JP5271479B2 - Liquid crystalline polyester resin composition - Google Patents

Abstract

The invention provides a liquid crystal polyester resin composition, including: 100 parts by weight of liquid crystal polyester resin comprising monomer unit (1) and/or (2): wherein amount of monomer unit (1) is less than 40 mol% based on whole monomer unit of polyester, and 10-250 parts by weight of galss fibre with ellipse cross section which the ratio of average long axis and minor axis is 1.5-6.0, and the length of the long axis is 10-40 mum. The LCP composition of this invention can provide molding with less buckling and high tenacity.

Description

  The present invention relates to a liquid crystal polyester resin composition that is excellent in mechanical properties, has little warpage, and hardly generates blisters.

  Thermotropic liquid crystalline polyester resin (hereinafter abbreviated as liquid crystalline polyester resin or LCP) is excellent in mechanical properties such as heat resistance and rigidity, chemical resistance, dimensional accuracy, etc. The use is expanding to various uses.

  Especially in the field of information and communication such as personal computers and mobile phones, high integration of parts, miniaturization, thinning, and low profile are rapidly progressing, resulting in the formation of very thin parts. There are many cases. Therefore, the amount of LCP used is greatly increased by taking advantage of its excellent moldability, that is, good fluidity and no characteristics of other resins such as no burrs.

  However, in recent years, the lead-free solder has led to higher reflow temperatures in electronic components such as connectors, and even in LCP molded products, the occurrence of blisters called blisters and the warping of molded products It is a problem.

  As a method for improving the problem of blistering and warping under high temperature, the aspect ratio is compared with a wholly aromatic polyester resin containing a large amount of 6-oxy-2-naphthoyl repeating unit of 40 to 75 mol% with respect to all structural units. Is a wholly aromatic polyester with a specific ratio of flat glass fiber having a cross-sectional shape of 1.5 to 4.0 having an elliptical or eyebrows shape and talc having an average particle diameter of 0.5 to 200 μm. Has been proposed (see Patent Document 1).

  However, the liquid crystal polyester resin composition disclosed in Patent Document 1 has problems such as low toughness (impact strength) and insufficient improvement in warpage. In addition, when talc is used as the plate-like filler, blistering is likely to occur due to the crystallization water of talc, and heat deformation temperature (load deflection temperature) and bending strength during high-temperature processing. There is a problem that the mechanical properties such as are deteriorated.

Therefore, development of a liquid crystal polyester resin composition that has excellent mechanical properties, exhibits a high heat distortion temperature, is less warped even when processed at high temperatures, and generates less blisters is desired.
JP 2003-268252 A

  An object of the present invention is to provide a liquid crystal polyester resin composition having excellent mechanical properties, exhibiting a high heat distortion temperature, little warping even when processed at a high temperature, and little blister generation.

The present invention includes a repeating unit represented by the formula [1] and / or a repeating unit represented by the formula [2], and the amount of the repeating unit represented by the formula [1] is all repeating units. Glass fiber having a cross-sectional shape of 100 parts by weight of a liquid crystal polyester resin that is less than 40% by mole, and an elliptical shape with an average ratio of major axis / minor axis of 1.5 to 6.0 and an average major axis diameter of 10 to 40 μm A liquid crystal polyester resin composition obtained by blending 10 to 250 parts by weight.

  The liquid crystalline polyester resin used in the liquid crystalline polyester resin composition of the present invention is a liquid crystalline polyester resin that forms an anisotropic molten phase called a thermotropic liquid crystalline polyester 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.

  The liquid crystalline polyester resin used in the present invention includes a repeating unit represented by the formula [1] and / or a repeating unit represented by the formula [2] and represented by the formula [1]. It is also possible to use a blend of two or more liquid crystal polyester resins whose amount is less than 40 mol% in all repeating units.

  The liquid crystal polyester resin used in the present invention may be either a semi-aromatic liquid crystal polyester resin having an aliphatic group in the molecular chain or a wholly aromatic liquid crystal polyester resin in which the molecular chain is entirely composed of aromatic groups. . Among these liquid crystal polyester resins, it is preferable to use a wholly aromatic liquid crystal polyester resin because of its 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. Can be mentioned

Among these repeating units, the liquid crystalline polyester resin used in the present invention is, as an aromatic oxycarbonyl repeating unit, a 6-oxy-2-naphthoyl repeating unit represented by the formula [1] and / or a formula [2 ] It contains the paraoxybenzoyl repeating unit represented by these essential.

  In the liquid crystal polyester resin used in the present invention, the amount of the repeating unit represented by the formula [1] in all repeating units is 40 mol in order that the obtained liquid crystal polyester resin composition exhibits high toughness (impact strength). %, Preferably 35 mol% or less, particularly preferably 30 mol% or less.

  In the liquid crystalline polyester resin used in the present invention, the amount of the repeating unit represented by the formula [2] in all repeating units is the same as that of the repeating unit represented by the formula [1]. As long as the amount in the unit is less than 40 mol%, it is not particularly limited, but it is preferably 80 mol% or less, and particularly preferably 75 mol% or less.

  Examples of the monomer that gives the repeating unit of the formula [1] include 6-hydroxy-2-naphthoic acid, and examples of the monomer that gives the repeating unit of the formula [2] include parahydroxybenzoic acid. These monomers may be used as ester-forming derivatives such as acylated products, ester derivatives and acid halides.

  When the liquid crystal polyester resin used in the present invention is composed of only the repeating units represented by the formulas [1] and [2], it is represented by the formula [1] in all the repeating units of the liquid crystal polyester resin. The content of the repeating unit is preferably 15 to 30 mol%, particularly preferably 20 to 30 mol%.

  The liquid crystalline polyester resin used in the present invention may contain an aromatic oxycarbonyl repeating unit other than those represented by formulas [1] and [2].

  Specific examples of the monomer that gives an aromatic oxycarbonyl repeating unit other than those represented by formula [1] and formula [2] include, for example, metahydroxybenzoic acid, orthohydroxybenzoic 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, alkyl, alkoxy or halogen substituents thereof, And alkyl, alkoxy or halogen substitutions of 6-hydroxy-2-naphthoic acid and parahydroxybenzoic acid. These monomers may be used as ester-forming derivatives such as acylated products, ester derivatives and acid halides.

  In the present invention, preferred wholly aromatic liquid crystal polyester resins include the repeating unit represented by the formula [1] and / or the repeating unit represented by the formula [2], and the aromatic dicarbonyl repeating unit and the aromatic dioxy. It consists of repeating units.

  Further preferred wholly aromatic liquid crystal polyester resin, the total amount of the repeating unit represented by the formula [1] and the repeating unit represented by the formula [2] is 50 to 90 mol% in all repeating units, and The content of the aromatic dioxy repeating unit and the aromatic dicarbonyl repeating unit is substantially equimolar.

  When the liquid crystal polyester resin used in the present invention as described above contains an aromatic dicarbonyl repeating unit and an aromatic dioxy repeating unit, the content of both repeating units in all the repeating units of the liquid crystal polyester resin is It is preferably substantially equimolar.

  Here, the content of the aromatic dicarbonyl repeating unit and the aromatic dioxy repeating unit is substantially equimolar means that the ratio (mol%) of both repeating units in the liquid crystal polyester resin is 95 /%. It means 100-100 / 95.

  In the liquid crystal polyester resin used in the present invention, specific examples of the monomer giving the aromatic dicarbonyl repeating unit include, for example, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2 , 7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, aromatic dicarboxylic acid such as 4,4′-dicarboxybiphenyl, alkyl, alkoxy or halogen-substituted products thereof, ester derivatives thereof, acid halides, etc. The ester-forming derivatives of 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.

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

  In the liquid crystal polyester resin used in the present invention, specific examples of the monomer giving an aromatic oxydicarbonyl repeating unit include, for example, 3-hydroxy-2,7-naphthalenedicarboxylic acid, 4-hydroxyisophthalic acid, and 5-hydroxy Examples thereof include hydroxyaromatic dicarboxylic acids such as isophthalic acid, alkyl, alkoxy or halogen-substituted products thereof, and ester-forming derivatives thereof such as acylated products, ester derivatives, and acid halides.

  In the liquid crystal polyester resin used in the present invention, specific examples of the monomer that gives an aliphatic dioxy repeating unit include aliphatic diols such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and the like. Of the acylated product. 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.

  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 hydroxy aromatic amines, aromatic diamines, aromatic amino carboxylic acids, mercapto aromatic carboxylic acids, and aromatic dithiols and hydroxy aromatic thiols. 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.

  Depending on the monomer composition and composition ratio, and the sequence distribution of each repeating unit in the polymer, some liquid crystal polyester resins that combine these repeating units may or may not form an anisotropic melt phase. The liquid crystalline polyester resin used in the invention is limited to those forming an anisotropic molten phase.

Specific examples of preferable liquid crystal polyester resins used in the present invention include those composed of the following monomer structural units.
1) 4-hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid copolymer 2) 4-hydroxybenzoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl copolymer 3) 4-hydroxybenzoic acid / terephthalic acid / Isophthalic acid / 4,4'-dihydroxybiphenyl copolymer 4) 4-hydroxybenzoic acid / terephthalic acid / isophthalic acid / 4,4'-dihydroxybiphenyl / hydroquinone copolymer 5) 4-hydroxybenzoic acid / terephthalic acid / Hydroquinone copolymer 6) 2-hydroxy-6-naphthoic acid / terephthalic acid / hydroquinone copolymer 7) 4-hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl Copolymer 8) 2-hydroxy-6-naphthoic acid / terephthalic acid / 4,4'-dihydroxybi Phenyl copolymer 9) 4-hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / hydroquinone copolymer 10) 4-hydroxybenzoic acid / 2,6-naphthalenedicarboxylic acid / 4,4'-dihydroxy Biphenyl copolymer 11) 4-hydroxybenzoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer 12) 4-hydroxybenzoic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer 13) 4 -Hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer 14) 4-hydroxybenzoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone / 4,4 '-Dihydroxybiphenyl copolymer 15) 4-hydroxybenzoic acid / tere Taric acid / ethylene glycol copolymer 16) 4-hydroxybenzoic acid / terephthalic acid / 4,4′-dihydroxybiphenyl / ethylene glycol copolymer 17) 4-hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalate Acid / ethylene glycol copolymer 18) 4-hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl / ethylene glycol copolymer 19) 4-hydroxybenzoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / 4,4′-dihydroxybiphenyl copolymer.

  In these, since it is excellent in heat resistance and mechanical property etc., it is preferable to use the copolymer selected from said 1), 13), or 19) as liquid crystal polyester resin.

  The crystal melting temperature (Tm) measured by a differential operation calorimeter of the liquid crystal polyester resin used in the present invention is not particularly limited, but is preferably 320 to 380 ° C., and preferably 325 to 380 ° C. from the viewpoint of heat resistance. More preferably, it is 330-380 degreeC.

The crystal melting temperature (Tm) is measured by the method described below.
<Method for measuring crystal melting temperature>
Exstar 6000 manufactured by Seiko Instruments Inc. is used as a differential scanning calorimeter. After measuring the endothermic peak temperature (Tm1) observed when a sample of liquid crystal polyester resin is measured at room temperature to 20 ° C./min, the sample is held at a temperature 20 to 50 ° C. higher than Tm1 for 10 minutes. Next, the sample was cooled to room temperature under a temperature lowering condition of 20 ° C./min, and an endothermic peak when measured again under a temperature rising condition of 20 ° C./min was observed, and the temperature showing the peak top of the liquid crystal polyester resin was observed. The crystal melting temperature (Tm) is used.

  Moreover, it is preferable that the load deflection temperature measured based on ASTM D648 of the liquid crystal polyester resin used for this invention is 270-340 degreeC, It is more preferable that it is 280-340 degreeC, It is 290-340 degreeC. Most preferably.

The load deflection temperature is measured by the method described below.
<Load deflection temperature measurement method>
A strip-shaped test piece having a length of 127 mm, a width of 12.7 mm, and a thickness of 3.2 mm was molded using an injection molding machine (UH1000-110 manufactured by Nissei Plastic Industry Co., Ltd.), and this was used to comply with ASTM D648. , Measured at a load of 1.82 MPa and a heating rate of 2 ° C./min.

  Further, the melt viscosity of the liquid crystalline polyester resin used in the present invention, as measured by a capillary rheometer, is preferably 10 to 100 Pa · s, more preferably 10 to 80 Pa · s, and 10 to 60 Pa · s. Most preferably.

The melt viscosity is measured by the method described below.
<Measuring method of melt viscosity>
Using a melt viscosity measuring apparatus (Capillograph 1D manufactured by Toyo Seiki Co., Ltd.), the viscosity at a shear rate of 10 ³ s ⁻¹ with a 0.7 mmφ × 10 mm capillary under the temperature condition of crystal melting temperature (Tm) + 30 ° C. Measure and use as melt viscosity.

Hereinafter, the manufacturing method of the liquid crystalline polyester resin used for this invention is demonstrated.
The production method of the liquid crystal polyester resin used in the present invention is not particularly limited, and a known polycondensation method for forming an ester bond comprising a combination of the above monomers, such as a melt acidolysis method or a slurry polymerization method, can be used. .

  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 any of the melt acidification method and the slurry polymerization method, the polymerizable monomer component used in producing the liquid crystal polyester is a modified form in which hydroxyl groups and / or amino groups are acylated at room temperature, that is, lower It can also be subjected to the reaction as an acylated product. 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 in the reaction.

  The monomer acylated product may be separately acylated and synthesized in advance, or it may be generated 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. You can also.

  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 organotin compounds such as dialkyltin oxide (eg dibutyltin oxide) and diaryltin oxide; organotitanium compounds such as titanium dioxide, antimony trioxide, alkoxytitanium silicate and titanium alkoxide; alkali or alkali of carboxylic acid Examples include earth metal salts (for example, potassium acetate); inorganic acid salts (for example, potassium sulfate); Lewis acid (for example, boron trifluoride); gaseous acid catalysts such as hydrogen halide (for example, hydrogen chloride).

  The ratio of the catalyst used is usually 10 to 1000 ppm, preferably 20 to 300 ppm, based on the total amount of monomers.

  The liquid crystal polyester resin obtained by the polycondensation reaction in this manner is extracted from the polymerization reaction tank in a molten state, and then processed into pellets, flakes, or powders.

  The liquid crystal polyester resin in the form of pellets, flakes, or powders may be heat-treated in a substantially solid state under reduced pressure or in an inert gas atmosphere for the purpose of increasing molecular weight and improving heat resistance. .

  The temperature of the heat treatment performed in the solid phase is not particularly limited as long as the liquid crystalline polyester resin is not melted, but it is preferably 260 to 350 ° C, preferably 280 to 320 ° C.

  The pellet-like, flake-like, or powder-like liquid crystal polyester resin obtained in this way is then used with a Banbury mixer, kneader, uniaxial or biaxial extruder, etc. It is melt-kneaded to obtain the liquid crystal polyester resin composition of the present invention.

  It is preferable that the melt-kneaded liquid crystal polyester resin composition is cut into a strand shape and formed into a pellet shape.

  In the present invention, the blending amount of the glass fiber having an elliptical cross-sectional shape is preferably 10 to 250 parts by weight, particularly preferably 15 to 100 parts by weight with respect to 100 parts by weight of the liquid crystal polyester resin. Most preferred is 25 to 70 parts by weight.

  In the present invention, glass fibers having an elliptical cross-sectional shape are those having an average ratio of major axis / minor axis of the cross section of 1.5 to 6.0, more preferably 3.0 to 5.5.

  The glass fiber having an elliptical cross-sectional shape has an average diameter of 10 to 40 μm, more preferably 12 to 35 μm, and most preferably 15 to 30 μm.

  The glass fiber having an elliptical cross-sectional shape may have an average fiber length in the composition of 20 to 500 μm, more preferably 150 to 400 μm, and most preferably 200 to 350 μm.

The average fiber length of the glass fibers in the composition is measured as follows.
<Glass fiber length measurement method>
A liquid crystal polyester resin composition in which liquid crystal polyester resin and glass fiber having an elliptical cross-sectional shape are melt-kneaded (may contain other fillers as long as the object of the present invention is not impaired) is completely ashed. The remaining glass fiber is completely stirred and dispersed in a mixed solution of pure water and a surfactant. The mixed solution is taken out into a 1 ml glass plate, and the glass fibers are observed with a microscope (Olympus Co., Ltd., BX60). The obtained image is taken into an image analysis software (manufactured by MITANI Corporation, Win Roof), and the glass fiber length is measured.

  In the present invention, the fact that the cross-sectional shape of the glass fiber is an elliptical shape does not only indicate that it is a geometrical elliptical shape. Anything that is recognized to be similar to an elliptical shape (for example, a rectangle with rounded corners) may be used.

  The liquid crystalline polyester resin composition of the present invention may be blended with an inorganic filler and / or an organic filler other than glass fibers having an elliptical cross-section within a range that does not impair the object of the present invention.

  Examples of the inorganic filler and / or organic filler that may be blended in the liquid crystal polyester resin of the present invention include glass fibers having a circular cross section, silica alumina fibers, alumina fibers, aramid fibers, mica, silica, graphite, One or more selected from the group consisting of wollastonite, glass beads, calcium carbonate, barium sulfate, and titanium oxide can be mentioned, except for plate-like ones. Among these, it is preferable to use glass fibers having a circular cross section from the viewpoint of excellent balance between physical properties and cost.

  In the liquid crystal polymer composition of the present invention, the blending amount of the inorganic filler and / or organic filler other than the glass fiber having an elliptical cross-sectional shape varies depending on the type of filler, but typically the liquid crystal polyester resin 100 The total amount of the glass fiber having an elliptical cross section is preferably 10 to 250 parts by weight with respect to parts by weight.

  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. Here, the higher fatty acid means one having 10 to 25 carbon atoms.

  Moreover, you may mix | blend another resin component with the liquid-crystal polyester resin composition of this invention in the range which does not impair the objective of this invention. Examples of other resin components include polyamide, polyester, polyacetal, polyphenylene ether, and modified products thereof, and thermoplastic resins such as polysulfone, polyethersulfone, polyetherimide, and polyamideimide, phenol resin, epoxy resin, and polyimide resin. And other thermosetting resins. 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, and may be appropriately determined according to the use and purpose of the liquid crystal polyester resin composition. 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 0.1 to 100 parts by weight, particularly 0.1 to 80 parts by weight.

  The liquid crystal polyester resin composition of the present invention thus obtained has a warp amount of 6.5 mm or less, preferably 6.0 mm, for example, by a warp test method described below using a disk-shaped test piece. In the following, particularly preferably, the amount of warpage is as small as 5.5 mm or less.

<Measurement method of warpage>
A disk-shaped test piece having a thickness of 1.0 mm and a diameter of 100 mm is prepared using an injection molding machine (manufactured by Nissei Plastic Co., Ltd., UH-1000-110). The test piece was allowed to stand at 23 ° C. and a relative humidity of 50% for 24 hours, and then, using a height gauge (manufactured by Mitutoyo Corporation, HDM-30) on the surface plate, Measure the distance and use it as the amount of warpage.

  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.

  In particular, the liquid crystalline polyester resin composition of the present invention is excellent in fluidity at the time of molding, and does not easily warp or blister even at high temperatures, so it is processed at high temperatures such as reflow, switches, relays, connectors, chips, It is suitably used as a molding material for optical pickups, inverter transformers, coil bobbins and the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

First, synthesis examples of liquid crystal polyester resins used in Examples and Comparative Examples will be described.
Hereinafter, the abbreviations in the synthesis examples represent the following compounds.
[Monomers used in the synthesis of liquid crystal polyester resin]
BON6: 6-hydroxy-2-naphthoic acid POB: parahydroxybenzoic acid HQ: hydroquinone BP: 4,4'-dihydroxybiphenyl TPA: terephthalic acid NDA: 2,6-naphthalenedicarboxylic acid

[Synthesis Example 1]

  POB: 628.4 g (4.55 mol), BON 6: 24.5 g (0.13 mol), HQ: 100.2 g (0.91 mol), NDA: 196.7 g (0.91 mol) and acetic anhydride : 684.9 g (6.71 mol) was charged into a 2 L glass reactor equipped with a stirring blade and a heat exchanger, and the temperature was raised from room temperature to 145 ° C. over 1 hour in a nitrogen gas atmosphere. Hold at temperature for 1 hour.

  Thereafter, the temperature was raised to 345 ° C. over 7 hours while acetic acid by-produced was distilled off. After carrying out the polymerization reaction at the same temperature for 30 minutes, the pressure was reduced to atmospheric pressure to 10 torr over 80 minutes. A predetermined stirring torque was reached when the reaction was further carried out for 1 hour under 10 torr. Therefore, after the reaction vessel was sealed, the reaction vessel was returned to atmospheric pressure with nitrogen gas, and the reaction was terminated. The contents were taken out in the molten state, cooled and pulverized to obtain a flaky polymer.

  The liquid crystal polyester resin had a deflection temperature under load of 275 ° C., a crystal melting temperature of 323 ° C., and a melt viscosity of 42 Pa · s.

[Synthesis Example 2]

POB: 211 kg (1529 mol), BP: 61 kg (328 mol), TPA: 47 kg (284 mol), NDA: 9 kg (44 mol), acetic anhydride 232 kg (2271 mol), and potassium acetate 7 g (0.07 mol) Was charged in a 0.5 m ³ SUS polymerization tank having a stirring blade and a heat exchanger, and the temperature was raised from room temperature to 145 ° C. in a nitrogen gas atmosphere over 2 hours, and kept at the same temperature for 1 hour.

Thereafter, the temperature was raised to 348 ° C. over 7 hours while acetic acid produced as a by-product was distilled off. Polymerization was carried out at the same temperature for 50 minutes, and a predetermined stirring torque was reached, so the system was sealed and the reaction was terminated.
Next, the inside of the polymerization tank was pressurized to 0.1 MPa with nitrogen gas, the valve at the bottom of the polymerization tank was opened, and a prepolymer in the form of a pellet was obtained by drawing it into a strand through a die.

  The crystal melting temperature of the obtained prepolymer measured by a differential scanning calorimeter was 349 ° C.

  After charging 10 kg of this prepolymer pellet into a 40 L tumble dryer at a temperature of 200 ° C. in the tank, the inside of the tank was replaced with nitrogen, and then substantially solid state while rotating at 15 rpm in a nitrogen stream of 120 L / hr. The bath temperature was raised to 300 ° C. over 1 hour, and solid state polymerization was carried out at the same temperature for 7 hours. After completion of the reaction, the inside of the tank was cooled, the rotation was stopped, and the pellets were extracted.

  The deflection temperature under load of this liquid crystal polyester resin was 330 ° C., the crystal melting temperature was 374 ° C., and the melt viscosity was 42 Pa · s.

[Synthesis Example 3]

POB: 248 Kg (1800 mol), BON6: 125 Kg (664 mol), acetic anhydride 259 Kg (2537 mol) were charged into a 0.5 m ³ SUS polymerization tank equipped with a stirring blade and a heat exchanger, and then placed in a nitrogen gas atmosphere. The temperature was raised from room temperature to 145 ° C. over 2 hours and held at the same temperature for 0.5 hours.

  Thereafter, the temperature was raised to 325 ° C. over 6 hours while acetic acid produced as a by-product was distilled off. After performing the polymerization reaction at the same temperature for 30 minutes, the pressure was reduced from atmospheric pressure to 100 torr at the same temperature over 90 minutes. As a result of continuing the polymerization for 10 minutes under 100 torr, a predetermined torque was reached. Therefore, the polymerization tank was sealed, and the inside of the polymerization tank was pressurized to 0.1 MPa with nitrogen gas to complete the reaction. Subsequently, the valve | bulb of the polymerization tank bottom part was opened, the die | dye was pulled out through the die | dye, and the pellet-shaped polymer was obtained.

  The obtained polymer had a crystal melting temperature of 279 ° C. measured by a differential scanning calorimeter, a load deflection temperature of 174 ° C., and a melt viscosity of 22 Pa · s.

[Synthesis Example 4]

  POB: 13.8 g (0.1 mol), BON6: 451.7 g (2.40 mol), BP: 232.7 g (1.25 mol), TPA: 207.6 g (1.25 mol) and acetic anhydride : 529.4 g (5.14 mol) was charged into a 2 L glass reaction vessel having a stirring blade and a heat exchanger, and the temperature was raised from room temperature to 143 ° C. over 1 hour in a nitrogen gas atmosphere. Hold at temperature for 1 hour.

  Thereafter, the temperature was raised to 365 ° C. over 8.5 hours while acetic acid produced as a by-product was distilled off. Thereafter, the pressure was reduced to atmospheric pressure to 10 torr over 60 minutes. When a further stirring and stirring were performed for 0.5 hours under a reduced pressure of 10 torr, a predetermined stirring torque was reached. After sealing the reaction vessel, the reaction vessel was returned to atmospheric pressure with nitrogen gas and the reaction was terminated. The contents were taken out in the molten state, cooled and pulverized to obtain a flaky polymer.

  The liquid crystal polyester resin had a deflection temperature under load of 310 ° C., a crystal melting temperature of 350 ° C., and a melt viscosity of 20 Pa · s.

[Examples 1 to 3, Comparative Examples 1 to 5 , Reference Examples 1 to 3 ]
The physical properties in the examples were measured by the methods described below.
(1) Bending test A test piece was prepared under the molding conditions shown in Table 1, and the bending strength was measured in accordance with ASTM D-790.
(2) Load deflection temperature A test piece was prepared under the molding conditions shown in Table 1 and measured according to the method described above.
(3) Warpage A test piece was prepared under the molding conditions shown in Table 2, and measured according to the method described above.
(4) Izod impact strength A test piece was prepared under the molding conditions shown in Table 3, and the Izod impact strength was measured in accordance with ASTM D-256.
(5) Blister evaluation Whether a test piece of 12.7 mm x 0.8 mm x 127 mm is prepared under the molding conditions shown in Table 4 and heat-treated at a predetermined temperature and time in a gear oven to determine whether or not swelling occurs on the surface Was visually evaluated. The criteria for visual evaluation are described below.
○: No blisters are generated or small blisters are slightly generated.
Δ: Small blisters are generated.
X: Many small blisters occur or large blisters occur.

  The liquid crystal polyester resins obtained in Synthesis Examples 1 to 4 and various fillers were melt kneaded and pelletized at a ratio shown in Table 5 with a twin screw extruder (TEX-30α manufactured by Nippon Steel Works, Ltd.). Using the obtained pellets of the liquid crystal polyester resin composition, various tests were performed by the above methods. The results obtained are shown in Table 6.

○ Glass fiber (elliptical shape): manufactured by Nittobo Co., Ltd., CSG 3PA-820
Average diameter of major axis = 28 μm, ratio of major axis / minor axis = 4
○ Glass fiber (circular shape): Nitto Boseki Co., Ltd., CS 3J-454S
Average diameter = 10 μm
○ Plate-shaped filler (talc): DS-34 manufactured by Fuji Talc Co., Ltd.
Average particle size = 30 μm

Table 6 shows a comparison between a system using elliptical glass fibers and a system using circular glass fibers (for example, Example 1 and Comparative Example 1, Reference Example 1 and Comparative Example 3). Comparison) shows that when glass fibers having an elliptical cross-sectional shape are used, the amount of warpage is extremely small and high toughness (Izod impact strength) is exhibited.

  Further, in the system (Comparative Example 2) in which talc is blended as a plate-like filler in addition to the glass fiber having an elliptical cross-sectional shape, the warping amount is low, but the load deflection temperature and bending strength are large and low. It can be seen that there is a problem in downsizing strength and that blisters are also likely to occur.

Further, when a liquid crystal polyester resin containing a large amount of the repeating unit represented by the formula [1] (that is, 6-oxy-2-naphthoyl repeating unit) is 48 mol% and a glass fiber having an elliptical cross-sectional shape (comparison) In Example 5), it is understood that the warpage amount is high and the toughness is extremely low.

Claims (11)

The repeating unit represented by the formula [1] and the repeating unit represented by the formula [2], and the amount of the repeating unit represented by the formula [1] is 2 mol% or more in all repeating units. 10 parts of a glass fiber having an elliptical shape with an average ratio of major axis / minor axis of 1.5 to 6.0 and an average diameter of major axis of 10 to 40 μm is added to 100 parts by weight of liquid crystal polyester resin of less than mol%. -250 weight part liquid crystal polyester resin composition formed by mixing , provided that the liquid crystal polyester resin composition does not contain a plate-like filler.

Of the liquid crystalline polyester resin composition, cross-section is the average fiber length of glass fiber 150~400μm an elliptical shape, a liquid crystal polyester resin composition according to claim 1. The liquid crystal polyester resin composition according to claim 1 or 2 , wherein an average ratio of major axis / minor axis of the glass fiber having an elliptical cross-sectional shape is 3.0 to 5.5. LCP is a wholly aromatic liquid crystal polyester resin, liquid crystal polyester resin composition according to claim 1 or et 3. The wholly aromatic liquid crystal polyester resin is composed only of the repeating unit represented by the formula [1] and the repeating unit represented by the formula [2], and among all the repeating units, the repeating unit represented by the formula [1] is 15 The liquid crystal polyester resin composition according to claim 4 , which is ˜30 mol%. The wholly aromatic liquid crystal polyester resin is composed of a repeating unit represented by the formula [1], a repeating unit represented by the formula [2], an aromatic dicarbonyl repeating unit and an aromatic dioxy repeating unit. The liquid crystal polyester resin composition according to claim 4 . The total amount of the repeating unit represented by the formula [1] and the repeating unit represented by the formula [2] is 50 to 90 mol% in all repeating units, and the aromatic dioxy repeating unit and the aromatic dicarbonyl The liquid crystal polyester resin composition according to claim 6 , wherein the content of the repeating unit is substantially equimolar. Further, with respect to 100 parts by weight of the liquid crystalline polyester resin, glass fiber having a circular cross section, silica alumina fiber, alumina fiber, aramid fiber, mica, silica, graphite, wollastonite, glass beads, calcium carbonate, barium sulfate, and Selected from the group consisting of titanium oxide, except that one or more organic or inorganic fillers, excluding plate-like ones, are 10 to 250 parts by weight in total with glass fibers having an elliptical cross section. The liquid crystal polyester resin composition according to any one of claims 1 to 7 , which is blended. The amount of warpage after a disc-shaped test piece having a thickness of 1.0 mm and a diameter of 100 mm obtained by molding the liquid crystalline polyester resin composition was allowed to stand for 24 hours at 23 ° C. and a relative humidity of 50% was 5 The liquid crystal polyester resin composition according to any one of claims 1 to 7 , which is 0.5 mm or less. Claim 1-9 molded into a molded article obtained liquid crystal polyester resin composition according to any one of. The molded article according to claim 10 , wherein the molded article is selected from a switch, a relay, a connector, a chip, an optical pickup, an inverter transformer, and a coil bobbin.