JP5216230B2 - Conductive resin composition - Google Patents

Description

  The present invention relates to a thermotropic liquid crystal polyester resin composition excellent in fluidity at the time of melt molding and excellent in conductivity, and a molded body obtained therefrom.

  Thermotropic liquid crystalline polyester resin or its composition has excellent fluidity at the time of melt molding derived from a rigid molecular structure, excellent heat resistance, and mechanical properties, mainly for electrical and electronic parts by injection molding. Its use is expanding. On the other hand, depending on the use of a molded product made of a thermotropic liquid crystal polyester resin or a composition thereof, it may be necessary to impart conductivity for the purpose of antistatic or electromagnetic shielding. As a method of imparting conductivity to the synthetic resin as an insulator, conductive inorganic fillers such as carbon black, graphite, metal powder, metal flakes, metal fibers, carbon fibers, metal-coated glass fibers and carbon fibers, etc. Is blended into the synthetic resin. Among them, carbon black, especially what is called conductive carbon black is often used. The same applies to the addition of conductivity to the thermotropic liquid crystal polymer and its composition.

  In Patent Document 1 (paragraph 0008), when conductive carbon black is blended with a resin composition composed of liquid crystal polyester and talc until the required conductivity is obtained, the melt viscosity is remarkably increased, and the composition is formed in a thin portion during molding. There is a description of the problem that not only the product is not sufficiently filled but also the impact strength is significantly reduced. Further, as a means for solving the problem, a resin composition in which specific graphite is blended with liquid crystal polyester is disclosed. However, in order to obtain a desired conductive resin composition, it is necessary to increase the amount of graphite, and as a result, there is a risk of impairing the original characteristics of the resin.

  Patent Document 2 discloses a conductive resin composition composed of a liquid crystal polymer and a conductive filler, and provides a resin composition that is easy to manufacture and mold and has excellent strength, conductivity, and sealing properties. There is a description. In this technique, a combination of a plurality of conductive fillers is disclosed, but there is no description regarding combinations of different types of carbon black, and their blending ratio, conductivity, and fluidity of the resin composition. Further, since graphite has poor dispersibility, it is necessary to increase the blending amount, and as a result, there is a risk of impairing the original characteristics of the resin.

  Patent Document 3 discloses a conductive thermoplastic resin composition comprising a thermoplastic resin, a plurality of carbon blacks having different DBP oil absorption and specific surface area, and carboxylic acid and / or anhydride thereof. However, this patent document does not include a description regarding the thermotropic liquid crystal polyester resin composition, and a detailed description regarding the composition, fluidity, and conductivity of the composition. Further, in the thermotropic liquid crystal polyester resin composition heated to a temperature around 400 ° C. during the production or molding, the addition of carboxylic acid and / or its anhydride induces decomposition of the resin, and the resulting resin composition and / Or lowers the mechanical properties of the molded product. Further, in the molded article, the carboxylic acid and / or its anhydride migrates to the surface, and there is also a problem that it is difficult to use the thermotropic liquid crystal polyester resin composition for electric / electronic parts, which is the main application.

As described above, it can be easily manufactured, maintains the high fluidity at the time of melting of the thermotropic liquid crystalline polyester resin, the molded product obtained therefrom has high conductivity, and is used as an electric / electronic component. At present, a thermotropic liquid crystal polyester resin composition having practicality has not been obtained yet.
Japanese Unexamined Patent Publication No. Hei 6-07083 (paragraph 0008) JP 2000-17179 A (Claims) JP 2002-322366 A (Claims)

  An object of the present invention is to provide a thermotropic liquid crystal polyester resin composition excellent in fluidity at the time of molding and excellent in conductivity, and a molded body obtained therefrom.

  In view of the problems of the prior art, the present inventors have conducted extensive research, and as a result, the thermotropic liquid crystal polyester resin, a plurality of carbon black having different specific DBP oil absorption, and if necessary, an inorganic filler, It is found that by blending at a specific ratio, a thermotropic liquid crystal polyester resin composition excellent in fluidity at the time of molding and excellent in conductivity of a molded product and a molded body comprising the same can be obtained, and the present invention is completed. It came to.

That is, the first of the present invention is 45 to 87 % by mass of a thermotropic liquid crystal polyester resin having a melting point of 320 ° C. to 420 ° C., 3 to 7 % by mass of carbon black having a DBP oil absorption of 300 to 600 ml / 100 g, and a DBP oil absorption. Thermotropic liquid crystal polyester obtained by melt-kneading carbon black of 10 to 30 % by mass and inorganic fillers of 0 to 30 % by mass (the total of all the components is 100% by mass) having a water content of 220 ml / 100 g or less The resin composition has a volume specific resistance of 1 × 10 ³ to 1 × 10 ⁹ Ω · cm of a molded product obtained therefrom, and does not contain a resin component other than the thermotropic liquid crystal polyester resin.

  A second aspect of the present invention is the thermotropic liquid crystal polyester resin composition according to the first aspect, wherein the inorganic filler is glass fiber and / or talc.

The third of the present invention, the Ri Do from the first or second thermotropic liquid-crystal polyester resin composition of any one of the invention, the conductivity of a volume resistivity of ^{1 × 10 3 ~1 × 10 9} Ω · cm is formed form you, comprising.

  Since the thermotropic liquid crystal polyester resin composition of the present invention is excellent in fluidity during molding, particularly injection molding, it is possible to easily mold a molded body such as a fine structure, a structure having a thin part, Since the obtained molded body has high electrical conductivity, it can be used for applications such as parts for electric and electronic fields that require antistatic properties or electrical conductivity.

  The thermotropic liquid crystal polyester resin used in the present invention forms an anisotropic melt, and among these, a wholly aromatic liquid crystal polyester obtained by a polycondensation reaction of substantially only an aromatic compound is preferable. .

  The structural unit of the thermotropic liquid crystal polyester resin constituting the thermotropic liquid crystal polyester resin composition of the present invention includes, for example, those composed of a combination of an aromatic dicarboxylic acid, an aromatic diol and an aromatic hydroxycarboxylic acid, Those comprising an aromatic hydroxycarboxylic acid, those comprising a combination of an aromatic hydroxycarboxylic acid and an aromatic dicarboxylic acid and an aromatic diol, and those obtained by reacting an aromatic hydroxycarboxylic acid with a polyester such as polyethylene terephthalate. Specific examples of the structural unit include the following.

Structural units derived from aromatic hydroxycarboxylic acids:

Structural units derived from aromatic dicarboxylic acids:

Repeating structural units derived from aromatic diols:

  From the viewpoint of the balance of heat resistance, mechanical properties, and processability, the preferred thermotropic liquid crystal polyester resin has a structural unit (A1) of 30 mol% or more, more preferably (A1) and (B1). It has 60 mol% or more.

  Particularly preferred thermotropic liquid crystalline polyester resins are p-hydroxybenzoic acid (I), terephthalic acid (II), 4,4′-dihydroxybiphenyl (III) (including these derivatives) in an amount of 80 to 100 mol% (however, , (I) and (II) are added in an amount of 60 mol% or more.) And (I), (II), or (II) and any other aromatic compound capable of decondensing with 0 to 20 mol%. Polyaromatic polyester resin having a melting point of 320 to 420 ° C. obtained by polycondensation, or p-hydroxybenzoic acid (I), terephthalic acid (II), 4,4′-dihydroxybiphenyl (III) (these derivatives 90 to 99 mol% (provided that the total of (I) and (II) is 60 mol% or more), and (I), (II) and (III) other decondensable reaction Melting point 320 obtained by polycondensation of 1 to 10 mol% of aromatic compound (both are combined to 100 mol%) 420 is a wholly aromatic liquid crystal polyester resin ° C.. Here, having a melting point in the range of 320 ° C. to 420 ° C. means that a melting peak is detected in this temperature range in DSC or TMA analysis, and even if a separate peak is detected outside this temperature range. Good.

As a combination of the above structural units,
(A1)
(A1), (B1), (C1)
(A1), (B1), (B2), (C1)
(A1), (B1), (B2), (C2)
(A1), (B1), (B3), (C1)
(A1), (B1), (B3), (C2)
(A1), (B1), (B2), (C1), (C2)
(A1), (A2), (B1), (C1)
As the particularly preferable monomer composition ratio, p-hydroxybenzoic acid, terephthalic acid, 4,4′-dihydroxybiphenyl (including these derivatives) is 80 to 100 mol%, and other aromatic diols, A wholly aromatic liquid crystal polyester resin obtained by polycondensation of an aromatic compound selected from the group consisting of an aromatic hydroxydicarboxylic acid and an aromatic dicarboxylic acid with 0 to 20 mol% (both are 100 mol% in total). It is. When p-hydroxybenzoic acid and terephthalic acid 4,4′-dihydroxybiphenyl are 80 mol% or less, the heat resistance tends to decrease, which is not preferable.

  As a method for producing the thermotropic liquid crystal polyester resin used in the present invention, a known method can be adopted, and a production method using only melt polymerization or a production method using two-stage polymerization of melt polymerization and solid phase polymerization can be used. it can. As a specific example, after a monomer selected from an aromatic dihydroxy compound, an aromatic hydroxycarboxylic acid compound, and an aromatic dicarboxylic acid compound is charged into a reactor, acetic anhydride is added to acetylate the hydroxyl group of the monomer , Produced by deacetic acid polycondensation reaction. For example, p-hydroxybenzoic acid, terephthalic acid, isophthalic acid, and 4,4'-dihydroxybiphenyl are charged into a reactor under a nitrogen atmosphere, acetic anhydride is added, and acetoxylation is performed under acetic anhydride reflux, followed by ascending. A method of producing a polyester resin by performing deacetic acid melt polycondensation while heating and distilling acetic acid in a temperature range of 150 to 350 ° C. can be mentioned. The polymerization time can be selected in the range of 1 hour to several tens of hours. In the production of the thermotropic liquid crystal polyester resin used in the present invention, the monomer may or may not be dried before the production.

  When solid phase polymerization is further performed on the polymer obtained by melt polymerization, the polymer obtained by melt polymerization is solidified and then pulverized into powder or flakes, and then a known solid phase polymerization method such as nitrogen For example, a method of heat treatment at 200 to 350 ° C. for 1 to 30 hours in an inert atmosphere is preferably selected. The solid phase polymerization may be performed with stirring, or may be performed in a standing state without stirring.

  In the polymerization reaction, a catalyst may or may not be used. As the catalyst to be used, those conventionally known as polyester polycondensation catalysts can be used, such as magnesium acetate, stannous acetate, tetrabutylthiocyanate, lead acetate, sodium acetate, potassium acetate, antimony trioxide, etc. And an organic compound catalyst such as N-methylimidazole.

  The polymerization reaction apparatus in melt polymerization is not particularly limited, but a reaction apparatus used for reaction of a general high viscosity fluid is preferably used. Examples of these reaction apparatuses include, for example, a stirring tank type polymerization reaction apparatus having a stirring apparatus having stirring blades of various shapes, such as a vertical type, a multistage type, a spiral band type, a helical shaft type, etc. And a kneader, a roll mill, a Banbury mixer, and the like, which are generally used for resin kneading.

  The shape of the thermotropic liquid crystal polyester resin used in the present invention may be any of powder, granule, and pellet, but is preferably powder or granule from the viewpoint of dispersibility when mixed with a filler.

  The blending ratio of the thermotropic liquid crystal polyester resin used in the thermotropic liquid crystal polyester resin composition of the present invention to the entire resin composition is 45 to 89% by mass, preferably 50 to 89% by mass. When it is less than this lower limit, the fluidity of the obtained resin composition is lowered, and it becomes difficult to produce and mold the resin composition. On the other hand, when this upper limit is exceeded, carbon black having a DBP oil absorption of 300 to 600 ml / 100 g and carbon black having a DBP oil absorption of 220 ml / 100 g or less cannot be blended at a predetermined ratio.

  In the thermotropic liquid crystal polyester resin composition of the present invention, by blending carbon black having a DBP oil absorption of 300 to 600 ml / 100 g, high conductivity is imparted by blending a small amount of carbon black.

  Ketjen black (trade name) manufactured by Ketjen Black International Co., Ltd. is used as the carbon black having a DBP oil absorption of 300 to 600 ml / 100 g. Ketjen black is a carbon black produced by a special furnace method and having a hollow structure. Ketjen Black EC300J (DBP oil absorption 360ml / 100g (catalog value)), Ketjen Black EC600J (DBP oil absorption 495ml / 100g (catalog value)) is used. The DBP oil absorption is measured according to ASTM D2414.

  Here, the descriptions of “carbon black with DBP oil absorption of 300 to 600 ml / 100 g” and “carbon black with DBP oil absorption of 220 ml / 100 g” have special meanings in the respective numerical ranges. The former means ketjen black, and the latter means carbon black other than ketjen black.

  The blending amount of carbon black having a DBP oil absorption of 300 to 600 ml / 100 g used in the thermotropic liquid crystal polyester resin composition of the present invention is 2 to 7.5% by mass, preferably 3 to 7% by mass with respect to the whole resin composition. %, More preferably 4 to 6% by mass. If it is less than this lower limit, the resulting molded product made of the resin composition tends to have insufficient conductivity. On the other hand, when this upper limit is exceeded, the fluidity at the time of melting of the obtained resin composition becomes insufficient, and the moldability tends to decrease.

  In the thermotropic liquid crystal polyester resin composition of the present invention, carbon black having a DBP oil absorption of 220 ml / 100 g or less is blended together with carbon black having a DBP oil absorption of 300 to 600 ml / 100 g. Carbon black having a DBP oil absorption of 220 ml / 100 g or less is not particularly limited, but specific examples include acetylene black, furnace black, thermal black, lamp black, channel black, and the like. Acetylene black is produced by thermal decomposition of acetylene, and furnace black is produced by incomplete combustion of hydrocarbon oil or natural gas. Thermal black is a carbon black having a large particle size produced by thermal decomposition of natural gas. Lamp black is manufactured by direct combustion of raw materials in a closed space, and channel black is manufactured by bringing a diffusion flame into contact with the bottom surface of the channel steel.

  The blending amount of carbon black having a DBP oil absorption of 220 ml / 100 g or less used in the thermotropic liquid crystal polyester resin composition of the present invention is preferably 9 to 33% by mass, and more preferably 10 to 30% by mass. If it is less than this lower limit, the resulting molded article made of the thermotropic liquid crystal polyester resin composition tends to have insufficient conductivity. On the other hand, when this upper limit is exceeded, it tends to be difficult to produce the resin composition.

  The inorganic filler used in the thermotropic liquid crystal polyester resin composition of the present invention is an inorganic filler excluding carbon black. There are no particular restrictions on the type, and known ones can be used, and by filling these, the effect of increasing mechanical properties and heat resistance, or the effect of reducing the anisotropy of the shrinkage of the molded article can be obtained. Specific examples of inorganic fillers include molybdenum disulfide, talc, mica, glass flake, clay, sericite, calcium carbonate, calcium silicate, silica, alumina, aluminum hydroxide, calcium hydroxide, potassium titanate, Examples thereof include glass fiber, carbon fiber, and various whiskers. These may be used alone or in combination of two or more. Among these inorganic fillers, talc, mica, milled glass, and glass fiber are preferable because of excellent balance of formability and heat resistance. Furthermore, talc and / or glass fiber are particularly preferred.

  In the thermotropic liquid crystal polyester resin composition of the present invention, when talc is used as the inorganic filler, there is no particular limitation as long as it is a known talc used as a material constituting the resin composition. The theoretical chemical structure of talc is hydrous magnesium silicate, but particularly natural products, it may contain impurities such as iron oxide and aluminum oxide.

  In the thermotropic liquid crystal polyester resin composition of the present invention, when glass fiber is used as the inorganic filler, there is no particular limitation as long as it is a known glass fiber used as a material constituting the resin composition, but the average fiber It is preferable to use glass fibers having a diameter of 1 to 20 μm and an average fiber length of 3 mm or less.

  The compounding quantity of the said inorganic filler is 0-33 mass% with respect to the said whole resin composition. When this upper limit is exceeded, it tends to be difficult to produce a resin composition and to mold a molded body using the resin composition.

  The thermotropic liquid crystal polyester resin composition of the present invention can be obtained by melting the thermotropic liquid crystal polyester resin and kneading with other components. The equipment and operation method used for melt kneading are generally the melting of the thermotropic liquid crystal polyester resin. There is no particular limitation as long as it is used for kneading. Among them, a method of melt-kneading using a kneader having a pair of screws, called a twin-screw kneader, and extruding into a pellet is preferable. Among the two-screw kneaders, those that have a turning mechanism and are of a different direction rotating type that enables uniform dispersion of the filler, and have a cylinder diameter of 30 mmφ or more with a large gap between the barrel and the screw that facilitates biting. In particular, a screw having a double thread type and a screw having a large mesh between screws, specifically, a mesh rate of 1.45 or more are particularly preferable.

  When a composition is produced using a biaxial kneader, the raw material is usually a thermotropic liquid crystal polyester resin, carbon black having a DBP oil absorption of 300 to 600 ml / 100 g, and a DBP oil absorption of 220 ml / 100 g or less. A carbon black, and if necessary, an inorganic filler is stirred and mixed using a blender such as a ribbon blender, tumbler mixer, Henschel mixer, etc., and the mixture is dried by equipment such as an oven if necessary. More supply methods are taken. Moreover, when using glass fiber as an inorganic filler, you may supply glass fiber in the middle of the barrel of a biaxial kneader (side feed) in order to maintain the glass fiber length in a composition as much as possible.

  The molding method for obtaining a molded body from the thermotropic liquid crystal polyester resin composition of the present invention is not particularly limited, and injection molding, extrusion molding, transfer molding, blow molding, compression molding, injection compression molding, extrusion injection molding, etc. Various general-purpose molding methods are used in the field of plastic resins. Of these, injection molding is preferred.

  The molding machine and molding conditions used in the present invention are not particularly limited as long as they are known ones that are generally used for molding thermotropic liquid crystal polyester resins and compositions thereof, and those skilled in the art can use them according to the application and shape. Can be easily selected as appropriate.

Further, to the composition of the present invention, usual additions such as antioxidants and heat stabilizers, ultraviolet absorbers, lubricants and mold release agents, dyes, plasticizers, flame retardants, etc. are made within the range not impairing the object of the present invention. An agent may be added to impart predetermined characteristics. However, these additives does not occur decomposition in the production and the temperature in the vicinity of 400 ° C. during molding of the thermotropic liquid crystal polyester resin composition, also it is necessary that it does not adversely affect the resin.

The volume resistivity of the molded body made of the thermotropic liquid crystal polyester resin composition of the present invention is 1 × 10 ³ to 1 × 10 ⁹ Ω · cm, preferably 1 × 10 ³ to 1 × 10 ⁵ Ω · cm. As a use of the thermotropic liquid crystal polyester resin composition of the present invention, there is no problem as long as the conductivity is about this lower limit. On the other hand, when the upper limit of the volume resistivity is exceeded, the antistatic property or conductivity of the molded product tends to be insufficient, which is not preferable.

  As described above, the reason is not clear, but when the present inventors blend carbon black having a DBP oil absorption of 300 to 600 ml / 100 g into the thermotropic liquid crystal polyester resin, the resin composition of the carbon black When the blending ratio with respect to the whole product is between 7 and 8% by mass, the melt viscosity of the resin composition rises rapidly, and further, carbon black having a DBP oil absorption of 220 ml / 100 g or less is added to the resin composition, It has been found that even when other inorganic fillers are blended, the blending ratio of carbon black having a DBP oil absorption of 300 to 600 ml / 100 g rapidly increases between 7 and 8% by mass. The thermotropic liquid crystal polyester resin and its composition are mainly used for injection molded articles having a fine structure for electric and electronic parts that make use of excellent fluidity at the time of melting. An increase in melt viscosity is a serious problem for moldability. Furthermore, in a specific region where the compounding ratio of carbon black having a DBP oil absorption of 300 to 600 ml / 100 g is less than 7 to 8% by mass, a carbon black having a DBP oil absorption of 220 ml / 100 g or less is specified here. It has been found that by blending at a ratio, the conductivity can be improved to the required level without substantially increasing the melt viscosity of the resulting resin composition.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to these Examples.

Test method:
The measuring methods and evaluation methods for the performance of the thermotropic liquid crystal polyester resin compositions and molded products obtained therefrom in Examples and Comparative Examples are shown below.
(1) Measurement of melt viscosity The melt viscosity of the thermotropic liquid crystal polyester resin composition is a capillary rheometer (Model 2010, manufactured by Intesco Corporation) with a capillary diameter of 1.00mm, length of 40mm, and inflow angle of 90 °. The apparent viscosity was measured at a shear rate of 100 sec ^-1 while heating at a constant rate from 300 ° C. to + 4 ° C./min, and the apparent viscosity at 350 ° C. was determined as a test value. In the test, resin composition pellets previously dried in an air oven at 150 ° C. for 4 hours were used.
(2) Measurement of volume resistivity The volume resistivity of the molded body was measured according to JIS K6271. That is, a test piece of 60 mm square and 1 mm thickness was prepared with an injection molding machine (Nissei Plastic Industries, UH-1000), and measured with a digital ohm meter (R-506, Kawaguchi Electric Co., Ltd.). .

Production example (Thermotropic liquid crystal polyester resin production):
In a 1700L polymerization tank (made by Kobe Steel Co., Ltd.) with a double helical stirring blade made of SUS316, p-hydroxybenzoic acid (Ueno Pharmaceutical Co., Ltd.) 298 g (2.16 kgol), 4,4'-dihydroxy Biphenyl (Honshu Chemical Industry Co., Ltd.) 134 kg (0.72 kgmol), Terephthalic acid (Mitsui Chemicals Co., Ltd.) 90 kg (0.54 kgmol), Isophthalic acid (Ai International Chemical Co., Ltd.) 30 kg (0.18 kgmol), catalyst As potassium acetate (manufactured by Kishida Chemical Co., Ltd.) 0.04 kg and magnesium acetate (manufactured by Kishida Chemical Co., Ltd.) 0.10 kg. 3.82 kilomoles) was added, and the temperature was raised to 150 ° C. over 1.5 hours at a rotation speed of a stirring blade of 45 rpm. After the completion of acetylation, acetic acid was distilled off and the temperature was raised at 0.5 ° C./min. When the reactor temperature reached 305 ° C., the polymer was taken out from the outlet at the bottom of the reactor and solidified by cooling with a cooling device. The obtained polymer was pulverized to 2.0 mm mesh or less by a pulverizer manufactured by Hosokawa Micron Corporation to obtain a prepolymer.
The obtained prepolymer was subjected to solid phase polymerization using a rotary kiln manufactured by Takasago Industry Co., Ltd. The prepolymer was filled in the kiln, nitrogen was passed at a flow rate of 16 Nm 3 / hr, the heater temperature was raised from room temperature to 350 ° C. in 1 hour at a rotation speed of 2 rpm, and held at 350 ° C. for 10 hours. After confirming that the temperature of the resin powder in the kiln reached 295 ° C., the heating was stopped and the rotary kiln was rotated and cooled for 4 hours to obtain a thermotropic liquid crystal polyester resin.

Inorganic filler:
The inorganic filler used in the following examples is shown.
(1) Glass fiber: PX-1 manufactured by Owens Corning Manufacturing Co., Ltd.
(2) Talc: Hayashi Kasei Co., Ltd., MSKY (average particle size 24 μm, aspect ratio 7)

Example 1
87% by mass of the powdered thermotropic liquid crystalline polyester obtained in the above production example with respect to the total resin composition, granular ketjen black EC300J (manufactured by ketjen black international KK, DBP oil absorption 376 ml / 100 g ) 3% by mass, carbon black REGAL99I (manufactured by Cabot Specialty Chemicals, Inc., DBP oil absorption 63ml / 100g) 10% by mass was mixed using a ribbon blender, and the mixture was mixed in an air oven at 150 ° C. Dry for hours. Using a twin-screw extruder with a cylinder diameter of 30 mm (PCM-30: 2-strip type manufactured by Ikegai Steel Co., Ltd.) with the maximum temperature of the cylinder set to 380 ° C, the dried mixture was put into the hopper, and the extrusion rate was 10 kg / The mixture was melt-kneaded in hr to obtain pellets of the desired thermotropic liquid crystal polyester resin composition. The obtained pellets were dried in an air oven at 150 ° C. for 4 hours, and the melt viscosity was measured by the above test method. The results are shown in Table 1.
The obtained pellets were dried in an air oven at 150 ° C. for 4 hours, and a test piece was molded by injection molding using an injection molding machine UH-1000 manufactured by Nissei Plastic Industry Co., Ltd. Using the obtained test piece, the volume resistivity was measured by the above test method. The results are shown in Table 1.

(Examples 2-6) and (Comparative Examples 1-6)
The same thermotropic liquid crystal polyester resin as used in Example 1, Ketjen Black EC300J, carbon black REGAL99I was used, and glass fiber or talc was blended as necessary, and the composition was as described in Table 1, respectively. Each thermotropic liquid crystal polyester resin composition was produced by the same equipment and operation method as in Example 1. In Example 5, the entire amount of glass fiber was supplied (side feed) in the middle of the barrel of the biaxial kneader. In Example 6, talc was mixed with other materials and supplied from a hopper of a twin-screw kneader. About the resin composition obtained in each example, melt viscosity was measured like Example 1, and the test piece was shape | molded by injection molding similarly to Example 1, and the volume specific resistance was measured. The results are shown in Table 1. In Comparative Example 6, as the blank test, only the thermotropic liquid crystal polyester resin was kneaded under the same conditions.

  When Examples 3 to 6 are compared with Comparative Examples 2 and 4, the melt viscosity of the composition rapidly increases in a region where the blending ratio of Ketjen Black EC300J to the entire resin composition is 7 to 8% by mass or more. I understand that. In addition, it has been clarified that by using a combination of Ketjen Black EC300J and carbon black REGAL99I within the composition range of the present invention, the resin composition exhibits excellent conductivity without significantly increasing the melt viscosity. It was.

  As described above, since the thermotropic liquid crystal polyester resin composition of the present invention is used, the fluidity at the time of melting is high and the moldability is excellent. Therefore, a structure having a fine structure or a thin part, particularly by injection molding. Since the molded body having the above can be easily molded, and the volume specific resistance of the obtained molded body is small, an electric / electronic component excellent in antistatic property and conductivity is provided.

Claims (3)

45 to 87 % by mass of thermotropic liquid crystalline polyester resin with a melting point of 320 ° C to 420 ° C, 3 to 7 % by mass of carbon black with a DBP oil absorption of 300 to 600ml / 100g, and carbon black with a DBP oil absorption of 220ml / 100g or less 10-30% by weight, and a thermotropic liquid crystal polyester resin composition inorganic filler 0-30 weight percent (total of all components is 100% by mass) is characterized by being obtained by melt-kneading, then give The molded product has a volume resistivity of 1 × 10 ³ to 1 × 10 ⁹ Ω · cm and does not contain any resin component other than the thermotropic liquid crystal polyester resin.   The thermotropic liquid crystal polyester resin composition according to claim 1, wherein the inorganic filler is glass fiber and / or talc. A molded article comprising the thermotropic liquid crystal polyester resin composition according to claim 1 or 2 and having a volume resistivity of 1 × 10 ³ to 1 × 10 ⁹ Ω · cm.