JP3450897B2 - Conductive resin masterbatch pellets and conductive thermoplastic resin products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive resin masterbatch pellet containing predetermined conductive carbon black and artificial graphite, and more particularly to a conductive thermoplastic resin product as a final product by using the masterbatch pellet. The present invention relates to a conductive resin masterbatch 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 in computers and VTRs.
In recent years, demand has been remarkably increasing mainly for applications such as antistatic and electromagnetic wave shielding of 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) is known. When blending, carbon black is
In addition to scattered parts, the working environment is deteriorated, and the heat generated by shearing of carbon black causes a reduction in the molecular weight of the resin, resulting in a problem that the resin strength is reduced. Also,
The conductive thermoplastic resin blended with carbon black is molded into various shapes depending on the application.However, the conductivity of the obtained molded product becomes extremely unstable, for example, when it is used as an IC tray container. It has been pointed out that this also leads to a cause of failure of a product IC chip. Among these problems, a method using a carbon black-rich resin masterbatch has been proposed, particularly for the purpose of preventing the scattering of carbon black (JP-A-54-58747).
issue). On the other hand, even if conductive carbon black is kneaded into a desired resin using a Banbury mixer or the like to produce a high-concentration masterbatch, conductive carbon black is extremely difficult to knead. When a final conductive resin product is manufactured by using, there is a problem that the conductive stability and surface smoothness of the obtained product are impaired.

Further, in order to prevent a decrease in mechanical strength of the resin due to moisture absorption of carbon black, a master batch containing 10 to 30% by weight of polyphenylene sulfide resin and the balance of carbon black and graphite is prepared. Has been proposed to be diluted with another resin (Japanese Patent Application Laid-Open No. 2-69565). However,
When carbon black and graphite highly blended resin masterbatch described herein are blended with the thermoplastic resin described in the publication, and this is kneaded with a known kneader, that is, a batch kneader and a 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 kneading is insufficient, and the obtained resin product has poor surface smoothness. Further, large shearing was partially applied during the kneading process, which impaired the excellent conductive performance inherent in carbon black, and the obtained product lacked conductive stability. Further, JP-A-3-9155
No. 6 proposes to improve the moldability and conductive stability of a resin product by adding fibrilable polytetrafluoroethylene to a thermoplastic resin, carbon black and graphite. However, polytetrafluoroethylene, which is an essential component, has poor compatibility with a thermoplastic resin, resulting in insufficient kneading, and the resulting conductive resin product has insufficient conductive stability. In addition, since polytetrafluoroethylene remains as a foreign substance in the conductive resin product, it lacks surface smoothness and not only impairs the commercial value, but also requires a pre-process for fibrillating the polytetrafluoroethylene. It was complicated and lacked practicality.

Japanese Patent Laid-Open Publication No. 64-11161 discloses that
For 100 parts by weight of thermoplastic resin or thermosetting resin,
The amount of expanded graphite per 15 parts by weight of carbon black having a DBP oil absorption of 400 ml / 100 g or more and 15 to 150 parts by weight of expanded graphite having an average particle size of 40 μm or more, and the total amount of carbon black and expanded graphite being 100 parts by weight 4
It is described that by setting the content to 0 to 90% by weight, a conductive resin composition having excellent mechanical strength, kneading properties and moldability can be obtained. Further, this publication describes, as a comparative example, a conductive resin composition comprising 30% by weight of artificial graphite using 13% by weight of carbon black and 57% by weight of a thermoplastic resin using artificial graphite instead of expanded graphite. .

[0005]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a final conductive resin product containing conductive carbon black and artificial graphite at a predetermined concentration and produced by adding the conductive carbon black and artificial graphite, thereby improving the conductive stability and surface smoothness. It is an object of the present invention to provide a conductive masterbatch pellet for a thermoplastic resin that can be used. Another object of the present invention is to provide a conductive thermoplastic resin product produced by adding the masterbatch pellet.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made based on the finding that the above problems can be effectively solved by combining a predetermined amount of specific carbon black and artificial graphite with a resin to form a masterbatch pellet. Things. That is, the present invention provides (a) a thermoplastic resin, and (b) 500 ml / 100 g when the DBP oil absorption is 300 ml / 100 g or more.
g of conductive carbon black and (c) artificial graphite as essential components, and the content of each component is (a) 95-5.
0% by weight, (b) 3-35% by weight, and (c) 2-15
The present invention provides a conductive resin masterbatch pellet characterized in that the pellet is a weight percentage. The present invention also provides a conductive thermoplastic resin product comprising 10 to 80% by weight of the conductive resin master batch pellets and 90 to 20% by weight of a thermoplastic resin.

[0007] The resin used for the conductive resin master batch pellets of the present invention has a strength corresponding to the use of the conductive thermoplastic resin obtained by using the master batch 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 resins such as styrene resin, polyethylene terephthalate resin and polybutylene terephthalate resin, polyamide resins 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 thereof include a super engineering resin such as a polyimide resin, a polyamide imide resin, and a fluorine resin, a polyvinyl chloride resin, a thermoplastic urethane resin, a polyacetal resin, and a polycarbonate resin-modified polyphenylene ether resin. 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, polyetherimide resin is preferred, particularly preferably polycarbonate resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polystyrene resin, polyphenylene sulfide resin, modified polyphenylene ether resin, poly It is an etherimide resin, and the content is 95 to
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 300ml / 100g
If it is less than 1, stable conductivity and good surface smoothness cannot be imparted to the master batch pellets and the molded product obtained after dilution. On the other hand, when the content is 500 ml / 100 g or more, the workability during the production of the master batch is significantly reduced. The 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, workability is remarkably reduced, and master batch pellets cannot be obtained.

The artificial graphite used as the component (c) in the present invention is obtained by molding and calcining petroleum coke or the like as a raw material and then graphitizing it at a high temperature of 2500 ° C. or higher. Generally, the shape is scaly. Although there are various types of particle sizes, in the present invention, those having an average particle size of 3 to 15 μm are preferably used, and those having an average particle size of 3 to 10 μm are particularly preferable. The content of the component (c) in the masterbatch pellet of the present invention is 2 to 15% by weight, preferably 3 to 10% by weight. If the amount is less than 2% by weight, the desired stable conductivity cannot be obtained. If the amount exceeds 15% by weight, workability is remarkably reduced, and master batch pellets cannot be obtained. When using natural graphite other than artificial graphite, for example, expanded graphite obtained by heating an acid such as sulfuric acid or nitric acid between flaky layers of natural graphite, the master batch pellet is used. The surface smoothness of the resulting conductive resin product is significantly impaired. In the present invention, the conductive carbon black and artificial graphite, which are the object of the present invention, are contained only by adopting the specific resin compounding amount and the specific amount of the specific conductive carbon black and artificial graphite as described above. ,
Further, it has been possible to provide a conductive carbon black masterbatch for a thermoplastic resin, which can improve the conductive stability of a final conductive resin product produced by addition. Therefore, as long as the effects of the present invention are not impaired, the masterbatch pellets of the present invention can contain an antioxidant, a deterioration inhibitor, an ultraviolet absorber, and the like.

When a conductive thermoplastic resin product is manufactured using the masterbatch pellets of the present invention, the thermoplastic resin blended with the masterbatch pellets is called a diluent resin. As the diluting resin, one or more of the above-mentioned thermoplastic resins can be used. At this time, as the dilution resin, it is preferable to use the same resin or the same type of resin as the thermoplastic resin in the master batch pellets to be used, but a different type of thermoplastic resin from the thermoplastic resin in the master batch pellets is used. Can also be used. In order to improve the heat resistance, dimensional stability, rigidity and mechanical strength of the conductive thermoplastic resin obtained using this masterbatch, mica, glass fiber, silica, talc, calcium carbonate, zinc oxide And inorganic fillers such as barium sulfate, stainless steel, copper oxide, nickel, nickel oxide, and zirconia silicate. These inorganic fillers are desirably used in a proportion of 5 to 300 parts by weight based on 100 parts by weight of the total of the thermoplastic resin, the conductive carbon black and the graphite. In addition, for the purpose of preventing deterioration and improving moldability during kneading of thermoplastic resin and conductive carbon black and graphite,
Known phenolic phosphorus-based antioxidants, such as metal soap,
Known flame retardants, plasticizers, and the like can be used according to molding aids such as lubricants such as fatty acid amide derivatives and the like and applications.

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 not lower than the melting temperature of the resin, cooling, and then forming into an appropriate shape such as granules, powders, and lumps. Manufactured. Of these, a columnar shape having a diameter of 2 to 4 mm and a length of 3 to 5 mm is preferable. As the kneading device, a single screw extruder, a twin screw extruder 2
Known devices such as a roll mill, a Banbury mixer, an intermix, and a pressure kneader can be used. The conductive masterbatch pellets of the present invention are used as a raw material when producing a conductive thermoplastic resin, and the masterbatch is prepared by diluting the masterbatch with a known inorganic filler, an antioxidant, a lubricant, a hardener, depending on a diluting resin or application. A conductive thermoplastic resin is manufactured by kneading with a fuel and a plasticizer. The amount of the masterbatch pellets of the present invention is usually 10 to 10% by weight in the produced conductive thermoplastic resin product.
The content should be 80% by weight, preferably 15 to 70% by weight. If the amount is less than 10% by weight, it becomes difficult to impart conductivity to the thermoplastic resin product obtained by using the master batch pellets of the present invention, while if the amount is more than 80% by weight, the obtained conductive thermoplastic resin product Tends to decrease in strength.

Conductivity for obtaining conductive thermoplastic resin products
There is no public method for mixing the masterbatch with diluent resin, etc.
The method of knowledge is used. For example, master batch pellets
Henschel mixer, tumbler, etc.
Method of dry blending with the mixer of the above, the above kneading equipment
And a method of kneading using a mixer. Also this
Injection molding, vacuum molding, and blow molding of the mixture
Molding 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.
You. Thus, the obtained conductive thermoplastic resin product
Means that the volume resistivity is 10 ⁰-10¹⁶Ωcm conductivity
It has excellent strength, so 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]

According to the present invention, there is provided a conductive masterbatch pellet capable of imparting extremely excellent conductive stability and surface smoothness to a final conductive resin product produced by addition. Also, by using the conductive masterbatch pellets of the present invention, when manufacturing a conductive thermoplastic resin product, there is no deterioration of the working environment due to the scattering of carbon, and by blending 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 applied to a twin-screw extruder at a cylinder temperature of 180 to 350 ° C.
Then, carbon black and artificial graphite were supplied from a portion where the resin was completely melted and kneaded, and after cooling, a cylindrical conductive masterbatch pellet (diameter 2 mm, length 3 mm) was obtained using a pelletizer. . By press-molding this master batch pellet at 180 to 350 ° C,
Prepare a 10cm × 10cm × 0.2cm conductivity measurement sample,
Next, the volume resistivity of the sample was measured. Table 1 and Table 2 show the composition, volume resistivity and moldability of the masterbatch pellet. In addition, the numerical value about each component in the parenthesis in a table | surface shows a weight part.

The following were used as carbon black, graphite, resin and the like. Carbon black A (CB-A): DBP oil absorption 480ml
/ 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 (manufactured by Chuetsu graphite), scale-like, average particle size 6 μm Expanded graphite (natural): BSP-3 (manufactured by Chuetsu graphite), average particle size 40 μm Polypropylene resin (PP): J-3050H (manufactured by Idemitsu Petrochemical) (MFR: 30 g / 10 min) Polycarbonate resin (PC): Toughlon A-2200
(Made by Idemitsu Petrochemical) (MFR: 12 g / 10 min) Polyethylene terephthalate resin (PET): Viropet EMC3074X04 (Toyobo) (MFR: 120 g / 10 min) Polyphenylene sulfide resin (PPS): M-288
8 (manufactured by Toray Philippe Petroleum) (MFR: 600 g / 10 min) Polystyrene resin (PS): Idemitsu Styrol IT-41
(Made by Idemitsu Petrochemical) (MFR: 22 g / 10 min) Modified polyphenylene ether resin (MPPE): Noryl 115 (manufactured by Nippon GE Plastics) (MFR: 10 g / 10 min)

Polyetherimide resin (PEI): Ultem 1010-1000 (manufactured by Nippon GE Plastics) (MFR: 18-20 g / 10 min) A composition that was difficult to knead with a screw extruder and did not form pellets, or that it was difficult to take strands into pellets and a master batch could not be produced was evaluated as x. In addition, the volume specific resistance was measured according to the Japan Rubber Association SRIS-2301.

[0017]

[Table 1] Table-1 The present invention ABCDEFGHI I CB-A 0 0 0 0 14 0 0 0 0 0 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 〜 〜 〜 〜 〜 〜 〜 〜 (Ω ・ cm) 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 × 10 ⁵ × 10 ¹ × 10 ^-1

[0018]

[Table 2] Table-2 Comparative Example KL MNO P CB-A 400 000 0 0 CB-B 0 2 0 40 20 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 Moldability × ○ ○ × ○ ○ Volume resistivity 2.3 3.8 4.8 4.0 (Ωcm) × 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, it can be seen that the products of the present invention (Nos. A to J) show good moldability and a good conductivity by blending a predetermined amount of carbon black and artificial graphite with various resins. It can be seen that a masterbatch pellet having very stable properties can be provided. On the other hand, in Comparative Examples (Nos. K to P) in Table 2, if the compounding amounts of carbon black and artificial graphite deviate from the present invention, production is impossible (Nos. K and N) or the conductive performance is poor. No expression (No.
L and O) do not function as master batch pellets. No. 3 using carbon black other than those specified in the present invention. The master batch pellets having the M composition had poor conductivity and were unstable, despite having the same composition as No. B in Table 1. N using natural expanded graphite
o. Master batch pellets with P composition are also No. B in Table 1.
It can be seen that the conductive deflection width is large and unstable despite the same composition.

Example 2 The master batch 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., cooled, and then formed into a columnar shape using a pelletizer. A pellet was obtained. Comparative Examples 12 to 14
Then, without using master batch pellets, after mixing the raw materials used, cylindrical pellets were obtained directly using a twin-screw extruder. These pellets are put into an injection molding machine, and a cylinder temperature 18
A conductive resin product of 7.5 cm × 7.5 cm × 0.3 cm was obtained by injection molding at 0 to 350 ° C., and the volume resistivity was measured. Regarding the surface smoothness, a 200 μm sheet was obtained by extrusion molding the above-mentioned pellets, the surface having less unevenness due to bumps caused by poor dispersion of the conductive agent on the surface was evaluated as “good”, and the one with many irregularities on the surface was evaluated as ×. And The composition and measurement results are shown in Tables 3 and 4. Incidentally, the volume resistivity value is calculated by the Japan Rubber Association SR
It measured according to IS-2301.

[0021]

[Table 3] Table-3 Composition of 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) 3B 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 17 18 19 19 L composition 0 0 0 90 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 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, it can be seen that in the product of the present invention (No. 1-11), the volume resistivity of the molded product obtained by diluting the master batch to various concentrations is 10 ² to 10 ¹⁰ Ω.・
In addition to exhibiting extremely stable conductivity in the range of 1 cm to 2 cm, the surface state when formed into a sheet has little unevenness and is excellent in smoothness. On the other hand, in Comparative Example of Table 4, carbon black alone was used. In 12 and 13,
The sheet has a large conductive deflection width and lacks stability, and the surface state of the sheet is extremely rugged and lacks practicality. In the case of using graphite alone, even if 15 parts by weight are blended, no conductivity is exhibited and the surface condition of the sheet is poor (No. 14). In compositions Nos. 16 and 18 obtained by diluting a master batch using carbon black and graphite other than the present invention, the width of the volume resistivity value is large and lacks stability, or the surface condition of the sheet is poor (unevenness) We cannot satisfy both. Further, No. 19 which does not employ the master batch dilution method of the present invention has a large deflection width of the volume specific resistance value and a poor surface state of the sheet.

Continuation of the front page (72) Inventor Hideo Komatsu 1-3-7 Honjo, Sumida-ku, Tokyo Inside Rion Co., Ltd. (56) References JP-A-62-246959 (JP, A) JP-A-62-227952 (JP, a) JP Akira 62-119272 (JP, a) JP Akira 61-200604 (JP, a) JP Akira 58-218703 (JP, a) (58 ) investigated the field (Int.Cl. ⁷ , DB name) C08J 3/22 C08L 1/00-101/16

Claims (2)

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