JP7365253B2 - Conductive resin composition, method for producing the same, and molded article - Google Patents

Description

The present invention relates to a conductive resin composition, a method for producing the same, and a molded article obtained from the conductive resin composition.

Thermoplastic resins are used in a wide range of fields such as automobile parts, electrical and electronic parts, and structural materials due to their excellent mechanical properties, heat resistance, moldability, and other characteristics. However, many thermoplastics are insulating. Therefore, in order to impart electrical conductivity to a thermoplastic resin, it is essential to combine the thermoplastic resin and a conductive material. Metal powders, metal fibers, and carbon materials are generally well known as conductive materials. Among these, carbon materials allow the molded body to be made lighter, and various types of carbon materials have been developed. Examples of carbon materials used as conductive materials include carbon black, graphite, carbon nanotubes, and the like. Compositeization of these carbon materials and thermoplastic resins is performed by forced kneading and dispersion using a kneading machine such as an extruder or a kneader.

However, carbon nanotubes have a particularly large specific surface area among carbon materials. Therefore, when compounded with a thermoplastic resin, a rapid increase in viscosity tends to occur, making kneading and dispersion difficult. Therefore, the use of various dispersants for conductive resin compositions containing carbon nanotubes is being considered.

For example, in Patent Document 1, a petroleum resin is proposed as a dispersant for carbon nanotubes. Further, Patent Document 2 proposes an aromatic-containing hydrocarbon having a conjugated double bond and having 6 to 22 carbon atoms as a dispersant for carbon nanotubes. Further, in Patent Document 3, a petroleum resin having a specific compatibility with resin is proposed as a dispersant for carbon nanotubes.

Patent No. 4913380 Japanese Patent Application Publication No. 2008-31461 Patent No. 5558702

In both documents, interaction between the π electrons present on the surface of carbon nanotubes and the π electrons present on the surface of the dispersant is expected, and the dispersibility of carbon nanotubes and, ultimately, the conductivity derived from carbon nanotubes is improved. Be expected. In the field of electrical and electronic components, it is also required that the molded product have a good appearance (surface gloss). However, with conventional compositions, flow marks and the like are likely to occur in the resulting molded product. Therefore, there is a need for a conductive resin composition that can form a molded article that has both good conductivity and good appearance.

The present invention has been made in view of the above circumstances, and provides a conductive resin composition and a method for producing the same, which can form a molded article having both high conductivity and an excellent appearance, and a method for producing the same. The purpose is to provide molded objects.

The present inventors have achieved electrical conductivity and surface gloss by combining a polymer (C) containing 50% by mass or more of a structure derived from aromatic substituted ethene or aromatic substituted propene with carbon nanotubes (B). It has been found that a conductive resin composition capable of forming a molded article having both of these characteristics can be obtained. That is, the present invention provides the following conductive resin composition.

[1] A thermoplastic resin containing a thermoplastic resin (A), a carbon nanotube (B), and a polymer (C) containing 50% by mass or more of a structural unit derived from an aromatic substituted ethene or an aromatic substituted propene, For 100 parts by mass of the total amount of the resin (A), the carbon nanotubes (B), and the polymer (C), 74.9 to 99.4 parts by mass of the thermoplastic resin (A) and the carbon nanotubes ( A conductive resin composition containing 0.5 to 25 parts by mass of B) and 0.1 to 10 parts by mass of the polymer (C).

[2] The conductive resin composition according to [1], wherein the polymer (C) satisfies the following (i) to (iv).
(i) The number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) is in the range of 300 to 5000. (ii) The weight average molecular weight measured by gel permeation chromatography (GPC) (Mw) and number average molecular weight (Mn) (Mw/Mn) is 9.0 or less (iii) Softening point measured according to JIS K2207 is in the range of 70 to 170°C (iv) JIS K7112 The ^density measured according to

[3] The conductive resin composition according to [1] or [2], wherein the polymer (C) is at least one polymer selected from styrene, α-methylstyrene, and isopropenyltoluene.

[4] The conductive resin composition according to any one of [1] to [3], wherein the thermoplastic resin (A) has a cyclic structure.
[5] The conductivity according to any one of [1] to [4], wherein the thermoplastic resin (A) is at least one resin selected from the group consisting of cycloolefin polymer, polyester, and polycarbonate. Resin composition.

The present invention also provides the following method for producing a conductive resin composition and a molded article.
[6] A method for producing a conductive resin composition according to any one of [1] to [5] above, comprising: the thermoplastic resin (A), the carbon nanotubes (B), and the polymer. A method for producing a conductive resin composition, the method comprising: preparing a masterbatch containing a combination (C); and melt-kneading the masterbatch and the thermoplastic resin (A).
[7] A molded article obtained from the conductive resin composition according to any one of [1] to [5] above.

According to the present invention, it is possible to provide a conductive resin composition capable of forming a molded article having both high conductivity and excellent surface gloss, a method for producing the same, and a molded article obtained from the same.

The present invention will be explained in detail below. In the following description, "~" indicating a numerical range represents from the above to the following unless otherwise specified.

1. Conductive Resin Composition The conductive resin composition of the present invention is a polymer containing a thermoplastic resin (A), a carbon nanotube (B), and a structural unit derived from aromatic substituted ethene or aromatic substituted propene in an amount of 50% by mass or more. Contains (C). In addition, in this specification, the polymer (C) containing 50 mass % or more of structural units derived from aromatic substituted ethene or aromatic substituted propene is also simply referred to as "polymer (C)."

In the conductive resin composition of the present invention, when the total of the thermoplastic resin (A), carbon nanotubes (B), and polymer (C) is 100 parts by mass, the amount of the thermoplastic resin (A) is 74. The amount is 9 to 99.4 parts by weight, preferably 80 to 99 parts by weight, and more preferably 85 to 98.5 parts by weight. From the viewpoint of increasing the surface gloss of the obtained molded article, it is preferable that the content of the thermoplastic resin (A) is high. In addition, when particularly high processability is required for the conductive resin composition, the lower limit of the thermoplastic resin (A) is preferably 93 parts by mass, more preferably 95 parts by mass, and even more preferably 97 parts by mass. Part by mass.

On the other hand, when the total of the thermoplastic resin (A), carbon nanotubes (B), and polymer (C) is 100 parts by mass, the amount of carbon nanotubes (B) is 0.5 to 25 parts by mass. , preferably 1 to 20 parts by weight, more preferably 1.5 to 15 parts by weight. By including 0.5 parts by mass or more of carbon nanotubes (B), the conductivity of the conductive resin composition and, by extension, the molded product thereof will be improved. Moreover, when the amount of carbon nanotubes (B) is 25 parts by mass or less, the surface glossiness of the obtained molded article becomes good. In addition, in order to obtain high conductivity, that is, a low volume resistivity value in the molded article, it is preferable that the amount of carbon nanotubes (B) is large. When particularly high conductivity is required for the molded article, the lower limit of the carbon nanotube (B) is preferably 3 parts by mass, more preferably 5 parts by mass, and even more preferably 7 parts by mass.

Further, when the total of the thermoplastic resin (A), carbon nanotubes (B), and polymer (C) is 100 parts by mass, the amount of the polymer (C) is 0.1 to 10 parts by mass, The amount is preferably 0.2 to 8 parts by weight, more preferably 0.3 to 5 parts by weight. By containing 0.1 part by mass or more of the polymer (C), the dispersibility of the carbon nanotubes (B) becomes good, and the conductivity of the conductive resin composition and, by extension, the molded article tends to become good. The surface gloss of the molded product also tends to be good. On the other hand, if the content of the polymer (C) containing 50 mass% or more of structural units derived from aromatic substituted ethene or aromatic substituted propene is 10 parts by mass or less, the inherent properties of the thermoplastic resin (A) will be impaired. However, the mechanical properties of the obtained molded product tend to be good.

Here, the conductivity of the conductive resin composition (or molded article) is evaluated by the volume resistivity value measured in accordance with ASTM D257. A preferable volume resistivity value of the conductive resin composition is appropriately selected depending on the application. For example, when the conductive resin composition of the present invention is used as a packaging material for semiconductor products such as IC trays, silicon wafer cases, and carrier tapes, the volume resistivity value of the conductive resin composition is 1.0×10 ⁷ to 1. .0×10 ⁹ Ω·cm is preferable. In addition, when the conductive resin composition is used as a clean room flooring material, a belt conveyor, a low electrical component for OA equipment, or an electrostatic coating base material, its volume resistivity value is 1.0×10 ⁴ to 1.0×10 ⁶ Ω·cm is preferable. Furthermore, when the conductive resin composition is used as an electromagnetic shielding member for office automation equipment, the volume resistivity value thereof is preferably 1.0×10 ⁻¹ to 1.0×10 Ω·cm. The volume resistivity value of the conductive resin composition is adjusted by the type and content of carbon nanotubes (B) and further by the type and content of polymer (C).

Furthermore, the flexural modulus of the conductive resin composition measured in accordance with JIS K7171 (ISO 178) is preferably higher than that of the thermoplastic resin (A) alone contained in the conductive resin composition. is 100 to 400%, more preferably 100 to 300%, even more preferably 100 to 250%. If the flexural modulus of the conductive resin composition is within the above range, there is little decrease in the flexural modulus of the conductive resin composition due to the addition of carbon nanotubes (B), and the conductive resin composition can be applied to various uses. It becomes easier to do. Here, the flexural modulus of the conductive resin composition is adjusted by the composition of the conductive resin composition (particularly the type of thermoplastic resin (A), the content of carbon nanotubes (B), etc.).

The components contained in the conductive resin composition, the physical properties of the conductive resin composition, etc. will be described below.

1-1. Thermoplastic resin (A)
1-1-1. Type of Thermoplastic Resin (A) The thermoplastic resin (A) contained in the conductive resin composition is appropriately selected depending on the use of the conductive resin composition. Representative examples of the thermoplastic resin (A) that can be used in the conductive resin composition include the following resins (1) to (16). The conductive resin composition may contain only one kind of these, or may contain two or more kinds. In addition, in this specification, the thermoplastic resin (A) does not include those corresponding to the polymer (C) containing 50% by mass or more of structural units derived from aromatic substituted ethene or aromatic substituted propene, which will be described later. shall be taken as a thing.

(1) Olefin polymer (2) Polyamide (3) Polyester (4) Polyacetal (5) Styrene resin (6) Acrylic resin (7) Polycarbonate (8) Polyphenylene oxide (9) Chlorine resin (10) Acetic acid Vinyl resins (11) Ethylene-(meth)acrylic acid ester copolymers (12) Ethylene-(meth)acrylic acid resins and their ionomer resins (13) Vinyl alcohol resins (14) Cellulose resins (15) Thermoplastics Elastomer (16) Various copolymer rubbers

Each of the thermoplastic resins (1) to (16) above will be specifically explained.

(1) Olefin polymer Examples of olefin polymers include olefin homopolymers such as polyethylene, polypropylene, poly-1-butene, poly4-methyl-1-pentene, and polymethylbutene; ethylene-α-olefin Olefin copolymers such as random copolymers, propylene-ethylene random copolymers, ethylene/α-olefin/non-conjugated polyene copolymers, 4-methyl-1-pentene/α-olefin copolymers; etc. It will be done. Among the above-mentioned olefin polymers, ethylene (co)polymers and propylene (co)polymers are preferable.

The ethylene (co)polymer is preferably an ethylene homopolymer (polyethylene) or a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms. Specific examples of ethylene homopolymers include ultra-high molecular weight polyethylene, high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and the like.

On the other hand, when the ethylene (co)polymer is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms, the amount (a) of structural units derived from ethylene is 91.0 to 99.9. The mol% is preferably 93.0 to 99.9 mol%, still more preferably 95.0 to 99.9 mol%, particularly preferably 95.0 to 99.0 mol%. On the other hand, the amount (b) of structural units derived from α-olefin having 3 or more carbon atoms is preferably 0.1 to 9.0 mol%, more preferably 0.1 to 7.0 mol%, and It is preferably 0.1 to 5.0 mol%, particularly preferably 1.0 to 5.0 mol%. However, (a)+(b)=100 mol%. The content ratio of structural units in the ethylene copolymer is determined by analysis of ¹³ C-NMR spectrum.

Here, examples of α-olefins having 3 to 12 carbon atoms include propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3- It includes linear or branched α-olefins such as methyl-1-pentene, 1-octene, 1-decene, and 1-dodecene. α-olefins are preferably propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene. More preferred is α-olefin having 3 to 8 carbon atoms, particularly preferred is propylene or 1-butene. When ethylene is copolymerized with propylene or 1-butene, the processability of the conductive resin composition becomes good, and the appearance (surface gloss), mechanical properties, etc. of the resulting molded product also become good. Note that the ethylene (co)polymer may use only one type of α-olefin, or may use two or more types in combination.

The melt flow rate (MFR) of the ethylene (co)polymer measured at 190°C and a load of 2.16 kg according to ISO 1133 is preferably 0.01 to 500 g/10 minutes, and 0.1 to 100 g/10 minutes. 10 minutes is more preferable. When the MFR of the ethylene (co)polymer is within the above range, fluidity during molding becomes good and a molded article with good mechanical properties is easily obtained.

On the other hand, the propylene (co)polymer is preferably a propylene homopolymer (polypropylene) or a copolymer of propylene and ethylene or an α-olefin having 4 to 12 carbon atoms.

When the propylene (co)polymer is a copolymer of propylene and ethylene, the amount of structural units derived from propylene is preferably 60 to 99.5 mol%. The amount of structural units derived from propylene is preferably 80 to 99 mol%, more preferably 90 to 98.5 mol%, and even more preferably 95 to 98 mol%. However, the total amount of the structural units derived from propylene and the amount of structural units derived from ethylene is 100 mol%. When a propylene (co)polymer having a large amount of propylene-derived structural units is used, the resulting molded product will have good heat resistance, appearance (surface gloss), and mechanical properties.

When the propylene (co)polymer is a copolymer of propylene and an α-olefin having 4 to 12 carbon atoms, examples of the α-olefin having 4 to 12 carbon atoms include 1-butene, 1- Linear or branched pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, etc. Contains α-olefins. Among them, 1-butene is particularly preferred. Further, the propylene/α-olefin copolymer may further contain a structural unit derived from an olefin having a carbon number other than 4 to 12, for example, a small amount, for example, 10 mol% or less, of a structural unit derived from ethylene. Good too. On the other hand, when the structural unit derived from ethylene is not included, the resulting molded product tends to have a particularly good balance between heat resistance and mechanical properties. For the propylene (co)polymer, one type of α-olefin may be used, or two or more types may be used in combination.

When the propylene (co)polymer is a propylene/α-olefin copolymer, the amount (a') of structural units derived from propylene is preferably 60 to 90 mol%, more preferably 65 to 88 mol%. The content is more preferably 70 to 85 mol%, particularly preferably 75 to 82 mol%. On the other hand, the amount (b') of structural units derived from α-olefins having 4 or more carbon atoms is preferably 10 to 40 mol%, more preferably 12 to 35 mol%, and still more preferably 15 to 30 mol%. and particularly preferably 18 to 25 mol%. However, (a')+(b')=100 mol%.

When the composition of the propylene/α-olefin copolymer is within the above range, a molded article with excellent appearance (surface gloss) can be obtained. Although the reason is not clear, the above composition slows down the crystallization rate and increases the flow time of the conductive resin composition on the mold or in the cooling process. As a result, it is thought that the surface tends to become smooth. Moreover, when the composition is within the above range, the mechanical properties and heat resistance of the obtained molded article will be good.

The melting point (Tm) of the propylene/α-olefin copolymer measured by differential scanning calorimetry (DSC) is preferably 60 to 120°C, preferably 65 to 100°C, and more preferably 70 to 90°C. It is ℃.

Further, the olefin polymer may be a polymer of ethylene/α-olefin/unsaturated cyclic compound or chain polyene. In this case, a copolymer of ethylene, an α-olefin having 3 to 12 carbon atoms, and an unsaturated cyclic compound or a chain polyene is preferred, and a random copolymer of these is more preferred. The α-olefin is preferably an α-olefin having 3 to 12 carbon atoms, examples of which include propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl- Includes 1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, etc.

Examples of unsaturated cyclic compounds include cyclopentene, cycloheptene, norbornene, 5-ethylidene-2-norbornene, dicyclopentadiene, 5-vinyl-2-norbornene, norbornadiene, methyltetrahydroindene, tetracyclododecene, etc. It will be done. Examples of linear polyenes include chains such as 1,4-hexadiene, 7-methyl-1,6-octadiene, 4-ethylidene-8-methyl-1,7-nonadiene, and 4-ethylidene-1,7-undecadiene. Contains non-conjugated polyenes. Among these, 5-ethylidene-2-norbornene, dicyclopentadiene, or 5-vinyl-2-norbornene is preferred. One type of unsaturated cyclic compound or chain polyene may be used, or two or more types may be used in combination.

Specific examples of the ethylene/α-olefin/unsaturated cyclic compound or chain polyene random copolymer include ethylene/propylene/diene terpolymer (EPDM).

Further, as the olefin polymer, propylene/α-olefin/unsaturated cyclic compound or chain polyene, 1-butene/α-olefin/unsaturated cyclic compound or chain polyene, etc. can also be used.

Furthermore, a 4-methyl-1-pentene/α-olefin copolymer can also be used as the olefin polymer. Specific examples of the 4-methyl-1-pentene/α-olefin copolymer include the polymer disclosed in International Publication No. 2011/055803. The amount of structural units derived from 4-methyl-1-pentene in the 4-methyl-1-pentene/α-olefin copolymer is preferably 5 to 95 mol%, and the number of carbon atoms excluding 4-methyl-1-pentene The amount of structural units derived from at least one α-olefin selected from 2 to 20 α-olefins is preferably 5 to 95 mol%. Further, a part of the 4-methyl-1-pentene/α-olefin copolymer may contain a structure derived from an unsaturated cyclic compound or a chain polyene, and a structure derived from an unsaturated cyclic compound or a chain polyene may be included. The amount of the structural unit is preferably 0 to 10 mol%. The total amount of these is 100 mol%.

There are no particular restrictions on the stereoregularity of the olefin polymer, but when the olefin polymer is a propylene (co)polymer, the propylene (co)polymer has a substantially syndiotactic structure. It is preferable to have. For example, when a propylene (co)polymer has a substantially syndiotactic structure, the molecular weight (Me) between entanglement points becomes small at the same molecular weight, and molecular entanglement increases. Therefore, the melt tension increases, making it difficult to cause dripping. Moreover, when manufacturing a molded article using a conductive resin composition containing a propylene (co)polymer, it becomes easy to properly adhere to a mold or a roll for molding. In addition, compared to general isotactic polypropylene (co)polymers, propylene (co)polymers with a syndiotactic structure have a slower crystallization rate, so cooling in molds and rolls is slower. Adhesion is improved. As a result, it is presumed that the surface gloss, abrasion resistance, scratch resistance, impact resistance, etc. of the molded article are improved.

Note that the propylene (co)polymer has a substantially syndiotactic structure when the peak area corresponding to 19.5 to 20.3 ppm in the ¹³ C-NMR spectrum is relative to the total peak area detected. This means that it is relatively 0.5% or more. When the syndiotacticity is within the above range, the crystallization rate will be sufficiently slow and the processability will be very good. In addition, propylene (co)polymers whose structural units derived from propylene have a substantially syndiotactic structure have better wear resistance and scratch resistance than general-purpose polyolefin resins such as polyethylene, block polypropylene, and isotactic polypropylene. is very good. Note that the propylene (co)polymer having a syndiotactic structure can be produced by various known production methods.

Moreover, a cycloolefin polymer can also be mentioned as an olefin polymer. Examples of the cycloolefin polymer include (co)polymers having structural units derived from cycloolefins such as cyclopentene, cycloheptene, norbornene, and tetracyclododecene. Examples of the copolymerization component include chain α-olefins having 2 to 8 carbon atoms such as ethylene, propylene, and 1-butene.

Here, when the thermoplastic resin (A) is the above-mentioned olefin polymer, the viewpoint is to maintain the shape of the carbon nanotubes (B) within the conductive resin composition and obtain a molded article having excellent conductivity. In this case, unmodified olefin polymers are preferred. At this time, the acid value of the olefin polymer is preferably less than 1 mgKOHmg/g, and the amount of styrene is preferably 5% by mass or less.

On the other hand, from the viewpoint of improving the heat resistance and mechanical properties of the conductive resin composition (or its molded product), the olefin polymer may be graft-modified with a polar compound containing a double bond. When the olefin polymer is graft-modified, the affinity between the thermoplastic resin (A) and the carbon nanotubes (B) increases, and a molded article having excellent heat resistance and mechanical properties is easily obtained.

Graft modification of the olefin polymer can be performed by a known method. The olefin polymer is dissolved in an organic solvent, and then a polar compound containing a double bond such as an unsaturated carboxylic acid, a radical polymerization initiator, etc. are added to the resulting solution, and the mixture is heated at 60 to 350°C (preferably 80 to 190°C). ) for 0.5 to 15 hours (preferably 1 to 10 hours).

The above organic solvent is not particularly limited as long as it can dissolve the olefin polymer. Examples of such organic solvents include aromatic hydrocarbon solvents such as benzene, toluene, and xylene; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane.

Another graft modification method is to react an olefin polymer with a polar compound containing a double bond such as an unsaturated carboxylic acid using an extruder or the like, preferably without using a solvent. Can be mentioned. In this case, the reaction temperature is preferably higher than the melting point of the olefin polymer, specifically preferably 100 to 350°C. The reaction time is usually preferably 0.5 to 10 minutes.

The above graft modification is preferably carried out in the presence of a radical polymerization initiator in order to efficiently graft copolymerize a polar compound containing a double bond. Examples of radical polymerization initiators include organic peroxides and organic peresters such as benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(peroxide benzoate), ) Hexyne-3,1,4-bis(t-butylperoxyisopropyl)benzene, lauroyl peroxide, t-butylperacetate, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3,2 , 5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butyl perbenzoate, t-butyl perphenylacetate, t-butyl perisobutyrate, t-butyl per-sec-octoate, t-butyl perpivalate, cumyl perpivalate, and t-butyl perdiethyl acetate), azo compounds (eg, azobisisobutyronitrile, dimethylazoisobutyrate), and the like.

Among these, dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(t- Dialkyl peroxides such as butylperoxy)hexane and 1,4-bis(t-butylperoxyisopropyl)benzene are preferred. The radical polymerization initiator is usually used in an amount of 0.001 to 1 part by mass per 100 parts by mass of the olefin polymer before modification.

Note that the shape of the graft-modified olefin polymer is not particularly limited, and may be, for example, particulate. As an example of a suitable method for obtaining a particulate graft-modified olefin polymer, a polymer comprising one or more α-olefins selected from α-olefins having 2 to 18 carbon atoms and having a melting point of 50 Examples include a method in which particles having a temperature of at least .degree. C. and below 250.degree. C. are subjected to a graft reaction with a monomer having an ethylenically unsaturated group and a polar functional group in the same molecule. The graft reaction can be carried out using the above-mentioned radical polymerization initiator at a temperature below the melting point (Tm) of the olefin polymer particles. The average particle size of the particles of the graft-modified olefin polymer can be, for example, 0.2 mm to 2.5 mm, but is not limited thereto. Further, the melting point of the olefin polymer particles used for preparing the particulate graft-modified olefin polymer is usually 50° C. or higher and lower than 250° C., but is not limited thereto. Although the above graft reaction can be carried out without a solvent, it is preferably carried out in the presence of an organic solvent.

(2) Polyamide Examples of polyamides include aliphatic polyamides such as nylon-6, nylon-66, nylon-10, nylon-11, nylon-12, nylon-46, nylon 66, nylon-610, and nylon-612; Aromatic polyamides produced from aromatic dicarboxylic acids and aliphatic diamines; etc. are included. Among these, nylon-6 is preferred.

(3) Polyester Examples of polyester include aromatic polyesters such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, polycaprolactone, polyhydroxybutyrate, and polyester elastomers. Among these, aromatic polyesters such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate are preferred.

(4) Polyacetal Examples of polyacetals include polyformaldehyde (polyoxymethylene), polyacetaldehyde, polypropionaldehyde, polybutyraldehyde, and the like. Among these, polyformaldehyde is particularly preferred.

(5) Styrenic resin The styrene resin may be a styrene homopolymer (polystyrene), or a binary copolymer of styrene and acrylonitrile, methyl methacrylate, α-methylstyrene, etc., such as acrylonitrile- It may also be a styrene copolymer. Further, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-acrylic rubber-styrene resin, acrylonitrile-ethylene rubber-styrene resin, (meth)acrylic acid ester-styrene resin, or various styrene-based elastomers may be used. The preferred molecular weight (MFR) of the styrenic resin measured according to ISO1133 is 0.5 to 30 g/10 minutes, more preferably 3 to 20 g/10 minutes, and even more preferably 5 to 10 g/10 minutes. When the molecular weight of the styrene resin is within the above range, a molded article with excellent moldability and mechanical strength can be easily obtained.

Acrylonitrile-butadiene-styrene (ABS) resin may contain 20 to 35 mol% of structural units derived from acrylonitrile, 20 to 30 mol% of structural units derived from butadiene, and 40 to 60 mol% of structural units derived from styrene. preferable. The total amount of these structural units is 100 mol%.

Further, as the styrene elastomer, a known styrene elastomer having a polystyrene phase as a hard segment can also be used. Specific examples include styrene-butadiene copolymer (SBR), styrene-isoprene-styrene copolymer (SIS), styrene-butadiene-styrene copolymer (SBS), and styrene-ethylene-butadiene-styrene copolymer ( SEBS), and their hydrides, styrene/isobutylene/styrene triblock copolymer (SIBS), styrene/isobutylene diblock copolymer (SIB), and the like. Among these, styrene/isobutylene/styrene triblock copolymer (SIBS) and styrene/isobutylene diblock copolymer (SIB) are preferred.

(6) Acrylic Resin Examples of acrylic resins include polymethacrylate and polyethyl methacrylate, with polymethyl methacrylate (PMMA) being preferred.

(7) Polycarbonate Examples of polycarbonates include bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, and 2,2-bis(4-hydroxyphenyl)propane. Includes polycarbonates obtained from (4-hydroxyphenyl)butane and the like. Among these, polycarbonate obtained from 2,2-bis(4-hydroxyphenyl)propane is preferred.

The melt flow rate (MFR) of polycarbonate measured at 300° C. and a load of 2.16 kg according to ISO 1133 is preferably 2 to 30 g/10 minutes, more preferably 5 to 20 g/10 minutes. When the polycarbonate MFR is within this range, processability will be good.

(8) Polyphenylene oxide As polyphenylene oxide, poly(2,6-dimethyl-1,4-phenylene oxide) is preferable.

(9) Chlorine resin Examples of chlorine resins include polyvinyl chloride, polyvinylidene chloride, and the like. Polyvinyl chloride may be a homopolymer of vinyl chloride, or a copolymer of vinyl chloride and vinylidene chloride, acrylic ester, acrylonitrile, propylene, or the like. On the other hand, polyvinylidene chloride is a resin that usually contains 85% by mass or more of structural units derived from vinylidene chloride, such as vinylidene chloride, vinyl chloride, acrylonitrile, (meth)acrylic ester, allyl ester, unsaturated ether, styrene, etc. It is a copolymer with Further, the chlorine-based resin may be a vinyl chloride-based elastomer.

(10) Vinyl acetate resin Examples of vinyl acetate resins include homopolymers of vinyl acetate (polyvinyl acetate) and copolymers of vinyl acetate, ethylene, and vinyl chloride. Among these, ethylene-vinyl acetate copolymer is preferred. It may also be a modified ethylene-vinyl acetate copolymer such as a saponified ethylene-vinyl acetate copolymer or a graft-modified ethylene-vinyl acetate copolymer.

(11) Ethylene-(meth)acrylic acid ester copolymer Ethylene-(meth)acrylic acid ester copolymer includes ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl methacrylate copolymer. Polymer, ethylene-ethyl methacrylate copolymer is preferred.

(12) Ethylene-(meth)acrylic acid resin and these ionomer resins Ethylene-(meth)acrylic acid copolymer is a copolymer of ethylene and various (meth)acrylic acids. These may be further converted into metal salts to form metal salts (ionomers). The metal element of the metal salt is preferably at least one selected from K, Na, Ca, and Zn. It is more preferable that the metal elements are K, Na, Ca, and Zn because they can be easily modified.

(13) Vinyl alcohol resin Examples of vinyl alcohol resins include polyvinyl alcohol, ethylene-vinyl alcohol resin, etc., and ethylene-vinyl alcohol resin is preferred. Ethylene-vinyl alcohol resin is obtained by hydrolysis of a copolymer of ethylene and vinyl acetate. Ethylene-vinyl alcohol resin has the high gas barrier properties, oil resistance, and transparency of polyvinyl alcohol, as well as the moisture resistance and melt extrusion properties of the ethylene component.

(14) Cellulose resin Examples of cellulose resins include acetyl cellulose. When cellulose resin is used, the properties of a thermoplastic resin can be obtained by using a plasticizer such as dibutyl phthalate.

(15) Thermoplastic Elastomer Examples of the thermoplastic elastomer include vinyl chloride elastomer, urethane elastomer, polyester elastomer, etc. Among these, urethane elastomer is preferred.

Examples of urethane-based elastomers include thermoplastic polyurethane materials. The structure of the thermoplastic polyurethane material consists of a soft segment made of a polymeric polyol (polymeric glycol), and a chain extender and diisocyanate that make up the hard segment.

Here, the same material as known thermoplastic polyurethane can be used as the raw material polymer polyol. Polymer polyols include polyester and polyether. Among these, polyether-based materials are preferred because they have a high rebound modulus and can synthesize thermoplastic polyurethane materials with excellent low-temperature properties. Examples of polyether polyols include polytetramethylene glycol, polypropylene glycol, etc., and polytetramethylene glycol is particularly preferred in terms of impact resilience and low-temperature properties. Further, the average molecular weight of the polymer polyol is preferably 1,000 to 5,000, and more preferably 2,000 to 4,000 in order to synthesize a thermoplastic polyurethane material with particularly high impact resilience.

On the other hand, chain extenders can be those used in the art regarding conventional thermoplastic polyurethane materials, examples of which include 1,4-butylene glycol, 1,2-ethylene glycol, 1,3-butanediol, , 6-hexanediol, 2,2-dimethyl-1,3-propanediol, and the like. However, it is not limited to these. The average molecular weight of these chain extenders is preferably 20 to 15,000.

Diisocyanates can be those used in the art for conventional thermoplastic polyurethane materials, examples of which include aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, etc. and aliphatic diisocyanates such as hexamethylene diisocyanate. However, it is not limited to these. Among these, 4,4'-diphenylmethane diisocyanate, which is an aromatic diisocyanate, is particularly preferred.

As the urethane elastomer made of the above-mentioned materials, commercially available products can be suitably used, such as Pandex T-8290, T-8295, and T8260 manufactured by DIC Bayer Polymer Co., Ltd., Rezamin 2593 manufactured by Dainichiseika Chemical Co., Ltd. 2597 etc. are mentioned.

(16) Various copolymer rubbers The thermoplastic resin may be various rubbers other than the above-mentioned elastomers. Examples of various copolymer rubbers include polybutadiene rubber, polyisoprene rubber, neoprene rubber, nitrile rubber, butyl rubber, halogenated butyl rubber, polyisobutylene rubber, natural rubber, silicone rubber, and the like. These rubbers may be used alone or in combination of two or more.

In addition, as the thermoplastic resin (A), among the above-mentioned thermoplastic resins (1) to (16), (1) olefin polymer (including its acid graft modified product), (3) polyester, ( 5) Styrene resins, (7) polycarbonates, (9) chlorine resins, (12) ethylene-(meth)acrylic acid resins and their ionomer resins, (15) thermoplastic elastomers, and (16) various copolymer rubbers. It is preferable that at least one resin is selected from the group consisting of: Further, at least one resin selected from the group consisting of olefin polymers, polyesters, polystyrene, acrylonitrile-butadiene-styrene copolymer resins (ABS resins), polyvinyl chloride, and polycarbonates is more preferred; ) polymers, propylene (co)polymers such as polypropylene, poly-1-butene, poly4-methyl-1-pentene, cycloolefin polymers, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyvinyl chloride, polystyrene, It is more preferably selected from polycarbonates obtained from acrylonitrile-butadiene-styrene copolymers and 2,2-bis(4-hydroxyphenyl)propane, and particularly preferably cycloolefin polymers, polyesters, or polycarbonates.

When a cycloolefin polymer is used as the thermoplastic resin (A), there is less odor, smoke, etc. during molding of the conductive resin composition, and the working environment tends to be favorable. Moreover, a good molded article with little burntness can be obtained. Furthermore, the use of polyester and polycarbonate makes it easier to apply the conductive resin composition to various uses.

Furthermore, it is preferable that the thermoplastic resin (A) has a cyclic structure in its molecular structure. Examples of cyclic structures include alicyclic structures and aromatic rings. When the thermoplastic resin (A) has an annular structure, the resulting molded product has transparency, making it easier to apply it to various uses.

1-1-2. Physical properties of thermoplastic resin (A) The ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn) measured by gel permeation chromatography (GPC) of thermoplastic resin (A) is 6. .0 or less is preferable. Mw/Mn is more preferably 4.0 or less, still more preferably 3.0 or less. When Mw/Mn is within the above range, there are fewer low molecular weight components that cause deterioration of physical properties, resulting in excellent appearance (surface gloss), heat resistance, and mechanical properties. Furthermore, since there are few polymers that cause an increase in melt viscosity during kneading, processability is excellent. Note that both the weight average molecular weight (Mw) and the number average molecular weight (Mn) are determined in terms of polystyrene.

It is preferable that the melting point (Tm) of the thermoplastic resin (A) measured by a differential scanning calorimeter (DSC) is 250° C. or lower or not observed. If a melting point is observed, the upper limit of the melting point is more preferably 230°C, even more preferably 200°C, particularly preferably 170°C. Further, the lower limit of the melting point is preferably 50°C, more preferably 70°C, even more preferably 90°C, particularly preferably 130°C, and more preferably 150°C. When the melting point is within the above range, smoke, odor, etc. are unlikely to occur when preparing a conductive resin composition by melt-kneading or when producing a molded article by melt molding. Furthermore, a molded article that is less likely to become sticky and has an excellent balance of heat resistance, mechanical properties, impact strength, and impact absorption properties can be obtained.

The glass transition temperature (Tg) of the thermoplastic resin (A) as measured by a differential scanning calorimeter (DSC) is preferably in the range of -140°C to 50°C, more preferably in the range of -120°C to 20°C. The temperature is more preferably -100°C to -10°C. When the glass transition temperature is within the above range, the resulting molded product will have a good balance of long-term stability, heat resistance, impact resistance, and mechanical properties.

The density of the thermoplastic resin (A), measured according to ISO 1183 and according to the density gradient tube method, is preferably in the range of 800 to 1800 kg/m ³ . The lower limit of the density of the resin (A) is more preferably 810 kg/m ³ , even more preferably 830 kg/m ³ , particularly preferably 860 kg/m ³ , and more preferably 900 kg/m ³ . The upper limit of the density of the resin (A) is more preferably 1300 kg/m ³ , even more preferably 1290 kg/m ³ , particularly preferably 1270 kg/m ³ , more preferably 1240 kg/m ³ , and even more preferably 1200 kg/m ³ preferable.

The flexural modulus of the thermoplastic resin (A) measured in accordance with JIS K7171:94 (ISO 178) is preferably 1 to 10,000 MPa. When the flexural modulus is 500 MPa or more, the flexural modulus is preferably 500 to 7,000 MPa, more preferably 700 to 5,000 MPa, particularly preferably 900 to 3,000 MPa, and still more preferably 1,000 to 2,300 MPa. It is. When the flexural modulus falls within the above range, not only the processability of the conductive resin composition is excellent, but also the resulting molded product has good scratch resistance, heat resistance, and mechanical properties. Moreover, when the bending elastic modulus is less than 500 MPa, it is preferably less than 300 MPa, more preferably less than 100 MPa, and even more preferably less than 50 MPa. When the flexural modulus is within the above range, a molded product not only has excellent flexibility but also excellent shock absorption, lightness, vibration damping, vibration damping, and sound damping properties. Furthermore, a molded article with excellent design properties such as mold transferability and grain transferability, and surface grip properties can be obtained.

1-2. Carbon nanotube (B)
The carbon nanotube (B) may be any carbon isotope in the form of a tube. The outer diameter of the carbon nanotube (B) is preferably 100 nm or less, more preferably 50 nm or less, and still more preferably 30 nm or less. When the outer diameter of the carbon nanotubes (B) is 100 nm or less, the carbon nanotubes (B) tend to form a network structure in the conductive resin composition, and the conductivity tends to increase. On the other hand, when the outer diameter of the carbon nanotubes (B) is 1 nm or more, the carbon nanotubes (B) tend to be easily dispersed.

Further, the fiber length of the carbon nanotubes (B) is preferably 3 to 500 μm, more preferably 5 to 300 μm, even more preferably 7 to 100 μm, particularly preferably 9 to 50 μm. When the fiber length is 3 μm or more, a network structure of carbon nanotubes (B) is easily formed in the conductive resin composition, and the conductivity is likely to be sufficient. On the other hand, when the fiber length is 500 μm or less, the dispersibility of carbon nanotubes (B) tends to be good. The outer diameter and fiber diameter of carbon nanotubes (B) can be determined by measuring the length and outer diameter of 100 carbon nanotubes using electron microscopy (SEM) and calculating the average value of each. Desired.

Further, the aspect ratio (fiber length/outer diameter) of the carbon nanotube (B) is preferably 30 to 50,000, more preferably 50 to 30,000, and even more preferably 100 to 20,000. When the aspect ratio of the carbon nanotubes (B) is within this range, the dispersibility tends to be good.

The carbon nanotube (B) may have any shape as long as it is tube-like, for example, needle-like, cylindrical tube-like, fishbone-like (fishbone, cup laminated type), playing card-like (platelet), or coil-like. etc. may be used. Further, the carbon nanotube (B) can be a graphite whisker, filamentous carbon, graphite fiber, ultrafine carbon tube, carbon fibril, carbon nanofiber, or the like. Among the above shapes, the shape of the carbon nanotube (B) is preferably a cylindrical tube.

The cylindrical tube-shaped carbon nanotube (B) has a structure in which one or more layers of graphite are wound into a cylindrical shape. The cylindrical carbon nanotube (B) may be a single-walled carbon nanotube with a structure in which only one graphite layer is wound, or a multi-walled carbon nanotube in which two or more graphite layers are wound. Moreover, these may be mixed. However, from the viewpoint of cost, multi-walled carbon nanotubes are preferred. Further, the carbon nanotube may have an amorphous structure instead of a graphite structure on its side surface.

Further, the carbon nanotube (B) may be subjected to various surface treatments, or may be a carbon nanotube derivative having a functional group such as a carboxyl group introduced onto the surface. Further, carbon nanotubes containing organic compounds, metal atoms, fullerene, etc. may also be used.

Here, the carbon nanotube (B) preferably has high carbon purity, and the amount of carbon in 100 mass% of the carbon nanotube (B) (hereinafter also referred to as "carbon purity") is preferably 85 mass% or more, and 90 mass%. % or more is more preferable, and even more preferably 95% by mass or more. When the carbon purity is 85% by mass or more, the conductivity of the conductive resin composition tends to increase.

Carbon nanotubes (B) may exist as secondary particles in the conductive resin composition. The secondary particle shape may be a state in which carbon nanotubes, which are primary particles, are intricately entangled, or a state in which linear carbon nanotubes are aggregated. Among these, a state in which linear carbon nanotubes are aggregated is preferable from the viewpoint that the conductivity of the conductive resin composition tends to be good.

The carbon nanotubes (B) can be produced by a known method, such as a laser ablation method, an arc discharge method, a thermal CVD method, a plasma CVD method, and a combustion method. However, a thermal CVD method using zeolite as a catalyst carrier and acetylene as a raw material is preferable from the viewpoint that it does not require purification and can efficiently produce highly pure carbon nanotubes.

The carbon nanotube (B) may be a commercially available product. Examples of commercially available products include K-Nanos 100P, 100T, 200P (all manufactured by Kumho Petrochemical), FloTube 9000, 9100, (all manufactured by CNano), NC7000 (manufactured by Nanocyl), and the like.

1-3. Polymer (C) containing 50% by mass or more of structural units derived from aromatic substituted ethene or aromatic substituted propene
As mentioned above, simply adding carbon nanotubes (B) to the thermoplastic resin (A) that is the base of the conductive resin composition will result in poor dispersibility of the thermoplastic resin (A) and carbon nanotubes (B). , it may not be possible to knead uniformly.

In particular, if the blending amount of carbon nanotubes (B) to the thermoplastic resin (A) is too large or the specific surface area of carbon nanotubes (B) is large, the viscosity increases during kneading, causing the carbon nanotubes (B) to is often difficult to disperse. Therefore, when molding the conductive resin composition, the processability tends to decrease and the uniformity of the molded product tends to be insufficient. As a result, the resulting molded product may not have sufficient conductivity, and may also have problems with its appearance (surface gloss) or have insufficient heat resistance, mechanical properties, and flexibility (elongation). Sometimes it wasn't.

On the other hand, the present inventors have found that when kneading the thermoplastic resin (A) and carbon nanotubes (B), a polymer containing 50% by mass or more of a structure derived from aromatic substituted ethene or aromatic substituted propene is used. It has become clear that by blending the combination (C), a conductive resin composition with good conductivity, appearance (surface gloss), heat resistance, mechanical properties, flexibility, and processability can be obtained.

Although the detailed mechanism is not clear, the polymer (C) containing 50% by mass or more of a structure derived from aromatic substituted ethene or aromatic substituted propene is a polymer in which the aromatic structure is present in the molecule of the carbon nanotube (B). Since it electrically interacts with heavy bonds, it has high affinity with carbon nanotubes (B). Further, the polymer (C) has a high affinity with various resins, and even when the thermoplastic resin (A) is a polar resin, for example, the compatibility is good. Therefore, the carbon nanotubes (B) are easily dispersed uniformly within the thermoplastic resin (A), and friction during kneading is reduced. It is estimated that the fluidity of the conductive resin composition is improved. Furthermore, by improving the fluidity of the conductive resin composition, the processability is improved, and the appearance (surface gloss) of the molded product is improved. Furthermore, due to the improved fluidity of the conductive resin composition, structural destruction of the carbon nanotubes (B) or their aggregates becomes less likely to occur, making it easier to obtain sufficient conductivity.

1-3-1. Physical Properties of Polymer (C) Here, the polymer (C) preferably satisfies the following requirements (i) to (iv), and more preferably also satisfies requirements (v) and (vi). The polymer (C) is a compound different from the above-mentioned thermoplastic resin (A), and can be separated based on, for example, the following physical properties.

(i) The number average molecular weight (Mn) of the polymer (C) measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably in the range of 300 to 5,000. The upper limit of the number average molecular weight (Mn) is more preferably 4,000, still more preferably 3,000, particularly preferably 2,000, and still more preferably 1,000. When the number average molecular weight of the polymer (C) is within the above range, the dispersibility of the carbon nanotubes (B) in the conductive resin composition increases, and the conductivity, appearance (surface gloss), and Mechanical properties become better. Further, the processability of the conductive resin composition also becomes better.

(ii) Weight average molecular weight (Mw) and number average molecular weight (Mn) measured by gel permeation chromatography (GPC) of polymer (C) containing 50% by mass or more of aromatic substituted ethene or aromatic substituted propene; The ratio (Mw/Mn) is preferably 9.0 or less. It is more preferably 6.0 or less, still more preferably 4.0 or less, particularly preferably 3.0 or less. If Mw/Mn is within the above range, the appearance (surface gloss) and heat resistance of the molded product obtained from the conductive resin composition will be affected due to the small amount of high molecular weight components with low dispersibility of carbon nanotubes (B). properties, mechanical properties, etc. are improved. Note that the weight average molecular weight (Mw) is also a polystyrene equivalent value.

The Mw/Mn of the polymer (C) can be adjusted by adjusting the type of catalyst during polymerization, the polymerization temperature, and the like. Generally, a Ziegler-Natta catalyst or a metallocene catalyst is used for polymerization of unmodified polyolefin wax, but in order to achieve the desired Mw/Mn, it is preferable to use a metallocene catalyst. Note that the Mw/Mn of the polymer (C) can also be adjusted by purifying the unmodified polyolefin wax.

(iii) The softening point of the polymer (C) measured according to JIS K2207 is preferably in the range of 70 to 170°C. The upper limit of the softening point is more preferably 160°C, still more preferably 150°C, particularly preferably 145°C. Further, the lower limit is more preferably 80°C, still more preferably 90°C, particularly preferably 95°C, particularly preferably 105°C. When the softening point is below the above upper limit, the processability of the conductive resin composition, the appearance (surface glossiness), heat resistance, and mechanical properties of the resulting molded product will be good. When the softening point is equal to or higher than the above lower limit, bleed-out of the polymer (C) is easily suppressed in the resulting conductive resin composition.

The softening point of the polymer (C) can be adjusted by the degree of polymerization of aromatic substituted ethene or aromatic substituted propene. For example, when the polymer (C) is a polymer of isopropenyltoluene described below, the softening point can be raised by increasing the degree of polymerization. The softening point may be adjusted by the catalyst species, polymerization temperature, and post-polymerization purification. Further, as described below, when the polymer (C) is a compound obtained by modifying a polyolefin wax with aromatic substituted ethene or aromatic substituted propene, its softening point can be adjusted by the composition of the unmodified polyolefin wax. More specifically, the softening point can be lowered by increasing the α-olefin content in the unmodified polyolefin wax. Further, it is also possible to adjust the softening point by changing the catalyst species and polymerization temperature during the preparation of unmodified polyolefin wax, and by purification after polymerization.

(iv) The density of the polymer (C) measured by density gradient tube method according to JIS K7112 is preferably in the range of 900 to 1200 kg/m ³ . More preferably 950 to 1150 kg/m ³ , even more preferably 1000 to 1100 kg/m ³ . When the density of the polymer (C) is within the above range, the dispersibility of the carbon nanotubes (B) will increase, and the resulting molded product will have good conductivity, appearance (surface gloss), and mechanical properties. Further, the processability of the conductive resin composition also becomes better.

When the polymer (C) is a compound obtained by modifying a polyolefin wax with aromatic substituted ethene or aromatic substituted propene, the density of the polymer (C) depends on the composition of the unmodified polyolefin wax described below and the polymerization temperature during polymerization. , can be adjusted by hydrogen concentration, etc.

(v) The melt viscosity of the polymer (C) measured at 160°C, a B-type viscometer, and a rotor rotation speed of 60 rpm is preferably 100 to 5000 mPa·s, more preferably 300 to 4500 mPa·s, and 600 to 4000 mPa·s. s is more preferred. When the melt viscosity of the polymer (C) at 160°C is within this range, the dispersibility of the carbon nanotubes (B) increases, and the resulting molded product has good conductivity, appearance (surface gloss), and mechanical properties. . Further, the processability of the conductive resin composition also becomes better.

1-3-2. Structure and manufacturing method of polymer (C) The structure of polymer (C) containing 50% by mass or more of structural units derived from aromatic substituted ethene or aromatic substituted propene is not particularly limited, and the structure of polymer (C) is not particularly limited. The propene-derived structural unit may be included in the main chain or in the side chain.

The polymer (C) may be, for example, a homopolymer of either aromatic substituted ethene or aromatic substituted propene, or may be a copolymer of aromatic substituted ethene and aromatic substituted propene, It may also be a copolymer of aromatic substituted ethene and/or aromatic substituted propene and other monomers. In these cases, structural units derived from aromatic substituted ethene or aromatic substituted propene are usually included in the main chain.

On the other hand, the polymer (C) may be a compound obtained by modifying an unmodified polyolefin wax with aromatic substituted ethene and/or aromatic substituted propene. In this case, a structural unit derived from aromatic substituted ethene or aromatic substituted propene is usually included in the side chain.

Among the above, the polymer (C) preferably has a structural unit derived from aromatic substituted ethene or aromatic substituted propene in the main chain.

Here, in this specification, aromatic substituted ethene or aromatic substituted propene is a compound in which an aromatic ring is bonded to ethylene, or a compound in which an aromatic ring is bonded to propene. The type of aromatic ring is not particularly limited, and may be a heterocycle, for example. Examples of aromatic rings include, but are not limited to, phenyl groups, pyridyl groups, quinolyl groups, carbazolyl groups, groups derived from pyrrolidone, and the like.

Specific examples of aromatic substituted ethene or propene include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, p-chlorostyrene, m-chlorostyrene, and p-chlorostyrene. Styrenic monomers such as methylstyrene; Pyridine monomers such as 4-vinylpyridine, 2-vinylpyridine, 5-ethyl-2-vinylpyridine, 2-methyl-5-vinylpyridine, 2-isopropenylpyridine; 2-vinyl Included are quinoline monomers such as quinoline and 3-vinylisoquinoline; N-vinylcarbazole; isopropenyltoluene and the like.

Among these, styrene monomers or isopropenyltoluene are particularly preferred, and compounds containing a structural unit derived from α-methylstyrene or isopropenyltoluene in the main chain are preferred.

The amount of structural units derived from aromatic substituted ethene or aromatic substituted propene in the polymer (C) may be 50% by mass, more preferably 60% by mass, based on the mass of the polymer (C). , more preferably 70% by mass, particularly preferably 80% by mass. When the amount of structural units derived from aromatic substituted ethene or aromatic substituted propene in the polymer (C) is 50% by mass or more, the compatibility between the polymer (C) and the carbon nanotubes (B) is good. . Therefore, the processability of the conductive resin composition is improved, and the resulting molded product has a good balance of appearance (surface gloss), heat resistance, and mechanical properties.

The amount of structural units derived from aromatic substituted ethene or aromatic substituted propene is calculated from the charging ratio of aromatic substituted ethene or aromatic substituted propene at the time of preparing the polymer (C). It can also be identified by extracting the polymer (C) using gel permeation chromatography (GPC) or the like and analyzing its structure using NMR or the like.

(Method for preparing polymer (C) obtained by polymerizing aromatic substituted ethene and/or aromatic substituted propene)
The polymer (C) of aromatic-substituted ethene and/or aromatic-substituted propene is prepared by using the above-mentioned aromatic-substituted ethene or aromatic-substituted propene alone, or by adding aromatic-substituted ethene and/or aromatic-substituted propene in the presence of a catalyst. Obtained by polymerizing propene and, if necessary, other monomers.

Catalysts used for polymerization include those generally known as Friedel-Crafts catalysts, such as aluminum chloride, aluminum bromide, dichloromonoethylaluminum, titanium tetrachloride, tin tetrachloride, boron trifluoride, etc. Contains various complexes. The amount of catalyst used is 0.01 to 5% by weight, preferably 0.05 to 3% by weight, based on the total amount of monomers.

In addition, during the polymerization reaction, at least one kind selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons, and alicyclic hydrocarbons is used to remove reaction heat and suppress increase in viscosity of the reaction mixture. It is preferred to use a hydrocarbon solvent of. Preferred hydrocarbon solvents include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, mesitylene, cumene, and cymene; aliphatic hydrocarbons such as pentane, hexane, heptane, and octane; and alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclohexane. or mixtures thereof. The hydrocarbon solvent may contain only one kind of these, or two or more kinds thereof. The amount of these reaction solvents used is preferably such that the initial concentration of monomers in the reaction mixture is 10 to 80% by mass.

The polymerization temperature is appropriately selected depending on the type and amount of the monomer and catalyst used. Generally, -30 to 50°C is preferred. The general polymerization time is about 0.5 to 5 hours, and the polymerization is usually almost completed in 1 to 2 hours. As the polymerization method, either a batch method or a continuous method can be adopted. Moreover, multistage polymerization can also be performed.

After completion of polymerization, it is preferable to wash to remove catalyst residues. As the cleaning liquid, an alkaline aqueous solution in which potassium hydroxide, sodium hydroxide, etc. are dissolved; alcohol such as methanol; etc. are preferable, and washing and deashing with methanol is particularly preferable. After washing, unreacted monomers, polymerization solvent, etc. are distilled off under reduced pressure to obtain a polymer (C) containing 50% by mass or more of structural units derived from aromatic substituted ethene or aromatic substituted propene.

Methods for removing the solvent include methods such as atmospheric distillation, vacuum distillation, and steam distillation that utilize the difference in vapor pressure of each substance, and open columns and flash columns that have an affinity for packing materials such as silica gel. One example is a method of concentration that takes advantage of the difference in molecular size. Among these, the vacuum distillation method is preferred from the viewpoint of suppressing thermal decomposition of the polymer (C) and concentration efficiency.

(Method for preparing polymer (C) obtained by modifying polyolefin wax with aromatic substituted ethene or aromatic substituted propene)
As mentioned above, the polymer (C) may be a compound obtained by modifying an unmodified polyolefin wax with the above-mentioned aromatic substituted ethene or aromatic substituted propene. Hereinafter, the structure of unmodified polyolefin wax and its preparation method will be explained first, and then the method of modifying it with aromatic substituted ethene or aromatic substituted propene will be explained.

-Structure of unmodified polyolefin wax The unmodified polyolefin wax is preferably at least one homopolymer or copolymer selected from ethylene and α-olefin having 3 to 12 carbon atoms. Examples of α-olefins having 3 to 12 carbon atoms include propylene having 3 carbon atoms, 1-butene having 4 carbon atoms, 1-pentene having 5 carbon atoms, 1-hexene having 6 carbon atoms, 4 -methyl-1-pentene, 1-octene having 8 carbon atoms, etc., and preferred are propylene, 1-butene, 1-hexene, and 4-methyl-1-pentene. The unmodified polyolefin wax may be made of a single type of polymer, or may be a mixture of two or more types of polymers.

Hereinafter, polyethylene wax, polypropylene wax, and 4-methyl-1-pentene wax will be explained as specific examples of unmodified polyolefin wax, but unmodified polyolefin wax is not limited to these.

(1) Polyethylene-based wax When the unmodified polyolefin wax is a polyethylene-based wax, polyethylene-based waxes described in JP-A-2009-144146 and the like are preferred. It will be briefly described below.

The polyethylene wax may be, for example, an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms. Specific examples of ethylene homopolymers include high-density polyethylene wax, medium-density polyethylene wax, low-density polyethylene wax, and linear low-density polyethylene wax.

On the other hand, when the polyethylene wax is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms, the amount (a) of structural units derived from ethylene is preferably 91.0 to 99.9 mol%. , more preferably 93.0 to 99.9 mol%, still more preferably 95.0 to 99.9 mol%, particularly preferably 95.0 to 99.0 mol%. On the other hand, the amount (b) of structural units derived from α-olefins having 3 or more carbon atoms is preferably 0.1 to 9.0 mol%, preferably 0.1 to 7.0 mol%, and more preferably 0.1 to 9.0 mol%. is 0.1 to 5.0 mol%, particularly preferably 1.0 to 5.0 mol%. However, (a)+(b)=100 mol%. The proportion of structural units in the polyethylene wax is determined by analysis of 13C-NMR spectrum.

Examples of α-olefins having 3 to 12 carbon atoms copolymerized with ethylene include propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, Contains linear or branched α-olefins such as 3-methyl-1-pentene, 1-octene, 1-decene, and 1-dodecene, preferably propylene, 1-butene, 1-hexene, and 4- Methyl-1-pentene and 1-octene, more preferably α-olefins having 3 to 8 carbon atoms, particularly preferably propylene and 1-butene, and still more preferably propylene. When ethylene is copolymerized with propylene or 1-butene, the polymer (C) tends to become harder and less sticky. Therefore, the surface properties of the molded product obtained are good. It is also preferable in terms of improving the mechanical properties and heat resistance of the molded product obtained. The reason for this is not clear, but compared to other α-olefins, propylene and 1-butene effectively lower their melting points with a small amount of copolymerization. Therefore, when compared at the same melting point, the degree of crystallinity tends to be higher, and this is presumed to be the cause. The α-olefin copolymerized with ethylene may be used alone or in combination of two or more.

The above polyethylene wax is particularly preferably used when the thermoplastic resin (A) is a polyolefin resin. When these are combined, the compatibility between the thermoplastic resin (A) and the polymer (C) increases, and the resulting molded product has a good balance of appearance (surface gloss), processability, mechanical properties, and heat resistance. Become. Polyethylene wax is also suitably used when the thermoplastic resin (A) is polycarbonate. In this case, the appropriate compatibility between the thermoplastic resin (A) (polycarbonate) and the polyethylene wax improves the processability of the semiconductor resin composition, the releasability of the resulting molded product from the mold, and the balance of mechanical properties. etc. tend to improve.

(2) Polypropylene wax The unmodified polyolefin wax may be a polypropylene wax. The polypropylene wax may be a propylene homopolymer, a copolymer of propylene and ethylene, or a copolymer of propylene and an α-olefin having 4 to 12 carbon atoms.

When copolymerizing propylene and ethylene, the structural units derived from propylene are 60 to 99
．． The content is preferably 5 mol%. The amount of structural units derived from propylene is more preferably 80 to 99 mol%, still more preferably 90 to 98.5 mol%, and particularly preferably 95 to 98 mol%. When such a polypropylene wax is used, a molded article with an excellent balance of appearance (surface gloss), mechanical properties, and heat resistance can be easily obtained.

When the polypropylene wax is a compound obtained by copolymerizing propylene and an α-olefin having 4 to 12 carbon atoms, examples of the α-olefin having 4 to 12 carbon atoms include 1-butene, 1 - Straight chain or branched such as pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, etc. α-olefins are included. Among these, 1-butene is particularly preferred.

When the polypropylene wax is a propylene/α-olefin copolymer, the amount (a') of structural units derived from propylene is preferably 60 to 90 mol%, more preferably 65 to 88 mol%, More preferably, it is 70 to 85 mol%, particularly preferably 75 to 82 mol%. On the other hand, the amount (b') of structural units derived from α-olefins having 4 or more carbon atoms is preferably 10 to 40 mol%, more preferably 12 to 35 mol%, and still more preferably 15 to 30 mol%. The content is particularly preferably 18 to 25 mol%. However, (a')+(b')=100 mol%.

Such polypropylene wax is particularly preferably used when the thermoplastic resin (A) is a polypropylene resin. When these are combined, the compatibility between the thermoplastic resin (A) and the polymer (C) increases, and the resulting molded product has a good appearance (surface gloss), a good balance of mechanical properties, and heat resistance. Further, the processability of the conductive resin composition also becomes better.

(3) 4-Methyl-1-pentene wax The unmodified polyolefin wax was obtained by thermally decomposing the 4-methyl-1-pentene/α-olefin copolymer described in International Publication No. 2011/055803. A 4-methyl-1-pentene polymer described in JP-A No. 2015-028187 is suitable.

(4) Method for preparing unmodified polyolefin wax The above-mentioned unmodified polyolefin wax may be one obtained by directly polymerizing ethylene, propylene, 4-methyl-1-pentene, etc., or a high molecular weight (co)polymer. It may also be obtained by preparing and pyrolyzing these. When thermally decomposing, it is preferable to thermally decompose at 300 to 450°C for 5 minutes to 10 hours. In this case, the unmodified polyolefin wax has unsaturated ends. When the number of vinylidene groups (unsaturated terminals) per 1000 carbon atoms is 0.5 to 5 as measured by ¹ H-NMR, 50% by mass or more of aromatic substituted ethene or aromatic substituted propene The affinity between the containing polymer (C) and carbon nanotubes (B) tends to increase. Note that the unmodified polyolefin wax may be purified by a method such as solvent fractionation based on the difference in solubility in a solvent, or distillation.

On the other hand, when obtaining an unmodified polyolefin wax by directly polymerizing ethylene, propylene, 4-methyl-1-pentene, etc., the method is not limited. Various known production methods can be applied; for example, ethylene or the like may be polymerized using a Ziegler/Natta catalyst or a metallocene catalyst.

(5) Modification method with aromatic substituted ethene or aromatic substituted propene The method of modifying the above-mentioned unmodified monomer with aromatic substituted ethene or aromatic substituted propene is not particularly limited. The aromatic substituted ethene or propene used may be any of the above-mentioned aromatic substituted ethene or aromatic substituted propene, but styrenic monomers are preferred, and styrene is particularly preferred.

For example, a method may be used in which raw material unmodified polyolefin wax and aromatic substituted ethene or aromatic substituted propene (such as styrene) are melt-kneaded in the presence of a polymerization initiator such as an organic peroxide. . Additionally, a polymerization initiator such as an organic peroxide is added to a solution in which the raw material unmodified polyolefin wax and aromatic substituted ethene or aromatic substituted propene (for example, styrene, etc.) are dissolved in an organic solvent, and the mixture is melt-kneaded. It may be a method.

For melt-kneading, known devices such as an autoclave, Henschel mixer, V-type blender, tumbler blender, ribbon blender, single-screw extruder, multi-screw extruder, kneader, Banbury mixer, etc. can be used. Among these, when a device having excellent batch-type melt-kneading performance such as an autoclave is used, a polymer (C) in which each component is uniformly dispersed and reacted can be obtained. Moreover, compared to the continuous type, the batch type is preferable from the viewpoint that it is easier to adjust the residence time and can take a longer residence time, so it is relatively easy to increase the modification rate and modification efficiency.

Note that, after modifying the unmodified polyolefin wax with aromatic substituted ethene or aromatic substituted propene, this may be processed in accordance with the method for producing the conductive resin composition. For example, the polymer (C) may be processed into a powder, a tablet, or a block. On the other hand, the polymer (C) may be dispersed or dissolved in water or an organic solvent. The method of dissolving or dispersing the polymer (C) in water or an organic solvent is not particularly limited. For example, the polymer (C) may be dissolved or dispersed by stirring. Alternatively, heating may be performed while stirring.

Furthermore, the polymer (C) may be made into fine particles by dissolving or dispersing it in water or an organic solvent and then precipitating it. Examples of methods for making the polymer (C) into fine particles include the following methods. First, the solvent composition is adjusted so that the polymer (C) precipitates at 60 to 100°C. Then, the mixture of the solvent and polymer (C) is heated to dissolve or disperse the aromatic substituted ethene or polymer (C) in the solvent. The solution is then cooled at an average cooling rate of 1 to 20°C/hour (preferably 2 to 10°C/hour) to precipitate the polymer (C). Further, after this, a poor solvent may be added to further promote precipitation.

1-4. Optional Components The conductive resin composition of the present invention may contain arbitrary components as long as the objects and effects of the present invention are not impaired. Examples of optional ingredients include flame retardants such as brominated bisphenols, brominated epoxy resins, brominated polystyrene, brominated polycarbonates, triphenyl phosphates, phosphonic amides and red phosphorus; antimony trioxide and sodium antimonate, etc. Flame retardant aids such as; heat stabilizers such as phosphoric acid esters and phosphorous esters; antioxidants such as hindered phenols; heat stabilizers; weathering agents; light stabilizers; mold release agents; flow modifiers ; coloring agent; lubricant; antistatic agent; crystal nucleating agent; plasticizer; foaming agent and the like.

The content of the optional component in the conductive resin composition is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, based on a total of 100 parts by mass of the thermoplastic resin (A) and carbon nanotubes (B). The amount is particularly preferably 10 parts by mass or less.

2. Method for Manufacturing Conductive Resin Composition The conductive resin composition of the present invention can be manufactured using various methods. For example, a thermoplastic resin (A), a carbon nanotube (B), the above polymer (C), and an optional component are mixed simultaneously or in any order in a tumbler, a V-type blender, a Nauta mixer, a Banbury mixer, A method of mixing using a kneading roll, a single-screw or twin-screw extruder, or the like may be used.

Alternatively, after impregnating carbon nanotubes (B) with the polymer (C), these may be mixed with the thermoplastic resin (A). The method of impregnating the carbon nanotubes (B) with the polymer (C) is not particularly limited. For example, with the molten polymer (C) and the carbon nanotubes (B) in contact with each other, tension may be applied to the carbon nanotubes (B) with a roll or bar, or the carbon nanotubes (B) may be widened and focused. Examples include a method of repeating the process or applying pressure or vibration to the carbon nanotube (B). According to these methods, the polymer (C) can be impregnated into the inside of the carbon nanotube (B).

The impregnation method may be a method in which carbon nanotubes (B) are brought into contact with the surface of a plurality of heated rolls or bars, and the carbon nanotubes (B) are brought into contact with the polymer (C) in an expanded state. good. Particularly suitable is a method in which the carbon nanotubes (B) are impregnated with the polymer (C) using a drawing die, a drawing roll, a roll press, or a double belt press. In addition, in the present invention, since the above polymer (C) containing 50% by mass or more of structural units derived from aromatic substituted ethene or aromatic substituted propene is used, even if such an impregnation operation is performed, the above polymer (C) is C) easily enters the carbon tube (B), allowing for efficient work in a short time.

Further, the conductive resin composition of the present invention includes a step of preparing a masterbatch containing a thermoplastic resin (A), a carbon nanotube (B), and the above polymer (C), a masterbatch, a thermoplastic resin It may be manufactured through a step of melt-kneading (A) and, if necessary, carbon nanotubes (B) or the above polymer (C).

The masterbatch contains a thermoplastic resin (A), carbon nanotubes (B), and the above polymer (C). In the conductive resin composition of the present invention, it may be difficult to uniformly disperse the carbon nanotubes (B) in the thermoplastic resin (A). Therefore, by preparing a masterbatch containing the thermoplastic resin (A), carbon nanotubes (B), and the above polymer (C), and further mixing the masterbatch and the thermoplastic resin (A), uniform dispersion is achieved. can be done. By producing a masterbatch, the polymer (C) can easily cover the carbon nanotubes (B), and the carbon nanotubes (B) can hardly protrude from the surface of the conductive resin composition (and thus the molded article). Therefore, the surface gloss of the molded product obtained is increased, and the aesthetic appearance and design of the molded product are improved. Furthermore, the polymer (C) can easily cover the carbon nanotubes (B), thereby improving mechanical properties and heat resistance.

The content mass ratio of carbon nanotubes (B) and the above polymer (C) in the masterbatch (carbon nanotubes (B)/the above polymer (C)) is preferably 0.1 to 30, more preferably 1 to 25. , 2 to 20 are more preferred. When the content mass ratio is 30 or less, the proportion of carbon nanotubes (B) is relatively not too high, so that the agglomerated structure of carbon nanotubes (B) is unlikely to be destroyed during production of the masterbatch. As a result, sufficient electrical conductivity can be obtained when used as a conductive resin composition or molded article. Further, when the content mass ratio is 0.1 or more, the proportion of the polymer (C) is not relatively too high, so the melt viscosity does not become too low, making it easy to manufacture a masterbatch. Furthermore, since the amount of carbon nanotubes (B) is not too small, high conductivity can be easily obtained.

Note that the masterbatch may contain the above-mentioned optional components. A masterbatch can be produced by mixing each component in a tumbler, V-type blender, Nauta mixer, Banbury mixer, kneading roll, single-screw or twin-screw extruder, or the like.

3. Applications of Conductive Resin Composition The conductive resin composition of the present invention is molded, for example, by injection molding, extrusion molding, compression molding, etc., and used as a molded article. Note that among these molding methods, injection molding is preferred from the viewpoint of design and moldability.

The conductive resin composition of the present invention is used for producing molded articles for a wide range of uses, from household goods to industrial goods. Examples of uses include electrical parts, electronic parts, automobile parts, mechanical parts, food containers, films, sheets, fibers, and the like. Specific examples include printers, personal computers, word processors, keyboards, PDAs (small digital assistants), telephones, mobile phones, smartphones, tablets, WiFi routers, fax machines, copiers, ECRs (electronic cash registers), and calculators. , electronic notebooks, electronic dictionaries, cards, holders, stationery, and other office/OA equipment; washing machines, refrigerators, vacuum cleaners, microwave ovens, lighting equipment, game consoles, irons, kotatsu, and other home appliances; TVs, VTRs, and video cameras. , digital cameras, single-lens reflex cameras, portable audio terminals, radio cassette players, tape recorders, mini discs, CD players, speakers, liquid crystal displays, and other AV equipment; connectors, relays, capacitors, switches, printed circuit boards, coil bobbins, semiconductor sealing materials, Includes electrical and electronic components such as wires, cables, transformers, deflection yokes, distribution boards, watches, and communication equipment.

Examples of applications include seats (filling, outer materials, etc.), belts, ceiling coverings, convertible tops, armrests, door trims, rear package trays, carpets, mats, sun visors, foil covers, tires, mattress covers, air bags, Insulating materials, hanging handles, hanging straps, wire covering materials, electrical insulation materials, paints, coating materials, cladding materials, flooring materials, corner walls, deck panels, covers, plywood, ceiling boards, partition boards, side walls, carpets , wallpaper, wall covering materials, exterior materials, interior materials, roofing materials, soundproof boards, heat insulation boards, window materials, and other materials for automobiles, vehicles, ships, aircraft, and construction; clothing, curtains, sheets, plywood, synthetic fiber boards, and carpets. Also included are doormats, sheets, buckets, hoses, containers, glasses, bags, cases, goggles, skis, rackets, tents, musical instruments, and other living and sporting goods.

Furthermore, examples of uses include bottles for shampoo and detergent, etc., seasoning bottles for cooking oil and soy sauce, bottles for beverages such as mineral water and juice, lunch boxes, heat-resistant food containers such as bowls for chawanmushi, plates, etc. This also includes tableware such as chopsticks, various other food containers, packaging films, packaging bags, etc.

The present invention will be explained in detail based on Examples, but the present invention is not limited to these Examples.

1. Preparation of raw materials [Thermoplastic resin (A)]
As the thermoplastic resin (A), Iupilon S-2000F (polycarbonate, MFR 10 g/10 min, density 1200 kg/m ³ , flexural modulus 2300 MPa) manufactured by Mitsubishi Engineering Plastics was used. Note that these physical properties were measured under the following conditions.

<MFR>
Measurement was performed at 300° C. and a load of 2.16 kg in accordance with ISO 1133.

<Density>
Measured according to ISO 1183.

[Carbon nanotube (B)]
K-Nanos 100P manufactured by Kumho Petrochemical (bulk density 20 to 40 g/L, outer diameter 3 to 15 nm, length 10 to 50 μm) was used. Note that these physical properties were measured under the following conditions.

<Bulk density>
Measured in accordance with ASTM D1895.

<Outer diameter and length>
The length and outer diameter of 100 carbon nanotubes were measured using electron microscopy (SEM), and their average values were used.

[Polymer (C) and Polymer (C')]
Polymers O1 to O3 shown in Table 1 were used as the polymer (C) containing 50% by mass or more of a structure derived from aromatic substituted ethene or aromatic substituted propene. Further, as the polymer (C') containing less than 50% by mass of a structure derived from aromatic substituted ethene or aromatic substituted propene, polymers O4 to O6 shown in Table 1 were used. The polymers O1 to O6 were produced by the production method described below. Further, Table 1 shows the results of analysis using the following method. In addition, in Table 1 below, C2 represents ethylene and C3 represents propylene.

<Composition and amount of aromatic substituted ethene or aromatic substituted propene>
The compositions of polymers O1 to O6 were determined by analysis of ¹³ C-NMR spectra. The amount of aromatic substituted ethene or aromatic substituted propene in the polymers O1 to O6 was determined from the charging ratio.

・^13C -NMR measurement conditions Equipment: AVANCE III cryo-500 nuclear magnetic resonance apparatus manufactured by Bruker Biospin Measuring nucleus: ^13C (125MHz)
Measurement mode: Single pulse proton broadband decoupling Pulse width: 45° (5.00 μsec)
Number of points: 64k
Measurement range: 250ppm (-55 to 195ppm)
Repetition time: 5.5 seconds Number of integration: 128 times Measurement solvent: Orthodichlorobenzene/benzene-d6 (4/1 (volume ratio))
Sample concentration: 60mg/0.6mL
Measurement temperature: 120℃
Window function: exponential (BF: 1.0Hz)
Chemical shift standard: δδ signal 29.73 ppm

<Number average molecular weight (Mn) and weight average molecular weight (Mw)>
The number average molecular weight (Mn) and weight average molecular weight (Mw) of the polymers O1 to O6 were determined by GPC measurement. The measurements were conducted under the following conditions. Then, the number average molecular weight (Mn) and weight average molecular weight (Mw) were determined from a calibration curve using commercially available monodisperse standard polystyrene.
Equipment: Gel permeation chromatograph Alliance GPC2000 type (manufactured by Waters)
Solvent: o-dichlorobenzene Column: TSKgel GMH6-HT x 2, TSKgel GMH6-HTL column x 2 (both manufactured by Tosoh Corporation)
Flow rate: 1.0ml/min Sample: 0.15mg/mL o-dichlorobenzene solution Temperature: 140°C

<Density>
Measured in accordance with JIS K7112.

<Softening point>
Measured in accordance with JIS K2207.

<Melt viscosity at 160°C>
The melt viscosity was measured at 160° C. using a B-type viscometer and a rotor rotation speed of 60 rpm.

<Preparation of polymer O1>
A mixture of α-methylstyrene as a monomer and dehydrated toluene as a solvent (volume ratio: α-methylstyrene/toluene = 1/1) was placed in an autoclave with an actual capacity of 1270 ml equipped with a stirring blade. A twice diluted boron trifluoride phenolate complex (1.7 times the equivalent of phenol) was continuously supplied, and a polymerization reaction was carried out at a reaction temperature of 5°C. The feed rate of the mixture of α-methylstyrene and toluene was 1.0 liter/hour, and the feed rate of the diluted catalyst was 90 ml/hour. Subsequently, this reaction mixture was transferred to the second stage autoclave and the polymerization reaction was continued at 5°C, and when the total residence time in the first and second stage autoclaves reached 2 hours, The reaction mixture was continuously discharged, and when the residence time reached three times, 1 liter of the reaction mixture was collected to terminate the polymerization reaction. After the polymerization was completed, a 1N NaOH aqueous solution was added to the collected reaction mixture to deash the catalyst residue. Further, the obtained reaction mixture was washed five times with a large amount of water, and then the solvent and unreacted monomers were distilled off under reduced pressure using an evaporator to obtain α-methylstyrene polymer O1.

<Preparation of polymer O2>
An isopropenyltoluene polymer O2 was obtained in the same manner as the above polymer O1 except that the monomer was changed to isopropenyltoluene.

<Preparation of polymer O3>
(1) Preparation of catalyst In a glass autoclave with an internal volume of 1.5 liters, 25 g of commercially available anhydrous magnesium chloride was suspended in 500 ml of hexane. While maintaining the temperature at 30°C, 92 ml of ethanol was added dropwise over 1 hour while stirring, and the mixture was allowed to react for 1 hour. Subsequently, 93 ml of diethylaluminium monochloride was added dropwise over 1 hour, and the reaction was continued for another 1 hour. Thereafter, 90 ml of titanium tetrachloride was added dropwise, the temperature of the reaction vessel was raised to 80° C., and the reaction was carried out for 1 hour. The solid portion was then washed with hexane by decantation until free titanium was no longer detected. Thereafter, the solid content (catalyst) was suspended in hexane, the titanium concentration was determined by titration, and the suspension was used to prepare an unmodified polyolefin wax.

(2) Preparation of ethylene-propylene copolymer (unmodified polyolefin wax) 930 ml of hexane and 70 ml of propylene were charged into a stainless steel autoclave with an internal volume of 2 liters which was sufficiently purged with nitrogen, and hydrogen was added at 20.0 kg/cm ² ( gauge pressure). Next, after raising the temperature in the system to 170°C, 0.1 mmol of triethylaluminum, 0.4 mmol of ethylaluminum sesquichloride, and a hexane suspension of the catalyst obtained by the above method were added to the titanium component. Ethylene was injected so that the amount of was 0.008 mmol in terms of atoms, and polymerization was started.
Thereafter, the total pressure was maintained at 40 kg/cm ² (gauge pressure) by continuously supplying only ethylene, and polymerization was carried out at 170° C. for 40 minutes. Then, a small amount of ethanol was added to the system to stop the polymerization, and unreacted ethylene and propylene were purged. The obtained polymer solution was dried overnight at 100°C under reduced pressure to obtain an ethylene-propylene copolymer (unmodified polyolefin wax).

(3) Styrene modification of unmodified polyolefin wax 200 g of unmodified polyolefin wax obtained by the above method was charged into a glass reactor and melted at 160° C. under a nitrogen atmosphere. Next, 300 g of styrene monomer and 30 g of di-t-butyl peroxide (hereinafter also referred to as "DTBPO") were continuously supplied to the reaction system (temperature: 160° C.) over a period of 5 hours. After heating and reacting for 1 hour, the mixture was degassed in a vacuum of 10 mmHg for 0.5 hour while in the molten state to remove volatile components. Thereafter, the reaction product was cooled to obtain polymer O3.

<Preparation of polymers O4 to O5>
Polymer O4 and polymer O5 were obtained in the same manner as the above polymer O3, except that the reaction time in preparing the unmodified polyolefin wax was changed.

<Preparation of polymer O6>
The unmodified polyolefin wax used to prepare Polymer O3 was designated as Polymer O6.

2. Preparation of conductive resin composition [Example 1]
Polymer (C) containing 93.5 parts by mass of thermoplastic resin (A), 5 parts by mass of carbon nanotubes (B), and 50% by mass or more of structural units derived from aromatic substituted ethene or aromatic substituted propene (polymer O1 ) was melt-kneaded using a co-rotating twin-screw extruder HK25D (manufactured by Parker Corporation: φ25 mm, L/D=41). Then, it was extruded at a cylinder temperature of 280° C. to obtain a pelletized conductive resin composition.

[Examples 2-3, Comparative Examples 1-3]
A conductive resin composition was obtained in the same manner as in Example 1, except that the polymer O1 was changed to one shown in Table 2.

[Comparative example 4]
A conductive resin composition was obtained in the same manner as in Example 1, except that polymers O1 to O6 were not added and the amount of thermoplastic resin (A) was 95 parts by mass.

3. Evaluation of Conductive Resin Composition The conductive resin compositions produced in each Example and Comparative Example were evaluated as follows. The results are shown in Table 2. Note that Table 2 also shows the composition (mass ratio) of each conductive resin composition.

<Torque>
In the above-mentioned Examples and Comparative Examples, the torque when the conductive resin composition was pelletized using a twin-screw extruder was measured, and the average value was calculated.

<Resin pressure>
In the above-mentioned Examples and Comparative Examples, the resin pressure when the conductive resin composition was pelletized using a twin-screw extruder was measured, and the average value was calculated.
<Resin temperature>
In the above-mentioned Examples and Comparative Examples, the resin temperature near the die was measured when the conductive resin composition was pelletized using a twin-screw extruder.

<Conductivity (volume specific resistance)>
After drying the pellets of the conductive resin compositions produced in each example and comparative example at 120°C for 8 hours, they were molded using an injection molding machine (Niigata NN100, manufactured by Niigata Machine Techno Co., Ltd.) at a cylinder temperature of 280°C. A test piece was prepared by injection molding under the conditions of a screw rotation speed of 60 rpm, an injection pressure of 130 MPa, and a mold temperature of 90°C. The shape of the test piece was a shape (100 x 100 x 3 mm) based on JIS K7194. Then, using the test piece, the volume resistivity was measured in accordance with JIS K7194.

<Glossiness (Flow Mark)>
Pellets of the conductive resin compositions prepared in each Example and Comparative Example were injection molded in the same manner as in the conductivity test to prepare test pieces. The shape of the test piece was in accordance with JIS K7161. The surface of the test piece was visually observed and the degree of flow marks was determined based on the following criteria.
◎: No flow mark ○: There is a flow mark with a size of less than 2 mm around the ejector pin mark △: There is a flow mark with a size of 2 mm or more and less than 5 mm around the ejector pin mark ×: Large flow mark around the eject pin mark There is a flow mark with a diameter of 5 mm or more.

<Tensile strength, tensile elongation>
Pellets of the conductive resin compositions prepared in each Example and Comparative Example were injection molded in the same manner as in the conductivity test to prepare test pieces. The shape of the test piece was in accordance with JIS K7161. Then, using the injection molded test piece (ISO universal test piece), tensile strength and tensile elongation were measured based on JIS K7161 under conditions of a chuck distance of 115 mm and a test speed of 50 mm/min.

<Bending strength, bending modulus>
Pellets of the conductive resin compositions prepared in each Example and Comparative Example were injection molded in the same manner as in the conductivity test to prepare test pieces. The shape of the test piece was in accordance with JIS K7171. Using the test piece (ISO universal test piece), bending strength and bending elastic modulus were measured based on JIS K7171 at a test speed of 2 mm/min and a bending span of 64 mm.

As shown in Table 2, the conductive resin compositions (Examples 1 to 3) containing the polymer (C) containing 50% by mass or more of aromatic substituted ethene or aromatic substituted propene are Compared to the conductive resin composition containing no polymer (C') (Comparative Example 4), the conductivity was high (volume resistivity was low) and the appearance was very excellent.

In addition, when containing a polymer (C') containing less than 50% by mass of aromatic substituted ethene or aromatic substituted propene, the conductive resin composition does not contain the polymer (C) or the polymer (C') at all. (Comparative Example 4) The conductivity was sometimes lower (volume resistivity increased) than (Comparative Examples 1 and 3). Furthermore, when the polymer (C') was included, flow marks were likely to occur and the gloss was poor (Comparative Examples 1 to 3).

According to the conductive resin composition of the present invention, a molded article having both high conductivity and excellent appearance can be obtained. Therefore, it can be applied to a wide range of uses ranging from household goods to industrial goods.

Claims (6)

Thermoplastic resin (A);
Carbon nanotubes (B) and
A polymer (C) containing 50% by mass or more of structural units derived from aromatic substituted ethene or aromatic substituted propene,
including;
The thermoplastic resin (A) does not contain a resin corresponding to the polymer (C) containing 50% by mass or more of structural units derived from aromatic substituted ethene or aromatic substituted propene,
74.9 to 99.4 parts by mass of the thermoplastic resin (A) to 100 parts by mass of the total amount of the thermoplastic resin (A), the carbon nanotubes (B), and the polymer (C); Containing 0.5 to 25 parts by mass of carbon nanotubes (B) and 0.1 to 10 parts by mass of the polymer (C),
The polymer (C) satisfies the following (i) to (iv),
Conductive resin composition.
(i) The number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) is in the range of 300 to 5000.
(ii) The ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn) measured by gel permeation chromatography (GPC) is 9.0 or less
(iii) Softening point measured according to JIS K2207 is in the range of 70 to 170°C
(iv) Density measured according to JIS K7112 is in the range of 900 to 1200 kg/m ³ The polymer (C) is at least one polymer selected from styrene, α-methylstyrene, and isopropenyltoluene,
The conductive resin composition according to claim 1 . The thermoplastic resin (A) has a cyclic structure,
The conductive resin composition according to claim 1 or 2 . The thermoplastic resin (A) is at least one resin selected from the group consisting of cycloolefin polymer, polyester, and polycarbonate.
The conductive resin composition according to any one of claims 1 to 3 . A method for producing a conductive resin composition according to any one of claims 1 to 4 , comprising:
preparing a masterbatch containing the thermoplastic resin (A), the carbon nanotubes (B), and the polymer (C);
Melting and kneading the masterbatch and the thermoplastic resin (A);
including,
A method for producing a conductive resin composition. Obtained from the conductive resin composition according to any one of claims 1 to 4 ,
Molded object.