JP5276248B2 - Conductive thermoplastic resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive thermoplastic resin composition which has conductivity and impact resistance in an excellent balance, further has excellent flowability, appearance and adhesiveness to coating films, and can be used in wide fields such as electric fields, electronic fields and automobiles. <P>SOLUTION: This conductive thermoplastic resin composition comprises a component (A): a polyamide resin, a component (B): the hydrogenation product of a block copolymer of a vinylaromatic compound polymer block (a) and a conjugated dienic compound polymer block (b) and/or an ethylene-&alpha;-olefin copolymer, a component (C): a modified hydrogenated block copolymer prepared by addition-reacting an unsaturated acid and/or its derivative to the hydrogenation product of a block copolymer of a vinylaromatic compound polymer block (a) and a conjugated dienic compound polymer block (b), a component (D): conductive carbon black and/or hollow carbon fibrils, and a component (E): ethylene-vinyl alcohol copolymer and/or a partial saponification product of ethylene-vinyl acetate copolymer. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to a thermoplastic resin composition having an excellent balance between electrical conductivity and impact resistance, and further having excellent fluidity, appearance, and adhesion to a coating film. It can be used in the field.

  Polyamide resin is excellent in mechanical properties such as moldability, chemical resistance, tensile strength, bending strength, and wear resistance, so it can be used in a wide range of fields such as electrical / electronic parts, mechanical parts, and automotive parts. It is used. Furthermore, in recent years, it has been required to impart electrical conductivity to polyamide resin, which is electrically insulating, in antistatic and electromagnetic shielding applications mainly for electric and electronic parts, and electrostatic coating applications mainly for automobile exterior materials. High impact resistance is required in applications such as automobile exterior materials.

  In general, conductive materials added to thermoplastic resins include ionic surfactants, nonionic surfactants, and organic compounds such as polymer antistatic agents having polyethylene glycol units and ionic functional groups. In addition, carbon black, carbon fibers, metal fibers, metal powders, inorganic substances such as metal oxides, and the like can be mentioned. In particular, addition of a small amount of a conductive material exhibits high conductivity, and a good appearance is obtained. Therefore, conductive carbon black and hollow carbon fibrils are widely used.

  On the other hand, adding a rubbery polymer as a means for improving the impact resistance of a polyamide resin is widely performed, and the rubbery polymer is modified with an unsaturated carboxylic acid or a derivative thereof in order to increase the compatibility. This is known as a known technique. For example, a composition comprising a polyamide resin and a modified hydrogenated block copolymer is disclosed (Patent Document 1), and further contains (A) a polyamide resin, (B) an acid-modified elastomer, and (C) a conductive filler. A polyamide resin composition excellent in surface smoothness, toughness, extrusion moldability, antistatic property and the like has been disclosed (Patent Document 2). However, with the conventional technologies as described above, the balance between conductivity and impact resistance is not sufficient, and increasing the amount of conductive carbon black to achieve high conductivity results in a significant decrease in impact resistance. However, there is a problem that molding processability (fluidity) is lowered.

  (A) polyamide resin, (b) hydrogenated block copolymer of vinyl aromatic compound polymer block A and olefin compound polymer block B, (c) carboxylic acid or its Polyamide resin composition consisting of a modified block copolymer with a derivative group added, excellent impact resistance, good balance of physical properties such as elastic modulus, heat resistance and weld strength, and improved moldability and appearance of molded products Product (Patent Document 3), (A) polyamide resin of specific end group, (B) hydrogenated block copolymer of vinyl aromatic compound and conjugated diene compound, (C) vinyl aromatic compound and conjugated diene compound A modified block copolymer in which a carboxylic acid group or a derivative group thereof is bonded to a hydrogenated block copolymer, (D) an ethylene-α-olefin copolymer, (E) There is a description of a polyamide resin composition (Patent Document 4) having improved low-temperature impact properties comprising an olefin-based polymer having an acid anhydride group only at the end, and an additive such as an antistatic agent is added to these compositions as an optional component It can be blended as

  However, these inventions are intended for the effect of the combination of the above components, and there is no example of blending a conductive agent in the examples, and there is no mention at all about the specific effect of improving the balance between conductivity and impact resistance. It has not been. In addition, Patent Document 2 describes that an elastomer other than the modified elastomer may be used in the range of 10 to 90% by weight in the elastomer component. No mention is made of the effect of improving the balance, and there has been a strong demand for an excellent balance between electrical conductivity and impact resistance and excellent fluidity.

  Further, in Patent Document 5, the polyamide resin (A) includes a copolymer of an olefin and a compound having both an unsaturated group and a polar group, such as an ethylene-acrylic acid copolymer and an ethylene-vinyl alcohol copolymer. A composition comprising a polymer (B) and a conductive substance (C) is disclosed, and the composition is described as having excellent electrical characteristics such as mechanical characteristics, fluidity, and conductivity. Has been.

  On the other hand, the present inventors have further studied to improve the releasability at the time of molding, to suppress residual mold release defects on the surface of the molded product, and to obtain a molded product having a good appearance. .

Japanese Examined Patent Publication No. 63-44784 Japanese Patent Laid-Open No. 10-292106 Japanese Patent Publication No. 7-26019 Japanese Patent No. 3330398 JP 2003-64254 A

  The present invention has been made in view of the above circumstances, and its purpose is to improve the electrical conductivity of the polyamide resin and to have excellent impact resistance and fluidity, appearance and coating film adhesion. It is to provide a composition.

  As a result of diligent studies to solve the above problems, the following resin composition was found to be excellent in conductivity and impact resistance, fluidity, appearance, and coating film adhesion, and completed the present invention. I let you.

That is, the present invention
Component (A): polyamide resin,
Component (B): hydrogenated block copolymer of vinyl aromatic compound polymer block a and conjugated diene compound polymer block b and / or ethylene-α-olefin copolymer,
Component (C): Hydrogenated product of block polymer with unsaturated acid and / or derivative thereof as hydrogenated product of block copolymer of vinyl aromatic compound polymer block a and conjugated diene compound polymer block b A modified hydrogenated block copolymer added to 0.3 to 2.5 parts by weight with respect to 100 parts by weight,
Component (D): conductive carbon black and / or hollow carbon fibrils having a dibutyl phthalate oil absorption of 200 ml / 100 g or more, and
Component (E): In a composition comprising an ethylene-vinyl alcohol copolymer and / or a partially saponified product of an ethylene-vinyl acetate copolymer, each of the above components is divided into component (A) and component (B), The weight ratio (A) / ((B) + (C)) of (C) is 90/10 to 50/50, and the weight ratio (B) / (C) of component (B) to component (C) is 10/90 to 90/10, and
1 to 15 parts by weight of component (D) with respect to 100 parts by weight of component (A), and component (E) with respect to a total of 100 parts by weight of components (A), (B), (C) and (D) It exists in the electrically conductive thermoplastic resin composition characterized by mix | blending in the ratio of 0.5-20 weight part.

  The present invention relates to a thermoplastic resin composition having an excellent balance between electrical conductivity and impact resistance, and further having excellent fluidity, appearance, and adhesion to a coating film. It can be used in the field.

  In particular, by containing a partially saponified product of component (E): ethylene-vinyl alcohol copolymer and / or ethylene-vinyl acetate copolymer, without impairing the melt fluidity and releasability of the composition, The adhesion of the coating film on the surface of the molded article made of the composition is remarkably improved. Therefore, it is particularly effective in a molded product to which electrostatic coating is applied.

Hereinafter, the present invention will be described in detail.
<Polyamide resin>
The polyamide resin of component (A) used in the thermoplastic resin composition of the present invention is an aliphatic polyamide resin having a -CONH- bond in the main chain and capable of being melted by heating. Typical examples include nylon-4, nylon-6, nylon-6.6, nylon-4.6, nylon-12, nylon-6.10, and other known monomers such as diamines and dicarboxylic acids. Examples thereof include polyamide resins containing components. Preferred polyamide resins are nylon-6 and nylon-6.6.

The polyamide resin preferably has a relative viscosity in the range of 2.1 to 3.5 measured at a temperature of 23 ° C., 98 wt% concentrated sulfuric acid at a polyamide resin concentration of 1 wt%. If the relative viscosity is less than 2.1, the rigidity, dimensional stability, impact resistance, and appearance are inferior, and if it exceeds 3.5, the moldability tends to be reduced and the appearance may be poor. The terminal group concentration is preferably a terminal carboxyl group content of 100 μeq / g or less, and the ratio of the terminal carboxyl group content to the terminal amino group content (terminal carboxyl group content / terminal amino group content) is 0.8 to The range of 4 is preferable. If this ratio is less than 0.8, the fluidity may decrease or the appearance may be poor. If it exceeds 4, the impact resistance may be insufficient.
<Hydrogenated block copolymer>
The hydrogenated product of the block copolymer of component (B) and component (C) used in the thermoplastic resin composition of the present invention is a vinyl aromatic compound polymer block a, a conjugated diene compound polymer block b, and The block copolymer is a hydrogenated product, and is a block copolymer in which the number of aliphatic unsaturated bonds in the block b is mainly reduced by hydrogenation.

  Further, the hydrogenated product of the block copolymer of component (B) and component (C) may be the same or different, but the hydrogenated product of the block copolymer of component (B) is functional. It is not modified with a group. The arrangement of the block a and the block b includes a linear structure or a branched structure (radial teleblock). Further, some of these structures may contain a random chain derived from a random copolymerized portion of a vinyl aromatic compound and a conjugated diene compound. Among these structures, those having a linear structure are preferable, those having an aba type triblock structure are particularly preferable in terms of impact resistance, and those having an ab type diblock structure are included. Also good.

  The monomer constituting the vinyl aromatic compound polymer block a of component (B) and component (C), the vinyl aromatic compound is preferably styrene, α-methylstyrene, paramethylstyrene, vinyltoluene, vinylxylene, etc. More preferably, it is styrene. The monomer constituting the conjugated diene compound polymer block b, that is, the conjugated diene compound is preferably 1,3-butadiene and 2-methyl-1,3-butadiene.

  The proportion of the repeating unit derived from the vinyl aromatic compound in the hydrogenated product of these block copolymers is preferably in the range of 10 to 70% by weight, and more preferably in the range of 10 to 40% by weight. Looking at the unsaturated bonds of the hydrogenated product of the block copolymer, the proportion of the aliphatic unsaturated bonds derived from the conjugated diene compound that are not hydrogenated is preferably 20% or less. 10% or less is more preferable. Further, about 25% or less of the aromatic unsaturated bond derived from the vinyl aromatic compound may be hydrogenated.

  As the hydrogenated product of such a block copolymer, when the monomer constituting the conjugated diene compound polymer block b, that is, the conjugated diene compound is 1,3-butadiene, styrene-ethylene / butylene is used. -Referred to as styrene copolymer (SEBS), and in the case of 2-methyl-1,3-butadiene, it is referred to as styrene-ethylene / propylene-styrene copolymer (SEPS), and various a-b-a A type of triblock structure is commercially available and is readily available.

In these components (B) and (C), the number average molecular weight of the hydrogenated product of the block copolymer is preferably 180,000 or less, more preferably 120,000. When the molecular weight exceeds 180,000, molding processability tends to be lowered, and the appearance may be deteriorated.
<Ethylene-α-olefin copolymer>
The component (B) ethylene-α-olefin copolymer used in the thermoplastic resin composition of the present invention is a rubbery copolymer containing ethylene and α-olefin as essential components, and is modified with a functional group. Point to something not. The weight ratio of ethylene to α-olefin is usually 90:10 to 20:80, preferably 75:25 to 40:60.

  The α-olefin used for copolymerization is an unsaturated hydrocarbon compound having 3 to 20 carbon atoms. Specific examples include propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 3 -Methylbutene-1, 4-methylpentene-1, etc. are mentioned, Preferably it is a C3-C10 linear alpha-olefin, Especially preferable are propylene, 1-butene, and 1-octene. .

  The ethylene-α-olefin copolymer of component (B) used in the thermoplastic resin composition of the present invention is not contained in a polymer obtained by copolymerizing a diene compound in addition to ethylene and the α-olefin. What introduced the saturated group can be used. The types of diene compounds used are alkenyl norbornenes, cyclic dienes, and aliphatic dienes, preferably 5-ethylidene-2-norbornene and dicyclopentadiene.

As these ethylene-α-olefin copolymers, the melt flow rate (MFR) (ASTM-D1238, 230 ° C., load 2.16 kg) is preferably in the range of 0.05 to 150 g / 10 min. The range of ˜50 g / 10 minutes is more preferable. If the MFR value is lower than 0.05, the moldability tends to be lowered, and if it is 150 or more, the impact resistance may be insufficient.
<Modified hydrogenated block copolymer>
Of the graft modifier, unsaturated acid and / or derivative thereof for obtaining the modified hydrogenated block copolymer of component (C) used in the thermoplastic resin composition of the present invention, the unsaturated acid is specifically Examples thereof include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, and nadic acid. The derivatives include acid anhydrides, acid halides, amides, imides, esters, and the like of the above-mentioned various unsaturated acids. Specifically, maleyl chloride, maleimide, maleic anhydride, itaconic anhydride, citraconic anhydride , Monomethyl maleate, dimethyl maleate and the like.

  In these, unsaturated dicarboxylic acid or its acid anhydride is preferable, and especially maleic acid, itaconic acid, or these acid anhydrides are suitable. These unsaturated acids or derivatives thereof are used alone or in combination.

  In component (C), the amount of the unsaturated acid and / or derivative thereof added to the modified block copolymer is 0.3 to 2.5 parts by weight with respect to 100 parts by weight of the hydrogenated product of the block copolymer. It is. If the addition amount is less than 0.3 parts by weight, the impact resistance of the thermoplastic resin composition is inferior.

  To efficiently obtain a modified hydrogenated block copolymer by adding the above-mentioned graft modifier, unsaturated acid and / or derivative thereof to the hydrogenated block copolymer of component (C) described above. It is preferable to use a radical generator. Examples of the radical generator include organic peroxides and azo compounds.

  Specifically, as the organic peroxide, (i) hydroperoxides: for example, t-butyl-hydroperoxide, cumene-hydroperoxide, 2,5-dimethylhexane-2,5-dihydroper Oxide, 1,1,3,3-tetramethylbutyl-hydroperoxide, p-menthane-hydroperoxide, diisopropylbenzene hydroperoxide, etc .; (b) Di-alkyl peroxides: for example, 2,5-dimethyl -2,5-di (t-butylperoxy) hexyne-3, di-t-butyl-peroxide, t-butyl-cumyl-peroxide, 2,5-dimethyl-2,5-di (t-butyl) Peroxy) hexane, di-cumyl peroxide, etc .; (c) peroxyketals: for example, 2,2- Tert-butylperoxy-butane, 2,2-bis-tert-butyl-peroxy-octane, 1,1-bis-tert-butylperoxy-cyclohexane, 1,1-bis-tert-butylperoxy- 3,3,5-trimethylcyclohexane and the like; (d) peroxyesters: for example, di-t-butylperoxyisophthalate, t-butylperoxybenzoate, t-butylperoxyacetate, 2,5-di- Methyl-2,5-di-benzoylperoxy-hexane, t-butylperoxyisopropyl carbonate, t-butylperoxyisobutyrate and the like; (e) diacyl peroxides: for example, benzoyl peroxide, m-toluoyl There are peroxide, acetyl peroxide, lauroyl peroxide and the like.

  Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 1- [(1-cyano-1-methylethyl) azo] formamide, 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 2,2′-azobis (2,4,4-trimethylpentane), 2, 2'-azobis (2-methylpropane) and the like. Dicumyl can be mentioned as another radical generator.

Of these radical generators, particularly preferred are radical generators having a half-life temperature of 120 ° C. or more in 10 hours. When the half-life temperature at 10 hours is less than 120 ° C., the dimensional stability and impact resistance may be insufficient.
<Conductive carbon black and / or hollow carbon fibril>
As component (D) used in the thermoplastic resin composition of the present invention, conductive carbon black and / or hollow carbon fibrils having a dibutyl phthalate oil absorption of 200 ml / 100 g or more are selected. These two types of conductive agents are preferably used in terms of a balance between conductivity and impact resistance.

  The conductive carbon black having a dibutyl phthalate oil absorption of 200 ml / 100 g or more is a carbon black having a dibutyl phthalate (DBP) oil absorption of 200 ml / 100 g or more as measured in accordance with ASTM D2414. Preferred is 400 ml / 100 g or more. The carbon black having such physical properties is in a form in which fine particles are connected unlike the carbon black for pigment added for the purpose of coloring to paint or the like. Preferable conductive carbon black includes acetylene black obtained by pyrolyzing acetylene gas, ketjen black produced by crude incomplete combustion using crude oil as a raw material, and the like.

The component (D) hollow carbon fibril used in the thermoplastic resin composition of the present invention has an outer region composed of an essentially continuous multi-layer of regularly arranged carbon atoms and an inner hollow region. Each layer and the hollow region are essentially cylindrical fibrils arranged substantially concentrically. Further, it is preferable that the regularly arranged carbon atoms in the outer region are graphite-like and the hollow region has a diameter in the range of 2 to 20 nm. Such hollow carbon fibrils are described in detail in Japanese Patent Publication No. 62-5000943 and US Pat. No. 4,663,230. As described in detail in the latter US patent specification, for example, transition metal-containing particles such as iron, cobalt, and nickel-containing particles supported by alumina are used as carbon monoxide, hydrocarbons, and the like. The carbon-containing gas is contacted at a high temperature of 850 to 1200 ° C., and carbon generated by thermal decomposition is grown in a fibrous form starting from the transition metal. Further, this type of hollow carbon fibril is sold by Hyperion Catharsis under the trade name of graphite fibril and can be easily obtained.
<Ethylene-vinyl alcohol copolymer>
The component (E) ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as (E1)) used in the thermoplastic resin composition of the present invention is a partially saponified product of an ethylene-vinyl acetate copolymer. The saponification degree of the vinyl acetate residue contained in the copolymer is 97 mol% or more. The content of the ethylene residue in (E1) is preferably in the range of 10 to 98 mol%, more preferably in the range of 20 to 70 mol%. When the ethylene residue content exceeds 98 mol%, the coating film adhesion of a molded product obtained from the resin composition containing the copolymer (E1) may be deteriorated. There is a possibility that the thermal stability of the resin composition may be insufficient, and the flexibility may be lowered.
<Partially saponified ethylene-vinyl acetate copolymer>
The partially saponified product of the ethylene-vinyl acetate copolymer of component (E) used in the thermoplastic resin composition of the present invention (hereinafter sometimes referred to as (E2)) is acetic acid in the ethylene-vinyl acetate copolymer. This means that the saponification degree of the vinyl residue is less than 97 mol%. The lower limit of the saponification degree is not particularly limited, but is usually 40 mol% or more. When the saponification degree is lower than 40 mol%, the thermal stability of the resulting resin composition at the time of melting tends to decrease. The saponification degree of (E2) is preferably 80 mol% or more.

  (E2) having such a composition has an MFR (melt flow rate) measured according to JIS-K6730 of 0.5 to 300 g / 10 min from the viewpoint of melt fluidity and strength of a resin composition containing the same. Is preferable, and the thing of 0.8-250 g / 10min is more preferable.

The component (E1) ethylene-vinyl alcohol copolymer and the component (E2) ethylene-vinyl acetate copolymer partially saponified product (hereinafter collectively referred to as the component (E)) are both as required. Other monomers (compounds) may be copolymerized in a small amount. Examples of copolymerizable monomers include propylene, isobutene, α-octene, α-dodecene, α-olefins such as α-octadecene; unsaturated carboxylic acids, salts thereof, partial alkyl esters, fully alkyl esters, and acid anhydrides. Acrylonitrile; acrylamide; unsaturated sulfonic acid or a salt thereof. The proportion of these optional monomer residues in the component (E) molecule is usually about 10 mol% or less, preferably about 5 mol% or less.
<Conductivity improvement aid>
The thermoplastic resin composition of the present invention may further contain a conductivity improving aid (component (F)) as necessary. Examples thereof include a conductivity improving aid (component (F)), specifically nigrosine (component (F1)), semi-aromatic polyamide resin (component (F2)), novolak phenol resin, lithium halide and the like. Among these, nigrosine (F1) and semi-aromatic polyamide resin (F2) are more preferable from the viewpoint of the balance between rigidity and impact resistance.

  Here, nigrosine (F1), which is an example of the conductivity improving aid (F), refers to COLOR INDEX and C.I. I. SOLVENT BLACK5 and C.I. I. A black azine condensation mixture of triphenazine oxazine and a phenazine azine compound as described in SOLVENT BLACK7. Examples of commercially available nigrosine include Nubian Black EP-3, Nubian Black PA-9800, Nubian Black PA0800 (all manufactured by Orient Chemical Industry Co., Ltd.). Among these, Nubian Black EP-3 is preferable because the effect of improving conductivity is particularly large.

  The content of nigrosine (F1) as the conductivity improving aid (F) is preferably selected in the range of 0.05 to 30 parts by weight with respect to 100 parts by weight of the component (A). If the blending amount of nigrosine (F1) is less than 0.05 parts by weight, the effect of improving the conductivity is small, and if the blending amount is more than 30 parts by weight, the thermal stability and heat resistance of the final resin composition are lowered, and the melt flow There is a possibility that it may cause deterioration of property and releasability. A more preferable blending amount of nigrosine (F1) is 0.1 to 20 parts by weight.

  Moreover, as semi-aromatic polyamide resin (F2) as conductivity improving aid (F), aliphatic dibasic acids and aromatic diamines, or aromatic dibasic acids and aliphatic diamines are used as raw materials. Polyamide resin obtained by polycondensation of Specifically, the raw material aliphatic dibasic acids include adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecadioic acid, hexadecadioic acid, hexadecenedioic acid, eico Examples include sandioic acid, eicosadienedioic acid, diglycolic acid, 2,2,4-trimethyladipic acid, 1,4-cyclohexanedicarboxylic acid, and the like. Examples of aromatic diamines include meta-xylene diamine and para-xylene diamine. Aromatic dibasic acids include terephthalic acid, isophthalic acid, and phthalic acid. Examples of the aliphatic diamines include hexamethylene diamine tetramethylene diamine, nonamethylene diamine, undecamethylene diamine, dodecamethylene diamine, 2,2,4 (or 2,4,4) -trimethylhexamethylene diamine, bis- (4 , 4'aminocyclohexyl) methane.

  Among these semi-aromatic polyamide resins, polyamide resins containing terephthalic acid and / or isophthalic acid and hexamethylenediamine as main components, that is, polyamide 6T, polyamide 6I, or 6I / 6T copolymerized polyamide, etc., and metaxylenediamine And / or a polyamide resin mainly composed of para-xylenediamine and adipic acid is particularly preferable because it has a large effect of improving the appearance of the molded product in addition to the conductivity promoting effect.

The blending amount of the semi-aromatic polyamide resin (F2) as the conductivity improving aid (F) is preferably selected in the range of 1 to 50 parts by weight with respect to 100 parts by weight of the component (A). When the blending amount of the semi-aromatic polyamide resin (F2) is less than 1 part by weight, the effect of improving conductivity is small. When the blending amount is more than 50 parts by weight, the heat resistance of the final resin composition is lowered and the melt fluidity is lowered. In some cases, it may cause a decrease in releasability during molding. A more preferable blending amount of the semi-aromatic polyamide resin (F2) is 2 to 30 parts by weight.
<Thermoplastic resin composition>
Component (A): polyamide resin, component (B): hydrogenated block copolymer of vinyl aromatic compound polymer block a and conjugated diene compound polymer block b in the thermoplastic resin composition of the present invention And / or ethylene-α-olefin copolymer, component (C): a hydrogenated product of a block copolymer of vinyl aromatic compound polymer block a and conjugated diene compound polymer block b. Modified hydrogenated block copolymer obtained by adding 0.3 to 2.5 parts by weight of a saturated acid and / or derivative thereof to 100 parts by weight of the block polymer, and component (D): 200 ml of dibutyl phthalate oil absorption / 100 g or more of conductive carbon black and / or hollow carbon fibrils, each of the above components is mixed in a weight ratio of component (A) to component (B), (C) (A) / ((B + (C)) is 90/10 to 50/50, the weight ratio (B) / (C) of component (B) to component (C) is 10/90 to 90/10, and component (B) The amount of D) is contained in the composition in a ratio of 1 to 15 parts by weight per 100 parts by weight of component (A).

  A thermoplastic resin composition when (A) exceeds 90 parts by weight and (B) + (C) is less than 10 parts by weight in a total of 100 parts by weight of components (A), (B), and (C). On the contrary, when (A) is less than 50 parts by weight and (B) + (C) is more than 50 parts by weight, the appearance and fluidity of the thermoplastic resin composition are lowered, and further, the matrix- This is not preferable because the domain structure is reversed and the conductivity is lowered.

  In a total of 100 parts by weight of components (B) and (C), if (B) is less than 10 parts by weight, the effect of improving conductivity is low, and if (C) is less than 10 parts by weight, the impact resistance is poor. Therefore, it is essential that the components (B) and (C) are used in a weight ratio of 10/90 to 90/10, more preferably the components (B) and (C) are 50/50 by weight. It is in the range of ~ 90/10.

  Next, for the component (D), if the amount is less than 1 part by weight relative to 100 parts by weight of the component (A), the effect of improving the conductivity is low, and if the component (D) exceeds 15 parts by weight, This is not preferable because impact resistance is lowered.

  The content of the component (E) used in the thermoplastic resin composition of the present invention is 0. 0 parts by weight relative to 100 parts by weight of the total amount of the component (A), the component (B), the component (C) and the component (D). 5 to 20 parts by weight. When the blending amount of the component (E) is less than 0.5 parts by weight, the effect of improving the coating adhesion of the molded product obtained from the polyamide resin composition according to the present invention is small, and when it exceeds 20 parts by weight, the polyamide resin Reaction with (A) and the modified hydrogenated block copolymer (C) proceeds, and the fluidity at the time of melting of the final resin composition decreases. The preferable compounding quantity of a component (E) is 1-15 weight part, More preferably, it is 2-10 weight part.

  Furthermore, in order to provide paint adhesion, as component (E), a partially saponified product of ethylene-vinyl alcohol copolymer and / or ethylene-vinyl acetate copolymer is added to components (A), (B), (C) and (D) It contains in the ratio of 0.5-20 weight part with respect to 100 weight part of total amounts. When the amount of component (E) is less than 0.5 parts by weight, the effect of improving adhesion is not exhibited, and when it is more than 20 parts by weight, the fluidity is poor and the thermal stability at the time of melting is also deteriorated.

  The production of the thermoplastic resin composition of the present invention is preferably a melt mixing method, and a typical method of melt mixing includes a method using a melt kneader that is generally put to practical use for thermoplastic resins. Examples of the melt kneader include a uniaxial or multiaxial kneading extruder, a roll, and a Banbury mixer.

  When using a kneading extruder, the components (A), (B) and (C) are mixed in advance, and then added to the upstream portion of the kneading extruder, reacted in a molten state, and then kneaded and extruded. A method in which the component (D) is introduced and mixed with the molten reactant in the middle part of the machine, or a master batch is prepared by previously mixing a part or all of the component (A) and the component (D). Then, this master batch and the components (A) to (C) are mixed, put into a kneading extruder, and reacted in a molten state to form a pellet of a thermoplastic resin composition. Also, a method in which the components (A), (B), (C) and (D) are mixed in advance, and collectively introduced into the upstream portion of the kneading extruder and reacted in a molten state to obtain pellets of the thermoplastic resin composition. Also mentioned.

  Among these methods, from the balance between conductivity and impact resistance, the components (A), (B) and (C) are melt-reacted in advance, and the component (D) is blended in the melt-reacted material and kneaded. Alternatively, a method in which the component (A) and the component (D) are previously masterbatched and kneaded is preferable.

  Components (E) and (F) can be blended at any stage, but preferably component (F) is blended at the same timing as component (B) to form a melt-kneaded product. E) is preferably blended by dry blending the component (E) pellets into pellets which are melt-kneaded components (A) to (D) {or further component (F)}.

  The thermoplastic resin composition of the present invention can contain other various resin additives in addition to the above components. Various resin additives include, for example, thermal stabilizers, antioxidants, weather resistance improvers, nucleating agents, foaming agents, flame retardants, impact resistance improvers, lubricants, plasticizers, fluidity improvers, dyes, organic A filler, a reinforcing agent, a dispersing agent, etc. are mentioned. Including a liquid crystal polymer is effective in improving rigidity, heat resistance, dimensional accuracy, and the like.

  The method for producing a molded product from the thermoplastic resin composition of the present invention is not particularly limited, and a molding method generally employed for thermoplastic resins, that is, an injection molding method, a hollow molding method, an extrusion molding method, A sheet molding method, a thermoforming method, a rotational molding method, a lamination molding method, a press molding method, or the like can be employed.

  The thermoplastic resin composition of the present invention can be used in a wide range of fields as a raw material for producing electrical equipment parts, electronic equipment parts, automobile parts and the like, and is particularly useful as a raw material for producing automobile exterior parts.

  EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these ranges. In the following examples and comparative examples, the blending amount means parts by weight.

In obtaining each resin composition of Examples and Comparative Examples, the following raw materials were prepared.
1. Component (A): Polyamide resin nylon-6: manufactured by Mitsubishi Engineering Plastics, product name-Novamid 1010J, 23 ° C. 98% concentrated sulfuric acid in a concentrated sulfuric acid at a resin concentration of 1% by weight, a relative viscosity of 2.5, terminal Carboxyl group content / terminal amino group content ratio 2.6 (hereinafter abbreviated as PA6-1)
2. Component (B): hydrogenated block copolymer, ethylene-α-olefin copolymer styrene-ethylene / butylene-styrene copolymer (SEBS): manufactured by Kraton Polymer Co., Ltd., product name-Clayton G1652, styrene content 29 wt%, number average molecular weight 49,000 (hereinafter abbreviated as SEBS)
Ethylene-butene copolymer: manufactured by Mitsui Petrochemical Co., Ltd., product name: TAFMER A-4085, MFR (ASTM-D1238, temperature = 230 ° C., load = 2.16 kg) = 6.7 g / 10 min (hereinafter referred to as EBR) Abbreviated)
3. Component (C): Modified hydrogenated block copolymer [Preparation of modified hydrogenated block copolymer]
SEBS (100 parts by weight), maleic anhydride (2.5 parts by weight) and radical generator (0.5 part by weight) are weighed in a bottle and mixed uniformly with a Henschel mixer. Manufactured, TEX-30XCT, screw diameter 30 mm, L / D = 42, barrel number 12), and subjected to a melt reaction at a cylinder temperature of 230 ° C. and a screw rotation speed of 300 rpm to give a modified hydrogenated block copolymer C-1 Obtained. As maleic anhydride, maleic anhydride manufactured by Mitsubishi Chemical Corporation is used, and as a radical generator, 1,3-bis (2-t-butylperoxyisopropyl) benzene (made by Kayaku Akzo) is used. , Product name-Parka Dox 14, half-life temperature 121 hours at 10 hours).

The modified hydrogenated block copolymer thus obtained was heated and dried under reduced pressure, and the amount of maleic anhydride added was determined by titration with sodium methylate. As a result, the amount of maleic anhydride added was 1.2 wt%. there were.
4). Component (D): Conductive agent (conductive carbon black having a dibutyl phthalate oil absorption of 200 ml / 100 g or more, hollow carbon fibril)
Conductive carbon black: manufactured by Lion, product name—Ketjen Black EC600JD, BET surface area 1270 m ² / g, DBP oil absorption 495 ml / 100 g (hereinafter abbreviated as CB1)
Hollow carbon fibril: Master batch (product name: PA6 / 20BN, manufactured by Hyperion Catalysis Co., Ltd.) containing 80% by weight of nylon-6 and 20% by weight of hollow carbon fibril (hereinafter abbreviated as 20BN)
Conductive carbon black for comparison: manufactured by Mitsubishi Chemical Corporation, product name-Mitsubishi Carbon Black # 3050B, nitrogen adsorption specific surface area 50 m ² / g, DBP oil absorption 175 ml / 100 g (hereinafter abbreviated as CB2)
5. Component (E): Ethylene-vinyl alcohol resin EVOH G156A: Ethylene-vinyl alcohol resin (manufactured by Kuraray Co., Ltd., trade name: Eval G156A, copolymerization ratio of ethylene is 47 mol%), with a density of 1.12 and MFR (JIS-K6730, temperature = 190 ° C., load = 2.16 kg) is 6 g / 10 min. (Hereafter abbreviated as E-1)
EVOH C109: ethylene-vinyl alcohol resin (manufactured by Kuraray Co., Ltd., trade name: Eval C109, copolymerization ratio of ethylene is 35 mol%), density is 1.17 g / cm ³ , MFR (same as E-1 above) (Measured under conditions) is 8 g / 10 min. (Hereafter abbreviated as E-2)
EVOH H6960: saponified ethylene-vinyl acetate copolymer (manufactured by Tosoh Corporation, trade name: Mersen H6960) having a density of 0.99 g / cm ³ and MFR (measured under the same conditions as E-1 above) of 40 g / 10 min, melting point is 113 ° C., vinyl acetate content is 4.2% by weight, and saponification degree is 90%. (Hereafter abbreviated as E-3)
6). Component (F): conductivity improving aid nigrosine EP-3: nigrosine (black azine dye, manufactured by Orient Chemical Co., Ltd., trade name: Nubian Black EP-3). (Hereinafter abbreviated as F-1)
X21F07: Semi-aromatic polyamide resin (6I / 6T copolymerized polyamide resin, manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name: Novamid X21F07). (Hereafter abbreviated as F-2)
7). Others YD5013: Bisphenol type epoxy compound (manufactured by Toto Kasei Co., Ltd., trade name: Epototo YD5013). (Hereafter abbreviated as G-1)
AC5120: ethylene-acrylic acid copolymer (manufactured by Honeywell, trade name: AC wax 5120, acrylic acid content 9.2% by weight). (Hereinafter abbreviated as G-2)
[Preparation of test piece]
The thermoplastic resin composition is injection molded using an injection molding machine (Toshiba IS150) under the conditions of a cylinder temperature of 280 ° C. and a mold temperature of 80 ° C., and an ASTM test piece, a disc-shaped molded product of 100 mmφ × 3 mmt, and a coating film A 100 × 100 mm × 3 mmt square molded product was prepared for adhesion evaluation.
[Evaluation method]
(1) Fluidity (MFR)
According to JIS K7210, MFR (unit: g / 10 minutes) was measured under conditions of a temperature of 280 ° C. and a load of 5 kg.
(2) Flexural modulus The flexural modulus (unit: MPa) was measured according to ASTM D790.
(3) Impact resistance (Izod impact strength)
Based on ASTM D256, Izod impact strength (unit: J / m) was measured with a test piece having a thickness of 3.2 mm and a notch.
(4) Conductivity (volume resistivity)
Cut parallel ends of ASTM No. 2 dumbbell test piece (thickness 3 mm) to have a length of 50 mm, apply silver paste to both ends produced by cutting, dry at room temperature, and then use a tester The resistance value (RL: unit Ω) between the surfaces was measured, and the volume resistivity R (unit: Ωcm) was calculated from the following equation.

R = RL × AL / L
(In the formula, AL means the cross-sectional area of the test piece (unit: cm ² ), and L means the length of the test piece (unit: cm).)
(5) Appearance Observe the appearance of the surface of the disk-shaped molded product visually, evaluate whether there are appearance defects such as mold release defects and silver streaks. Was evaluated as ○.
(6) Paint film adhesion (%)
A square plate-shaped test piece having a size of 100 mm × 100 mm and a thickness of 3 mm is prepared. First, an acrylic / urethane paint (OP-Z-NY, manufactured by Origin Electric Co., Ltd.) is applied to the surface of the test piece. And baked at a temperature of 80 ° C. for 60 minutes. Next, 100 squares of slits having a 1 mm width on one side were formed on the painted film surface after baking. A cellophane tape was attached to the surface of the coating film, and when this cellophane tape was peeled off, it was visually observed whether the coating film surface was peeled off together. The coating film surface was not peeled off by the cellophane tape, and was represented by the residual rate (%) of the mass remaining on the surface of the test piece. The larger this value, the better the coating film adhesion.
[Methods for producing compositions of Examples and Comparative Examples]
[Examples 1 to 5]
First, components (A), (B), and (C) are mixed with a tumbler mixer, and a twin-screw extruder (manufactured by Nippon Steel Works, TEX-30XCT, L / D = 42, barrel number 12) is used. The mixture was charged from the barrel 1 and the component (D) was side-fed from the barrel 5 and melt kneaded under the conditions of a cylinder temperature of 230 ° C. and a screw rotation speed of 400 rpm.

Next, the pellet of the component ( E ) is mixed with the pellet obtained by melt-kneading the components (A), (B), (C), and (D) with a tumbler mixer, and this dry blend is used. Molding and evaluation were performed. The results are shown in Table 1.
[Examples 6 and 7]
The components (A), (B), and (C) were produced by the same method as in Example 1 except that the component (F) was also blended at the same time when they were mixed with a tumbler mixer. The results are shown in Table 1 .
[Comparative Example 1]
Manufactured in the same manner as in Example 1 except that component (E) was not blended. The results are shown in Table 1.
[Comparative Examples 2 and 3]
When the component (A) was blended, the component (G) was blended at the same time, and the component (E) was produced in the same manner as in Example 1 except that the component (E) was not blended. The results are shown in Table 1.

［実施例、比較例の品質評価結果］
上記手法により求められた組成物の評価結果は以下の通りであった。
［実施例１〜５と比較例１〜３］
実施例１〜５は成分（Ｅ）を配合しなかった比較例１或いは他の塗装性改良剤である成分（Ｇ）を配合した比較例２，３に比べ、耐衝撃、導電性を保持したまま、外観、塗装膜密着性に優れている事が分かる。
［実施例１と実施例６、７］
実施例１の組成物に成分（Ｆ）を配合した実施例６、７では、更に導電性も改良されていることが分かる。

[Quality evaluation results of Examples and Comparative Examples]
The evaluation results of the composition obtained by the above method were as follows.
[Examples 1-5 and Comparative Examples 1-3]
Examples 1 to 5 maintained impact resistance and conductivity as compared with Comparative Example 1 in which component ( E ) was not blended or Comparative Examples 2 and 3 in which component (G), which was another coating property improving agent, was blended. It can be seen that the appearance and adhesion of the coating film are excellent.
[Example 1 and Examples 6 and 7]
In Examples 6 and 7 in which the component ( F ) was added to the composition of Example 1, it can be seen that the conductivity was further improved .

The thermoplastic resin composition of the present invention is a thermoplastic resin composition having improved electrical conductivity, excellent impact resistance, excellent fluidity, appearance, and coating film adhesion. It can be used in a wide range of fields such as parts and automobile parts.

Claims (6)

Component (A): polyamide resin,
Component (B): hydrogenated block copolymer of vinyl aromatic compound polymer block a and conjugated diene compound polymer block b and / or ethylene-α-olefin copolymer,
Component (C): Hydrogenated product of block polymer with unsaturated acid and / or derivative thereof as hydrogenated product of block copolymer of vinyl aromatic compound polymer block a and conjugated diene compound polymer block b A modified hydrogenated block copolymer added to 0.3 to 2.5 parts by weight with respect to 100 parts by weight,
Component (D): conductive carbon black and / or hollow carbon fibrils having a dibutyl phthalate oil absorption of 200 ml / 100 g or more, and
Component (E): In a composition comprising an ethylene-vinyl alcohol copolymer and / or a partially saponified product of an ethylene-vinyl acetate copolymer, each of the above components is divided into component (A) and component (B), The weight ratio (A) / ((B) + (C)) of (C) is 90/10 to 50/50, and the weight ratio (B) / (C) of component (B) to component (C) is 50/50 to 90/10, and
1 to 15 parts by weight of component (D) with respect to 100 parts by weight of component (A), and component (E) with respect to a total of 100 parts by weight of components (A), (B), (C) and (D) A conductive thermoplastic resin composition characterized by being blended at a ratio of 0.5 to 20 parts by weight.   The hydrogenated products of the block copolymers of the component (B) and the component (C) were both formed by the vinyl aromatic compound polymer block a and the conjugated diene compound polymer block b, ab- The conductive thermoplastic resin composition according to claim 1, which has an a-type triblock structure.   The conductive thermoplastic resin composition according to claim 1 or 2, wherein the component (C) is a modified hydrogenated block copolymer to which an unsaturated acid and / or a derivative thereof is added in the presence of a radical generator.   Component (A) has a relative viscosity of 2.1 to 3.5 measured at a temperature of 23 ° C., 98 wt% concentrated sulfuric acid at a polyamide resin concentration of 1 wt%, and has a terminal carboxyl group content and a terminal amino group content. The conductive thermoplastic resin composition according to any one of claims 1 to 3, which is a polyamide resin having a ratio (terminal carboxyl group content / terminal amino group content) of 0.8 to 4.   The conductive thermoplastic resin according to any one of claims 1 to 4, further comprising 0.05 to 30 parts by weight of component (F1): nigrosine based on 100 parts by weight of component (A). Composition.   Furthermore, 1 to 30 weight part of component (F2): semi-aromatic polyamide resin is mix | blended with respect to 100 weight part of component (A), The electroconductive heat as described in any one of Claim 1 thru | or 5 Plastic resin composition.