JPH07286103A - Masterbatch pellet of electrically conductive resin and product of electrically conductive thermoplastic resin - Google Patents

Abstract

PURPOSE:To obtain an electrically conductive masterbatch pellet for a thermoplastic resin, containing electrically conductive carbon and artificial graphite at prescribed concentrations and capable of providing excellent electrically conductive stability and surface smoothness of the final product of the electrically conductive resin produced by adding the pellet thereto. CONSTITUTION:This masterbatch pellet of an electrically conductive resin contains (a) a thermoplastic resin, (b) electrically conductive carbon black having >=300 and <500ml/100g volume of DBP oil absorption and (c) artificial graphite as essential constituent components. The contents of the respective components are 95-50wt.% component (a), 3-35wt.% component (b) and 2-15wt.% component (c).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a conductive resin masterbatch pellet containing a predetermined conductive carbon black and artificial graphite, and in particular to a conductive thermoplastic resin product as a final product by using the masterbatch pellet. The present invention relates to a conductive resin master batch pellet capable of imparting excellent conductive stability and surface smoothness, and a conductive thermoplastic resin product.

[0002]

2. Description of the Related Art Conductive resins are used for computers and VTRs.
In recent years, there has been a marked increase in demand centered on applications such as anti-static and electromagnetic wave shielding for home appliances and the like. Conventionally, as a method of imparting conductivity to a thermoplastic resin, a method of filling carbon black (JP-A-60-65064 and JP-A-55-31103) has been known. When blending, carbon black
There is a problem in that the molecular weight of the resin decreases due to the shearing heat generation of the carbon black, resulting in a decrease in the resin strength in addition to the fact that some of it scatters and deteriorates the working environment. Also,
The conductive thermoplastic resin containing carbon black is molded into various shapes depending on the application, but the conductivity of the resulting molded product becomes extremely unstable. For example, when used as an IC tray container. It has been pointed out that this may also lead to defective IC chips in products. Among these problems, a method using a carbon black highly-blended resin masterbatch has been proposed for the purpose of preventing carbon black from scattering (Japanese Patent Laid-Open No. 54-58747).
issue). On the other hand, even if an electrically conductive carbon black is kneaded into a desired resin using a Banbury mixer or the like to produce a high-concentration masterbatch, the electrically conductive carbon black is extremely difficult to be kneaded, and a masterbatch produced in this manner is also used. When the final conductive resin product is produced using, there is a problem that the conductive stability and surface smoothness of the obtained product are impaired.

In order to prevent the mechanical strength of the resin from lowering due to the absorbed moisture of carbon black, a master batch having 10 to 30% by weight of polyphenylene sulfide resin and the balance of carbon black and graphite is prepared. It has been proposed that the resin be diluted with another resin (Japanese Patent Laid-Open No. 2-69565). However,
Carbon black and graphite high-mixing resin masterbatch described here, blended with the thermoplastic resin described in the publication, when kneading it with a known kneader, i.e., batch-type kneader and continuous kneader, Since the amount of carbon black and graphite in the masterbatch is large, there is a problem that the moldability of the blend is poor and the kneading is insufficient, resulting in poor surface smoothness of the obtained resin product. Further, a large amount of shearing was partially applied during the kneading process, impairing the excellent conductive performance originally possessed by carbon black, and the obtained product lacked conductive stability. Furthermore, JP-A-3-9155
No. 6, it is proposed to add moldable polytetrafluoroethylene to thermoplastic resin, carbon black, and graphite to improve moldability and conductive stability of the resin product. However, polytetrafluoroethylene, which is an essential component, has poor compatibility with the thermoplastic resin, and insufficient conductive stability of the obtained conductive resin product resulted in insufficient kneading. In addition, since polytetrafluoroethylene remains as a foreign substance in the conductive resin product, it lacks surface smoothness and impairs commercial value, and requires a pre-process for fibrillating polytetrafluoroethylene. It became complicated and lacked in practicality.

Further, Japanese Patent Laid-Open No. 64-11161 discloses that
For 100 parts by weight of thermoplastic resin or thermosetting resin,
An amount of expanded graphite per 100 parts by weight of carbon black having an DBP oil absorption of 400 ml / 100 g or more and expanded graphite having an average particle size of 40 μm or more, and 15 to 150 parts by weight. 4
It is described that the content of 0 to 90% by weight makes it possible to obtain a conductive resin composition excellent in mechanical strength, kneadability and moldability. Further, in this publication, a conductive resin composition containing 30% by weight of artificial graphite, 13% by weight of carbon black and 57% by weight of a thermoplastic resin using artificial graphite instead of expanded graphite is described as a comparative example. .

[0005]

DISCLOSURE OF THE INVENTION The present invention has excellent conductivity stability and surface smoothness of a final conductive resin product produced by containing and adding conductive carbon black and artificial graphite in a predetermined concentration. It is an object of the present invention to provide a conductive masterbatch pellet for a thermoplastic resin, which can be prepared. The present invention also aims to provide a conductive thermoplastic resin product produced by adding the masterbatch pellets.

[0006]

The present invention was made based on the finding that the above problems can be effectively solved by combining a specific amount of specific carbon black and artificial graphite with a resin to form a masterbatch pellet. It is a thing. That is, according to the present invention, (a) a thermoplastic resin and (b) a DBP oil absorption of 300 ml / 100 g or more and 500 ml / 100.
Conductive carbon black of less than g and (c) artificial graphite are essential constituent components, and the content of each component is (a) 95-5.
0% by weight, (b) 3 to 35% by weight, and (c) 2 to 15
Provided is a conductive resin masterbatch pellet, which is characterized in that it is in weight%. The present invention also provides a conductive thermoplastic resin product characterized by containing 10 to 80% by weight of the conductive resin masterbatch pellets and 90 to 20% by weight of a thermoplastic resin.

The resin used for the conductive resin masterbatch pellets of the present invention has strength according to the application of the conductive thermoplastic resin obtained by using the masterbatch pellets,
It is a thermoplastic resin having heat resistance. Specifically, high,
Medium, low density polyethylene resin, linear low density polyethylene resin, polypropylene resin, poly-1,2-butadiene resin, ethylene-butene copolymer, ethylene-vinyl acetate copolymer, polystyrene resin, ABS resin, AS resin, etc. Polyester resin such as styrene resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyamide resin such as 6-nylon resin, 6,6-nylon resin, polysulfone resin, modified polysulfone resin, polyallyl sulfone resin, polyketone resin , Polyetherimide resin, polyarylate resin, polyphenylene sulfide resin, liquid crystal polymer, polyether sulfone resin, polyether ether ketone resin,
Examples include polyimide resins, polyamide-imide resins, super engineering resins such as fluororesins, polyvinyl chloride resins, thermoplastic urethane resins, polyacetal resins, and polycarbonate resin-modified polyphenylene ether resins. Among them, polyethylene resin, polypropylene resin, polycarbonate resin, polyethylene terephthalate resin polybutylene terephthalate resin, 6-nylon resin, 6,6-nylon resin, polystyrene resin,
Polyphenylene sulfide resin, thermoplastic urethane resin, modified polyphenylene ether resin, polyether imide resin is preferable, and particularly preferably, polycarbonate resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polystyrene resin, polyphenylene sulfide resin, modified polyphenylene ether resin, poly It is an ether imide resin, and the content is 95-
It is 50% by weight, preferably 92 to 65% by weight.

The conductive carbon black used as the component (b) in the present invention has a DBP oil absorption of 300 ml / 10.
It is 0 g or more and less than 500 ml / 100 g, preferably 340 ml / 100 g or more and less than 500 ml / 100 g. DBP oil absorption is 300ml / 100g
If the amount is less than the above, stable electrical conductivity and good surface smoothness cannot be imparted to the master batch pellets and the molded articles obtained after dilution. Further, when the amount is 500 ml / 100 g or more, the workability during masterbatch production remarkably deteriorates. Carbon black content is 3 to 35% by weight, preferably 5 to 25
% By weight. If it is less than 3% by weight, the desired stable conductivity cannot be obtained, and if it exceeds 35% by weight, the workability is remarkably deteriorated and a masterbatch pellet cannot be obtained.

The artificial graphite used as the component (c) in the present invention is formed from petroleum coke as a raw material, fired, and graphitized at a high temperature of 2500 ° C. or higher. Generally, the shape is scaly. There are various particle sizes, but in the present invention, it is preferable to use one having an average particle size of 3 to 15 μm, and particularly preferably 3 to 10 μm. The content of the component (c) in the masterbatch pellets of the present invention is 2 to 15% by weight, preferably 3 to 10% by weight. If it is less than 2% by weight, the desired stable conductivity cannot be obtained, and if it exceeds 15% by weight, the workability is remarkably deteriorated, and a masterbatch pellet cannot be obtained. It should be noted that when natural graphite other than artificial graphite, for example, expanded graphite obtained by putting an acid such as sulfuric acid or nitric acid between scaly layers of natural graphite and heating the same, the master batch pellets are used. The surface smoothness of the resulting electrically conductive resin product is significantly impaired. In the present invention, for the first time by adopting a specific resin blending amount and a specific amount of specific conductive carbon black and artificial graphite as described above, the conductive carbon black and artificial graphite which are the objects of the present invention are contained. ,
Moreover, it has been possible to provide a conductive carbon black masterbatch for a thermoplastic resin, which can improve the conductive stability of the final conductive resin product produced by adding it. Therefore, the masterbatch pellets of the present invention may contain an antioxidant, a deterioration inhibitor, an ultraviolet absorber, etc. within a range that does not impair the effects of the present invention.

When a conductive thermoplastic resin product is produced using the masterbatch pellets of the present invention, the thermoplastic resin blended with the masterbatch pellets is called a diluting resin. As the diluting resin, one kind or two or more kinds of the above-mentioned thermoplastic resins can be used. At this time, as the diluting resin, it is preferable to use the same resin or the same type of resin as the thermoplastic resin in the master batch pellets used, but a thermoplastic resin different from the thermoplastic resin in the master batch pellets. It can also be used. Further, in order to improve the heat resistance, dimensional stability, rigidity and mechanical strength of the conductive thermoplastic resin obtained by using this masterbatch, mica, glass fiber, silica, talc, calcium carbonate, zinc oxide Inorganic fillers such as barium sulfate, stainless steel, copper oxide, nickel, nickel oxide and zirconia silicate can also be blended. These inorganic fillers are preferably used in a proportion of 5 to 300 parts by weight based on 100 parts by weight of the total amount of the thermoplastic resin, conductive carbon black and graphite. Further, for the purpose of preventing deterioration and improving moldability during kneading of the thermoplastic resin, conductive carbon black and graphite,
Known phenol-based phosphorus-based antioxidants, metal soaps,
A lubricant such as a fatty acid amide derivative, a molding aid such as a lubricant, or a known flame retardant or a plasticizer may be used depending on the application.

The conductive masterbatch pellets of the present invention are prepared by kneading conductive carbon black and artificial graphite with a thermoplastic resin at a temperature higher than the melting temperature of the resin, and after cooling, form an appropriate shape such as granules, powder or lumps. Manufactured. Of these, a cylindrical shape having a diameter of 2 to 4 mm and a length of 3 to 5 mm is preferable. As a kneading device, a single-screw extruder, a twin-screw extruder 2
Known devices such as the present roll mill, Banbury mixer, intermix, and pressure kneader can be used. The conductive masterbatch pellets of the present invention are used as a raw material when manufacturing a conductive thermoplastic resin, and this masterbatch is a known inorganic filler, an antioxidant, a lubricant, or a hard material depending on the diluting resin or the application. A conductive thermoplastic resin is produced by kneading with a flame retardant and a plasticizer. The compounding amount of the masterbatch pellets of the present invention is usually 10 to 100% by weight of the electroconductive thermoplastic resin product produced.
It should be 80% by weight, preferably 15 to 70% by weight. If it is less than 10% by weight, it becomes difficult to impart conductivity to the thermoplastic resin product obtained by using the masterbatch pellets of the present invention, while if it is more than 80% by weight, the conductive thermoplastic resin product obtained. Tend to decrease in strength.

Conductivity for obtaining conductive thermoplastic resin products
As a mixing method of the water-repellent masterbatch and diluted resin, etc.,
The method of knowledge is used. For example, masterbatch pellet
Henschel mixer, tumbler, etc.
Dry blending with a mixer, the above kneading equipment
Examples of the method include kneading using an apparatus. Also this
Injection molding, vacuum molding, blow molding of the mixture
Molded by known molding methods such as shape and inflation molding
Sheet, film, plate, irregular shape, etc.
A conductive thermoplastic resin product with a shape suitable for the application can be obtained.
It Conductive thermoplastic resin product obtained in this way
Has a volume resistivity value of 10 ⁰-10¹⁶Ω ・ cm conductivity
Since it has excellent strength, it can be used for packaging electronic devices, ICs, etc.
It can be used in a wide range of fields such as materials and tray carriers.
Wear.

[0013]

EFFECTS OF THE INVENTION The present invention provides a conductive masterbatch pellet capable of imparting extremely excellent conductive stability and surface smoothness to the final conductive resin product produced by adding it. Further, by using the conductive masterbatch pellets of the present invention, when producing a conductive thermoplastic resin product, there is no deterioration of the working environment due to the scattering of carbon, and in the formulation of a small amount of conductive masterbatch pellets, A conductive thermoplastic resin product having stable conductivity and excellent resin strength can be obtained. Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0014]

【Example】

Example 1 A predetermined amount of carbon black, artificial graphite and a thermoplastic resin were used in a twin-screw extruder, and the cylinder temperature was 180 to 350 ° C.
At that time, carbon black and artificial graphite were supplied from the portion where the resin was completely melted and kneaded, and after cooling, columnar conductive masterbatch pellets (diameter 2 mm, length 3 mm) were obtained using a pelletizer. . By press molding the master batch pellets at 180 to 350 ° C.,
Make a sample for conductivity measurement of 10 cm × 10 cm × 0.2 cm,
Then, the volume resistivity value of the sample was measured. The composition, volume resistivity and moldability of the masterbatch pellets are shown in Table-1 and Table-2. The numerical values for each component in parentheses in the table are parts by weight.

The carbon black, graphite, resin and the like used below. Carbon black A (CB-A): DBP oil absorption 480 ml
/ 100g of carbon black Carbon black B (CB-B): DBP oil absorption 370ml
/ 100g of carbon black Carbon black C (CB-C): DBP oil absorption 210ml
/ 100 g of carbon black Artificial graphite: GX-6 (made by Chuetsu Graphite), scaly shape, average particle size 6 μm Expanded graphite (natural): BSP-3 (made by Chuetsu Graphite), average particle size 40 μm Polypropylene resin (PP): J-3050H (manufactured by Idemitsu Petrochemical) (MFR: 30g / 10min) Polycarbonate resin (PC): Tafflon A-2200
(Made by Idemitsu Petrochemical) (MFR: 12g / 10min) Polyethylene terephthalate resin (PET): Vyroppet EMC3074X04 (Toyobo) (MFR: 120g / 10min) Polyphenylene sulfide resin (PPS): M-288
8 (manufactured by Toray Philippe Petroleum) (MFR: 600 g / 10 min) Polystyrene resin (PS): Idemitsu Styrol IT-41
(Manufactured by Idemitsu Petrochemical) (MFR: 22g / 10min) Modified polyphenylene ether resin (MPPE): Noryl 115 (manufactured by Nippon GE Plastics) (MFR: 10g / 10min)

Polyetherimide resin (PEI): Ultem 1010-1000 (manufactured by Nippon GE Plastics) (MFR: 18 to 20 g / 10 min) Moldability is such that the resin composition that enables a masterbatch with a twin-screw extruder is ○, 2 A composition in which a masterbatch cannot be prepared due to difficulty in kneading with a shaft extruder or in the form of pellets, or difficulty in taking strands for forming pellets was evaluated as x. The volume resistivity value was measured according to Japan Rubber Association SRIS-2301.

[0017]

[Table 1] Table-1 The present invention ABCD E F G H I J CB-A 0 0 0 0 14 0 0 0 10 0 CB-B 14 14 14 14 0 5 25 7 0 30 Artificial graphite 6 6 6 6 6 15 4 3 10 15 PP 80 0 0 0 0 0 0 0 0 0 PC 0 80 0 0 0 80 0 0 0 0 PET 0 0 0 0 80 0 0 0 0 0 PPS 0 0 0 0 0 0 71 0 0 0 PS 0 0 0 0 0 0 0 0 0 55 MPPE 0 0 0 80 0 0 0 0 80 0 PEI 0 0 80 0 0 0 0 90 0 0 Formability ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Volume specific 5.3 8.0 6.2 1.2 9.0 4.6 4.1 7.4 8.0 1.2 Resistance value 〜 〜〜〜〜〜〜〜〜〜〜〜 (Ωcm) 5.7 8.6 6.4 1.5 9.1 5.0 4.2 8.0 8.8 1.3 × 10 ¹ × 10 ¹ × 10 ¹ × 10 ¹ × 10 ^-1 × 10 ² × 10 ^-1 x 10 ⁵ x 10 ¹ x 10 ^-1

[0018]

[Table 2] Table-2 Comparative Example K L M N O P CB-A 40 0 0 0 0 0 CB-B 0 2 0 40 2 0 CB-C 0 0 14 0 0 14 Artificial graphite 20 1.5 6 20 1.5 0 Expanded graphite 0 0 0 0 0 6 PP 40 96 0 0 0 0 PC 0 0 80 0 0 80 PEI 0 0 0 40 96 0 Formability × ○ ○ × ○ ○ Volume resistivity 2.3 3.8 4.8 4.0 (Ω · cm) × 10 ¹² × 10 ¹⁰ × 10 ¹² × 10 ¹ − to 6.5 to 7.5 − to 2.5 to 7.5 × 10 ¹⁴ × 10 ¹¹ × 10 ¹⁴ × 10 ³

From Table 1, in the products of the present invention (Nos. A to J), by mixing a predetermined amount of carbon black and artificial graphite with various resins, good moldability and good conductivity can be obtained. It can be seen that a masterbatch pellet having extremely stable properties can be provided. On the other hand, in Comparative Examples (No. K to P) of Table-2, if the blending amounts of carbon black and artificial graphite deviate from the present invention, it is impossible to manufacture (No. K and N) or the conductive performance is Not expressed (No.
L and O) do not function as masterbatch pellets. Nos. Using carbon black other than those specified in the present invention. Although the masterbatch pellets of M composition have the same composition as No. B in Table-1, they have poor conductivity and are unstable. N using natural expanded graphite
o. Masterbatch pellets with P composition are also No. B in Table-1.
It can be seen that although the composition is the same, the width of the conductive range is large and unstable.

Example 2 The masterbatch pellets described in Example 1 and a thermoplastic resin as a diluting resin were kneaded using a twin-screw extruder at a cylinder temperature of 180 to 350 ° C., and after cooling, a columnar shape was obtained using a pelletizer. Pellets were obtained. In addition, Comparative Examples 12 to 14
Then, the raw materials were mixed without using the masterbatch pellets, and then the columnar pellets were directly obtained by using the twin-screw extruder. These pellets are put into an injection molding machine, a predetermined mold is used, and a cylinder temperature of 18
A 7.5 cm x 7.5 cm x 0.3 cm conductive resin product was obtained by injection molding at 0 to 350 ° C, and the volume resistivity value was measured. Regarding the surface smoothness, a sheet having a thickness of 200 μm was obtained by extrusion molding the above pellets, and the surface was smooth with little unevenness due to the unevenness caused by poor dispersion of the conductive agent, and the surface was uneven. And The compositions and measurement results are shown in Table-3 and Table-4. The volume resistivity value is based on the Japan Rubber Association SR
It was measured according to IS-2301.

[0021]

[Table 3] Table-3 The present invention No. composition Volume resistivity value Surface smoothness (Ω · cm) 1 A composition PP 1.9 to 3.2 × 10 ⁷ ○ (30) (70) 2 A composition PP 7.3 to 7.7 × 10 ³ ○ (75 ) (25) 3 B composition PPS 4.0 to 4.5 × 10 ³ ○ (75) (25) 4 C composition PEI 4.2 to 7.5 × 10 ⁸ ○ (15) (85) 5 D composition MPPE 8.3 to 8.9 × 10 ³ ○ (60) (40) 6 E composition PET 6.3 to 6.8 × 10 ⁵ ○ (50) (50) 7 F composition PC 5.2 to 6.3 × 10 ⁶ ○ (80) (20) 8 G composition PC 2.8 ~ 3.3 × 10 ⁹ ○ (20) (80) 9 H composition PEI 7.9 ~ 8.5 × 10 ¹⁰ ○ (90) (10) 10 I composition PS MPPE 3.2 ~ 4.0 × 10 ⁸ ○ (40) (10) ( 50) 11 J composition PS 2.1 to 2.5 × 10 ² ○ (50) (50)

[0022]

[Table 4] Table-4 Comparative Example No. 12 13 14 15 16 16 17 18 19 L composition 0 0 0 90 0 0 0 0 0 M composition 0 0 0 0 90 0 0 0 O composition 0 0 0 0 0 90 0 0 P composition 0 0 0 0 0 0 75 0 CB-A 10 0 0 0 0 0 0 0 0 CB-B 0 10 0 0 0 0 0 7 Artificial graphite 0 0 15 0 0 0 0 3 PP 90 90 85 10 0 0 25 0 PC O 0 0 0 10 0 0 90 PEI 0 0 0 0 0 10 0 0 Volume resistivity 1.5 3.5 6.3 7.0 1.0 (Ωcm) × 10 ¹ × 10 ² × 10 ¹² × 10 ³ × 10 ⁵ ~ 〜> 10 ¹⁶ > 10 ¹⁶ ~> 10 ¹⁶ ~ ~ 3.5 9.5 1.5 4.2 9.0 × 10 ³ × 10 ⁴ × 10 ¹⁴ × 10 ⁶ × 10 ⁷ Surface smoothness × × × ○ ○ ○ × ×

From Table 3, in the product of the present invention (No. 1-11), the volume resistivity value of the molded product obtained by diluting the masterbatch to various concentrations is 10 ² to 10 ¹⁰ Ω.・
In addition to exhibiting a very stable conductivity in the range of cm, the surface condition when formed into a sheet has little unevenness and is excellent in smoothness. On the other hand, in Comparative Example of Table 4, No. 1 in which carbon black was used alone. In 12 and 13,
The conductive film has a wide width and lacks stability, and the surface condition of the sheet is extremely uneven, which is not practical. Further, in the case of using graphite alone, even if it is blended in an amount of 15 parts by weight, conductivity is not exhibited and the surface condition of the sheet is poor (No. 14). In the No. 16 and 18 compositions obtained by diluting the master batch using carbon black and graphite other than the present invention, the fluctuation range of the volume resistivity value is large and lacks stability, or the surface state of the sheet is bad (unevenness). We cannot satisfy both sides. Further, No. 19 which does not adopt the masterbatch dilution method of the present invention has a large fluctuation range of the volume resistivity value and the surface condition of the sheet is poor.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hideo Komatsu 1-3-7 Main Office, Sumida-ku, Tokyo Lion Corporation

Claims (2)

[Claims] 1. A thermoplastic resin, (b) DBP oil absorption of 300 ml / 100 g or more and 500 ml / 100 g.
Less than conductive carbon black, and (c) artificial graphite as essential constituent components, and the content of each component is (a) 95-50.
%, (B) 3 to 35% by weight, and (c) 2 to 15% by weight, a conductive resin masterbatch pellet. 2. The conductive resin masterbatch pellet according to claim 1, 10 to 80% by weight, and the thermoplastic resin 90 to 2.
A conductive thermoplastic resin product characterized by containing 0% by weight.