JP2023155573A - Liquid crystal polyester resin composition and method of manufacturing same and molded article made from same - Google Patents

Abstract

To provide a liquid crystalline polyester resin composition having excellent flow stability and low anisotropy, and a molded article made from the same.SOLUTION: The liquid crystal polyester resin composition is provided, including liquid crystal polyester resin (A), a plate-like filler (B), and a fibrous filler (C), wherein the particle diameter of the filler in the liquid crystal polyester resin composition satisfies the following formula (R) in a particle diameter distribution curve obtained from the relationship between frequency (unit%, vertical axis) and particle diameter (unit μm, horizontal axis, common logarithm). 0.70≤(P/Q)≤1.20 (R) (P is a particle size distribution curve from the highest point corresponding to the mode diameter to the maximum value of the particle size in the particle size distribution curve, and an area of a portion surrounded by a line parallel to the horizontal axis corresponding to a frequency of 0.15% and a perpendicular line from the highest point corresponding to the mode diameter to the horizontal axis.) Q is an area of a portion surrounded by a particle diameter distribution curve from the highest point to the minimum value of the particle diameter, a line parallel to the horizontal axis corresponding to a frequency of 0.15%, and a perpendicular line from the highest point to the horizontal axis.SELECTED DRAWING: Figure 1

Description

The present invention relates to a liquid crystal polyester resin composition, a method for producing the same, and a molded article made from the same. More specifically, the present invention relates to a liquid crystal polyester resin composition, a method for producing the same, and a molded article made from the same.

Liquid crystal polyester resin has excellent heat resistance and is used in a wide range of fields that require these properties, such as electrical and electronic parts and automobile parts. In particular, in electrical and electronic component applications, high rigidity is required as components become smaller and thinner, and liquid crystal polyester resin compositions containing fibrous fillers have been proposed. However, when only a fibrous filler is contained, warping occurs in the product due to residual pressure due to molding shrinkage due to orientation and deterioration of fluidity. Therefore, liquid crystal polyester resin compositions that use both fibrous fillers and plate-like fillers have been proposed. For example, liquid crystal polyester resin compositions containing plate-like fillers with defined particle diameters and particle thicknesses (for example Patent Document 1), a liquid crystalline polyester resin composition containing mica that defines the cumulative degree in a volume cumulative particle size distribution curve (for example, Patent Document 2), and a liquid crystal polyester resin composition containing mica that defines the degree of accumulation in a volume cumulative particle size distribution curve, and a method for determining the volume average particle diameter and median diameter measured by cumulative particle size distribution measurement. A liquid crystal polyester resin composition containing mica with a specified ratio (for example, Patent Document 3), the ratio of the cumulative degree 80% fiber length (D80) and the cumulative degree 20% fiber length (D20) obtained from the cumulative particle size distribution curve is A liquid crystal polyester resin composition containing a specified fibrous filler (for example, Patent Document 4), a liquid crystal polyester resin composition containing a scale-like filler and a fibrous filler (for example, Patent Document 5), etc. Liquid crystalline polyester resin compositions that have both rigidity and low warpage have been proposed.

Japanese Patent Application Publication No. 2001-106923 International Publication No. 2012/137271 International Publication No. 2013/128887 JP2009-191088A Japanese Patent Application Publication No. 2003-321598

However, although the liquid crystalline polyester resin compositions described in Patent Documents 1 to 5 have improved rigidity and warpage resistance to some extent, there was a problem in flow stability due to uneven filling of thin-walled molded products during continuous molding. In addition, since liquid crystal polyester resin has a rigid molecular structure that is difficult to bend, it can be oriented in the MD direction (flow direction) due to slight shear stress due to less entanglement of molecules, and the MD/TD (flow direction/perpendicular direction) Due to the difference in strength, there was a problem of large anisotropy.

An object of the present invention is to provide a liquid crystal polyester resin composition that has excellent flow stability and low anisotropy, a method for producing the same, and a molded article made from the same.

As a result of intensive studies to solve the above problems, the present inventors have developed a liquid crystal polyester resin composition containing a liquid crystal polyester resin and a filler having a specific particle size distribution, which has excellent flow stability and low anisotropy. The inventors have discovered that it is possible to obtain a molded article with excellent properties, and have arrived at the present invention.

That is, the present invention has been made to solve at least part of the above-mentioned problems, and can be realized as the following forms.

That is, the present invention is as follows:
(1) A liquid crystal polyester resin composition containing a liquid crystal polyester resin (A) and a filler including a plate-like filler (B) and a fibrous filler (C), the filling in the liquid crystal polyester resin composition A liquid crystal polyester resin composition obtained from a particle size distribution curve of a material, and in which P and Q defined below satisfy formula (R).
0.70≦(P/Q)≦1.20...(R)
(In the particle size distribution curve obtained by plotting the particle size of the filler in the liquid crystal polyester resin composition, the horizontal axis is the particle size (μm, common logarithm display) and the vertical axis is the frequency (%), the particle size distribution Particle size distribution curve from the highest point corresponding to the mode diameter on the curve to the maximum particle size, a line parallel to the horizontal axis corresponding to a frequency of 0.15%, drawn down from the highest point corresponding to the mode diameter to the horizontal axis The area surrounded by the perpendicular line is P, the particle size distribution curve from the highest point corresponding to the mode diameter on the particle size distribution curve to the minimum particle size, parallel to the horizontal axis corresponding to the frequency of 0.15%. Let Q be the area surrounded by the perpendicular line drawn from the highest point corresponding to the mode diameter to the horizontal axis.)
(2) The liquid crystal polyester resin composition according to (1), wherein the liquid crystal polyester resin (A) is a liquid crystal polyester resin containing the following structural units (I) to (VI).

(3) The liquid crystal polyester resin composition according to (1) or (2), wherein the plate-shaped filler (B) is one or more selected from the group consisting of talc and mica.
(4) Liquid crystal obtained by melt-kneading a liquid crystal polyester resin composition containing a liquid crystal polyester resin (A) and a filler including a plate-like filler (B) and a fibrous filler (C) using a twin-screw extruder. A method for producing a polyester resin composition, wherein the median diameter (S (μm)) of a plate-like filler (B) before blending and the number average fiber length (T (mm)) of a fibrous filler (C) before blending )) satisfies formula (U), the total screw length of the twin-screw extruder is set to A method for producing a characteristic liquid crystal polyester resin composition.
1.0≦(T/S)≦30.0...(U)
(5) A molded article made of the liquid crystal polyester resin composition according to any one of (1) to (3).
(6) The molded product according to (5), wherein the molded product is selected from the group consisting of a connector, a relay, a switch, a coil bobbin, and an actuator component of a camera module.

Since the liquid crystal polyester resin composition of the present invention has excellent flow stability and low anisotropy, it is possible to obtain a molded product having a thin wall portion with little filling variation and low anisotropy. Such a resin composition is particularly suitable for electrical/electronic parts and mechanical parts, such as connectors, relays, switches, coil bobbins, and actuator parts of camera modules, which have a thin box or cylindrical shape.

It is a schematic diagram showing a particle size distribution curve of a filler in a liquid crystal polyester resin composition.

The present invention will be explained in detail below.

<Liquid crystal polyester resin (A)>
Liquid crystal polyester resins are polyesters that form an anisotropic melt phase. Examples of such polyester resins include polyesters composed of structural units selected from among oxycarbonyl units, dioxy units, dicarbonyl units, etc. described below so as to form an anisotropic melt phase.

In the present invention, liquid crystal polyester resins described below are preferably used from the viewpoint of excellent flow stability and low anisotropy.

The structural units constituting a preferable liquid crystal polyester resin will be explained.
The liquid crystal polyester resin of the present invention has excellent flow stability and from the viewpoint of low anisotropy, the oxycarbonyl unit is derived from the following p-hydroxybenzoic acid based on 100 mol% of the total structural units of the liquid crystal polyester resin. The content of structural unit (I) is preferably 25 mol% or more, more preferably 35 mol% or more, and even more preferably 45 mol% or more.

On the other hand, from the viewpoint of excellent flow stability and low anisotropy, the liquid crystal polyester resin of the present invention contains 75 mol% or less of the structural unit (I) based on 100 mol% of the total structural units of the liquid crystal polyester resin. is preferable, 65 mol% or less is more preferable, and even more preferably 55 mol% or less.

The liquid crystal polyester resin of the present invention has excellent flow stability and from the viewpoint of low anisotropy, the following 6-hydroxy-2-naphthoic acid is added as an oxycarbonyl unit to 100 mol% of the total structural units of the liquid crystal polyester resin. The structural unit (II) derived from is preferably contained in an amount of 1 mol % or more, more preferably 2 mol % or more, and even more preferably 3 mol % or more.

On the other hand, from the viewpoint of excellent flow stability and low anisotropy, the liquid crystal polyester resin of the present invention contains 20 mol% or less of the structural unit (II) based on 100 mol% of the total structural units of the liquid crystal polyester resin. is preferable, 15 mol% or less is more preferable, and even more preferably 10 mol% or less.

The liquid crystalline polyester resin of the present invention has excellent flow stability, and from the viewpoint of low anisotropy, the molar ratio of the content of structural units (I) and (II) ([I]/[II]) is 3 or more. It is preferably 5 or more, more preferably 7 or more. On the other hand, from the viewpoint of excellent flow stability and low anisotropy, [I]/[II] is preferably 20 or less, more preferably 18 or less, and even more preferably 16 or less.

In addition, as the oxycarbonyl unit, a structural unit derived from m-hydroxybenzoic acid or the like can be used within a range that does not impair the effects of the present invention.

The liquid crystalline polyester resin of the present invention has excellent flow stability and is derived from the following 4,4'-dihydroxybiphenyl as a dioxy unit with respect to 100 mol% of the total structural units of the liquid crystalline polyester resin from the viewpoint of low anisotropy. The content of the structural unit (III) is preferably 1 mol % or more, more preferably 3 mol % or more, and even more preferably 5 mol % or more.

On the other hand, from the viewpoint of excellent flow stability and low anisotropy, the structural unit (III) is preferably at most 25 mol%, more preferably at most 20 mol%, and even more preferably at most 15 mol%.

The liquid crystal polyester resin of the present invention has excellent flow stability and from the viewpoint of low anisotropy, the following structural unit (IV) derived from hydroquinone is added as a dioxy unit to 100 mol% of the total structural units of the liquid crystal polyester resin. The content is preferably 1 mol% or more, more preferably 4 mol% or more, and even more preferably 7 mol% or more.

On the other hand, from the viewpoint of excellent flow stability and low anisotropy, the structural unit (IV) is preferably 30 mol% or less, more preferably 25 mol% or less, and even more preferably 20 mol% or less.

The liquid crystal polyester resin of the present invention has excellent flow stability and from the viewpoint of low anisotropy, the total amount of structural units (III) and (IV) is 2 mol per 100 mol% of the total structural units of the liquid crystal polyester resin. % or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, particularly preferably 15 mol% or more.

On the other hand, the liquid crystal polyester resin of the present invention has excellent flow stability and from the viewpoint of low anisotropy, the sum of structural units (III) and (IV) is It is preferably 35 mol% or less, more preferably 30 mol% or less, and even more preferably 25 mol% or less.

The liquid crystalline polyester resin of the present invention has excellent flow stability, and from the viewpoint of low anisotropy, the molar ratio of the content of structural units (III) and (IV) ([III]/[IV]) is less than 0. It is preferably large, more preferably 0.3 or more, and even more preferably 0.6 or more. On the other hand, from the viewpoint of excellent flow stability and low anisotropy, [III]/[IV] is preferably smaller than 1.5, more preferably 1.2 or less, and even more preferably 1.0 or less.

Other dioxy units include resorcinol, t-butylhydroquinone, phenylhydroquinone, chlorohydroquinone, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 3,4'-dihydroxybiphenyl, 2,2-bis(4- Structural units derived from aromatic diols such as hydroxyphenyl)propane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, and 4,4'-dihydroxybenzophenone; ethylene Structural units derived from aliphatic diols such as glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol; fats such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol Structural units derived from cyclic diols can be used within a range that does not impair the effects of the present invention.

The liquid crystal polyester resin of the present invention has excellent flow stability and from the viewpoint of low anisotropy, the following structural unit derived from terephthalic acid ( The content of V) is preferably 2 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, and particularly preferably 15 mol% or more.

On the other hand, from the viewpoint of excellent flow stability and low anisotropy, the liquid crystal polyester resin of the present invention contains 35 mol% or less of the structural unit (V) based on 100 mol% of the total structural units of the liquid crystal polyester resin. is preferable, 30 mol% or less is more preferable, and even more preferably 25 mol% or less.

The liquid crystal polyester resin of the present invention has excellent flow stability and from the viewpoint of low anisotropy, the following structural unit derived from isophthalic acid ( VI) is preferably contained in an amount of 0.01 mol% or more, more preferably 0.05 mol% or more, and even more preferably 0.1 mol% or more.

On the other hand, from the viewpoint of excellent flow stability and low anisotropy, the liquid crystal polyester resin of the present invention contains 10 mol% or less of the structural unit (VI) based on 100 mol% of the total structural units of the liquid crystal polyester resin. is preferable, 7 mol% or less is more preferable, and even more preferably 4 mol% or less.

In addition, as dicarbonyl units, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 3,3'-diphenyldicarboxylic acid, 2,2'-diphenyldicarboxylic acid, 1,2-bis(phenoxy ) Structures derived from aromatic dicarboxylic acids such as ethane-4,4'-dicarboxylic acid, 1,2-bis(2-chlorophenoxy)ethane-4,4'-dicarboxylic acid, and 4,4'-diphenyl ether dicarboxylic acid. Units: Structural units derived from aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and hexahydroterephthalic acid; Alicyclic units such as 1,4-cyclohexanedicarboxylic acid and 1,3-cyclohexanedicarboxylic acid Structural units derived from the formula dicarboxylic acid can be used within the range that does not impair the effects of the present invention.

The liquid crystal polyester resin of the present invention has excellent flow stability and has a molar ratio of the content of structural units (VI) and (II) ([VI]/[II]) of less than 1 from the viewpoint of low anisotropy. It is preferably 0.9 or less, and more preferably 0.9 or less. On the other hand, the lower limit of [VI]/[II] is not particularly limited, and may be 0.005 or more. From the viewpoint of excellent flow stability and low anisotropy, [VI]/[II] is preferably 0.01 or more, more preferably 0.05 or more.

In addition to the above structural units (I) to (VI), structural units produced from p-aminobenzoic acid, p-aminophenol, etc. may be used in the liquid crystal polyester resin to the extent that the effects of the present invention are not impaired. can do.

The liquid crystalline polyester resin of the present invention exhibits the effects of the present invention, such as excellent flow stability and low anisotropy, by containing all of the structural units (I) to (VI) in the above-mentioned ranges. From the viewpoint of not impairing the effects of the present invention, the total amount of the structural units (I) to (VI) is preferably 99 mol% or more, more preferably 99.5 mol% or more, and even more preferably 100 mol%. .

Further, the ratio of the total amount of structural units (III) and (IV) to the total amount of structural units (V) and (VI) (([III] + [IV])/([V] + [VI] ) is preferably 0.9 or more and 1.1 or less from the viewpoint of polymerization control.

The monomers serving as raw materials constituting each of the above-mentioned structural units are not particularly limited as long as they have a structure that can form each structural unit. In addition, carboxylic acid derivatives such as acylated products of hydroxyl groups, esterified products of carboxyl groups, acid halides, and acid anhydrides of such monomers may also be used.

The method for calculating the content of each structural unit in the liquid crystal polyester resin of the present invention is shown below. First, liquid crystal polyester resin is weighed into an NMR (nuclear magnetic resonance) test tube and dissolved in a solvent in which the liquid crystal polyester resin is soluble (for example, pentafluorophenol/deutetrachloroethane-d2 mixed solvent). Next, the obtained solution is subjected to 1H-NMR spectrum measurement, and calculation can be made from the peak area ratio derived from each structural unit.

From the viewpoint of heat resistance, the melting point (Tm) of the liquid crystal polyester resin is preferably 280°C or higher, more preferably 300°C or higher, and even more preferably 320°C or higher. On the other hand, from the viewpoint of processability, the melting point (Tm) of the liquid crystal polyester resin is preferably 370°C or lower, more preferably 360°C or lower, and even more preferably 350°C or lower.

From the viewpoint of heat resistance, the melt viscosity of the liquid crystal polyester resin is preferably 3 Pa·s or more, more preferably 5 Pa·s or more, and even more preferably 7 Pa·s or more. On the other hand, from the viewpoint of fluidity, the melt viscosity of the liquid crystal polyester resin is preferably 50 Pa·s or less, preferably 30 Pa·s or less, and more preferably 20 Pa·s or less.

The melt viscosity is a value measured using a Koka type flow tester at a temperature of +20° C. to the melting point (Tm) of the liquid crystal polyester resin and at a shear rate of 1000/sec.

<Method for manufacturing liquid crystal polyester resin>
The method for producing the liquid crystal polyester resin of the present invention is not particularly limited, and can be produced according to known polyester polycondensation methods. Specifically, the following may be mentioned, taking as an example a liquid crystal polyester resin consisting of structural units derived from oxycarbonyl units, dioxy units, and dicarbonyl units.

(1) Liquid crystalline polyester resin produced by deacetic acid condensation reaction from p-acetoxybenzoic acid, 6-acetoxy-2-naphthoic acid, 4,4'-diacetoxybiphenyl, 1,4-diacetoxybenzene, terephthalic acid and isophthalic acid. How to manufacture.

(2) After reacting p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 4,4'-dihydroxybiphenyl, hydroquinone, terephthalic acid, and isophthalic acid with acetic anhydride to acetylate the phenolic hydroxyl group, A method for producing liquid crystalline polyester resin by deacetic acid polymerization.

(3) Producing liquid crystalline polyester resin from p-hydroxybenzoate, phenyl 6-hydroxy-2-naphthoate, 4,4'-dihydroxybiphenyl, hydroquinone, diphenyl terephthalate, and diphenyl isophthalate by dephenolization polycondensation reaction. Method.

(4) After reacting p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, terephthalic acid, and isophthalic acid with a predetermined amount of diphenyl carbonate to form phenyl esters, 4,4'-dihydroxybiphenyl and hydroquinone are produced. A method of producing liquid crystalline polyester resin by adding phenol and dephenol polycondensation reaction.

Among them, (2) p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 4,4'-dihydroxybiphenyl, hydroquinone, terephthalic acid, and isophthalic acid were reacted with acetic anhydride to acetylate the phenolic hydroxyl group. A method of producing a liquid crystal polyester resin by subsequently carrying out acetic acid depolymerization is preferably used because it is industrially superior in controlling the degree of polymerization of the liquid crystal polyester resin.

As a method for producing the liquid crystal polyester resin used in the present invention, it is also possible to complete the polycondensation reaction by solid phase polymerization. Examples of the treatment using the solid phase polymerization method include the following methods. First, a polymer or oligomer of liquid crystal polyester resin is pulverized using a pulverizer. The reaction is completed by heating the pulverized polymer or oligomer under a nitrogen stream or under reduced pressure and polycondensing it to a desired degree of polymerization. The above heating is preferably carried out for 1 to 50 hours at a temperature in the range of -50°C to -5°C (for example, 200 to 300°C), the melting point of the liquid crystal polyester.

The polycondensation reaction of liquid crystal polyester resins proceeds without a catalyst, but stannous acetate, tetrabutyl titanate, potassium acetate and sodium acetate, antimony trioxide, metallic magnesium, etc. can also be used as catalysts.

<Filling material>
The liquid crystal polyester resin composition of the present invention is characterized by containing a filler. From the viewpoint of low anisotropy, the blending amount of the filler is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, based on 100 parts by weight of the liquid crystal polyester. On the other hand, from the viewpoint of improving flow stability, the amount of the filler added is preferably 80 parts by weight or less, more preferably 55 parts by weight or less, based on 100 parts by weight of the liquid crystal polyester.

In the present invention, a plate-like filler (B) and a fibrous filler (C) are used together as fillers.

<Plate-shaped filler (B)>
The liquid crystal polyester resin composition of the present invention is characterized by containing a plate-like filler as a filler. Examples of the plate-like filler for the liquid crystal polyester resin composition of the present invention include mica, talc, kaolin, glass flakes, clay, molybdenum disulfide, and wollastenite. From the viewpoint of excellent flow stability and low anisotropy, mica and talc are preferred.

From the viewpoint of low anisotropy, the blending amount of the plate-like filler in the liquid crystal polyester resin composition of the present invention is preferably 1 part by weight or more, more preferably 5 parts by weight or more, based on 100 parts by weight of the liquid crystal polyester. On the other hand, the blending amount of the plate-shaped filler is preferably 75 parts by weight or less, more preferably 45 parts by weight or less, from the viewpoint of reducing filling variation in the molded product.

The median diameter of the plate-like filler blended into the liquid crystal polyester resin composition of the present invention is preferably 1 μm or more, more preferably 5 μm or more, from the viewpoint of excellent flow stability and low anisotropy. On the other hand, from the viewpoint of excellent flow stability and low anisotropy, the median diameter of the filler in the liquid crystal polyester resin composition is preferably 100 μm or less, more preferably 70 μm or less, and even more preferably 50 μm or less.

The median diameter here can be determined by the following method. 100 mg of the filler was weighed out and dispersed in an ultrasonic cleaner for 10 minutes with 6 g of water and 10 mg of a surfactant to obtain the filler. Thereafter, 100 mg of the filler was weighed and dispersed with 6 g of water and 10 mg of surfactant in an ultrasonic cleaner for 10 minutes. The diameter distribution was measured three times, and the particle diameter at which the cumulative frequency obtained was 50% was defined as the median diameter of the filler.

<Fibrous filler (C)>
The liquid crystal polyester resin composition of the present invention is characterized by containing a fibrous filler as a filler. Examples of fibrous fillers include glass fibers, PAN-based and pitch-based carbon fibers, stainless steel fibers, metal fibers such as aluminum fibers and brass fibers, organic fibers such as aromatic polyamide fibers and polyester fibers, gypsum fibers, ceramic fibers, Asbestos fibers, zirconia fibers, alumina fibers, silica fibers, titanium oxide fibers, silicon carbide fibers, rock wool, potassium titanate whiskers, barium titanate whiskers, aluminum borate whiskers, silicon nitride whiskers, wollastenite, and acicular titanium oxide Examples include. Glass fiber is preferred from the viewpoint of excellent flow stability and low anisotropy. The type of glass fiber is not particularly limited as long as it is generally used for reinforcing resins, and examples include chopped strands and milled fibers of long fiber type and short fiber type.

The surface of the filler may be treated with a known coupling agent (for example, a silane coupling agent, a titanate coupling agent, etc.) or other surface treatment agent. Further, it may be coated or bundled with a thermoplastic resin such as ethylene/vinyl acetate copolymer or a thermosetting resin such as epoxy resin.

From the viewpoint of low anisotropy, the blending amount of the fibrous filler in the liquid crystal polyester resin composition of the present invention is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, based on 100 parts by weight of the liquid crystal polyester. On the other hand, from the viewpoint of improving flow stability, the blending amount of the fibrous filler is preferably 75 parts by weight or less, more preferably 45 parts by weight or less, based on 100 parts by weight of the liquid crystal polyester.

From the viewpoint of excellent flow stability and low anisotropy, the average fiber length of the fibrous filler is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. On the other hand, from the viewpoint of excellent flow stability and low anisotropy, the average fiber length of the fibrous filler to be blended is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 120 μm or less.

The average fiber length of the fibrous filler herein is the number average fiber length, and can be determined by the following method. The average fiber length of the fibrous filler was measured by scattering the fibers on a microscope slide so that they did not overlap, taking a micrograph at a magnification of 800 times, and randomly selecting 500 fibers from the micrograph. The fiber length of more than one fiber was measured, and the number average value was taken as the average fiber length.

<Other fillers>
Further, other fillers may be contained in order to impart mechanical strength and other properties to the liquid crystal polyester resin composition. The filler used in the present invention is not particularly limited, but includes, for example, powdered and granular fillers. Specific examples include silica, glass beads, titanium oxide, zinc oxide, calcium polyphosphate, and graphite.

<Combination of plate-like filler (B) and fibrous filler (C)>
In the present invention, the median diameter of the plate-shaped filler and It is preferable that the number average fiber length of the fibrous filler is a close value, and the median diameter (S (μm)) of the plate-like filler (B) and the fibrous filler (C It is preferable that the number average fiber length (T (mm)) of ) satisfies formula (U).
1.0≦(T/S)≦31.0...(U)

From the viewpoint of excellent flow stability and low anisotropy, the T/S ratio is more preferably 1.5 or more, and even more preferably 2.0 or more. On the other hand, from the viewpoint of excellent flow stability and low anisotropy, the T/S ratio is more preferably 25 or less, and even more preferably 20 or less. Furthermore, in a method of measuring the median diameter and number average fiber length of only a specific filler from a mixture of a plate-like filler and a fibrous filler, it is possible to separate and measure the specific gravity difference. This is used as a filler that requires a median diameter using methylene iodide (specific gravity 3.33), 1,1,2,2-tetrabromoethane (specific gravity 2.970), ethanol (specific gravity 0.789), etc. The mixture is dispersed in a mixed solution that has been appropriately mixed to have a specific gravity of 10,000 rpm, and then centrifuged at a rotation speed of 10,000 rpm for 5 minutes, and then taken out by filtration. Thereafter, 100 mg of the obtained filler is weighed, and the median diameter and number average fiber length of only the specific filler in the composition can be obtained by the method described above.

<Particle size and particle size distribution of filler in resin composition>
The liquid crystal polyester resin composition of the present invention has a specific particle size distribution of the filler in the liquid crystal polyester resin composition by combining an appropriate liquid crystal polyester resin with an appropriate plate-like filler and a fibrous filler. It is possible to obtain a liquid crystalline polyester resin composition with excellent flow stability and low anisotropy.

In the particle size distribution of the filler in the liquid crystal polyester resin composition of the present invention, P and Q defined below satisfy formula (R).
0.70≦(P/Q)≦1.20...(R)

Here, P and Q are the particle diameters obtained by plotting the particle diameter of the filler in the liquid crystal polyester resin composition, with the horizontal axis plotting the particle diameter (μm, expressed in common logarithm) and the vertical axis plotting the frequency (%). In the distribution curve, the particle size distribution curve from the highest point corresponding to the mode diameter on the particle size distribution curve to the maximum particle size, a line parallel to the horizontal axis corresponding to the frequency of 0.15%, and the highest point corresponding to the mode diameter. The area surrounded by the perpendicular line drawn from the high point to the horizontal axis is P, and the particle size distribution curve from the highest point to the minimum particle size corresponds to the mode diameter in the particle size distribution curve, with a frequency of 0.15%. Let Q be the area surrounded by a line parallel to the corresponding horizontal axis and a perpendicular line drawn from the highest point corresponding to the mode diameter to the horizontal axis. The particle size distribution curve and mode diameter can be determined by the following method. The resin component is removed by heating 50 g of the liquid crystal polyester resin composition in air at 550° C. for 3 hours, and the residue remaining as a nonflammable substance is used as a filler in the resin composition. Weighed 100 mg of the obtained filler, dispersed it in an ultrasonic cleaner for 10 minutes with 6 g of water and 10 mg of surfactant, and then dispersed it using a laser diffraction/scattering particle size distribution meter (“MT3300EXII” manufactured by Microtrac). The particle size distribution curve is obtained by measuring the particle size distribution three times and from the relationship between the frequency (unit (%), vertical axis) and particle size (unit (μm), horizontal axis, common logarithm). And so. In addition, the most frequent particle size in the particle size distribution curve was defined as the mode diameter. In addition, in the above measurement, if the frequency is less than 0.15%, it exceeds the measurement ability of the instrument and reliable data cannot be obtained. Therefore, a line parallel to the horizontal axis corresponding to the frequency of 0.15% is drawn to The intersection point with the distribution curve was defined as the minimum particle size value and the maximum particle size value.

The mode diameter of the filler in the liquid crystal polyester resin composition of the present invention is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more, from the viewpoint of excellent flow stability and low anisotropy. On the other hand, from the viewpoint of excellent flow stability and low anisotropy, the mode diameter of the filler in the liquid crystal polyester resin composition is preferably 100 μm or less, more preferably 60 μm or less, and even more preferably 40 μm or less.

FIG. 1 shows a schematic diagram of a particle size distribution curve of a filler in a liquid crystal polyester resin composition obtained by a laser diffraction/scattering particle size distribution meter. The horizontal axis shows the particle size (μm) expressed in common logarithm, and the vertical axis shows the frequency (%) of the filler corresponding to each particle size. In FIG. 1, the area P is the particle size distribution from the mode 2 (mode diameter) of the particle size distribution curve 1 to the maximum particle size point 3, which is the intersection of the particle size distribution curve and the frequency of 0.15%. Curve, area of the part surrounded by a line parallel to the horizontal axis corresponding to the frequency of 0.15% and a perpendicular line drawn from the mode 2 to the horizontal axis (particle size distribution curve from points 2 to 3, frequency of 0.15%) The area surrounded by a line parallel to the horizontal axis and a perpendicular line drawn from point 2 to the horizontal axis at 15% is shown. That is, P is an index indicating the proportion of large particle diameter components in the filler in the liquid crystal polyester resin composition. On the other hand, the area Q is the particle size distribution curve from the mode 2 of the particle size distribution curve 1 to the maximum particle size point 4, which is the intersection of the particle size distribution curve and the frequency of 0.15%. The area surrounded by a line parallel to the horizontal axis corresponding to % and a perpendicular line drawn from the mode 2 to the horizontal axis (particle size distribution curve from points 2 to 4, The area surrounded by the parallel lines and the perpendicular line drawn from point 2 to the horizontal axis is shown. That is, Q is an index indicating the proportion of small particle diameter components in the filler in the liquid crystal polyester resin composition.

The larger the value of the area ratio P/Q, the higher the proportion of fillers with large particle diameters in the fillers in the liquid crystal polyester resin composition. As a general liquid crystal polyester resin composition, for example, when measuring the particle size distribution of a composition containing a plate-like filler and a fibrous filler in a known liquid crystal polyester resin, the area ratio P/Q is 1. The value exceeds .20. This result shows that in the case of known liquid crystal polyester resin compositions, the particle size distribution width becomes wider due to breakage of the filler during melt-kneading, and the larger particle size side, which is the particle size of the filler before melt-kneading, increases. It is thought that this is because a certain amount of the particles remains and the area P on the large particle diameter side increases.

The liquid crystal polyester resin composition of the present invention has a particle size distribution that satisfies the above formula (R). The value of the area ratio P/Q is an index indicating the proportion of large particle size components in the particle size distribution in the liquid crystal polyester resin composition, and the above formula (R) is calculated as follows: This means that the particle size component and the small particle size component are in equal or nearly equal amounts. If the value of P/Q exceeds 1.20, the proportion of large particle diameter components in the filler in the liquid crystal polyester resin composition will increase, flow stability will decrease, and anisotropy will increase. From the viewpoint of excellent flow stability and low anisotropy, the value of P/Q is preferably less than 1.15, more preferably less than 1.10. If the value of P/Q is less than 0.70, the proportion of small particle size components in the filler in the liquid crystal polyester resin composition will increase, flow stability will decrease, and anisotropy will increase. From the viewpoint of excellent flow stability and low anisotropy, the value of P/Q is preferably 0.75 or more, and more preferably 0.80 or more.

The means to set the P/Q value within the above range is to suppress breakage of the filler and prevent the range from widening in the particle size distribution. For example, melt kneading with a twin screw extruder described below In, the median diameter (S, unit (μm)) of the plate-shaped filler (B) to be mixed and the number average fiber length (T, unit (mm)) of the fibrous filler (C) are 1.0≦(T /S)≦30.0, the liquid crystal polyester resin (A) input port is 0.0, and the total length of the screw is 1.0X, which is greater than 0.50X when viewed from the upstream side. The approach of supplying filler material from a location makes it easy to control the value of P/Q. In addition, a method using a liquid crystal polyester resin containing all of the above-mentioned structural units (I) to (VI) and having low shear rate dependence, and a fibrous filler to be blended so that the particle size range does not expand even if it breaks. It is more preferable to combine the methods of selecting the average fiber length within the above-mentioned preferred range.

In addition, the method for measuring the median diameter of plate-shaped fillers and the average fiber length of fibrous fillers in a liquid crystal polyester resin composition containing plate-shaped fillers and fibrous fillers is based on the method of measuring 50 g of the composition. After removing the resin component by heating at 550°C in air for 3 hours, the filler was separated in the same way as when separating the filler before blending, and the median family of the plate-shaped filler before blending was measured. It is possible to measure it by the same method as the measurement of the number average molecular weight of the fibrous filler before blending.

The median diameter of the plate-like filler in the liquid crystal polyester resin composition of the present invention is preferably 1 μm or more, more preferably 5 μm or more, from the viewpoint of excellent flow stability and low anisotropy. On the other hand, from the viewpoint of excellent flow stability and low anisotropy, the median diameter of the filler in the liquid crystal polyester resin composition is preferably 100 μm or less, more preferably 60 μm or less, and even more preferably 40 μm or less.

From the viewpoint of excellent flow stability and low anisotropy, the average fiber length of the fibrous filler in the liquid crystal polyester resin composition is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. On the other hand, from the viewpoint of excellent flow stability and low anisotropy, the average fiber length of the fibrous filler is preferably 110 μm or less, more preferably 90 μm or less, and even more preferably 80 μm or less.

<Other additives>
The liquid crystal polyester resin composition of the present invention may further contain antioxidants, heat stabilizers (for example, hindered phenols, phosphites, thioethers, substituted products thereof, etc.), and ultraviolet absorbers to the extent that the effects of the present invention are not impaired. agents (e.g. resorcinol, salicylates), color inhibitors such as phosphites, hypophosphites, lubricants and mold release agents (montanic acid and its metal salts, its esters, its half esters, stearyl alcohol, stearamide and polyethylene wax, etc.), colorants containing dyes or pigments, carbon black as conductive agents or colorants, crystal nucleating agents, plasticizers, flame retardants (brominated flame retardants, phosphorus flame retardants, red phosphorus, silicone flame retardants, etc.) ), flame retardant aids, and antistatic agents can be included.

<Method for manufacturing liquid crystal polyester resin composition>
The method for producing the liquid crystal polyester resin composition of the present invention is not particularly limited. For example, a dry blend method in which liquid crystal polyester resin (A) is blended with plate-shaped filler (B), fibrous filler (C), and other solid additives, etc. Material (B), solution compounding method of blending other liquid additives etc. with fibrous filler (C), liquid crystal polyester resin (A), plate-shaped filler (B), fibrous filler (C) A method of melt-kneading and other additives can be used, and a method of melt-kneading is particularly preferred. A known method can be used for melt-kneading. For example, using a Banbury mixer, a rubber roll machine, a kneader, a single-screw or twin-screw extruder, or the like, a liquid crystal polyester resin composition can be obtained by melt-kneading at a temperature below the melting point of the liquid crystal polyester +50°C. Among these, a twin screw extruder is preferred.

The kneading method is as follows: 1) A method in which the liquid crystal polyester resin (A), the plate-like filler (B), the fibrous filler (C), and other additives are introduced all at once from a feeder and kneaded (batch kneading). method), 2) After adding the liquid crystal polyester resin (A) and other additives from the original feeder and kneading them, the plate-like filler (B) and the fibrous filler (C) are added from the side feeder. Kneading method (side feed method 1), 3) Liquid crystal polyester resin (A), plate-shaped filler (B) and other additives are introduced from the original feeder and kneaded, then fibrous filler (C) 4) A method of adding and kneading from a side feeder (side feed method 2), 4) After adding liquid crystal polyester resin (A), fibrous filler (C) and other additives from a stock feeder and kneading, There is a method of adding and kneading the plate-shaped filler (B) from a side feeder (side feed method 3). Method 2) is preferable from the viewpoints of being able to control the value of P/Q within the above-mentioned range, having excellent flow stability, and having low anisotropy.

In addition, from the viewpoint of controlling the P/Q value within the above range, excellent flow stability, and low anisotropy, the total length of the screw of the twin screw extruder is set to X, and the liquid crystal polyester resin (A) input port is When it is 0, it is preferable to supply the filler from a position larger than 0.50X. By side-feeding the plate-like filler (B) and the fibrous filler (C), it is possible to suppress breakage of the filler and prevent the distribution of particle diameters from spreading.

<Molded product>
The liquid crystalline polyester resin composition of the present invention can be molded with excellent surface appearance (color tone), mechanical properties, and heat resistance by ordinary molding methods such as injection molding, extrusion molding, press molding, solution casting film formation, and spinning. It is possible to process it into products. The molded products here include injection molded products, extrusion molded products, press molded products, sheets, pipes, various films such as unstretched films, uniaxially stretched films, biaxially stretched films, unstretched yarns, superstretched yarns, etc. Examples include various fibers. Injection molding is particularly preferred from the viewpoint of processability. In the case of melt molding, from the viewpoint of suppressing deterioration of the liquid crystal polyester resin composition and improving mechanical strength, melt molding is preferably carried out at 380°C or lower, more preferably 370°C or lower.

A molded article obtained by molding the liquid crystal polyester resin composition of the present invention can be preferably used as an electric/electronic component. Examples of electrical and electronic components include computers, GPS devices, mobile phones, millimeter wave and sub-millimeter wave radars such as collision prevention radars, and flexible printed circuit boards used in antennas for mobile communication and electronic devices such as tablets and smartphones. , laminated circuit boards, printed wiring boards, and three-dimensional circuit boards; lamp reflectors and lamp sockets for LEDs, communication base station small cells and microcell parts for mobile communication terminals, antenna covers, housings, sensors, and actuators for camera modules. These include parts, connectors, relay cases and bases, switches, coil bobbins, capacitors, etc. In particular, from the viewpoint of excellent flow stability and low anisotropy, it is useful for connectors, relays, switches, coil bobbins, actuator parts of camera modules, etc. that have thin, complex-shaped parts.

Hereinafter, the present invention will be explained using Examples, but the present invention is not limited by the Examples. In the examples, the composition and characteristic evaluation of the liquid crystal polyester resin were measured by the following methods.

(1) Composition analysis of liquid crystal polyester resin Composition analysis of liquid crystal polyester resin was determined by 1H-nuclear magnetic resonance spectrum (1H-NMR) measurement. Weighed 50 mg of liquid crystal polyester resin into an NMR test tube, dissolved it in 800 μL of solvent (pentafluorophenol/1,1,2,2-tetrachloroethane-d2 = 65/35 (weight ratio) mixed solvent), and mixed it with UNITY INOVA500. 1H-NMR measurement was carried out using a type NMR device (manufactured by Varian) at an observation frequency of 500 MHz and a temperature of 80°C, and the composition was analyzed from the peak area ratio derived from each structural unit observed around 7 to 9.5 ppm. did.

(2) Melting point (Tm) measurement of liquid crystal polyester resin Endothermic peak observed when liquid crystal polyester resin is heated from room temperature at 20°C/min using differential scanning calorimeter DSC-7 (manufactured by PerkinElmer) After observing the temperature (Tm ₁ ), it was held at a temperature of Tm ₁ +20°C for 5 minutes, then cooled to room temperature under a temperature decreasing condition of 20°C/min, and then heated again under a temperature increasing condition of 20°C/min. The observed endothermic peak temperature was defined as the melting point (Tm).

[Manufacture example 1]
In a 5 L reaction vessel equipped with a stirring blade and a distillation tube, 776 parts by weight of p-hydroxybenzoic acid (HBA), 66 parts by weight of 6-hydroxy-2-naphthoic acid (HNA), and 4,4'-dihydroxybiphenyl (DHB) were added. ), 168 parts by weight of hydroquinone (HQ), 447 parts by weight of terephthalic acid (TPA), 29 parts by weight of isophthalic acid (IPA) and 1278 parts by weight of acetic anhydride (1.07 equivalents of the total phenolic hydroxyl groups). After reacting at 145°C for 120 minutes with stirring under a nitrogen gas atmosphere, the temperature was raised from 145°C to 360°C over 4 hours. Thereafter, the polymerization temperature was maintained at 360° C., and the pressure was reduced to 1.0 mmHg (133 Pa) over 1.0 hours, and the reaction was further continued, and the polymerization was completed when a predetermined stirring torque was reached. Next, the polymer was discharged in the form of a strand through a nozzle having one circular discharge port with a diameter of 6 mm, and pelletized with a cutter to obtain a liquid crystal polyester resin (A-1).

A compositional analysis of this liquid crystal polyester resin (A-1) revealed that the proportion of structural units derived from p-hydroxybenzoic acid was 48.0 mol%, and the proportion of structural units derived from 6-hydroxy-2-naphthoic acid was 48.0 mol%. 3 mol%, the proportion of structural units derived from 4,4'-dihydroxybiphenyl is 11.5 mol%, the proportion of structural units derived from hydroquinone is 13.0 mol%, and the proportion of structural units derived from terephthalic acid is 23.0 mol%. The proportion of structural units derived from isophthalic acid was 1.5 mol%. The total of the structural units derived from 4,4'-dihydroxybiphenyl and the structural units derived from hydroquinone was 24.5 mol% with respect to 100 mol% of the total structural units of the polyester. Moreover, Tm was 335°C.

[Manufacture example 2]
In a 5L reaction vessel equipped with a stirring blade and a distillation tube, 870 parts by weight of p-hydroxybenzoic acid (HBA), 302 parts by weight of 4,4'-dihydroxybiphenyl (DHB), 119 parts by weight of hydroquinone (HQ), and terephthalic acid were added. (TPA) 247 parts by weight, isophthalic acid (IPA) 202 parts by weight, and acetic anhydride 1302 parts by weight (1.09 equivalents of the total phenolic hydroxyl group) were charged and reacted at 145°C for 1 hour with stirring under a nitrogen gas atmosphere. After that, the jacket temperature was raised from 145°C to 330°C over 4 hours. Thereafter, the polymerization temperature was maintained at 330° C., the pressure was reduced to 1.0 mmHg (133 Pa) in 1.0 hours, and the reaction was further continued, and the polymerization was completed when the torque required for stirring reached 20 kg·cm. Next, the polymer was discharged in the form of a strand through a nozzle having one circular discharge port with a diameter of 6 mm, and pelletized with a cutter to obtain a liquid crystal polyester resin (A-2).

A compositional analysis of this liquid crystal polyester resin (A-2) revealed that the proportion of structural units derived from p-hydroxybenzoic acid was 53.8 mol%, and the proportion of structural units derived from 4,4'-dihydroxybiphenyl was 13% by mole. The proportion of structural units derived from hydroquinone was 9.2 mol%, the proportion of structural units derived from terephthalic acid was 12.7 mol%, and the proportion of structural units derived from isophthalic acid was 10.4 mol%. Ta. The total of the structural units derived from 4,4'-dihydroxybiphenyl and the structural units derived from hydroquinone was 23.0 mol% with respect to 100 mol% of the total structural units of the polyester. Further, Tm was 310°C.

Plate-shaped filler (B)
(B-1) Talc manufactured by Fuji Talc Industries (RL217, median diameter 20 μm)
(B-2) Talc manufactured by Fuji Talc Industries (ML110, median diameter 11 μm)
(B-3) Mica made by Yamaguchi Mica (J-31M, median diameter 35 μm)
(B-4) Mica made by Yamaguchi Mica (SJ-010, median diameter 10 μm)

Fibrous filler (C)
(C-1) Asahi fiberglass milled fiber (MF06MW2-20, number average fiber length 63μm)
(C-2) Asahi fiberglass milled fiber (MF20MH2-20, number average fiber length 160 μm)
(C-3) Glass chopped strand manufactured by Nippon Electric Glass (ECS03T747H, number average fiber length 3 mm)

[Examples 1 to 9, Comparative Examples 1 to 4]
In a Toshiba Machine TEM35B twin-screw extruder equipped with a side feeder, liquid crystal polyester resins (A-1, A-2) obtained in each production example were charged from a hopper in the blending amounts shown in Table 1, and plate-shaped. Filler (B) and fibrous filler (C) are added from the main feeder or side feeder in the amounts shown in Table 1, the cylinder temperature is set to the melting point of the liquid crystal polyester resin +10°C, and the mixture is melted and kneaded to form pellets. did. The obtained pellets of the liquid crystal polyester resin composition were dried with hot air at 150° C. for 3 hours, and then evaluated as described in (3) to (5) below. The results are shown in Table 1.

(3) Median diameter, particle size distribution, and P/Q value in particle size distribution of filler in liquid crystal polyester resin composition 50 g of pellets obtained in each example and comparative example were heated in air at 550°C for 3 hours. By doing so, the resin component was removed and the filler material, which is a non-combustible material, was taken out. Weighed 100 mg of the obtained filler, dispersed it in an ultrasonic cleaner for 10 minutes with 6 g of water and 10 mg of surfactant, and then dispersed it using a laser diffraction/scattering particle size distribution meter (“MT3300EXII” manufactured by Microtrac). The particle size distribution curve is obtained by measuring the particle size distribution three times and from the relationship between the frequency (unit (%), vertical axis) and particle size (unit (μm), horizontal axis, common logarithm). And so. Further, the most frequent particle diameter in the particle size distribution curve was defined as the mode diameter, and the particle diameter at which the cumulative frequency was 50% was defined as the median diameter. Furthermore, in order to obtain the P/Q value in the particle size distribution, the particle size distribution curve from the highest point corresponding to the mode diameter in the particle size distribution curve to the maximum particle size value, the horizontal axis corresponding to the frequency of 0.15%, The area of the part surrounded by the perpendicular line drawn down to the horizontal axis from the highest point corresponding to the line drawn in parallel and the mode diameter was determined as P. On the other hand, the particle size distribution curve from the highest point corresponding to the mode diameter on the particle size distribution curve to the minimum particle size value, the line drawn parallel to the horizontal axis corresponding to the frequency of 0.15% and the mode diameter The area surrounded by a perpendicular line drawn from the highest point to the horizontal axis was determined as Q, and the P/Q value in the particle size distribution was calculated.

(4) Evaluation of anisotropy The pellets obtained in each example and comparative example were supplied to a FANUC α30C injection molding machine (manufactured by FANUC), and the cylinder temperature was set to the melting point of the liquid crystal polyester resin +20°C, and the mold temperature was set to 90°C. A square shaped product measuring 80 mm x 80 mm x 1 mm thick was molded. The obtained square plate molded product was punched out in the resin flow direction (MD) into a "JIS K-7139-A23" shape into two samples per square plate using an SD type lever-type sample cutter to obtain dumbbell test pieces by punching in the MD direction. Created. Ten tensile tests were performed on this test piece using a tensile tester UTA2.5T (manufactured by Orientec) according to JIS K-7162, and the average value of the obtained tensile strengths was taken as the tensile strength in the MD direction. On the other hand, the obtained square plate molded product was punched out in the above-mentioned method in the direction perpendicular to the resin flow (TD) using an SD type lever-type sample cutter, a tensile test was performed, and the average value of the obtained tensile strength was It was defined as strength. The ratio of the tensile strength in the TD direction to the tensile strength in the MD direction was calculated as anisotropy. The closer the ratio is to 1, the better the anisotropy is.

(5) Evaluation of flow stability (evaluation of flow length variation)
The pellets obtained in each Example and Comparative Example were fed to a TUPARL TR30EHA injection molding machine (manufactured by Sodick Plastics), and the mold temperature was set at 90°C, and a rod-shaped test piece with a width of 5.0 mm and a thickness of 0.2 mm was molded. Molding was performed for 350 shots under the conditions of injection cylinder temperature, injection speed, and molding pressure such that the length of the product was 30 mm. The length of the obtained test pieces was 29 mm or less, or 31 mm or more, and the number of test pieces with variations in length was counted. The smaller the number of length variations, the better the flow stability.

From the results in Table 1, by using a liquid crystal polyester resin composition containing a filler having a specific particle size distribution, a molded article with excellent flow stability and low anisotropy can be obtained.

The liquid crystalline polyester resin composition of the present invention has excellent flow stability and low anisotropy, so it is suitable for use in electrical/electronic parts and mechanical parts such as connectors, relays, switches, coil bobbins, and actuator parts for camera modules. It is.

1 Particle size distribution curve of filler 2 Mode of particle size distribution curve (mode diameter)
3 Point corresponding to the maximum particle size 4 Point corresponding to the minimum particle size

Claims (6)

A liquid crystal polyester resin composition containing a liquid crystal polyester resin (A) and a filler including a plate-like filler (B) and a fibrous filler (C), the particles of the filler in the liquid crystal polyester resin composition A liquid crystal polyester resin composition obtained from a diameter distribution curve, in which P and Q defined below satisfy formula (R).
0.70≦(P/Q)≦1.20...(R)
(In the particle size distribution curve obtained by plotting the particle size of the filler in the liquid crystal polyester resin composition, the horizontal axis is the particle size (μm, common logarithm display) and the vertical axis is the frequency (%), the particle size distribution Particle size distribution curve from the highest point corresponding to the mode diameter on the curve to the maximum particle size, a line parallel to the horizontal axis corresponding to a frequency of 0.15%, drawn down from the highest point corresponding to the mode diameter to the horizontal axis The area surrounded by the perpendicular line is P, the particle size distribution curve from the highest point corresponding to the mode diameter on the particle size distribution curve to the minimum particle size, parallel to the horizontal axis corresponding to the frequency of 0.15%. Let Q be the area surrounded by the perpendicular line drawn from the highest point corresponding to the mode diameter to the horizontal axis.) The liquid crystal polyester resin composition according to claim 1, wherein the liquid crystal polyester resin (A) is a liquid crystal polyester resin containing the following structural units (I) to (VI).

The liquid crystal polyester resin composition according to claim 1, wherein the plate-like filler (B) is one or more selected from the group consisting of talc and mica. A liquid crystal polyester resin composition in which a liquid crystal polyester resin composition containing a liquid crystal polyester resin (A) and a filler including a plate-like filler (B) and a fibrous filler (C) is melt-kneaded using a twin-screw extruder. A method for manufacturing a product, wherein the median diameter (S (μm)) of a plate-like filler (B) before blending and the number average fiber length (T (mm)) of a fibrous filler (C) before blending are It is characterized by satisfying the formula (U), supplying the filler from a position larger than 0.50X, assuming that the total screw length of the twin screw extruder is X and the input port of the liquid crystal polyester resin (A) is 0. A method for producing a liquid crystal polyester resin composition.
1.0≦(T/S)≦30.0...(U) A molded article comprising the liquid crystal polyester resin composition according to any one of claims 1 to 3. 6. The molded article of claim 5, wherein the molded article is selected from the group consisting of connectors, relays, switches, coil bobbins, and actuator parts of camera modules.
Effects: Low anisotropy (high strength regardless of MD/TD direction), flow stability (evaluation of flow length variation)