JP2014009329A - Electroconductive resin composition and its molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon nano tube-containing resin composition for molding, capable of enhancing the electrical conductivity without damaging flowability at molding or appearance after molding by favorable dispersion of the carbon nano tube.SOLUTION: A resin composition for molding contains a thermoplastic resin (A) and a carbon nano tube (B) and is capable of enhancing the electrical conductivity by favorable dispersion of the carbon material by using a star polymer dispersant having a vinyl polymer chain via a branch part (C) and has excellent dispersion properties.

Description

  The present invention relates to a molding resin composition containing a carbon material.

  Thermoplastic resins are widely used in all industries because of their ease of production and molding. For example, a polyamide resin is used as a molding material for automobile fuel parts in pipes, connectors, filters, injection parts and the like. Aromatic polycarbonate resins are widely used in the fields of electronic equipment and automobiles such as personal computers, electronic equipment, liquid crystal televisions and the like, lamp covers, interior and exterior parts, and the like.

Resin molded products used for these materials are required to have good conductivity in accordance with their advanced progress. In electronic equipment, injection molding is used as a molding method to obtain molding materials that have a complex shape by increasing the density of semiconductor packages due to high performance, miniaturization, and weight reduction, and increasing the speed and integration of LSIs. As the significance of the product increases, further improvements in quality are required. In addition to the components themselves, countermeasures against static electricity are required not only for the components themselves, but also for the peripheral components such as transporting components, assembly equipment environments, assembly equipment, etc. The demand for functional resins is increasing.

  As one of methods for imparting conductivity to a resin molded product, there is a method of blending a conductive filler into a resin material. In recent years, methods for mixing carbon materials such as carbon nanotubes (CNT), graphite, and carbon black with thermoplastic resins instead of metals such as copper, aluminum, and stainless steel having electrical conductivity have been actively studied. These carbon materials can exhibit high conductivity with a small content, and can reduce deterioration of molding processability, appearance, and high specific gravity as compared with metal materials.

  However, if these carbon materials are not filled at a high concentration, sufficient conductivity cannot be obtained. On the other hand, if they are filled at a high concentration, the good fluidity inherent in thermoplastic resins is impaired. For example, a short shot at the rib portion at the time of injection molding, a short shot to the farthest gate portion in a mold having a large L / T, and the like may occur.

As a method for improving fluidity, there is a method of adding a low molecular weight lubricant, for example, a fatty acid metal salt (metal soap) or a fatty acid amide, but it is a low molecular compound and decomposes and sublimates during thermoforming, which is a molded product. There may be a flow mark or silver streak on the surface, which may deteriorate the appearance of the molded product.
On the other hand, the electroconductivity which melt-molds, after adding 0.1-5 weight% of pentaerythritol fatty acid ester to the composition containing a thermoplastic resin and carbon black, carrying out the dispersion | distribution process and pelletizing by melt-kneading previously. A composition is known (see, for example, Patent Document 1). Since pentaerythritol fatty acid ester is superior in heat resistance as compared with fatty acid metal salts (metal soaps) and fatty acid amides, it is possible to improve fluidity without decomposition or sublimation even during injection molding (paragraph 0012). (Refer to Fig. 4), it becomes possible to add a large amount of carbon black.

However, this type of fatty acid ester may not be miscible unless it is a polar thermoplastic such as polyamide, and its range of use may be limited.
In addition, although it is superior in heat resistance as compared with fatty acid metal salts and fatty acid amides, it does not describe heat resistance of 250 ° C. or higher, and carbon black when used in a resin processed and processed at a high temperature of 250 ° C. or higher. In addition, there is a possibility that the dispersibility may not be sufficiently obtained, and the dispersing agent itself is thermally decomposed and poorly differentiated, and there is a concern that appearance defects may occur due to floating on the surface after molding.

  Attempts have also been made to increase the dispersibility of carbon nanotubes by adding a graft type resin dispersant (see Patent Document 2). However, in order to impart conductivity, a considerable amount of carbon nanotubes is required, and in the injection molding in which the carbon nanotubes are easily oriented, the problem that the conductivity of the molded product is greatly reduced has not yet been solved.

JP 2008-143991 A JP 2010-03753 A

  An object of the present invention is to improve the electrical conductivity even at a low blending concentration by the good dispersion of the carbon nanotube in the molding resin composition containing the carbon nanotube, and the fluidity at the time of molding. Another object is to provide a molding resin composition in which the appearance after molding is not impaired.

  The present inventors have found that the above-mentioned problems can be solved by using a dispersant capable of dispersing carbon nanotubes. As the dispersant, a star polymer dispersant having a vinyl polymer chain via a branched portion. However, by dispersing carbon nanotubes well, the conductivity can be increased, thermoforming can be performed without impairing the fluidity of the thermoplastic resin used as a molding resin, and the appearance after molding is also good. I found out.

  That is, the present invention comprises a thermoplastic resin (A), a carbon nanotube (B), and a star polymer dispersant having a vinyl polymer chain via a branched portion, and a polymer dispersant (C). A resin composition for molding is provided.

  Moreover, this invention provides the molded object and electronic member which use the said resin composition for a shaping | molding.

According to the present invention, carbon nanotubes can be favorably dispersed in a thermoplastic resin, thermoforming is possible without impairing the fluidity of the thermoplastic resin used as a molding resin, and conductivity and thermal conductivity are improved. In the above, a molded article having a good appearance after molding can be obtained.
A molded body using the molding resin composition of the present invention is particularly useful as an electronic material.

(Thermoplastic resin (A))
The thermoplastic resin (A) used in the present invention is not basically limited, and a known molding resin can be used.
For example, polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, acrylic resin such as polymethyl methacrylate and polyethyl methacrylate, polystyrene, acrylonitrile-butadiene-styrene resin, acrylonitrile-acrylic rubber-styrene Resin, acrylonitrile-ethylene rubber-styrene resin, (meth) acrylic ester-styrene resin, styrene resin such as styrene-butadiene-styrene resin, ionomer resin, polyacrylonitrile, polyamide resin such as nylon, ethylene-vinyl acetate resin, Ethylene-acrylic acid resin, ethylene-ethyl acrylate resin, ethylene-vinyl alcohol resin, polyvinyl chloride and poly Chlorine resins such as polyvinylidene fluoride, fluororesins such as polyvinyl fluoride and polyvinylidene fluoride, polycarbonate resins, modified polyphenylene ether resins, methylpentene resins, cellulose resins, etc., as well as olefin elastomers, vinyl chloride elastomers, styrene elastomers, urethanes Thermoplastic elastomers such as elastomers, polyester elastomers, polyamide elastomers, polyphenylene sulfide resins, polyether imide resins, polyether ether ketone resins, thermoplastic polyimide resins, and mixtures of two or more thereof.

(Carbon nanotube (B))
The carbon nanotube (B) used in the present invention has a cylindrical shape obtained by winding one surface of graphite, which will be described later, and a single-wall nanotube (SWNT) having a structure wound in one layer, two or more layers Examples include multi-walled nanotubes (MWNTs) wound around, any of which can be used. Among these, multiwall nanotubes having a diameter of 20 nm or less are preferable, and the length is not particularly limited, but is preferably 100 nm or more so that a conductive path formed by adjacent carbon nanotubes can be efficiently performed. .

The carbon nanotube (B) used in the present invention can be generally produced by a laser ablation method, an arc heat radiation CVD method, a plasma CVD method, a gas phase method, a combustion method, etc., but the carbon nanotube produced by any method may be used. .
Further, the surface and end of the multi-walled carbon nanotube may be modified with a functional group in order to increase the affinity with the resin as long as the properties of the composition of the present invention are not impaired. Functionalization may be performed with a carboxyl group or an amino group. Further, carbon nanotubes may be used after being pretreated with a coupling agent, and examples of such a coupling agent include isocyanate compounds, organic silane compounds, organic titanate compounds, and epoxy compounds.

  The content of the carbon nanotube (B) is preferably 0.01 to 30 parts by weight, more preferably 0.15 to 15 parts by weight with respect to 100 parts by weight of the thermoplastic resin (A). When the content of the carbon nanotube (B) is too small, the amount of conductive paths formed by the adjacent carbon nanotubes in the molded product becomes insufficient, and preferable conductivity cannot be obtained. In some cases, the interface between the carbon nanotubes and the resin in the molded article increases, and the fluidity decreases due to an increase in viscosity due to the interaction, resulting in poor appearance.

  When the resin composition in the present invention is molded, in order to effectively increase the conductive path formed by the adjacent carbon nanotubes (B) in the molded product, the carbon nanotubes are localized on the surface of the molded product. It is preferable to make it. Since the carbon nanotube (B) is highly dispersed and localized on the surface of the molded product, preferable conductivity can be obtained even if the amount of the carbon nanotube (B) added is small. Is desirable.

(Star-type polymer dispersant (C) having a vinyl polymer chain via a branched portion)
In the present invention, the star polymer dispersant (C) having a vinyl polymer chain via a branched portion (hereinafter sometimes referred to as a star polymer dispersant (C)) is composed of a core portion composed of atoms or atomic groups. A polymer having a branched polymer structure in which three or more vinyl polymer chains (D) extend radially from the core portion, and contributes to high dispersion of carbon nanotubes in the molding resin.
Regarding star polymers, Takuhei Nose, Seiichi Nakahama, and Kiyozo Miyata “Graduate Polymer Chemistry” (Kodansha) p. 39-43.

  The method for synthesizing the star polymer dispersant (C) is not limited as long as it can synthesize a polymer having a structure that matches the definition of the star polymer dispersant. Specifically, after synthesizing a core part consisting of atoms or atomic groups, a method of attaching a side chain by polymerizing a monomer that becomes a side chain, first synthesizing a side chain polymer, and then bonding to the core part The method etc. are mentioned. The synthesis of star polymers and polymer synthesis using them are described in Chapter 1 of Koji Ishizu, “Nanotechnology of Branched Polymers” (IPC).

(Vinyl polymer chain (D))
The vinyl polymer chain in the branched polymer dispersant (C) having a vinyl polymer chain through the branched portion of the present invention is hereinafter referred to as a vinyl polymer chain (D). The vinyl polymer chain (D) is a vinyl polymer, and is a side chain extending radially from the core of the star-shaped polymer dispersant (C) having a vinyl polymer chain via the branched portion. Examples of the vinyl polymer chain (D) preferably include those composed of polystyrene, poly (meth) acrylic acid ester, poly (meth) acrylamide, polyvinyl ether, polyvinyl ester, and the like. It may have a partial structure such as a functional group. The vinyl polymer chain (D) may be linear or may have a branched structure having a branched portion in the middle or at the end of the chain.

  The vinyl polymer chain (D) can be obtained by heating a polymerizable monomer capable of constituting the above various vinyl polymer chains in a reaction vessel in the presence of a polymerization initiator and aging as necessary. The reaction conditions vary depending on, for example, the polymerization initiator and the solvent, but the reaction temperature is 30 to 150 ° C, preferably 60 to 120 ° C. The polymerization can be carried out in the presence of a non-reactive solvent.

  Examples of the polymerization initiator include peroxides such as t-butyl peroxybenzoate, di-t-butyl peroxide, cumene peroxide, acetyl peroxide, benzoyl peroxide, lauroyl peroxide; azobisisobutylnitrile, azobis Examples include azo compounds such as -2,4-dimethylvaleronitrile and azobiscyclohexanecarbonitrile.

  Examples of the non-reactive solvent include aliphatic hydrocarbon solvents such as hexane and mineral spirit; aromatic hydrocarbon solvents such as benzene, toluene and xylene; ester solvents such as butyl acetate; alcohols such as methanol and butanol. Solvent; aprotic polar solvents such as dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone and the like. These solvents may be used alone or in combination. As these solvents, those capable of dissolving the resulting vinyl polymer chain (D) can be appropriately selected and used.

  The star polymer dispersant (C) of the present invention may contain various partial structures depending on the purpose. For example, by introducing a functional group (E) having excellent carbon material adsorptivity into the lower alkyl molecule that is the core portion or the vinyl polymer chain (D) that is the side chain, the star polymer dispersant (C) The adsorptivity to the surface of the carbon material can be further improved.

  Preferred examples of the acidic group as the functional group (E) excellent in carbon material adsorption include a carboxylic acid group, a sulfonic acid group, a monosulfate group, a phosphate group, a monophosphate group, and a borate group. Among them, a carboxylic acid group, a sulfonic acid group, a monosulfate group, a phosphoric acid group, and a monophosphate group are more preferable, and a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group are particularly preferable.

Examples of the vinyl monomer having an acidic group as the functional group (E) excellent in carbon material adsorption that can be used for synthesis include a vinyl monomer having a carboxyl group and a vinyl monomer having a sulfonic acid group.
Examples of the vinyl monomer having a carboxyl group include (meth) acrylic acid, vinyl benzoic acid, maleic acid, maleic acid monoalkyl ester, fumaric acid, itaconic acid, crotonic acid, cinnamic acid, and acrylic acid dimer. Further, addition reaction product of a monomer having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and a cyclic anhydride such as maleic anhydride, phthalic anhydride, or cyclohexanedicarboxylic anhydride, ω-carboxy-polycaprolactone Mono (meth) acrylates can also be used. Moreover, you may use anhydride containing monomers, such as maleic anhydride, itaconic anhydride, and citraconic anhydride, as a precursor of a carboxyl group.
Examples of the vinyl monomer having a sulfonic acid group include 2-acrylamido-2-methylpropanesulfonic acid, and examples of the vinyl monomer having a phosphoric acid group include phosphoric acid mono (2-acryloyloxyethyl ester) and phosphoric acid mono (1-methyl-2-acryloyloxyethyl ester) and the like.

Specific examples of the vinyl monomer having a basic nitrogen atom as a functional group include (meth) acrylic acid ester, (meth) acrylic acid N, N-dimethylaminoethyl, (meth) acrylic acid N, N-dimethylamino. Propyl, 1- (N, N-dimethylamino) -1,1-dimethylmethyl (meth) acrylate, N, N-dimethylaminohexyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, (Meth) acrylic acid N, N-diisopropylaminoethyl, (meth) acrylic acid N, N-di-n-butylaminoethyl, (meth) acrylic acid N, N-di-i-butylaminoethyl, (meth) Morpholinoethyl acrylate, piperidinoethyl (meth) acrylate, 1-pyrrolidinoethyl (meth) acrylate, (meth) acrylic acid , N- methyl-2-pyrrolidyl-aminoethyl and (meth) acrylic acid and N, N- methylphenylamino ethyl.
Further, as (meth) acrylamides, N- (N ′, N′-dimethylaminoethyl) acrylamide, N- (N ′, N′-dimethylaminoethyl) methacrylamide, N- (N ′, N′-diethylamino) Ethyl) acrylamide, N- (N ′, N′-diethylaminoethyl) methacrylamide, N- (N ′, N′-dimethylaminopropyl) acrylamide, N- (N ′, N′-dimethylaminopropyl) methacrylamide, N- (N ′, N′-diethylaminopropyl) acrylamide, N- (N ′, N′-diethylaminopropyl) methacrylamide, 2- (N, N-dimethylamino) ethyl (meth) acrylamide, 2- (N, N-diethylamino) ethyl (meth) acrylamide, 3- (N, N-diethylamino) propyl (meth) acrylamide, 3- (N, N-dimethylamino) propyl (meth) acrylamide, 1- (N, N-dimethylamino) -1,1-dimethylmethyl (meth) acrylamide and 6- (N, N-diethylamino) hexyl (meth) acrylamide Morpholino (meth) acrylamide, piperidino (meth) acrylamide, N-methyl-2-pyrrolidyl (meth) acrylamide and the like.

(Nuclear part consisting of atoms or atomic groups)
In the star-shaped polymer dispersant (C) in the present invention, the core part composed of atoms or atomic groups is preferably a lower alkyl molecule. Here, the lower alkyl molecule means methane, ethane, propane, etc., and methane, ie, a polymer chain extending from one carbon atom in 3 or 4 directions, ethane, ie, 3 to 6 directions from two adjacent carbon atoms. In this case, propane, that is, a polymer chain extending in the 3 to 8 direction from three adjacent carbon atoms can be exemplified. Each polymer chain may be linear or branched. The lower alkyl molecule may contain various functional groups.

  The star polymer dispersant (C) in the present invention preferably has a functional group (E) excellent in carbon material adsorptivity, and in particular, the carbon material adsorptivity with respect to the lower alkyl molecule as a core portion. It is preferable to introduce an excellent functional group (E) because the adsorptivity of the star polymer dispersant (C) to the carbon surface can be further improved.

In order to introduce the functional group (E) excellent in the carbon material adsorptivity into the lower alkyl molecule as the core part, the monovalent containing at least one functional group (E) excellent in the carbon material adsorptivity It is preferable to introduce an adsorption site (hereinafter referred to as adsorption site (E1)) which is an organic group.
As the functional group (E) excellent in carbon material adsorption at the adsorption site (E1), a group having a basic nitrogen atom, a heterocyclic group having a basic nitrogen atom, an acidic group, and a hydroxyl group are preferable.
Examples of the “heterocyclic structure” include thiophene, furan, xanthene, pyrrole, pyrroline, pyrrolidine, dioxolane, pyrazole, pyrazoline, pyrazolidine, imidazole, oxazole, thiazole, oxadiazole, triazole, thiadiazole, pyran, pyridine, piperidine , Dioxane, morpholine, pyridazine, pyrimidine, piperazine, triazine, trithiane, isoindoline, isoindolinone, benzimidazolone, benzothiazole, succinimide, phthalimide, naphthalimide, hydantoin, indole, quinoline, carbazole, acridine, acridone, anthraquinone, etc. Is mentioned.
Examples of the “acidic group” include a carboxylic acid group, a sulfonic acid group, a monosulfate group, a phosphate group, a monophosphate group, and a borate group.
Examples of the “group having a basic nitrogen atom” include an amino group (—NH 2) and a substituted imino group.

  In the synthesis of the star-shaped polymer dispersant (C), a method for polymerizing a monomer that becomes a side chain from a core portion to attach a side chain is not particularly limited, but a mercaptan compound having an adsorption site (E1) as the lower alkyl molecule A method of forming a vinyl polymer chain (D), which is a side chain, by radical polymerization of a vinyl monomer by using as a core part is preferred.

  The mercaptan compound having the adsorption site (E1) includes a compound having 4 or more mercapto groups in one molecule, and a compound having an adsorption site (E1) and a functional group capable of reacting with the mercapto group. It can be synthesized by a method of addition reaction.

  The “compound having four or more mercapto groups in one molecule” is not particularly limited as long as it has three or more functional groups, but pentaerythritol tetrakis (2-mercaptoacetate, pentaerythritol tetrakis ( 3-mercaptopropionate), trimethylol methane tris (2-mercaptoacetate), trimethylol methane tris (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate), dipentaerythritol hexakis (3-mercaptopropionate) etc. can be illustrated.

In the compound having the adsorption site (E1) and having a functional group capable of reacting with a mercapto group, the “functional group capable of reacting with a mercapto group” includes acid halide, alkyl halide, isocyanate, carbon-carbon double Preferred examples include a bond. It is particularly preferable that the “functional group capable of reacting with a mercapto group” is a carbon-carbon double bond, and the addition reaction is a radical addition reaction. The carbon-carbon double bond is more preferably a substituted or disubstituted vinyl group in terms of reactivity with the mercapto group.
Although it does not restrict | limit especially as a compound which has an adsorption site (E1) and has a carbon-carbon double bond, The following are mentioned. Vinyl pyrrolidine, vinyl imidazole, vinyl oxazole, vinyl thiazole, vinyl pyridine, vinyl piperidine, vinyl furan, methacrylic acid, acrylic acid, itaconic acid, vinyl sulfonic acid, acrylamide sulfonic acid, vinyl amine, allylamine, dimethylaminoethyl methacrylate, diethylamino Examples include ethyl methacrylate and dimethylaminoethyl acrylamide.

In the star polymer dispersant (C) in the present invention, the mercaptan compound having the adsorption site (E1) is:
The above-mentioned “compound having 4 or more mercapto groups in one molecule” and the “compound having an adsorption site and a carbon-carbon double bond” are dissolved in an appropriate solvent, and radicals are generated therein. It is obtained using a method (thiol-ene reaction method) of adding an agent and adding at about 50 ° C. to 100 ° C. When synthesizing the mercaptan compound having the adsorption site (E1), the “compound having 4 or more mercapto groups in one molecule” and the “compound having an adsorption site and a carbon-carbon double bond” "Compound having" means that in the mercaptan compound having the adsorption site (E1), the "compound having an adsorption site and having a carbon-carbon double bond" has 3 or more unreacted mercapto groups in one molecule. To react.
Examples of suitable solvents used in the thiol-ene reaction method include the above-mentioned “compound having 4 or more mercapto groups in one molecule”, the above “having an adsorption site and a carbon-carbon double bond. It can be arbitrarily selected depending on the solubility of the “compound having” and the produced “mercaptan compound having the adsorption site (E1)”.

In the star polymer dispersant (C), when the vinyl polymer (D) as a side chain is polymerized, the “adsorption site (E1)” is caused by the presence of the “mercaptan compound having an adsorption site (E1)”. Since the mercaptan compound having) acts as a chain transfer agent, the vinyl polymer chain (D) is bonded to the “mercaptan compound having the adsorption site (E1)”. At this time, since the “mercaptan compound having an adsorption site (E1)” contains three or more unreacted mercapto groups with which the vinyl polymer (D) can react, three or more vinyl polymer chains (D) are present. A bonded branched star polymer dispersant (C-2) can be obtained.
The molar ratio of the “mercaptan compound having an adsorption site (E1)” and the monomer constituting the vinyl polymer chain (D) in the star polymer dispersant (C) is the same as that of the monomer and “adsorption site (E1). The “mercaptan compound having an adsorption site (E1)” is preferably 1 to 20 mol% and more preferably 2 to 10 mol% with respect to 100 mol% of the total amount of “mercaptan compound having”.

The star-shaped polymer dispersant (C) is produced in the presence of a monomer constituting the vinyl polymer chain (D), a polymerization initiator, and a “mercaptan compound having an adsorption site (E1)”. Although it is carried out by suspension or solution polymerization, a solution polymerization method is generally preferred.
The solvent used for the solution polymerization is preferably a solvent that can dissolve any of the monomer, the polymerization initiator, the “mercaptan compound having an adsorption site (E1)”, and the resulting star polymer dispersant (C).
The molecular weight of the star-shaped polymer dispersant (C) is adjusted by adjusting the amount of the polymerization initiator and the amount of the “mercaptan compound having an adsorption site (E1)” relative to the amount of the monomer constituting the vinyl polymer chain (D). Can do. If the amount of the polymerization initiator, “mercaptan compound having an adsorption site (E1)” is increased, the molecular weight is decreased accordingly.

In addition, the star polymer dispersant (C) having a vinyl polymer chain via a branched portion of the present invention has an ethylenically unsaturated double bond at the end of the vinyl polymer chain (D) as the vinyl polymer chain (D). It may be a macromonomer type star dispersant (C2) using a macromonomer (D-2) obtained by copolymerizing a structural unit derived from a polymerizable oligomer.
The macromonomer (D-2) used in the present invention comprises a polymerizable functional group having a vinyl polymer chain (D) moiety and an ethylenically unsaturated double bond at the terminal thereof. From the viewpoint of obtaining a desired macromonomer type star polymer dispersant (C), having such a group having an ethylenically unsaturated double bond only at one end of the vinyl polymer chain (D). preferable. As the group having an ethylenically unsaturated double bond, a (meth) acryloyl group and a vinyl group are preferable, and a (meth) acryloyl group is particularly preferable.

In the macromonomer (D-2) used in the present invention, the vinyl polymer chain (D) has an alkyl (meth) acrylate, (meth) acrylamide, N-alkyl (meth) acrylamide, N, N′-dialkyl ( It is a homopolymer or copolymer formed from at least one monomer selected from the group consisting of (meth) acrylamide, styrene, and (meth) acrylonitrile.
These vinyl polymer chains (D) may further have a substituent. Examples of the substituent that can be introduced include a halogen atom, an alkenyl group, an aryl group, a hydroxyl group, an alkoxy group, an alkoxycarbonyl group, an amino group, and an acylamino group. And carbamoyl group.

Specific examples of the alkyl group in the alkyl (meth) acrylate, N-alkyl (meth) acrylamide, etc. that form the vinyl polymer chain (D) include a methyl group, an ethyl group, a propyl group, a butyl group, and a heptyl group. Hexyl group, octyl group, decyl group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group, octadecyl group, 2-chloroethyl group, 2-bromoethyl group, 2-methoxycarbonylethyl group, 2-methoxyethyl group, 2- Bromopropyl group, 2-butenyl group, 2-pentenyl group, 3-methyl-2-pentenyl group, 2-hexenyl group, 4-methyl-2-hexenyl group, benzyl group, phenethyl group, 3-phenylpropyl group, naphthyl Methyl group, 2-naphthylethyl group, chlorobenzyl group, bromobenzyl group, methyl Benzyl group, ethylbenzyl group, methoxybenzyl group, dimethylbenzyl group, dimethoxybenzyl group, cyclohexyl group, 2-cyclohexylethyl group, 2-cyclopentylethyl group, bicyclo [3.2.1] oct-2-yl group, 1 -Adamantyl group, dimethylaminopropyl group, acetylaminoethyl group, N, N-dibutylaminocarbamoylmethyl group and the like can be mentioned.

  The macromonomer (D-2) may be a commercially available product or an appropriately synthesized product. Examples of the commercially available product include a one-end methacryloylated polystyrene oligomer (trade name: AS-6). , Manufactured by Toa Gosei Chemical Co., Ltd.), one-end methacryloylated polymethyl methacrylate oligomer (trade name: AA-6, manufactured by Toa Gosei Chemical Co., Ltd.), one-end methacryloylated poly-n-butyl acrylate oligomer (product) Name: AB-6, manufactured by Toa Synthetic Chemical Industry Co., Ltd.).

(Other components in star polymer dispersant (C))
The star polymer dispersant (C) of the present invention may contain a non-reactive solvent used in the production of the star polymer dispersant (C), and the non-reactive solvent used in the production is distilled off. After that, another solvent may be newly added.
The star polymer dispersant (C) of the present invention may contain some components other than the star polymer dispersant (C) as long as the effects of the present invention are not impaired. In the present invention, the “main component” indicates that the branched polymer used in the present invention may be contained within a range in which the effects of the present invention can be obtained. Examples of other components include by-products generated during the production of the star polymer dispersant (C), or non-reactive thermoplastic resins.

(Resin composition for molding)
The molding resin composition of the present invention must contain the thermoplastic resin (A), the carbon nanotube (B), and the star polymer dispersant (C) having a vinyl polymer chain via a branched portion. However, a known additive may be added as long as the effects of the present invention are not impaired. For example, examples of the additive include an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, and an inorganic filler.
As an example of the antioxidant, an antioxidant composed of a phenol, phosphorus, sulfur, or lactone may be added singly or in combination to prevent heat deterioration during processing of the resin. Is necessary, a benzophenone-based, salicylate-based, benzotriazole-based, cyanoacrylate-based, or hindered amine-based compound may be used as an ultraviolet absorber or light stabilizer.
Examples of the inorganic filler include calcium carbonate, talc, precipitated barium sulfate, mica, kaolin clay, hydrotalcite, diatomaceous earth, and metal oxides such as magnesium oxide and aluminum oxide. These additives may be used alone or in combination of two or more.

Moreover, you may add a coloring agent to the resin composition for shaping | molding in this invention. The addition amount of the colorant varies depending on the type of colorant and the target color tone, but is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, with respect to 100 parts by weight of the thermoplastic resin (A). It is.
The colorant to be used is not particularly limited, and conventional inorganic pigments, organic pigments and dyes used for coloring general thermoplastic resins can be used according to the intended design. For example, inorganic pigments such as titanium oxide, titanium yellow, iron oxide, complex oxide pigments, ultramarine, cobalt blue, chromium oxide, bismuth vanadate, carbon black, zinc oxide, calcium carbonate, barium sulfate, silica, talc; azo Pigments, phthalocyanine pigments, quinacridone pigments, dioxazine pigments, anthraquinone pigments, isoindolinone pigments, isoindoline pigments, perylene pigments, perinone pigments, quinophthalone pigments, thioindigo pigments and diketopyrrolo Organic pigments such as pyrrole pigments; metal complex pigments and the like. In addition, it is preferable to use one or two dyes mainly selected from the group of oil-soluble dyes.

(Formulation method)
The molding resin composition of the present invention can be blended by a known method. For example, a thermoplastic resin (such as a kneader generally used in thermoplastic resins, such as a single or twin screw extruder, a continuous kneader such as an FCM or a kneader, or a batch kneader such as a Banbury mixer or a kneader). A star polymer dispersant (C) having a vinyl polymer chain is added via a branching portion while highly dispersing A) and the carbon nanotube (B), and can be produced as a conductive composition. It is also possible to produce a master batch by adding carbon nanotubes (B) and a star-shaped polymer dispersant (C) at high concentrations, dilute with the thermoplastic resin (A), and use for molding.

(Molding method)
As a molding method of the molding resin composition of the present invention, a molding method generally used for thermoplastic resins can be adopted. Specific examples include press molding, injection molding, film, sheet molding, blow molding, profile extrusion molding, and spinning. Further, there is no problem in post-processing the sheet-formed sheet by vacuum forming or the like.

(Use)
In the molding resin composition using the carbon nanotube (B), the star-shaped polymer dispersant (C) having a vinyl polymer chain via the branched portion is particularly dispersible when the molding resin composition is melted at a high temperature. Since the effect of improving the localization of the carbon nanotube (B) on the surface of the molded product is high, it is possible to impart high conductivity by adding a low concentration of the carbon nanotube (B). The amount of the star-shaped polymer dispersant (C) with respect to the amount of the carbon nanotube (B) at this time is preferably in the range of 1 to 500% by weight. The molded body obtained by such blending has good moldability due to the low concentration of carbon nanotubes (B), and can exhibit high conductivity, and automobiles such as engine-use tubes and fuel tanks. It can be used for various applications including electronic members such as members, IC trays, wafer cases, electromagnetic shielding materials, and heat radiation sheets.

  Next, the present invention will be specifically described with reference to examples and comparative examples. Unless otherwise indicated, “parts” and “%” are weight standards.

Synthesis Example 1 Synthesis of Mercaptan Compound Having Adsorption Site Pentaerythritol tetrakis (3-mercaptopropionate) [manufactured by SC Chemical Industry Co., Ltd.] 84 parts and N-vinylimidazole 16 parts were converted to methyl ethyl ketone (hereinafter referred to as MEK). This was dissolved in 100 parts and heated to 60 ° C. under a nitrogen stream. To this, 0.2 part of 2,2′-azobis (2,4-dimethylvaleronitrile) [V-65, manufactured by Wako Pure Chemical Industries, Ltd.] was added and heated for 5 hours. By cooling to room temperature, a 50% solution of a mercaptan compound having an adsorption site was obtained.

(Synthesis Example 2-a) Synthesis of Macromonomer (2-a) 100 parts of MEK was kept at 80 ° C. in a nitrogen stream, and while stirring, 75 parts of stearyl acrylate, 19 parts of butyl acrylate, 6 parts of thioglycolic acid, and A mixture composed of 0.2 part of a polymerization initiator (“Perbutyl (registered trademark) O” [active ingredient t-butyl peroxy-2-ethylhexanoate, manufactured by NOF Corporation)) was added dropwise over 4 hours. After completion of the dropwise addition, 0.5 part of “Perbutyl (registered trademark) O” was added every 4 hours and stirred at 80 ° C. for 12 hours. Next, 10.2 parts of glycidyl methacrylate and 3.2 parts of tetrabutylammonium bromide were charged, stirred while blowing air in place of nitrogen, reacted at 70 ° C. for 6 hours, and then MEK was distilled off to remove the vinyl polymer-containing macromonomer. (2-a) was obtained. The macromonomer (2-a) had a weight average molecular weight of 4,200.

(Synthesis Example 2-b) Synthesis of Macromonomer (2-b) In place of 75 parts of stearyl acrylate and 19 parts of butyl acrylate mixed in Synthesis Example 2-a, 66 parts of benzyl methacrylate and 28 parts of lauryl methacrylate were used. The same operation as in Synthesis Example 2-a was performed except that it was used to obtain a MEK solution of macromonomer (2-b). The obtained macromonomer (2-b) had a weight average molecular weight of 4,600.

(Synthesis Example 3-a) Synthesis of Macromonomer Type Star Polymer Dispersant (3-a) 100 parts of MEK was charged into a flask equipped with a stirrer, reflux condenser, nitrogen blowing tube, and thermometer, and in a nitrogen stream. While maintaining at 80 ° C. with stirring, 12 parts of a 50% solution of a mercaptan compound having an adsorption site obtained in Synthesis Example 1, 180 parts of the vinyl polymer-containing macromonomer (2-a) obtained in Synthesis Example 2, and butyl acrylate 10 And a mixture consisting of 0.5 part of a polymerization initiator (“Perbutyl O”) was added dropwise over 4 hours. After completion of the dropwise addition, 0.5 part of “perbutyl O” was added every 4 hours and stirred at 80 ° C. for 12 hours. After completion of the reaction, MEK was distilled off by desolvation under reduced pressure to obtain a macromonomer type star polymer dispersant (3-a) having a weight average molecular weight of 20000.

(Synthesis Example 3-b) Synthesis of Macromonomer Type Star Polymer Dispersant (3-b) To 180 parts of a 50% solution of macromonomer (3-a) blended in Synthesis Example 3-a and 10 parts of butyl acrylate Instead, the macromonomer type star polymer dispersant (3-b) was prepared in the same manner as in Synthesis Example 3-a, except that 120 parts of a 50% solution of the macromonomer (2-b) and 40 parts of lauryl methacrylate were used. A MEK solution was synthesized. The macromonomer type star polymer dispersant (3-b) had a weight average molecular weight of 20,000.
(Synthesis Example 3-c) Synthesis of Macromonomer Type Star Polymer Dispersant (3-c) To 180 parts of a 50% solution of macromonomer (3-a) blended in Synthesis Example 3-a and 10 parts of butyl acrylate Instead, a macromonomer-type star polymer dispersing agent (similar to Synthesis Example 3-a) except that 20 parts of silicon macromonomer Silaplane FM-0711 (manufactured by JNC), 60 parts of styrene, and 20 parts of acrylonitrile were used. A MEK solution of 3-c) was synthesized. The macromonomer type star polymer dispersant (3-c) had a weight average molecular weight of 22,000.

(Comparative Synthesis Example 1) Synthesis of Comb Dispersant (3-d) 100 parts of MEK was kept at 80 ° C. in a nitrogen stream and stirred with 80 parts of stearyl acrylate, 20 parts of butyl acrylate, 6 parts of thioglycolic acid, And a mixture of 0.2 parts of a polymerization initiator ("Perbutyl (registered trademark) O" [active ingredient t-butyl 2-ethylhexanoate, manufactured by NOF Corporation)) was added dropwise over 4 hours. After completion of the dropwise addition, 0.5 part of “Perbutyl (registered trademark) O” was added every 4 hours and stirred at 80 ° C. for 12 hours. After completion of the reaction, MEK was added to adjust the nonvolatile content to obtain a MEK solution of a vinyl polymer having a nonvolatile content of 50% and having a carboxyl group at one end. Next, in a flask equipped with a stirrer, reflux condenser, nitrogen blowing tube and thermometer, 100 parts of xylene, 186 parts of MEK solution of vinyl polymer and 20% aqueous solution of polyallylamine (“PAA-05 manufactured by Nitto Boseki Co., Ltd.) ”, A mixture consisting of 35 parts of a number average molecular weight of about 5,000) was stirred at 140 ° C. while stirring under a nitrogen stream, and MEK and water were distilled off using a separator, and xylene was added to the reaction solution. The reaction was carried out at 140 ° C. for 8 hours while returning. After completion of the reaction, xylene was distilled off to obtain a comb-type dispersant (3-d) having a weight average molecular weight of 7,500 and an amine value of 33.5 mg KOH / g.

(Comparative Synthesis Example 2) Synthesis of Graft Polymer Dispersant (3-e) Into a flask equipped with a stirrer, reflux condenser, nitrogen blowing tube, and thermometer, 20 parts of MEK was charged and kept at 80 ° C. in a nitrogen stream. While stirring, 160 parts of a 50% solution of the macromonomer (2-a) obtained in Synthesis Example 2-a, 10 parts of methacrylic acid, 10 parts of hydroxyethyl methacrylate, and a polymerization initiator ("Perbutyl O") 4.0 The mixture consisting of parts was added dropwise over 4 hours. After completion of the dropwise addition, 0.5 part of “perbutyl O” was added every 4 hours and stirred at 80 ° C. for 12 hours. After completion of the reaction, non-MEK was distilled off to obtain a graft polymer dispersant (3-e). The macromonomer type graft polymer dispersant (3-e) had a weight average molecular weight of 8,000.

[Example 1]
Nanocyl multi-walled carbon nanotubes (diameter 9.5 nm, length 1.5 μm, bulk density 0.06 / cm 3) 1.5 parts, macromonomer type star polymer dispersant (3-a) 3.0 parts, Laboplast mill R-60 (manufactured by Toyo Seiki Seisakusho Co., Ltd.) containing 95.5% of polycarbonate ("Iupilon S3000" manufactured by Mitsubishi Engineering Plastics Co., Ltd.) and a rotor rotation speed of 100 The resin composition for molding (F-1) was obtained by kneading under conditions of rotation / min and kneading time of 5 minutes. The molding resin composition (F-1) obtained by the kneading method was dried for 8 hours in a 120 ° C. vacuum dryer, and then a cylinder set temperature of 300 ° C. was used using an injection molding machine “MS-55” manufactured by Toshiba Machine. And a back pressure of 1 MPa. Molding was performed under two conditions of a mold temperature of 90 ° C. and an injection speed of 20 mm / s to obtain a flat test piece (F-1-s) having a major axis of 90 mm × minor axis of 50 mm × thickness of 3 mm.

[Surface resistance value]
About the said test piece (F-1-s), the surface resistance value was measured using the resistivity meter Loresta-EP MCP-T360 (made by Mitsubishi Chemical Analytech Co., Ltd.). When the surface resistance value exceeded the measurement range (−10 ^ 6Ω), the overrange (OR) was determined.
[Unsolvability]
By molding the resin composition for molding (F-1) with an IMC-1819-A type hot press with a 50 kN load cell manufactured by Imoto Seisakusho Co., Ltd. (set temperature 200 ° C., pressure 40 kg / cm 2, pressure holding time 3 minutes) Then, a 1 mm thick test piece was prepared, cut into a 1 mm square size, and a film (F-1) using the above heating press machine (setting temperature 200 ° C., pressure 10 kg / cm 2, pressure holding time 1 minute). -F) was molded. The obtained film (F-1-f) was observed with an optical microscope OPTIPHOT-2 manufactured by Nikon Corporation at a magnification of 100 times to evaluate the peptizability of the resin composition. ○ When the area of less than 5% in the field of view is unresolved (black streaks), Δ when the area of 5% to 10% in the field of view (black lines) is recognized, and 10 in the field of view The case where unraveling defects (black streaks) were recognized in an area of% or more was marked as x. (A resin composition having poor fluidity is observed as a black streak-like pattern in the visual field because the carbon nanotubes are not completely dissolved in the resin under the injection conditions.)
[Dispersibility]
The obtained film (F-1-f) was observed with an optical microscope OPTIPHOT-2 manufactured by Nikon Corporation at a magnification of 100 times, and the maximum particle diameter of the carbon nanotube aggregated particles recognized in the field of view was measured. Dispersibility was evaluated.
A case where a carbon nanotube aggregate diameter of 50 μm or more is not recognized in the field of view, a case where a carbon nanotube aggregate of 50 μm to 100 μm is recognized Δ, a case where a carbon nanotube aggregate of 100 μm or more is recognized × did.

[Example 2]
Instead of using the macromonomer type star polymer dispersant (3-a) obtained in Synthesis Example 3-a, the macromonomer type star polymer dispersant (3-b) obtained in Synthesis Example 3-b is used. Were the same operations as in Example 1 to obtain a molding resin composition (F-2), a test piece (F-2-s), and a film (F-2-f).

Example 3
Instead of using the macromonomer type star polymer dispersant (3-a) obtained in Synthesis Example 3-a, the macromonomer type star polymer dispersant (3-c) obtained in Synthesis Example 3-c is used. Performed the same operation as Example 1, and obtained the resin composition for molding (F-3), the test piece (F-3-s), and the film (F-3-f).

<Comparative Example 1>
Instead of using the macromonomer-type star polymer dispersant (3-a) obtained in Synthesis Example 3, Example 1 is used except that the comb-modified polyamine dispersant (3-d) obtained in Comparative Synthesis Example 1 is used. The same operation was performed to obtain a molding resin composition (H-1), a test piece (H-1-s), and a film (H-1-f).

<Comparative example 2>
Instead of using the macromonomer type star polymer dispersant (3-a) obtained in Synthesis Example 3, the macromonomer type graft polymer dispersant (3-e) obtained in Comparative Synthesis Example 2 was used. The same operation as 1 was performed to obtain a molding resin composition (H-2), a test piece (H-2-s), and a film (H-2-f).

The evaluation results of Examples and Comparative Examples are shown in Table 1 below.

  As shown in Table 1, there was a clear difference in the peptizability, dispersibility, and surface resistance value in the injection molded product for the carbon nanotube blending system.

  In the molding resin composition containing the thermoplastic resin (A) and the carbon nanotube (B), the use of the star-shaped polymer dispersant (C) having a vinyl polymer chain via the branch portion makes it possible to improve the carbon material. It becomes possible to provide a molding resin composition which can be dispersed to enhance conductivity and thermal conductivity and has excellent dispersibility.

Claims (4)

A molding resin composition comprising a thermoplastic resin (A), a carbon nanotube (B), and a star polymer dispersant (C) having a vinyl polymer chain via a branched portion. The molding resin composition according to claim 1, wherein the star polymer dispersant (C) having a vinyl polymer chain via the branched portion is a macromonomer type star polymer dispersant (C2). The molded object formed by shape | molding the resin for shaping | molding of Claim 1 or 2. A conductive material using the molding resin composition according to claim 1.