition are shown in Table 1.

Example 5
A test piece was obtained using LCP-I in the same manner as in Example 1 except that the amount of calcium carbonate (Ca-III) shown in Table 1 was blended, and dielectric characteristics and surface roughness characteristics were evaluated. . The dielectric properties and surface roughness of the obtained resin composition are shown in Table 1.

Example 6
Similar to Example 1 except that calcium carbonate (Ca-III) in the amount shown in Table 1 is used and glass fiber in the amount shown in Table 1 (FT-591, manufactured by Asahi Fiber Glass Co., Ltd.) is further blended. A test piece was obtained using LCP-I, and dielectric characteristics and surface roughness characteristics were measured. The dielectric properties and surface roughness of the obtained resin composition are shown in Table 1.

Comparative Example 1
The granulation operation of the liquid crystal polyester resin composition was performed in the same manner as in Example 1 except that the cylinder temperature of the twin screw extruder (manufactured by Nippon Steel Works, TEX30α) was changed to 290 ° C. At this time, pyrolysis was caused in the twin-screw extruder, and the granulation operation was difficult.

Comparative Example 2
After mixing with a Henschel mixer as in Example 1, except that LCP-I was changed to LCP-II and phosphoric acid-treated calcium carbonate (Ca-IV) was blended in the composition shown in Table 1, Using a twin screw extruder (manufactured by Nippon Steel Works, TEX30α), granulation was performed in a pellet form at a cylinder temperature of 380 ° C. At this time, pyrolysis was caused in the twin-screw extruder, and the granulation operation was difficult.

Comparative Example 3
After mixing with a Henschel mixer as in Example 1, except that LCP-I was changed to LCP-II and phosphoric acid-treated calcium carbonate (Ca-IV) was blended in the composition shown in Table 1, Using a twin screw extruder (manufactured by Nippon Steel Works, TEX30α), granulation was performed in a pellet form at a cylinder temperature of 380 ° C. At this time, pyrolysis was caused in the twin-screw extruder, and the granulation operation was difficult.

Comparative Example 4
LCP-I was changed to LCP-III, and phosphoric acid-treated calcium carbonate (Ca-IV) was blended with the composition shown in Table 1, mixed with a Henschel mixer, and then a twin screw extruder (manufactured by Nippon Steel Works, Ltd.). , TEX30α) was granulated into a pellet at a cylinder temperature of 300 ° C. At this time, pyrolysis was caused in the twin-screw extruder, and the granulation operation was difficult.
These results are also shown in Table 1.

表１の結果から、本発明の特定の液晶ポリエステル樹脂組成物は、低誘電正接かつ良好な表面平滑性を有していることが判る。また、２９０℃以上で液晶ポリエステル樹脂組成物の造粒を行った、比較例のものは何れも安定した造粒操作を行うことができないものであった。

From the results of Table 1, it can be seen that the specific liquid crystal polyester resin composition of the present invention has a low dielectric loss tangent and good surface smoothness. Moreover, the thing of the comparative example which granulated the liquid crystal polyester resin composition at 290 degreeC or more was a thing which cannot perform stable granulation operation.

Example 7
Using the flat test piece used in Example 3, alkali etching treatment was performed under the following conditions. When the surface state of the molded product after etching was observed with an electron microscope, it was confirmed that uniform unevenness was formed on the surface of the test piece.
FIG. 1 shows an electron micrograph of the etched specimen surface and an electron micrograph of the specimen before etching.

[Etching conditions]
Alkaline aqueous solution: 48 wt% KOH aqueous solution Treatment temperature: 70 ± 5 ° C.
Immersion time: 1Hr

It is a figure which shows the surface state before and behind carrying out the alkali etching process of the molded article using the liquid crystalline polyester resin composition of this invention.

Claims (10)

A liquid crystal polyester resin composition that, when molded, gives a molded product having a dielectric loss tangent (tan δ) at 10 GHz measured by a cavity resonance method of 0.004 or less, and has a melting point of 200 measured by a differential scanning calorimeter. The liquid crystal polyester resin 100 parts by weight of ˜260 ° C. and 5-100 parts by weight of particulate and / or fibrous calcium carbonate is 20-80 ° C. higher than the melting point of the liquid crystal polyester resin, and 280 ° C. Fibrous aragonite-type calcium carbonate obtained by melt-kneading at a temperature of and having particulate and / or fibrous calcium carbonate having an average fiber diameter of 0.3 to 2 μm and an average fiber length of 10 to 35 μm And / or a liquid that is particulate calcite-type calcium carbonate having an average particle size of 0.03 to 2 μm Polyester resin composition.   2. The liquid crystal polyester resin composition according to claim 1, wherein the particulate and / or fibrous calcium carbonate is fibrous aragonite-type calcium carbonate having an average fiber diameter of 0.3 to 2 μm and an average fiber length of 10 to 35 μm. .   The liquid crystal polyester resin composition according to claim 1 or 2, wherein the calcium carbonate is untreated.   The liquid crystal polyester resin composition according to claim 1, wherein the liquid crystal polyester resin is a wholly aromatic liquid crystal polyester resin. The liquid crystal polyester resin composition according to claim 4, wherein the liquid crystal polyester resin comprises the following repeating units.

[The number on the lower right of the repeating unit represents the mol% of each repeating unit in the liquid crystalline polyester resin. ]   100 to 100 parts by weight of a liquid crystalline polyester resin having a melting point of 200 to 260 ° C. measured by a differential scanning calorimeter and 5 to 100 parts by weight of particulate and / or fibrous calcium carbonate are 20 to 20 parts from the melting point of the liquid crystalline polyester resin. 2. The method for producing a liquid crystal polyester resin composition according to claim 1, wherein melt kneading is performed at a temperature of 80 ° C. and a temperature of 280 ° C. or lower.   A molded article using the liquid crystal polyester resin composition according to any one of claims 1 to 5.   The molded article according to claim 7, wherein the arithmetic average roughness (Ra) measured in accordance with JIS B0601 is 1 µm or less and the maximum height (Rz) is 4 µm or less.   The molded article according to claim 7 or 8, which has been subjected to electroless plating.   The molded article according to any one of claims 7 to 9, wherein the molded article is an ETC antenna, a wireless LAN antenna, or an antenna for an inter-vehicle collision prevention system.

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