KR20230116010A - Conductive liquid crystalline resin composition - Google Patents

Abstract

A conductive liquid crystalline resin composition is provided which gives a molded article having excellent molding processability and having a low volume resistivity as well as a small fluctuation in volume resistivity regardless of thickness. The conductive liquid crystalline resin composition according to the present invention contains (A) a liquid crystalline resin, (B) a fibrous conductive filler, (C) a particulate conductive filler, and (D) a non-conductive filler, and (B) a fibrous conductive filler. The total content of the conductive filler and the (C) particulate conductive filler is 25 to 50% by mass, and the mass ratio of the content of the fibrous conductive filler (B) to the content of the particulate conductive filler (C) is 0.50 to 3.00, The content of the non-conductive filler (D) is 2 to 8% by mass.

Description

Conductive liquid crystalline resin composition

The present invention relates to a conductive liquid crystalline resin composition.

Liquid crystalline resins represented by liquid crystalline polyester resins have excellent mechanical strength, heat resistance, chemical resistance, electrical properties, etc. in a well-balanced manner, and also have excellent dimensional stability, so they are widely used as high-performance engineering plastics. In addition, taking advantage of the excellent fluidity of the liquid crystalline resin and adding a conductive filler to the liquid crystalline resin to impart conductivity (for example, Patent Document 1) has been practiced.

Japanese Unexamined Patent Publication No. 2005-187696

In recent years, with the transition from LTE to 5G, significant improvements in signal transmission speed and signal accuracy are required in many products such as connectors, transmission boards, and antennas. While conductive materials such as connector materials are being developed in connection with high-speed communication, the importance of thermoplastic conductive materials capable of imparting complex shapes is becoming increasingly important as a countermeasure against noise by shielding electromagnetic waves or forming ground points. Such a conductive material not only has a low volume resistivity as an index of conductivity, but also has excellent molding processability so that it can be easily molded into a complex shape, and after being molded into a complex shape, the volume resistivity fluctuates regardless of the thickness of the molded body. This small thing is required.

A liquid crystalline resin composition is mentioned as a candidate for the above-mentioned conductive material. However, according to the study of the present inventors, in the conventional liquid crystalline resin composition, since the volume resistivity is originally high and the melt viscosity is high, molding processability is not sufficient. The present invention has been made to solve the above problems, and its object is to provide a conductive liquid crystalline resin composition that gives a molded article having excellent molding processability, low volume resistivity, and small fluctuation in volume resistivity regardless of thickness. will be.

The inventors of the present invention repeated intensive studies in order to solve the above problems. As a result, a liquid crystalline resin, a fibrous conductive filler, a granular conductive filler, and a non-conductive filler are contained, the total content of the fibrous conductive filler and the granular conductive filler is within a predetermined range, and the fibrous shape relative to the content of the granular conductive filler By using a conductive liquid crystalline resin composition in which the mass ratio of the content of the conductive filler is within a predetermined range and the content of the non-conductive filler is within a predetermined range, it is found that the above problems can be solved, and the present invention has been completed. More specifically, the present invention provides the following.

(1) (A) a liquid crystalline resin, (B) a fibrous conductive filler, (C) a granular conductive filler, and (D) a non-conductive filler, wherein the (B) fibrous conductive filler and the (C) granular The total content of the conductive filler is 25 to 50% by mass, the mass ratio of the content of the fibrous conductive filler (B) to the content of the particulate conductive filler (C) is 0.50 to 3.00, and the (D) non-conductive filler The conductive liquid crystalline resin composition having a content of 2 to 8% by mass.

(2) The conductive liquid crystalline resin composition according to (1), wherein the (B) fibrous conductive filler is carbon fiber and the (C) particulate conductive filler is carbon black.

(3) The (D) non-conductive filler is one selected from the group consisting of talc, mica, glass flakes, silica, glass beads, glass balloons, potassium titanate whiskers, calcium silicate whiskers, milled glass fibers, and glass fibers The conductive liquid crystalline resin composition according to the above (1) or (2).

(4) The conductive liquid crystalline resin composition according to any one of (1) to (3), wherein the (D) non-conductive filler is at least one selected from the group consisting of talc, mica, silica, and glass fiber.

ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide a conductive liquid crystalline resin composition that gives a molded article that is excellent in molding processability and has a low volume resistivity as well as a small fluctuation in volume resistivity regardless of thickness.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described. In addition, this invention is not limited to the following embodiment.

<Conductive liquid crystalline resin composition>

The conductive liquid crystalline resin composition of the present invention contains (A) a liquid crystalline resin, (B) a fibrous conductive filler, (C) a particulate conductive filler, and (D) a non-conductive filler.

[(A) liquid crystalline resin]

The (A) liquid crystalline resin used in the present invention refers to a melt-processable polymer having a property capable of forming an optically anisotropic molten phase. The properties of the anisotropic molten phase can be confirmed by a conventional polarization inspection method using an orthogonal polarizer. More specifically, confirmation of the anisotropic molten phase can be performed by observing a molten sample placed on a Leitz hot stage under a nitrogen atmosphere at a magnification of 40 times using a Leitz polarization microscope. When the liquid crystalline polymer applicable to the present invention is inspected between orthogonal polarizers, even in a melt-stopped state, for example, polarized light is normally transmitted and exhibits optical anisotropy.

The type of the above (A) liquid crystalline resin is not particularly limited, and is preferably an aromatic polyester and/or an aromatic polyester amide. In addition, polyesters partially containing aromatic polyesters and/or aromatic polyesteramides in the same molecular chain are also within that range. (A) The liquid crystalline resin preferably has a logarithmic viscosity of at least about 2.0 dl/g, more preferably 2.0 to 10.0 dl/g when dissolved in pentafluorophenol at a concentration of 0.1% by mass at 60°C ( I.V.) is preferably used.

Particularly preferably, the aromatic polyester or aromatic polyesteramide as (A) liquid crystalline resin applicable to the present invention contains a repeating unit derived from one or two or more aromatic hydroxycarboxylic acids and derivatives thereof. It is the aromatic polyester or aromatic polyesteramide which has as a structural component.

More specifically,

(1) polyester mainly composed of repeating units derived from one or two or more of aromatic hydroxycarboxylic acids and their derivatives;

(2) Mainly (a) a repeating unit derived from one or two or more of aromatic hydroxycarboxylic acids and their derivatives, and (b) one or more of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives Polyester which consists of repeating units derived from 2 or more types;

(3) Mainly (a) a repeating unit derived from one or two or more of aromatic hydroxycarboxylic acids and their derivatives, and (b) one or more of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives polyester comprising repeating units derived from two or more species, and (c) repeating units derived from at least one or two or more of aromatic diols, alicyclic diols, aliphatic diols, and their derivatives;

(4) Mainly (a) a repeating unit derived from one or two or more of aromatic hydroxycarboxylic acids and their derivatives, and (b) one or two or more of aromatic hydroxyamines, aromatic diamines, and their derivatives Polyesteramide consisting of repeating units derived from (c) aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and repeating units derived from one or two or more of their derivatives;

(5) Mainly (a) a repeating unit derived from one or two or more of aromatic hydroxycarboxylic acids and their derivatives, and (b) one or two or more of aromatic hydroxyamines, aromatic diamines, and their derivatives A repeating unit derived from (c) a repeating unit derived from one or two or more of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives, and (d) aromatic diols, alicyclic diols, and aliphatic diols , and repeating units derived from at least one or two or more of these derivatives. Moreover, you may use together a molecular weight modifier with the said structural component as needed.

Preferable examples of specific compounds constituting the (A) liquid crystalline resin applicable to the present invention include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid; 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, hydroquinone, resorcin, a compound represented by the following general formula (I), and the following general Aromatic diols, such as a compound represented by Formula (II); 1,4-phenylenedicarboxylic acid, 1,3-phenylenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and represented by the following general formula (III) Aromatic dicarboxylic acid, such as a compound which becomes; and aromatic amines such as p-aminophenol, p-phenylenediamine, and N-acetyl-p-aminophenol.

(X: a group selected from alkylene (C ₁ to _{C 4} ), alkylidene, -O-, -SO-, -SO ₂ -, -S-, and -CO-)

(Y: A group selected from -(CH ₂ ) _n -(n = 1 to 4) and -O(CH ₂ ) _n O- (n = 1 to 4).)

Preparation of the (A) liquid crystalline resin used in the present invention can be carried out by a known method using a direct polymerization method or a transesterification method from the above monomer compounds (or mixtures of monomers), usually a melt polymerization method, A solution polymerization method, a slurry polymerization method, a solid-state polymerization method, or the like, or a combination of two or more of these methods is used, and a melt polymerization method or a combination of a melt polymerization method and a solid-state polymerization method is preferably used. The compounds having ester-forming ability may be used for polymerization in their original form, or may be modified from precursors to derivatives having ester-forming ability in the previous stage of polymerization. When polymerizing these, various catalysts can be used, and typical examples are potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, antimony trioxide, tris(2,4-pentanedionate ) metal salt-based catalysts such as cobalt (III), and organic compound-based catalysts such as N-methylimidazole and 4-dimethylaminopyridine. The amount of catalyst used is generally about 0.001 to 1% by mass, particularly preferably about 0.01 to 0.2% by mass, based on the total mass of the monomers. Polymers produced by these polymerization methods can be further increased in molecular weight by solid-state polymerization by heating under reduced pressure or in an inert gas, if necessary.

The melt viscosity of the (A) liquid crystalline resin obtained by the above method is not particularly limited. In general, a melt viscosity at a molding temperature of 3 Pa·s or more and 500 Pa·s or less at a shear rate of 1000 sec ^-1 can be used. However, those having excessively high viscosity themselves are undesirable because the fluidity is greatly deteriorated. Moreover, the mixture of 2 or more types of liquid crystal resins may be sufficient as said (A) liquid crystalline resin.

In the liquid crystalline resin composition of the present invention, the content of the liquid crystalline resin (A) is preferably 42 to 73 mass%, more preferably 47.3 to 67.7 mass%, still more preferably 52.5 to 64.5 mass%. am. If the content of component (A) is within the above range, it is preferable in terms of fluidity, heat resistance, and the like.

[(B) fibrous conductive filler]

The conductive liquid crystalline resin composition according to the present invention contains a fibrous conductive filler. Fibrous conductive fillers can be used alone or in combination of two or more.

(B) The average fiber length of the fibrous conductive filler is not particularly limited, and from the viewpoint of conductivity, for example, it may be 50 μm or more and 10 mm, 80 μm or more and 8 mm, or 100 μm or more and 7 mm. In the present specification, (B) the average fiber length of the fibrous conductive filler, 10 stereomicroscope images of the fibrous conductive filler are transferred from the CCD camera to the PC, and each stereomicroscope image is taken by the image measuring device according to the image processing technique. The average of the measured fiber length values for 100 fibrous conductive fillers, that is, 1000 fibrous conductive fillers in total, is adopted. The average fiber length of the fibrous conductive filler (B) in the conductive liquid crystalline resin composition is measured by applying the above method to the fibrous conductive filler remaining after carbonizing the conductive liquid crystalline resin composition by heating at 500° C. for 4 hours.

(B) The fiber diameter of the fibrous conductive filler is not particularly limited, and may be, for example, 0.2 to 15 μm, 0.25 to 13 μm, or 0.3 to 11 μm from the viewpoint of conductivity. In the present specification, as the fiber diameter of the (B) fibrous conductive filler, the fibrous conductive filler is observed with a scanning electron microscope and the average of the values obtained by measuring the fiber diameter for 30 fibrous conductive fillers is adopted. The fiber diameter of the fibrous conductive filler (B) in the conductive liquid crystalline resin composition is measured by applying the above method to the fibrous conductive filler remaining after carbonizing the conductive liquid crystalline resin composition by heating at 500° C. for 4 hours.

(B) Examples of the fibrous conductive filler include carbon fiber; conductive fibers such as metal fibers; Examples include inorganic fibrous substances coated with metals such as nickel and copper to impart conductivity, and carbon fibers are preferable from the viewpoint of conductivity.

Examples of carbon fibers include PAN-based carbon fibers using polyacrylonitrile as a raw material and pitch-based carbon fibers using pitch as a raw material.

Examples of metal fibers include fibers made of mild steel, stainless steel, steel and alloys thereof, copper, brass, aluminum and alloys thereof, titanium, lead, and the like. These metal fibers may also be coated with other metals to impart additional conductivity if necessary according to their conductivity.

Examples of the inorganic fibrous material include glass fiber, milled glass fiber, asbestos fiber, silica fiber, silica/alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate whisker, calcium silicate whisker (fibrous bolastonite ) and the like.

[(C) Granular Conductive Filler]

The conductive liquid crystalline resin composition according to the present invention contains a granular conductive filler. The particulate conductive filler can be used alone or in combination of two or more.

(C) The median diameter of the particulate conductive filler is not particularly limited, and from the viewpoint of conductivity, for example, it may be 10 nm or more and 50 μm or less, 15 nm or more and 20 μm or less, or 18 nm or more and 10 μm or less. . In addition, in this specification, a median diameter refers to the volume-based median value measured by the laser diffraction/scattering type particle size distribution method.

(C) Examples of the granular conductive filler include carbon black, granular metal powder (eg aluminum, iron, copper), granular conductive ceramics (eg zinc oxide, tin oxide, indium tin oxide), etc. From the point of view, carbon black is preferred. Carbon black is not particularly limited as long as it is generally available for use in resin coloring. Usually, carbon black contains lumps formed by aggregation of primary particles, but as long as it does not contain significantly more lumps with a size of 50 μm or more, the resin composition of the present invention is molded It is difficult to generate many boots (fine millet-like protrusions (fine irregularities) in which carbon black is aggregated) on the surface of the molded body. When the content of the particles having a particle size of 50 µm or more is 20 ppm or less, the smoothness of the surface of the molded article tends to increase. A preferable content rate is 5 ppm or less.

The total content of (B) fibrous conductive filler and (C) particulate conductive filler is 25 to 50% by mass, preferably 29 to 45% by mass, more preferably in the conductive liquid crystalline resin composition of the present invention. is 33 to 40% by mass. When the content of the above total is 25% by mass or more, the volume resistivity of the molded body tends to be low, and it is easy to obtain a molded body with improved conductivity. When the content of the above total is 50% by mass or less, the flowability of the conductive liquid crystalline resin composition is easily improved and the conductive liquid crystalline resin composition excellent in molding processability is easily obtained.

The mass ratio of the content of the fibrous conductive filler (B) to the content of the particulate conductive filler (C) is 0.50 to 3.00, preferably 0.60 to 2.50, more preferably 0.70 to 2.00. When the mass ratio is 0.50 or more, the flowability of the conductive liquid crystalline resin composition is easily improved, it is easy to obtain a conductive liquid crystalline resin composition having excellent molding processability, and the thickness dependence of the conductivity of a molded body is easily reduced, regardless of the thickness, It is easy to obtain molded articles with small fluctuations in volume resistivity. When the mass ratio is 3.00 or less, the thickness dependence of the conductivity of the molded body is easily reduced, and a molded body with small variation in volume resistivity is easily obtained regardless of the thickness.

[(D) non-conductive filler]

A non-conductive filler is contained in the conductive liquid crystalline resin composition according to the present invention. A non-conductive filler can be used individually by 1 type or in combination of 2 or more types. (D) As a non-conductive filler, a plate-shaped non-conductive filler, a particulate non-conductive filler, and a fibrous non-conductive filler are mentioned, for example.

The median diameter of the plate-like nonconductive filler is not particularly limited, and may be, for example, 10 to 100 μm, 12 to 50 μm, or 14 to 30 μm. When the plate-like non-conductive filler has a median diameter of 10 to 100 µm, the thickness dependence of the conductivity of the molded body is easily reduced, and a molded body with small variation in volume resistivity is easily obtained regardless of the thickness. Examples of the plate-shaped non-conductive filler include talc, mica, and glass flakes.

The median diameter of the granular non-conductive filler is not particularly limited, and may be, for example, 0.3 to 50 µm, 0.4 to 25 µm, or 0.5 to 5.0 µm. When the median diameter of the granular non-conductive filler is 0.3 to 50 µm, the thickness dependence of the conductivity of the molded body is easily reduced, and a molded body with small variation in volume resistivity is easily obtained regardless of the thickness. Examples of the granular non-conductive filler include silicates such as silica, quartz powder, glass beads, glass balloons, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, and wollastonite; metal oxides such as iron oxide, titanium oxide, zinc oxide, and alumina; metal carbonates such as calcium carbonate and magnesium carbonate; metal sulfates such as calcium sulfate and barium sulfate; silicon carbide; silicon nitride; Boron nitride etc. are mentioned.

The average fiber length of the fibrous non-conductive filler is not particularly limited, and may be, for example, 50 μm or more and 10 mm, 80 μm or more and 7 mm, or 100 μm or more and 4 mm. When the average fiber length of the fibrous non-conductive filler is 50 μm or more and 10 mm, the thickness dependence of the conductivity of the molded article is easily reduced, and a molded article with small variation in volume resistivity is easily obtained regardless of the thickness. The fiber diameter of the fibrous non-conductive filler is not particularly limited, and may be, for example, 0.2 to 15 μm, 0.25 to 13 μm, or 0.3 to 11 μm. When the fiber diameter of the fibrous non-conductive filler is 0.2 to 15 μm, the thickness dependence of the conductivity of the molded body is easily reduced, and a molded body with small variation in volume resistivity is easily obtained regardless of the thickness. As the average fiber length of the fibrous non-conductive filler and the fiber diameter of the fibrous non-conductive filler, the average of the values measured in the same manner as described above for (B) the fibrous conductive filler is adopted. As the fibrous non-conductive filler, for example, glass fiber, milled glass fiber, asbestos fiber, silica fiber, silica/alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate whisker, calcium silicate whisker ( and inorganic fibrous substances such as fibrous wollastonite).

Since the thickness dependence of the conductivity of the molded object is more easily reduced and it is easier to obtain a molded object having a smaller fluctuation in volume resistivity regardless of the thickness, (D) the non-conductive filler is preferably talc, mica, glass flake, At least one selected from the group consisting of silica, glass beads, glass balloons, potassium titanate whiskers, calcium silicate whiskers, milled glass fibers, and glass fibers, more preferably composed of talc, mica, silica, and glass fibers at least one selected from the group, and even more preferably at least one selected from the group consisting of talc, mica, and silica.

(D) The content of the non-conductive filler in the conductive liquid crystalline resin composition of the present invention is 2 to 8% by mass, preferably 2.3 to 7.7% by mass, more preferably 2.5 to 7.5% by mass. When the content is 2 to 8% by mass, the flowability of the conductive liquid crystalline resin composition is easily improved, and the conductive liquid crystalline resin composition excellent in molding processability is easily obtained.

[Other Ingredients]

In the liquid crystal resin composition of the present invention, other polymers, other fillers, known substances generally added to synthetic resins, that is, stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, Other components such as flame retardants, colorants such as dyes and pigments, lubricants, crystallization accelerators, crystal nucleating agents, and mold release agents may also be appropriately added according to required performance. The other components may be used singly or in combination of two or more.

Examples of other polymers include epoxy group-containing copolymers. Other polymers may be used singly or in combination of two or more.

Other fillers refer to fillers other than (B) fibrous conductive filler, (C) particulate conductive filler, and (D) non-conductive filler, examples of which include conductive fillers other than component (B) and component (C). can Other fillers may be used alone or in combination of two or more. Examples of conductive fillers other than component (B) and component (C) include plate-shaped conductive fillers.

[Preparation Method of Conductive Liquid Crystalline Resin Composition]

The preparation method of the conductive liquid crystalline resin composition of this invention is not specifically limited. For example, a conductive liquid crystalline resin composition is prepared by blending at least one of the above components (A) to (D) and optionally other components, and melt-kneading them using a single screw or twin screw extruder. .

[Conductive Liquid Crystalline Resin Composition]

The conductive liquid crystalline resin composition of the present invention obtained as described above has a melt viscosity of preferably 150 Pa·sec or less, more preferably 145 Pa·sec or less, and 140 Pa·sec or less, from the viewpoint of fluidity during melting and molding processability. It is more preferable that it is sec or less. In this specification, as the melt viscosity, a value obtained by a measuring method based on ISO 11443 under conditions of a cylinder temperature 10 to 20° C. higher than the melting point of the liquid crystalline resin and a shear rate of 1000 sec ^-1 is employed.

<Conductive material>

A conductive material can be produced using the conductive liquid crystalline resin composition of the present invention. The conductive material of the present invention consists of a molded article of the conductive liquid crystalline resin composition of the present invention. The conductive material of the present invention not only has a low volume resistivity, but also has a small variation in volume resistivity regardless of its thickness. Therefore, the conductive material of the present invention can be suitably used for complex shaped products having various thicknesses, and specifically, can be used for connectors, transmission boards, antennas, and the like.

Example

The present invention will be described in more detail by way of examples below, but the present invention is not limited only to these examples.

<liquid crystalline resin>

ㆍ Liquid crystalline polyesteramide resin

After putting the following raw materials into the polymerization vessel, the temperature of the reaction system was raised to 140°C and reacted at 140°C for 1 hour. Thereafter, the temperature was further raised to 340° C. over 4.5 hours, and from there the pressure was reduced to 10 Torr (i.e., 1330 Pa) over 15 minutes to remove acetic acid, excess acetic anhydride, and other low specific contents. Melt polymerization was performed while distilling. After the stirring torque reached a predetermined value, nitrogen was introduced to a pressurized state from a reduced pressure state through normal pressure, the polymer was discharged from the lower portion of the polymerization vessel, and the strands were pelletized to obtain pellets. The obtained pellets were subjected to heat treatment at 300°C for 2 hours under a nitrogen stream to obtain a target polymer. The melting point of the obtained polymer was 336°C, and the melt viscosity at 350°C was 19.0 Pa·s. In addition, the melting point of the polymer was measured according to the melting point measurement method described later, and the melt viscosity of the polymer was measured in the same manner as the melt viscosity measurement method described later.

(I) 4-hydroxybenzoic acid (HBA); 1380 g (60 mol%)

(II) 2-hydroxy-6-naphthoic acid (HNA); 157 g (5 mol %)

(III) 1,4-phenylenedicarboxylic acid (TA); 484 g (17.5 mol%)

(IV) 4,4'-dihydroxybiphenyl (BP); 388 g (12.5 mol%)

(V) N-acetyl-p-aminophenol (APAP); 126 g (5 mol %)

metal catalyst (potassium acetate catalyst); 110 mg

acylating agents (acetic anhydride); 1659g

<Materials other than liquid crystalline resin>

ㆍFibrous conductive filler: Teijin Co., Ltd. HTC432 (PAN-based carbon fiber, chopped strand, fiber diameter 7 ㎛, length 6 mm)

ㆍCarbon black: VULCAN XC305 (manufactured by Cabot Japan Co., Ltd., central diameter 20 nm, particle diameter 50 ㎛ or more particle ratio is 20 ppm or less)

ㆍTalc: Crown Talc PP (manufactured by Matsumura Industrial Co., Ltd., talc, central diameter 14.6 ㎛)

ㆍMica: AB-25S (manufactured by Yamaguchi Mica Co., Ltd., mica, center diameter 25.0 ㎛)

ㆍSilica: Denka Fused Silica FB-5SDC (manufactured by Denka Co., Ltd., silica, central diameter 4.0 μm)

ㆍGlass fiber: ECSO3T-786H (manufactured by Nippon Electric Glass Co., Ltd., chopped strand, fiber diameter 10 ㎛, length 3 mm)

[Method of measuring melting point]

A DSC manufactured by TA Instruments Co., Ltd., after measurement of the endothermic peak temperature (Tm1) observed when the liquid crystalline resin was heated from room temperature at a temperature rise condition of 20°C/min, held at a temperature of (Tm1+40)°C for 2 minutes, then 20 The temperature of the endothermic peak observed when the mixture was once cooled to room temperature at a temperature decrease condition of °C/min and then heated again at a temperature increase condition of 20 °C/min was measured.

<Preparation of conductive liquid crystalline resin composition>

The above components were melt-kneaded at a cylinder temperature of 350° C. using a twin-screw extruder (TEX30 α type manufactured by Nippon Seikosho Co., Ltd.) at the ratios (unit: mass%) shown in Table 1 or Table 2, and conductive liquid crystalline resin Composition pellets were obtained.

<melt viscosity>

Compliant with ISO11443 at a shear rate of 1000/sec, using an orifice with an inner diameter of 1 mm and a length of 20 mm, at a temperature 10 to 20°C higher than the melting point of the liquid crystalline resin, using Capillograph type 1B manufactured by Toyo Seiki Seisakusho Co., Ltd. The melt viscosity of the conductive liquid crystalline resin composition was measured. In addition, the measurement temperature was 350 degreeC. The results are shown in Table 1 and Table 2.

<Volume resistivity>

The pellets of Examples and Comparative Examples were molded using a molding machine ("SE100DU" manufactured by Sumitomo Heavy Machinery Co., Ltd.) under the following molding conditions, and formed into flat test pieces 1 or 80 mm × 80 mm of 80 mm × 80 mm × 1 mmt. A flat test piece 2 of × 2 mmt was obtained. Using the flat test piece 1, the volume resistivity (hereinafter also referred to as "1 mmt volume resistivity") was measured in accordance with JIS K 7194 using a resistivity meter ("Loresta-GP" manufactured by Nitto Seiko Analytech Co., Ltd.) . In addition, using flat test piece 2, a resistivity meter (“Loresta-GP” manufactured by Nitto Seiko Analytech Co., Ltd.) was used to measure volume resistivity (hereinafter also referred to as “2 mmt volume resistivity”) in accordance with JIS K 7194. measured. In addition, the difference between the 1 mmt volume resistivity and the 2 mmt volume resistivity was calculated. The results are shown in Table 1 and Table 2. When the absolute value of the difference was 0.10 Ω·cm or less, it was evaluated that the change in volume resistivity was small regardless of the thickness.

[Molding conditions]

Cylinder temperature: 350℃

Mold temperature: 80℃

Injection speed: 33mm/sec

As is evident from the results described in Tables 1 and 2, it is confirmed that the compositions of Examples have low melt viscosity and high fluidity, so that they are excellent in molding processability, and molded articles provided by the compositions of Examples have low volume resistivity. In addition, it was confirmed that the variation of the volume resistivity was small regardless of the thickness.

Claims (4)

(A) a liquid crystal resin, (B) a fibrous conductive filler, (C) a particulate conductive filler, and (D) a non-conductive filler;
The total content of the fibrous conductive filler (B) and the particulate conductive filler (C) is 25 to 50% by mass,
The mass ratio of the content of the fibrous conductive filler (B) to the content of the particulate conductive filler (C) is 0.50 to 3.00,
The conductive liquid crystalline resin composition in which the content of the (D) non-conductive filler is 2 to 8% by mass. According to claim 1,
The (B) fibrous conductive filler is carbon fiber,
The (C) particulate conductive filler is a conductive liquid crystalline resin composition of carbon black. According to claim 1 or 2,
The (D) non-conductive filler is at least one selected from the group consisting of talc, mica, glass flakes, silica, glass beads, glass balloons, potassium titanate whiskers, calcium silicate whiskers, milled glass fibers, and glass fibers, conductive A liquid crystalline resin composition. According to any one of claims 1 to 3,
The (D) non-conductive filler is at least one selected from the group consisting of talc, mica, silica, and glass fibers, the conductive liquid crystalline resin composition.