JPH02201811A - Conductive resin mixture - Google Patents

Abstract

PURPOSE:To provide the smaller quantity of conductive grains by adding carbon black mainly in a specific phase, namely, a polyamide phase. CONSTITUTION:Carbon black is allowed to be contained mainly in a specific phase, namely, a polyamide phase. The carbon black being used in conductive carbon black wherein fine grains range together. A polyamide resin is formed from such a polyamide type that consists mainly of amino acid, lactam, or diamine and carboxylic acid. Polyphenylene ether is required to have the quantity of 5 through 80 pts.wt., while the polyamide to have the quantity of 95 through 20 pts.wt. To add the carbon black mainly in the polyamide phase, the carbon black is pre-dispersed uniformly in the polyamide and subsequently mixed with the polyphenylene ether.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a resin mixture comprising polyphenylene ether and polyamide, which contains carbon black to reduce surface resistance, and a method for producing the same.

[Conventional technology]

Many thermoplastic resins are non-conductive, so in order to electrostatically paint molded thermoplastic resin products, they must be primed with a conductive primer or mixed with conductive particles or flakes, especially conductive carbon black. There is. Resin compositions containing polyphenylene ether and polyamide are increasingly being used because of their well-balanced physical properties, and there is a demand for electrostatic coating of molded products.

(Problems to be Solved by the Invention) The present invention provides a method for reducing the surface resistance of a molded article by mixing conductive particles into a resin composition containing polyphenylene ether and polyamide to make it suitable for electrostatic coating. The goal is to achieve this goal with a small amount of conductive particles.

[Means to solve the problem]

The present inventor has discovered that in mixing carbon black into a resin composition containing polyphenylene ether and polyamide,
It has been found that the above problem can be solved by mainly containing carbon black in a specific phase, that is, the polyamide phase.

That is, the present invention is a conductive resin mixture containing polyphenylene ether, polyamide, and carbon black, characterized in that carbon black is mainly contained in the polyamide phase.

The present invention also provides a method for producing a conductive resin mixture containing polyphenylene ether, polyamide, and carbon black, which is characterized in that carbon black is uniformly dispersed in polyamide in advance, and then this is mixed with polyphenylene ether. It is.

The carbon black is preferably a conductive carbon black in which fine particles are connected.

In the present invention, polyphenylene ether is known per se, and includes, for example, the general formula (A) (wherein R1, R2,
R3 and R4 are hydrogen, halogen, alkyl group, alkoxy group, haloalkyl group and haloalkoxy group having at least two carbon atoms between the halogen atom and the phenyl ring, and do not contain a tertiary α-carbon (indicates a monovalent substituent selected from It may also be a copolymer in which these are combined. In a preferred embodiment, R
1 and R2 are alkyl groups having 1 to 4 carbon atoms, and R
3, R4 is hydrogen or an alkyl group having 1 to 4 carbon atoms. For example, poly(2,6-dimethyl-1,4-phenylene) ether, poly(2,6-diethyl-1,4-
phenylene) ether, poly(2-methyl-6-ethyl-1,4-phenylene) ether, poly(2-methyl-
6-probyl-1,4-phenylene) ether, poly(2
, 6-diprobyl-1,4-phenylene) ether, poly(2-ethyl-6-brobyl-1,4-phenylene)
Examples include ether. A particularly preferred polyphenylene ether resin is poly(2,6-cymethyl-1,4-
phenylene) ether. Further, as polyphenylene ether copolymers, alkyl trisubstituted phenols such as 2, 3.
A copolymer partially containing 6-trimethylphenol can be mentioned. Alternatively, a copolymer in which a styrene compound is grafted onto these polyphenylene ethers may be used. The styrene-based compound-grafted polyphenylene ether is a copolymer obtained by graft polymerizing a styrene-based compound such as styrene, α-methylstyrene, vinyltoluene, chlorostyrene, etc. to the above-mentioned polyphenylene ether.

The polyamide resin used in the present invention is a polyamide whose main components are an amino acid, a lactam, or a diamine and a dicarboxylic acid. A specific example of a constituent component is ε
- Lactams such as caprolactam, enantlactam, ω-laurolactam, amino acids such as ε-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, tetramethylenediamine, hexamethylenediamine, undecamethylenediamine, dodecamethylene Diamine, 2.2.4-/2,4.4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, m-xylylenediamine, p-xylylenediamine, 1
．． Diamines such as 3-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane, bis-p-aminocyclohexylmethane, bis-p-aminocyclohexylpropane, isophoronediamine, adipic acid, speric acid, azelaic acid, sebacic acid, There are dicarboxylic acids such as dodecanionic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, and dimer acid. These constituent components may be subjected to polymerization alone or in the form of a mixture of two or more thereof, and both polyamide homopolymers and copolymers thus obtained can be used in the present invention. Polyamides particularly useful in the present invention include polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebaamide (nylon 610), polyundecaneamide (nylon 11), Polydodecanamide (nylon 1
2), and copolymers and mixtures of these polyamides. There is no particular restriction on the degree of polymerization of the polyamide used here, and any polyamide having a relative viscosity of 1% concentrated sulfuric acid solution at 25° C. within the range of, for example, 1.5 to 5.0 can be used.

The end groups of these polyamides are typically used for melt viscosity adjustment,
In order to improve thermal stability, terminal blocking etc. are carried out.
The molar ratio of terminal amino groups to terminal carboxyl groups (hereinafter referred to as terminal group ratio) is suppressed to 1 or less. The polyamide used in the present invention preferably has a terminal group ratio of greater than 1 (but is not limited thereto). Such a polyamide can be obtained by adding an extra compound having a group that reacts with a carboxyl group, such as a diamine, during the polymerization of the polyamide. Alternatively, it can also be obtained by polymerizing polyamide and then reacting it with a compound having a group that reacts with a carboxyl group. When a polyamide with an end group ratio of more than 1 is used, the appearance and mechanical strength of the molded article are dramatically improved compared to when a polyamide with an end group ratio of 1 or less is used. The terminal group ratio is preferably 1.1 or more, more preferably 1.3 or more.

Preferably in the present invention, the amount of polyphenylene ether is from 5 to 80 parts by weight, especially from 30 to 70 parts by weight, and the amount of polyamide is from 95 to 20 parts by weight, especially from 70 to 30 parts by weight. In molded articles comprising this amount range, the polyphenylene ether is dispersed as a small particle phase in the polyamide matrix phase. In order to improve the compatibility between both resins, known compatibilizers such as polycarboxylic acids and their derivatives such as citric acid, malic acid, etc., maleic anhydride, etc., can contain (a) double bonds or triple bond and (b)
Examples include compounds having a carboxylic acid group, an acid anhydride group, an acid amide group, an imide group, a carboxylic acid ester group, or an eboxy group, trimellitic anhydride chloride, and the like.

These compatibilizers can be used alone or in combination of two or more, optionally together with peroxide. The compatibilizer is present in the resin composition of the present invention in an amount of 0.0
Preferably, it is used in an amount of 1 to 10 parts by weight.

Methods for making polyphenylene ether and polyamide compatible include a method of simply adding and mixing a compatibilizing agent, or a method of reacting polyphenylene ether with citric acid, maleic anhydride, etc. to modify it in advance, and then kneading it with polyamide. You can also use this method. Note that when polyphenylene ether is modified using trimellitic anhydride chloride, it is preferable to add a chlorine acceptor, such as a metal oxide.

The conductive carbon black preferably used in the present invention is different from the pigment carbon black that is added to paints etc. for the purpose of coloring, and has the form of a series of fine particles, and is commercially available as Ketchen Black. There is.

The amount of conductive carbon black is preferably from 1 to 20 parts by weight, especially from 2 to 10 parts by weight, based on a total of 100 parts by weight of polyphenylene ether and polyamide.

In the present invention, the resin mixture can further contain additives. In particular, to improve impact resistance, a total of 10% of rubber-like polymers are used, including polyphenylene ether and polyamide.
It can be contained preferably in an amount of 20 parts by weight or less relative to 0 parts by weight. Examples of rubbery polymers include styrene-ethylene-butadiene-styrene block copolymer, styrene-butadiene-styrene block copolymer, and styrene-butadiene-styrene block copolymer.
Examples include isoprene-styrene block copolymers, styrene-ethylene-propylene block copolymers, and styrene-butadiene block copolymers.

These rubbery polymers may be hydrogenated, partially hydrogenated, or acid-modified with maleic anhydride or the like. In consideration of heat aging resistance, hydrogenated materials are preferred.

Furthermore, as is well known, a polystyrene resin may be added to improve processability. Polystyrene (wherein R is hydrogen or an alkyl group having 1 to 4 carbon atoms, Z represents a substituent that is a halogen or an alkyl group having 1 to 4 carbon atoms, and p is an integer of 1 to 5) The polymer must contain at least 25% or more of repeating structural units derived from the vinyl aromatic compound represented by the formula.

Such polystyrene resins include, for example, polymers of styrene or its derivatives (such as α-methylstyrene, vinyltoluene, vinylxylene, ethylvinylxylene, vinylnaphthalene, and mixtures thereof), as well as polybutadiene, polyisoprene, butyl rubber, E.
Styrenic polymers modified by mixing or interaction with natural or synthetic elastomer materials, such as PDM rubber, polyethylene-propylene copolymer, natural rubber, polysulfide rubber, polyurethane rubber, shrimp chlorohydrin, and also styrene. Containing copolymers, e.g. styrene-
Acrylonitrile copolymer (SAND, styrene-butadiene copolymer, styrene-maleic anhydride copolymer,
Examples include styrene-acrylonitrile-butadiene terpolymer (ABS), poly-α-methyl-styrene, copolymer of ethylvinylbenzene and divinylbenzene, etc. Further, preferred resins for the present invention are polystyrene homopolymer, or polystyrene homopolymer. Butadiene rubber or EP
3-30% by weight of DM rubber, preferably 4-12% by weight
Rubber-modified polystyrene mixed with or grafted with. The mixing ratio of the styrene resin is preferably within a range that does not impair the excellent properties of the polyphenylene ether resin and polyamide. Preferably, it is a ratio.

Furthermore, the resin composition of the present invention may contain other additives such as pigments, dyes, reinforcing agents, fillers, heat resistant agents, oxidative deterioration inhibitors, weathering agents, A lubricant, a mold release agent, a crystal nucleating agent, a plasticizer, a flame retardant, a fluidity improver, an antistatic agent, etc. can be added.

In order to contain carbon black mainly in the polyamide phase in the present invention, carbon black is uniformly dispersed in the polyamide in advance and then mixed with polyphenylene ether. By doing so, the majority of the carbon black, preferably 70% by weight or more, especially 90% by weight
Most preferably, 95% by weight or more is contained in the polyamide phase. To uniformly disperse the carbon black in the polyamide, the polyamide can be melted and mixed by conventional mixing means. For this, an extruder,
You can use a Nigoo, roll mixer, Banbury mixer, etc. These conventional means can also be used in the subsequent mixing with polyphenylene ether.

The conductive resin mixture in the present invention includes the above-mentioned mixtures and molded products.

Examples The polyphenylene ether used in the examples was poly(2,
6-dimethyl-1,4-phenylene)ether (NOr
VI: Trademark, Engineering Plastics Co., Ltd., intrinsic viscosity in chloroform at 25°C 0.48 dρ/7
).

The polyamide is nylon 6 (trademark, Unitika Nylon Resin A 8030A).

As a rubbery polymer, 5EBS (trademark, Kraton (31
651, Shell Chemical Co., Ltd.) was used.

In addition, polystyrene (trademark, Dick Styrene CR35
00, Dainippon Ink & Chemicals Co., Ltd. was also added.

As the conductive carbon black, Ketchien Black EC600JD (manufactured by Lion Corporation) was used.

Using a twin-screw extruder set at a cylinder temperature of 270° C., nylon 6 with a 92-fold suspension and Ketchen Black with an 8-fold suspension were uniformly melted and kneaded and extruded to make a master pellet.

Next, the pellets were triblended uniformly with other ingredients in the weight ratio shown in Table 1, and then the cylinder temperature was 300'.
Pellets were made by extrusion using a twin screw extruder set at C. After drying the obtained pellets 1 to 1 at 120°C for 4 hours, test pieces of 50x50x3ffllll+ were prepared using an injection molding machine set at a cylinder temperature of 280'C1 and a mold wetness of 80°C.

The surface resistance of the obtained test piece was measured. The results are shown in Table 1.

Comparative Example 20 parts by weight of conductive carbon black was uniformly kneaded into 80 parts by weight of molten polystyrene using a Panbury mixer set at 200°C, and then using a twin screw extruder set at 200°C. I made a master pellet.

The master pellets 1 to 1 were homogeneously triblended in advance with other components in the weight ratios shown in Table 1. Thereafter, pellets were made by extrusion in the same manner as in Examples, and test pieces were made in the same manner.

The amounts of each resin and the amount of conductive carbon black used were the same in the Examples and Comparative Examples.

Table Nylon 6 Masterbatch 37.5 Bo1 Nostyrene Masterbatch (Uraketchen Black) Polyphenylene Ether Citric Acid (3,0) (3,0) Nylon 6 (Total amount of Nylon 6) 6.5 Polystyrene (Polystyrene Total amount) From the above coating, it can be seen that although the Examples and Comparative Examples have exactly the same composition, the surface resistance of the molded product in the Examples is significantly lower.

Claims (2)

[Claims] 1. A conductive resin mixture containing polyphenylene ether, polyamide and carbon black, characterized in that the carbon black is mainly contained in the polyamide phase. 2. A method of making a conductive resin mixture comprising polyphenylene ether, polyamide and carbon black,
A method characterized by uniformly dispersing carbon black in polyamide in advance and then mixing this with polyphenylene ether.