JP5352364B2 - Thermoplastic resin composition and molded article thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition excellent in electric properties such as electroconductivity and antistatic property without impairing mechanical strength and heat resistance which are intrinsic to a thermoplastic resin, and to provide a molded product thereof. <P>SOLUTION: This thermoplastic resin composition includes hollow carbon fibrils contained by 0.1-20 wt.% and dispersed therein. The thermoplastic resin is a blend of polyphenylene ether and aromatic vinyl compound polymer or a blend of polyphenylene ether and polyamide. The carbon fibrils include sole fibrils and aggregated fibrils, and the dispersion state of the fibrils has the ratio of soleness/aggregation of 8/92-40/60 and the average length of sole fibrils of 20-200 nm as expressed by an index based on a transmission electron microscope photograph determination. The molded product of the thermoplastic resin composition is also provided. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a thermoplastic resin composition excellent in mechanical strength and heat resistance, and excellent in electrical properties such as conductivity and antistatic properties, and a molded article.

  Originally, it has been practiced for a long time to blend conductive materials into thermoplastic resins that are electrically insulating, and to have properties such as conductivity and antistatic properties. For this reason, various conductive materials have been used. Yes. Examples of commonly used organic conductive materials such as ionic or nonionic organic surfactants, polymer antistatic agents having polyethylene glycol units or ionic functional groups, carbon black, carbon fibers, Examples thereof include inorganic conductive materials such as metal fibers, metal powders, and metal oxides. However, when these conductive materials are blended, the surface resistance value, which is a measure of conductivity, can be lowered, but the organic conductive material has an adverse effect on heat resistance, and the inorganic conductive material has impact strength and It had sacrificed the inherent properties of thermoplastics such as adversely affecting the surface appearance.

  On the other hand, in terms of needs, demands for conductive resins are becoming stricter year by year. For example, OA equipment and electronic equipment are becoming smaller, lighter, more integrated, and more accurate. There is an increasing demand to reduce the adhesion of dust and dust as much as possible. For example, in the case of computers, semiconductor wafers, IC chips, internal parts of hard disks, etc. are the best examples, and in order to prevent the adhesion of dust and dust, the antistatic property is given to the transportation and packaging materials of these parts. Has been done. For these materials, polycarbonate and polyphenylene ether resins (blends of polyphenylene ether and polystyrene) are usually used from the viewpoint of dimensional accuracy and heat resistance, and conductive grades with conductivity are provided. However, as described above, when an organic conductive material is used, heat resistance is sacrificed, and when an inorganic conductive material is used, there is a problem of generation of dust due to dropping off of the inorganic material.

  Further, in automobile parts, particularly exterior and outer plate parts, “electrostatic coating” is performed in which electricity is applied to a resin molded product imparted with conductivity, and a paint having an opposite charge is sprayed. This is to improve the adhesion rate of the paint by utilizing the property of attracting each other by imparting opposite charges to the surface of the molded article and the paint. For these automobile parts, blends of polycarbonate and polyester and blends of polyphenylene ether and polyamide are usually used because of their rigidity, impact strength, heat resistance and chemical resistance. However, in order to impart conductivity to these resin materials, heat resistance is sacrificed when an organic conductive material is used, and when using an inorganic conductive material, appearance deterioration and impact strength are reduced. There was a problem of decline.

Japanese Patent No. 2862578 Japanese Patent No. 2641712 JP-A-9-111135

  As techniques for improving these problems, techniques using hollow carbon fibrils have recently been disclosed in Japanese Patent No. 2862578, Japanese Patent No. 2641712, Japanese Patent Laid-Open No. 9-111135, and the like. Hollow carbon fibrils can be imparted with a small amount of conductivity due to their unique shape, minimizing the reduction in appearance and impact strength that has been a problem with conventional inorganic conductive materials. It is expected to be possible. However, this hollow carbon fibril is inferior in dispersibility with the thermoplastic resin, and if it is simply mixed, the expected conductivity cannot be obtained, and an appearance defect resulting from poor dispersion is caused. In order to solve this, Japanese Patent No. 2862578 discloses that hollow carbon fibrils used are aggregates intertwined with each other, and those having a diameter of 0.10 to 0.25 mm give good dispersion. . However, in this case as well, the conductivity with respect to the added amount is not always satisfactory, and there is no description about the dispersion state of the hollow carbon fibrils in the resin. When hollow carbon fibrils are blended with a thermoplastic resin, the dispersion state of the hollow carbon fibrils in the resin greatly affects the electrical properties of the molded product, and the expected electrical properties are difficult to obtain unless a good dispersion state is achieved. Conventionally, in order to obtain good electrical properties, the amount of hollow carbon fibrils added is increased, resulting in deterioration of the surface appearance of the molded body and reduction in impact strength, and the properties of hollow carbon fibrils have been fully utilized. There wasn't.

  An object of the present invention is to provide a thermoplastic resin composition excellent in electrical properties such as conductivity and antistatic property and a molded article thereof without impairing the mechanical strength and heat resistance inherent to the thermoplastic resin. Is.

  As a result of intensive studies to solve the above problems, the present inventors have added a small amount by controlling the hollow carbon fibrils to a specific dispersion state when blending the hollow carbon fibrils with the thermoplastic resin. Thus, the inventors have found that good electrical characteristics (conductivity and antistatic properties) can be obtained, and that the mechanical strength and heat resistance inherent to the thermoplastic resin can be maintained, and the present invention has been achieved.

That is, the present invention includes hollow carbon fibrils dispersed in a thermoplastic resin, and the content of the hollow carbon fibrils is 0.00. 7 to 2.0 % by weight of the thermoplastic resin composition, wherein the thermoplastic resin is a blend of a polyphenylene ether and an aromatic vinyl compound polymer, or a blend of polyphenylene ether and a polyamide, and the carbon fibril Is composed of single fibrils and aggregated fibrils, and the dispersion state of the carbon fibrils is expressed by an index based on the measurement of fluoroscopic electron micrographs, and the single / aggregation ratio is in the range of 8/92 to 40/60. And the single fibril average length exists in the range of 20-200 nm, The thermoplastic resin composition characterized by the above-mentioned is provided.

  The thermoplastic resin molded article of the present invention is excellent in mechanical strength, heat resistance and impact strength, and has improved electrical conductivity and antistatic properties. Therefore, its industrial utility is great. It is useful in many fields such as transportation of electric and electronic parts, packaging materials, and automobile parts for electrostatic coating.

2 is a transmission electron micrograph of the surface of a molded product section of Example 1. FIG. FIG. 3 is a schematic diagram of a transmission electron micrograph of the surface of a molded body section of Example 1.

Hereinafter, the present invention will be described in detail.
(1) Thermoplastic resin The thermoplastic resin used in the present invention is not particularly limited as long as it can be melted and molded. Specific examples include polycarbonate, polyphenylene ether, polyamide, polyester, aromatic vinyl compound polymer, polyolefin, polyacetal, polyphenylene sulfide, polysulfone, and polyether ether ketone.

As the polycarbonate polycarbonate, aromatic polycarbonate, aliphatic polycarbonate, and aromatic-aliphatic polycarbonate can be used, but aromatic polycarbonate is preferable. An aromatic polycarbonate is an optionally branched thermoplastic polymer or copolymer obtained by reacting an aromatic hydroxy compound or a small amount thereof with a diester of phosgene or carbonic acid. The production method can be arbitrarily selected from a phosgene method (interfacial polymerization method), a melting method (transesterification method) and the like. Furthermore, the aromatic polycarbonate which adjusted the amount of OH groups of the terminal group manufactured by the melting method can also be used. Specific examples of the aromatic dihydroxy compound include 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A), tetramethylbisphenol A, bis (4-hydroxyphenyl) -p-diisopropylbenzene, hydroquinone, resorcinol, 4,4-dihydroxydiphenyl and the like can be mentioned, and bisphenol A is preferred. Further, for the purpose of further improving the flame retardancy, a compound or oligomer having both ends of a phenolic OH group having a siloxane structure and / or a compound in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compound is used. You can also To obtain a branched aromatic polycarbonate, phloroglucin, 4,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptene-2, 4,6-dimethyl-2,4,6-tri (4 -Hydroxyphenyl) heptane, 2,6-dimethyl-2,4,6-tri (4-hydroxyphenylheptene-3,1,3,5-tri (4-hydroxyphenyl) benzene, 1,1,1- A polyhydroxy compound represented by tri (4-hydroxyphenyl) ethane or the like, or 3,3-bis (4-hydroxyaryl) oxindole (= isatin bisphenol), 5-chloruisatin, 5,7-dichloroisatin, 5-bromoisatin Etc. may be used as part of the aromatic dihydroxy compound, and the amount used is 0.01 to 10 mol%, preferably In order to adjust the molecular weight, monovalent aromatic hydroxy compounds may be used, and m- and p-methylphenol, m- and p-propylphenol, p-tert-butylphenol and p. -Long chain alkyl substituted phenols, etc. The aromatic polycarbonate is preferably a polycarbonate resin derived from 2,2-bis (4-hydroxyphenyl) propane, or 2,2-bis (4-hydroxyphenyl). ) Polycarbonate copolymers derived from propane and other aromatic dihydroxy compounds, and polymers or oligomers having a siloxane structure can be copolymerized for the purpose of enhancing flame retardancy. May be used by mixing two or more resins. The molecular weight of the bonate is 13,000 to 30,000, more preferably 15,000 to 27,000 in terms of viscosity average molecular weight converted from the solution viscosity measured at a temperature of 25 ° C. using methylene chloride as a solvent. Yes, most preferably from 17,000 to 24,000 If the viscosity average molecular weight is less than 13,000, the mechanical strength is insufficient, and if it exceeds 30,000, the moldability is poor, which is not preferred.

Polyphenylene ether Polyphenylene ether is the following general formula (1)

(Wherein Q1 represents a halogen atom, a primary or secondary alkyl group, an aryl group, an aminoalkyl group, a hydrocarbonoxy group or a halohydrocarbonoxy group, and Q2 represents a hydrogen atom, A homopolymer having a structure represented by a halogen atom, a primary or secondary alkyl group, an aryl group, a haloalkyl group, a hydrocarbonoxy group or a halohydrocarbonoxy group, wherein m represents a number of 10 or more. Or it is a copolymer. Suitable examples of primary alkyl groups for Q1 and Q2 are methyl, ethyl, n-propyl, n-butyl, n-amyl, isoamyl, 2-methylbutyl, n-hexyl, 2,3-dimethylbutyl, 2- , 3- or 4-methylpentyl or heptyl. Suitable examples of secondary alkyl groups are isopropyl, sec-butyl or 1-ethylpropyl. In many cases, Q1 is an alkyl group or a phenyl group, particularly an alkyl group having 1 to 4 carbon atoms, and Q2 is a hydrogen atom. Suitable homopolymers of polyphenylene ether include, for example, those composed of 2,6-dimethyl-1,4-phenylene ether units. A suitable copolymer is a random copolymer comprising a combination of the above units and 2,3,6-trimethyl-1,4-phenylene ether units. Many suitable homopolymers or random copolymers are described in the patents and literature. Also suitable are polyphenylene ethers containing molecular constituents that improve properties such as, for example, molecular weight, melt viscosity and / or impact strength. The polyphenylene ether used here is preferably one having an intrinsic viscosity at 30 ° C. of 0.2 to 0.8 dl / g measured in chloroform. More preferably, the intrinsic viscosity is 0.2 to 0.7 dl / g, and particularly preferably 0.25 to 0.6 dl / g. If the intrinsic viscosity is less than 0.2 dl / g, the impact resistance of the composition is insufficient, and if it exceeds 0.8 dl / g, the moldability is unsatisfactory.

Polyamide Polyamide is a thermoplastic polymer having a -CONH- bond in the main chain. Typical examples include nylon-4, nylon-6, nylon-6,6, nylon-4,6, nylon-12, and nylon-6,10. In addition, a crystalline or amorphous polyamide containing a monomer component such as a known aromatic diamine or aromatic dicarboxylic acid may be used. As used herein, the amorphous polyamide refers to a material having substantially no crystallinity measured by a scanning scanning calorimeter (DSC). Preferred polyamides are nylon-6, nylon-6,6, and semi-aromatic nylon, and it is also preferable to use these together with amorphous polyamide. Further, the polyamide preferably has a relative viscosity of 2.0 to 6.0 measured in 25 ° C. and 98% concentrated sulfuric acid. If it is less than 2.0, the mechanical strength is insufficient, and if it exceeds 6.0, the moldability is inferior.

Examples of the polyester polyester include thermoplastic polyesters obtained by condensing dicarboxylic acid or its lower alkyl ester, acid halide, acid anhydride and other derivatives with glycol or dihydric phenol. Specific examples of dicarboxylic acids suitable for the production of this polyester include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid and other aliphatic dicarboxylic acids, terephthalic acid, isophthalic acid, and the like. Acid, p, p'-dicarboxydiphenylsulfone, p-carboxyphenoxyacetic acid, p-carboxyphenoxypropionic acid, p-carboxyphenoxybutyric acid, p-carboxyphenoxyvaleric acid, 2,6-naphthalene dicarboxylic acid, 2,7- Aromatic dicarboxylic acids such as naphthalene dicarboxylic acid or a mixture of these carboxylic acids. Specific examples of glycols suitable for the production of polyester include linear alkylene glycols having 2 to 12 carbon atoms such as ethylene glycol, 1,3-propylene glycol, 1,4-butene glycol, 1,6-hexene glycol, In addition to aliphatic glycols such as 1,12-dodecamethylene glycol, aromatic glycols such as p-xylylene glycol, and alicyclic glycols such as 1,4-cyclohexanedimethanol are exemplified. Includes pyrocatechol, resorcinol, hydroquinone or alkyl-substituted derivatives of these compounds. Other examples of polyesters include polyesters obtained by ring-opening polymerization of lactones. For example, polypivalolactone, poly (ε-caprolactone) and the like. Still another example of the polyester is a polyester as a polymer that forms a liquid crystal in a molten state (Thermotropic Liquid Crystal Polymer; TLCP). Typical examples of polyesters that fall into these categories are X7G from Eastman Kodak, Xyday from Dartco, Econol from Sumitomo Chemical, Vectra from Celanese. Among the various polyesters listed above, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polynaphthalene terephthalate (PEN), poly (1,4-cyclohexanedimethylene terephthalate) (PCT), liquid crystalline polyester, and the like. The polyester is suitable for the present invention.

Aromatic vinyl compound polymer Aromatic vinyl compound polymer refers to the following general formula (2)

(In the formula, R represents a hydrogen atom, a lower alkyl group or a halogen atom, Z represents a hydrogen atom, a lower alkyl group, a chlorine atom or a vinyl group, and n represents an integer of 1-5.)
A polymer derived from a monomer compound having a structure represented by: Specific examples of the aromatic vinyl compound polymer include polystyrene, rubber-reinforced polystyrene, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer, styrene-maleic anhydride copolymer, styrene-maleimide copolymer, and the like. is there.

Polyolefin polyolefin is mainly composed of α-olefin homopolymer, α-olefin copolymer or α-olefin (multiple types), and other unsaturated monomer (multiple types). A copolymer as an accessory component. Here, the copolymer may be any type of copolymer such as block, random, graft, or a composite thereof. In addition, these olefin polymers are modified by chlorination, sulfonation, carbonylation and the like. Examples of the α-olefin include ethylene, propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, and the like, and those having C2 to C8 are preferable from the standpoint of availability. Examples of the unsaturated monomer include acrylic acid, methacrylic acid (hereinafter abbreviated as “(meth) acrylic acid”), (meth) acrylic acid ester, maleic acid, and the like. Derivatives such as unsaturated organic acids or esters thereof, anhydrides, unsaturated aliphatic cyclic olefins and the like can be mentioned. Specific examples of polyolefin include low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, polybutene, poly-4-methyl-pentene-1, propylene-ethylene block or random copolymer, ethylene and other copolymers. Examples thereof include a copolymer with a polymerizable monomer.

The polyacetal polyacetal is a high molecular weight polymer produced by polymerization of formaldehyde or trioxane, and includes a homopolymer having an oxymethylene group as a repeating unit. In order to increase heat resistance and chemical resistance, it is common practice to convert terminal groups to ester groups or ether groups. The polyacetal may be a block copolymer. This type of copolymer is composed of a homopolymer block having the above oxymethylene group as a repeating unit and another type of polymer block. Specific examples of other types of polymer blocks include polyalkylene glycol, polythiol, vinyl acetate-acrylic acid copolymer, and hydrogenated butadiene-acrylonitrile copolymer. The polyacetal may also be a random copolymer. In this type of copolymer, formaldehyde and trioxane are copolymerized with other aldehydes, cyclic ethers, vinyl compounds, ketene, cyclic carbonates, epoxides, isocyanates, ethers, and the like. Specific examples of the compound to be copolymerized include ethylene oxide, 1,3-dioxane, 1,3-dioxepene, epichlorohydrin, propylene oxide, isobutylene oxide, and styrene oxide. In this type of copolymer, the polymerization catalyst is generally deactivated, terminal-stabilized, and the like after cationic polymerization. A copolymer containing an oxymethylene group as a main repeating unit and containing an oxyalkylene group having 2 or more carbon atoms is widely used.

Polyphenylene sulfide Polyphenylene sulfide is the following structural formula (3)

Is a crystalline resin containing a repeating unit represented by As a polymerization method of polyphenylene sulfide, a method in which sodium sulfide and p-dichlorobenzene are reacted in an amide solvent such as N-methylpyrrolidone or dimethylacetamide or a sulfone solvent such as sulfolane is suitable. A method of polymerizing dichlorobenzene in the presence of sulfur and sodium carbonate, a method of polymerizing in the presence of sodium sulfide or sodium hydrosulfide and sodium hydroxide or hydrogen sulfide and sodium hydroxide in a polar solvent, p-chlorothiophenol Self-condensation can also be used. The polyphenylene sulfide includes various polymers as long as the above repeating unit is a main constituent. That is, a homopolymer consisting of only the above repeating unit, a copolymer containing this as a main constituent (80 mol% or more) and containing one or more other repeating units in a proportion of 20 mol% or less. Can be used.

  Moreover, the above-mentioned various thermoplastic resins may be used alone or in combination of two or more. Among these, one or a combination of two or more selected from the group consisting of polycarbonate, polyphenylene ether, polyamide, polyester, and aromatic vinyl compound polymer is preferable.

(2) Hollow carbon fibril The hollow carbon fibril used in the present invention has an outer region composed of an essentially continuous multi-layer of regularly arranged carbon atoms, and an inner hollow region. Are essentially cylindrical fibrils arranged substantially concentrically around the cylinder axis of the fibrils. Furthermore, the regularly arranged carbon atoms in the outer region are preferably graphite-like, and the diameter of the hollow region is preferably 2 to 20 nm. The outer diameter of the hollow carbon fibril used in the present invention is preferably 3.5 to 70 nm, more preferably 4 to 60 nm, and the aspect ratio (referring to the ratio of length / outer diameter) is preferably 5 Above, more preferably 10 or more. When the fibril outer diameter is less than 3.5 nm, the dispersibility in the resin is inferior, and when it exceeds 70 nm, the conductivity of the resulting thermoplastic resin molded article is unsatisfactory. On the other hand, if the aspect ratio is less than 5, the resulting thermoplastic resin molding is unsatisfactory. Such hollow carbon fibrils are described in detail in Japanese Patent Publication No. 62-5000943 and US Pat. No. 4,663,230. As for the production method, as described in the above-mentioned patent publications and US patent specifications, transition metal-containing particles (for example, iron, cobalt, nickel-containing particles using alumina as a support) are mixed with carbon such as CO and hydrocarbons. There is a method in which the contained gas is brought into contact at a high temperature of 850 to 1200 ° C., and carbon generated by thermal decomposition is grown in a fiber form starting from a transition metal. The hollow carbon fibril used in the present invention is commercially available from Hyperion Catalysis under the trade name “Graphite Fibril” and is easily available.

(3) Optional component In the present invention, the thermoplastic resin composition may be added with stabilizers such as ultraviolet absorbers and antioxidants, pigments, dyes, lubricants, flame retardants, release agents, etc., as necessary. An inorganic reinforcing agent such as an agent, glass fiber, glass flake, potassium titanate, wollastonite, talc and mica can be added and blended. Moreover, the elastomer normally used as an impact resistance improving agent can also be added to a thermoplastic resin composition.

(4) Composition ratio When the composition ratios of the respective components described above (all are expressed in terms of% by weight based on the total weight of the thermoplastic resin composition containing the components (1) to (3)) are summarized as follows: Street.
Thermoplastic resin: 80 to 99.9% by weight, preferably 90 to 99.6% by weight, particularly preferably 95 to 99.3% by weight in the thermoplastic resin composition. If it is less than 80% by weight, the mechanical strength and moldability are unsatisfactory, and if it exceeds 99.9% by weight, the conductivity is insufficient.
Content of hollow carbon fibrils: 0.1 to 20% by weight, preferably 0.4 to 10% by weight, particularly preferably 0.7 to 5% by weight in the thermoplastic resin composition. If it is less than 0.1% by weight, the electrical conductivity is unsatisfactory, and if it exceeds 20% by weight, the mechanical strength and moldability are unsatisfactory.

(5) Production of composition In the present invention, the method for obtaining the thermoplastic resin composition includes various kneaders such as uniaxial and multiaxial kneaders, Banbury mixers, rolls, Brabender plastograms, etc. The above components are added to and dissolved in a suitable solvent, for example, hydrocarbons such as hexane, heptane, benzene, toluene, xylene, and their derivatives, or components to be dissolved. A solution mixing method in which insoluble components are mixed in a suspended state is used. The melt-kneading method is preferable from the industrial cost, but is not limited thereto. Among them, a thermoplastic resin and hollow carbon fibrils are once melt-kneaded so that the hollow carbon fibril content is 10 to 30% by weight to obtain a master batch, and this master batch is melt-kneaded again with the remaining thermoplastic resin. Is preferred in order to obtain good dispersion.

(6) Dispersion state of hollow carbon fibril The hollow carbon fibril in the thermoplastic resin composition or the thermoplastic resin molded article of the present invention is composed of single fibrils and aggregated fibrils, and the dispersion state of the hollow carbon fibrils is as follows: The ratio to the aggregated fibrils and the length of the single fibrils must be within the following predetermined range, expressed by the following index.
Single / aggregation ratio = 8/92 to 40/60
Single fibril average length = 20 to 200 nm
If the “single / aggregation ratio” is outside the predetermined range, the conductivity is insufficient, and if the “single fibril average length” is less than 20 nm, the conductivity is insufficient, and if it exceeds 200 nm, the appearance of the molded article is unsatisfactory. . Preferably, the single / aggregation ratio is 9/91 to 35/65, and the single fibril average length is 25 to 180 nm, and particularly preferably, the single / aggregation ratio is 10/90 to 30/70 and single The average fibril length is 30 to 160 nm.
The dispersion state of the hollow carbon fibrils can be easily confirmed by using an electron microscope. In the present specification, the above “single / aggregation ratio” and “single fibril average length” are the transmission electron. Measured from a 50,000 times photograph taken with a microscope. Specifically, an ultra-thin section having a thickness of 60 to 200 nm, preferably 100 ± 20 nm, is cut out from the thermoplastic resin molded body using an ultramicrotome, placed on a sample stage of a transmission electron microscope, and the section is cut. A photograph (FIG. 1) of the surface of the slice perpendicular to the thickness direction is taken at a magnification of 50,000 with the transmitted light in the thickness direction.
If a photograph (FIG. 1) is described according to a schematic diagram (FIG. 2), in the figure, a indicates a single fibril (indicated by a thick line), and b indicates an aggregated fibril (indicated by a thin line) (note that this schematic diagram is only a single It was created to conceptually clarify the positional relationship between fibrils and aggregated fibrils, and is independent of the actual size). A plurality of photographs are taken at different locations on the section surface. Next, the length of all the fibrils on the photographed photograph is measured separately for single fibrils and aggregated fibrils, and the number is counted only for single fibrils. Of course, the length measured from the photograph is the projection length of the fibrils in the ultrathin section onto the predetermined plane, and does not indicate the absolute length of the fibrils. The “single / aggregation ratio” and “single fibril average length” calculated from the length by the following formula are used as indices.
Single / aggregation ratio = total length of all single fibrils / total length of all aggregate fibrils Average single fibril length = total length of all single fibrils / number of all single fibrils where “single fibril” is The distinction from “aggregated fibrils” is performed as follows. That is, typically, an image of a fibril has a continuous string shape from one end to the other end, and a single fibril is not crossed with another fibril. In addition, even if a loop is made, if it does not cross another fibril, it is set as “single fibril”. All other fibrils shall be “aggregated fibrils”. It should be noted that in this measurement method, those that only show point images are not included in the length of any fibril and are not counted in the number. The length can be measured using an appropriate image analysis software, but in principle, the distance from one end to the other end along the center line of the image of each fibril, This is done by measuring using a map measure or the like. In order to obtain such a dispersed state of hollow carbon fibrils, it is important to set conditions for the melt-kneading process. That is, if the shear stress is too high during melt-kneading, the hollow carbon fibrils are damaged and the length of the single fibril is shortened. Conversely, if the shear stress is too low, the dispersion of the hollow carbon fibrils is insufficient and there are many aggregated fibrils. As a result, sufficient conductivity cannot be obtained. The optimum conditions for melt-kneading differ depending on the type of the extruder and cannot be specified unconditionally, but in the preferred type, the twin-screw extruder, the set value of the cylinder temperature is, in the case of a crystalline resin, Melting point + 20 ° C. to melting point + 100 ° C. In the case of an amorphous resin, it is preferably between glass transition temperature + 100 ° C. and glass transition temperature + 180 ° C., and the screw speed is between 100 and 300 rpm. It is preferable. Of course, melt kneading may be performed under any conditions as long as the dispersion state of the hollow carbon fibrils within the predetermined range is achieved.

(7) Molded body The method for obtaining the thermoplastic resin molded body of the present invention is not particularly limited, and molding methods generally used for thermoplastic resin compositions, such as injection molding, hollow molding, and extrusion molding. A molding method such as sheet molding, thermoforming, rotational molding, and lamination molding can be applied. The thermoplastic resin molded article of the present invention is not limited to a specific application, but as an application that can best bring out the effects of the present invention, transportation of electrical and electronic parts, packaging materials, and automobile parts to be electrostatically coated Is particularly preferred. The transporting and packaging materials for electrical and electronic parts here include IC chip trays, IC component boxes, wafer trays, circuit board storage boxes, hard disks, CDs, DVDs, MO, and other light and magnetic recording media boards, housings And trays for parts such as heads and storage boxes. In addition, examples of automobile parts to be electrostatically coated include automobile parts such as bumpers, fenders, door panels, wheel caps, door handles and the like that include electrostatic painting in the painting process.
The surface resistance value of the molded article of the present invention is preferably 10 ² to 10 ¹² Ω, more preferably 10 ⁴ to 10 ¹⁰ Ω. If it exceeds 10 ¹² Ω, the electrical conductivity is insufficient, and if it is less than 10 ² Ω, the resistance value is too low. As thermoplastic resins used for these applications, polycarbonate and polyphenylene ether resins are preferable from the viewpoints of heat resistance and dimensional accuracy for the transportation and packaging materials of electrical and electronic parts, and rigidity and heat resistance for automobile parts. From the viewpoint of impact strength, a blend of polycarbonate and polyester and a blend of polyphenylene ether and polyamide are preferred. Here, the polyphenylene ether-based resin is a blend of polyphenylene ether and an aromatic vinyl compound polymer, and preferably contains 40% by weight or more of polyphenylene ether. In the blend of polycarbonate and polyester, the ratio of polycarbonate to polyester is preferably in the range of 9: 1 to 5: 5, more preferably in the range of 8: 2 to 6: 4, and the blend of polyphenylene ether and polyamide Then, the ratio of polyphenylene ether and polyamide is preferably in the range of 1: 9 to 5: 5, and more preferably in the range of 2: 8 to 4: 6. In the case of a blend of polyphenylene ether and polyamide, it is preferable to use a compatibilizing agent in order to improve the compatibility. As a preferable compatibilizing agent, maleic anhydride is used. The compound which has both a saturated group and a polar group is mentioned.

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the following examples, the following components were used.
(A) Thermoplastic resin (A-1) Polycarbonate: Poly-4,4-isopropylidenediphenyl carbonate, manufactured by Mitsubishi Engineering Plastics, viscosity average molecular weight 21,000 (hereinafter abbreviated as PC)
(A-2) Polyphenylene ether: Poly-2,6-dimethyl-1,4-phenylene ether, manufactured by Mitsubishi Engineering Plastics, having an intrinsic viscosity of 0.40 dl / g when measured in chloroform at 30 ° C. (Hereafter abbreviated as PPE)
(A-3) Polyamide: Polyamide 6, Kanebo Co., Ltd., trade name Kanebo Nylon MC112L, having a relative viscosity of 2.7 when measured in 25 ° C. 98% sulfuric acid (hereinafter abbreviated as PA-1)
(A-4) Polyamide: Polyamide 6, manufactured by Kanebo Co., Ltd., trade name Kanebo Nylon MC161, having a relative viscosity of 6.5 when measured in 25 ° C. 98% sulfuric acid (hereinafter abbreviated as PA-2)
(A-5) Polyester: Polybutylene terephthalate, manufactured by Mitsubishi Engineering Plastics, trade name Novadour 5010 (hereinafter abbreviated as PBT)
(A-6) Aromatic vinyl compound polymer: Rubber reinforced polystyrene, manufactured by A & M, trade name A & M styrene HT478
(B) Hollow carbon fibrils:
(B-1) A master batch (trade name: PC / 15BN) manufactured by Hyperion Catalysis Co., containing 15% by weight of graphite fibril BN and 85% by weight of polycarbonate. Graphite fibril BN is a hollow carbon fibril (B-2) Hyperion Catalysis with an outer diameter of 10 nm and a length of 5,000 nm. Masterbatch containing 20% by weight of graphite fibril BN and 80% by weight of polyamide 6 (Product name: PA / 20BN). Graphite fibril BN is a hollow carbon fibril (B-3) Hyperion Catalysis with an outer diameter of 10 nm and a length of 5,000 nm, and is a masterbatch containing 20% by weight of graphite fibril BN and 80% by weight of polystyrene ( Product name: PS / 20BN). Graphite fibrils BN are hollow carbon fibrils with an outer diameter of 10 nm and a length of 5,000 nm (C). Conductive substance (C-1) compared with carbon fiber: with a volume resistivity of 10 μΩm, product of Toho Rayon Co., Ltd. : Best Fight C6-SR (hereinafter abbreviated as CF)
(C-2) Carbon Black: Lion Corporation product, trade name: Ketjen EC (hereinafter abbreviated as CB)
(D) Other additives (D-1) Elastomer: Hydrogenated styrene-butylene-styrene block copolymer, manufactured by Shell Chemical Co., Ltd., trade name: Kraton G1651 (hereinafter abbreviated as SEBS)
(D-2) Elastomer: Core / shell type elastomer made of acrylic (core) / butadiene (shell), manufactured by Kureha Co., Ltd., trade name Paraloid EXL2603 (hereinafter abbreviated as EXL)
(D-3) Compatibilizer: Maleic anhydride, reagent grade (hereinafter abbreviated as MANH)

Examples 1-3
The resin composition blended in the proportions shown in Table 1 was uniformly mixed with a tumbler mixer, and then pelletized using a twin screw extruder (30 mmφ) at a cylinder temperature of 300 ° C. and a screw rotation speed of 150 rpm. Next, this pellet is injection-molded by using an injection molding machine (Sumitomo Nestal product, mold clamping force 75T) under the conditions of a cylinder temperature of 280 ° C. and a mold temperature of 80 ° C. Evaluation was performed by various methods. The results were as shown in Table 1. The surface resistance showed a low order, and both the charge relative value and the half-life, which are measures of antistatic performance, were small values. Moreover, mechanical strength and heat resistance were also favorable. Further, the dispersion state of the hollow carbon fibrils in the molded body is good, and it can be used as a material for conveying and packaging electrical and electronic parts.

Comparative Example 1
In Example 3, a molded body was prepared and evaluated in the same manner as in Example 3 except that the cylinder temperature was 240 ° C. and the screw rotation speed was 400 rpm. The results were as shown in Table 1. The impact strength was low and the surface resistance was high. Moreover, the charging relative value was high, resulting in inferior antistatic performance. The dispersion state of the hollow carbon fibrils in the molded body was also poor.

Comparative Example 2
In Example 3, a single-screw extruder (40 mmφ) was used instead of the twin-screw extruder, and the cylinder temperature was changed to 280 ° C. and the screw rotation speed was 50 rpm. Evaluation was performed. The results were as shown in Table 1. The impact strength was low and the surface resistance was high. Moreover, the charging relative value was high, resulting in inferior antistatic performance. The dispersion state of the hollow carbon fibrils in the molded body was also poor.

Comparative Example 3
As shown in Table 1, a molded body was produced and evaluated in the same manner as in Comparative Example 1 except that the blending amount of the hollow carbon fibril was changed. The results were as shown in Table 1. Although the surface resistance was low and showed a good value, the impact strength was low, and the dispersion state of the hollow carbon fibrils in the molded product was poor.

Comparative Example 4
As shown in Table 1, the carbon fiber was used in place of the hollow carbon fibrils, the amount was changed, and the carbon fiber was fed from another feed port provided on the downstream side of the extruder, as in Example 1. Thus, a molded body was produced and evaluated. The results were as shown in Table 1. The surface resistance was too low, the half-life was very long, and the antistatic performance was poor. Further, the impact strength was greatly reduced, and the surface appearance of the molded article was poor due to severe floating of the filler.

Comparative Example 5
As shown in Table 1, a molded body was produced and evaluated in the same manner as in Example 1 except that carbon black was used instead of hollow carbon fibrils and the blending amount was changed. The results were as shown in Table 1. The surface resistance showed a high value, the charging relative value was high, and the antistatic performance was inferior. Further, the impact strength was greatly reduced, and the surface appearance of the molded product was poor with some floating of the filler.

Examples 4-7
The first feed and the second feed blended in the proportions shown in Table 2 are mixed uniformly with a tumbler mixer, and then fed from feed ports provided at two locations using a twin screw extruder (30 mmφ). And pelletized at a cylinder temperature of 300 ° C. and a screw speed of 150 rpm. Next, this pellet is injection-molded by using an injection molding machine (Sumitomo Nestal product, mold clamping force 75T) under the conditions of a cylinder temperature of 280 ° C. and a mold temperature of 80 ° C. Evaluation was performed by various methods. The results were as shown in Table-2. The surface resistance was low, and the mechanical strength and heat resistance were also good. Moreover, the dispersion state of the hollow carbon fibrils in the molded body is good, and it can be used as an automobile part to be electrostatically coated.

Comparative Example 6
A molded body was produced and evaluated in the same manner as in Example 5 except that the cylinder temperature was changed to 240 ° C. and the screw rotation speed was changed to 400 rpm. The results were as shown in Table-2. The impact strength was low and the surface resistance was high. Moreover, the dispersion state of the hollow carbon fibrils in the molded body was poor.

Comparative Example 7
In Example 5, the first feed and the second feed are fed to the same tumbler mixer without being divided, and a single-screw extruder (40 mmφ) is used instead of the twin-screw extruder, and feeding is performed from a single feed port. A molded body was prepared and evaluated in the same manner as in Example 5 except that the cylinder temperature was 280 ° C. and the screw rotation speed was changed to 50 rpm. The results were as shown in Table-2. The impact strength was low and the surface resistance was high. Moreover, the dispersion state of the hollow carbon fibrils in the molded body was poor.

Comparative Example 8
As shown in Table-2, a molded body was produced and evaluated in the same manner as in Example 5 except that the polyamide of the second feed was changed from PA-1 to PA-2. The results were as shown in Table-2. Although the impact strength was high, the surface resistance showed a high value. Moreover, the dispersion state of the hollow carbon fibrils in the molded body was poor.

Examples 8-10
The resin composition blended at the ratio shown in Table 3 was uniformly mixed with a tumbler mixer, and then pelletized using a twin screw extruder (30 mm fee) at a cylinder temperature of 300 ° C. and a screw rotation speed of 150 rpm. Next, this pellet is injection-molded by using an injection molding machine (Sumitomo Nestal product, mold clamping force 75T) under the conditions of a cylinder temperature of 280 ° C. and a mold temperature of 80 ° C. Evaluation was performed by various methods. The results were as shown in Table-3. The surface resistance was low, and the mechanical strength, heat resistance and impact resistance were also good. Moreover, the dispersion state of the hollow carbon fibrils in the molded body is good, and it can be used as an automobile part to be electrostatically coated.

Comparative Example 9
In Example 10, a molded body was produced and evaluated in the same manner as in Example 10 except that the cylinder temperature was 240 ° C. and the screw rotation speed was 400 rpm. The results were as shown in Table-3. The impact strength was low and the surface resistance was high. Moreover, the dispersion state of the hollow carbon fibrils in the molded body was poor.

Comparative Example 10
As shown in Table 3, a molded body was produced and evaluated in the same manner as in Example 10 except that the blending amounts of PC and hollow carbon fibrils were changed. The results were as shown in Table-3. The surface resistance was low, but the impact strength was low. Moreover, the dispersion state of the hollow carbon fibrils in the molded body was poor.

Comparative Example 11
As shown in Table 3, a molded body was produced and evaluated in the same manner as in Example 8 except that the blending amounts of PC and hollow carbon fibril were changed. The results were as shown in Table-3. Although the impact strength was high, the surface resistance was high.

Examples 11 and 12
The resin composition blended in the ratio shown in Table 4 was uniformly mixed with a tumbler mixer, and then pelletized using a twin screw extruder (30 mmφ) at a cylinder temperature of 320 ° C. and a screw rotation speed of 150 rpm. Next, this pellet is injection-molded by using an injection molding machine (Sumitomo Nestal product, clamping force 75T) under conditions of a cylinder temperature of 300 ° C. and a mold temperature of 80 ° C. Evaluation was performed by various methods. The result was as shown in Table-4. The surface resistance showed a low order, and both the charge relative value and the half-life, which are measures of antistatic performance, were small values. Moreover, mechanical strength and heat resistance were also favorable. Further, the dispersion state of the hollow carbon fibrils in the molded body is good, and it can be used as a material for conveying and packaging electrical and electronic parts.

Comparative Example 12
In Example 11, a molded body was produced and evaluated in the same manner as in Example 11 except that the cylinder temperature was 260 ° C. and the screw rotation speed was 400 rpm. The result was as shown in Table-4. The impact strength was low and the surface resistance was high. Moreover, the charging relative value was high, resulting in inferior antistatic performance. The dispersion state of the hollow carbon fibrils in the molded body was also poor.

[Evaluation method]
(1) Flexural modulus A three-point bending test was performed according to a bending test method according to ASTM D790.
(2) Deflection temperature under load According to ASTM D648, a load deflection test was performed under the condition of 1.82 MPa.
(3) Izod impact strength A notched Izod test was conducted on a 3.2 mm thick test piece in accordance with ASTM D256.
(4) Surface resistance Using a square plate molded body of 50 mm × 90 mm × 3.2 mmt, measurement was performed with a Loresta or Hiresta manufactured by Mitsubishi Chemical Corporation. (For those with a value of 10 4 Ω or higher, Hiresta was used, and for those with lower values, Loresta was used.)
(5) Antistatic performance Using a square plate molded product of 50 mm x 90 mm x 3.2 mmt, measurements were made with respect to a charge relative value and a charge half-life. The charging relative value and the charging half-life were measured using a static Honest meter under conditions of an imprinting voltage of 10 kV and an imprinting time of 1 minute.
(6) Dispersion state of hollow carbon fibrils Using an ultramicrotome from the central part of a 50 mm × 90 mm × 3.2 mmt square plate molded body, an ultrathin section having a thickness of 100 nm was cut out from the central part of the thickness, and this section was cut into transmission electron The photo was taken with a microscope at a magnification of 50,000 times. The length of all hollow carbon fibrils in this photograph is divided into single fibrils and aggregated fibrils, measured using a map measure, and the sum of the lengths is calculated. At the same time, the number of single fibrils in the photo was counted. From these, single / aggregation ratio and single fibril average length were calculated.

Example 13
Using the composition obtained in Example 1, a hard disk-based transport / storage container was produced by injection molding. The surface resistance of the obtained container is as good as 3 × 10 ⁷ Ω, and the charged voltage measured using Kasuga KSD-0102 after the container is subjected to 10 reciprocating frictions with a Bencott is 0V. Showed good antistatic performance.

Example 14
Using the composition obtained in Example 11, an IC chip transport tray was prepared by injection molding. The surface resistance of the obtained tray is as good as 4 × 10 ⁷ Ω, and the charged voltage measured with a Kasuga KSD-0102 is 0 V after the tray is subjected to 10 reciprocating frictions with a Bencott. Showed good antistatic performance.

Example 15
Using the composition obtained in Example 4, an automobile fender was prepared by injection molding. The surface resistance of the obtained fender was as good as 6 × 10 ⁷ Ω, and as a result of electrostatic coating of this fender, good paint adhesion was shown.

Example 16
Using the composition obtained in Example 8, an automobile fender was produced by injection molding. The obtained fender had a good surface resistance of 6 × 10 ⁸ Ω, and as a result of electrostatic coating of the fender, good paint adhesion was shown.

Claims (7)

  A thermoplastic resin composition comprising hollow carbon fibrils dispersed in a thermoplastic resin, wherein the content of the hollow carbon fibrils is 0.7 to 2.0% by weight, wherein the thermoplastic resin comprises polyphenylene ether and aromatic It is a blend of vinyl compound polymer or a blend of polyphenylene ether and polyamide, and the carbon fibril is composed of a single fibril and an aggregated fibril, and the dispersion state of the carbon fibril is measured with a transmission electron micrograph. A thermoplastic resin composition characterized in that the single / aggregation ratio is in the range of 8/92 to 40/60, and the single fibril average length is in the range of 20 to 200 nm.   The thermoplastic resin composition according to claim 1, wherein the hollow carbon fibrils are hollow carbon fibrils having an outer diameter of 3.5 to 70 nm.   In a thermoplastic resin molded article containing hollow carbon fibrils dispersed in a thermoplastic resin and having a content of hollow carbon fibrils of 0.7 to 2.0% by weight, the thermoplastic resin comprises polyphenylene ether and aromatic vinyl It is a blend of compound polymers or a blend of polyphenylene ether and polyamide, and the carbon fibril is composed of single fibrils and aggregated fibrils, and the dispersion state of the carbon fibrils is based on the measurement of a transmission electron micrograph. Expressed as an index, a thermoplastic resin molded article having a single / aggregation ratio in the range of 8/92 to 40/60 and a single fibril average length in the range of 20 to 200 nm.   The thermoplastic resin molded article according to claim 3, wherein the hollow carbon fibrils are hollow carbon fibrils having an outer diameter of 3.5 to 70 nm. The surface-resistance value of a molded object is 10 < ² > -10 < ¹² > (omega | ohm), The thermoplastic resin molded object of Claim 3 or 4 characterized by the above-mentioned.   The thermoplastic resin molded article according to claim 5, wherein the molded article is a material for conveying and packaging electrical and electronic parts.   6. The thermoplastic resin molded article according to claim 5, wherein the molded article is an automobile part to be electrostatically coated.

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