JPH059466B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polymer composition with dramatically improved stability such as electrical conductivity and heat aging resistance. Synthetic resins and synthetic rubbers are generally non-conductive, but if they can be made conductive, they are expected to be used in many fields where other conductive materials are unsatisfactory. For this reason, various studies have been made to obtain conductive compositions by blending conductive fillers with synthetic resins and synthetic rubbers. Among the conductive fillers, carbon black is the most commonly considered, and among these, Ketsuchen Black (trade name of AKZO) is known to be the most suitable due to its characteristics of providing a high degree of conductivity in small amounts. . However, because conventional ketchen black contains a large amount of impurity metal residue (ash), the heat aging resistance of the conductive resin or rubber composition in which it is blended is extremely poor, and it also has a large effect on the conductivity of the composition.
Although DBP oil absorption is at a high level among carbon blacks, it has not been possible to obtain oil absorption above a certain level due to restrictions in the manufacturing method. The present invention achieves extremely high conductivity by blending a special carbon black with low ash content and extremely high DBP oil absorption, which has been obtained by a specific method, into synthetic resin or synthetic rubber. We succeeded in obtaining a composition with excellent stability. In other words, the present invention aims to partially oxidize (a) 3 to 97% by weight of synthetic resin or synthetic rubber and (b) liquid hydrocarbon with molecular oxygen and water vapor in a furnace to simultaneously convert it into synthetic gas. In producing conductive carbon black, the carbon atom/hydrogen atom weight ratio of the hydrocarbon is 9 or more, and the furnace is heated at a temperature range of 1300 to 1450°C and an internal pressure of 25 to 80°C.
Kg/cm ² , the amount of steam supplied into the furnace is 400 to 800 kg per ton of the hydrocarbon, and the highly conductive carbon black 70 to 3 has a DBP oil absorption of 350 ml/100 g or more. % by weight. The composition of the present invention not only has significantly improved conductivity, but also has dramatically improved durability stability such as heat aging resistance, and has achieved unexpected effects. This composition has previously been impossible to apply.
It also enables use in packaging materials for high-performance electronic devices and parts, transportation containers, anti-static materials, etc. As the synthetic resin used in the present invention, a thermoplastic resin or a thermosetting resin is used. Thermoplastic resins include polyethylene (low, medium, high density, linear low density), polypropylene, polyα such as propylene/ethylene blocks or random copolymers.
-Olefin; polystyrene; acrylic resins such as acrylonitrile-butadiene-styrene terpolymer and polymethacrylate; polyvinyl halides such as polyvinyl chloride; polyamides such as nylon 6 and nylon 66; polyethylene terephthalate, polybutylene Saturated polyesters such as terephthalate; polyethers such as polyphenylene oxide; polysulfone: polyphenylene sulfide; polyvinylidene fluoride; polytetrafluoroethylene; ethylene/vinyl acetate copolymer, ethylene/acrylic acid copolymer, ethylene/ α-olefin/vinyl monomer copolymers such as methacrylic acid copolymers; modified resins such as maleic anhydride-modified polypropylene, maleic anhydride-modified polyethylene, and maleic anhydride-modified polystyrene; hydrogenated products of styrene-butadiene block copolymers These can be used singly or in combination. As the thermosetting resin, epoxy resin, phenol resin, unsaturated polyester resin, melamine resin, polyurethane, etc. may be used alone or in mixtures. As the synthetic rubber, ethylene/propylene rubber, styrene/butadiene rubber, isoprene rubber, etc. may be used alone or as a mixture. These synthetic resins or synthetic rubbers contain 2,6-
di-t-butyl-4-methylphenol, 1,
1,3-tri(2-methyl-4-hydroxy-5
Phenolic antioxidants such as -t-butylphenyl)butane, tetrakis[methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane, dilauryl-thio-dipropionic acid ester, In addition to stabilizers such as sulfur-based antioxidants such as stearyl-thio-dipropionic acid ester, ultraviolet absorbers, neutralizers, lubricants, etc. can be blended. Further, the highly conductive carbon black used in the present invention is manufactured under the above conditions. Liquid hydrocarbons with a carbon atom/hydrogen atom weight ratio of 9 or more used in the method include, for example, naphtha pyrolysis oil (ethylene heavy end), liquid hydrocarbons prepared by mixing carbon with aromatic liquid hydrocarbons ( Parts with a weight composition ratio of carbon atoms and hydrogen atoms (carbon atoms/hydrogen atoms) determined by elemental analysis of 9 or more, such as mixed oils such as carbon oil) and aromatic liquid hydrocarbons mixed with C heavy oil, etc. A general term for liquid raw materials when supplied into an oxidation furnace. Among these, ethylene heavy end, carbon oil, and the like having a carbon atom/hydrogen atom weight composition ratio of 12 or more are particularly preferable because they can reduce the ash content in the resulting carbon. carbon atom/
If the weight ratio of hydrogen atoms is less than 9, it is difficult to maintain the desired production of carbon black, as even if the processing conditions in the furnace are changed, the carbon black DBP oil absorption decreases and the yield decreases. The carbon atom/hydrogen atom weight ratio of the above raw materials is 9
Even if the above conditions are met, it is not preferable to use a substance that becomes solid or becomes a highly viscous liquid hydrocarbon or carbon oil, which makes it difficult to supply to the furnace. That is, it is preferable that the raw material hydrocarbon fed into the furnace is in a liquid state and has a viscosity of 30 cst or less at the time of feeding. In addition, the furnace for performing the partial oxidation reaction has an internal temperature range of 1300 to 1450°C, preferably 1360 to 1420°C, an internal pressure of 25 to 80 Kg/cm ² , preferably 25 to 35 Kg/cm ² , and supply into the furnace. The operation is carried out under conditions in which the amount of steam produced is 400 to 800 kg, preferably 450 to 600 kg, per ton of hydrocarbon feedstock. By satisfying these operating conditions and the characteristics of the raw material hydrocarbon at the same time, it is possible to produce carbon black in good yield with excellent high conductivity and low ash content, which could not be achieved with conventionally known conditions. It became like that. Partial oxidation methods that use liquid hydrocarbons as raw materials include the Shell gasification process and the Texaco gasification process, which react the hydrocarbons with molecular oxygen and water vapor in a furnace to produce synthesis gas and at the same time produce carbon black as a by-product. AKZO's ``Ketschen Black'' is known as carbon black produced by the shell gasification process. Carbon black produced by the conventional partial oxidation method using liquid hydrocarbon as raw material has a high ash content, as seen in "Ketschen Black".
There was a limit to the improvement of DBP oil absorption. On the other hand, in the partial oxidation method using liquid hydrocarbon as a raw material, liquid hydrocarbon with a specific carbon atom/hydrogen atom weight ratio is used, and the The produced carbon black has a low ash content and high DBP oil absorption. The conductive carbon black applied to the composition of the present invention is obtained by the above-mentioned novel manufacturing method,
and DBP oil absorption is 350ml/100g or more,
In particular, 400ml/10g or more has excellent conductivity, and one with a low ash content of 0.3% by weight or less is selected. Above all, 350ml/100g or more in terms of carbon black productivity and dispersibility into synthetic resin or rubber.
Preferably less than 400ml/100g. The blending ratio of the composition of the present invention is 9 to 30% by weight of synthetic resin or synthetic rubber and 3 to 70% by weight of the above-mentioned novel carbon black, based on the total composition. If the proportion of the synthetic resin or synthetic resin is less than 30% by weight, the moldability of the composition will be poor, and if it exceeds 97% by weight, high conductivity cannot be expected. The specific blending amount is determined depending on the required performance for each application. A particularly preferred blending ratio is 95 to 80% by weight of the synthetic resin or synthetic rubber and 5 to 20% by weight of the carbon black. The composition of the present invention contains a synthetic resin or synthetic rubber, a new carbon black, and an inorganic or organic filler in an amount of 60% by weight or less, preferably 3 to 3% by weight.
It can be blended in a range of 50% by weight. Inorganic fillers include calcium carbonate, talc, mica, glass fiber, wollastonite, glass beads, magnesium hydroxide, aluminum hydroxide,
Barium sulfate, graphite, molybdenum disulfide, carbon fiber, silica, silicon carbide fiber, aluminum fiber, brass fiber, stainless steel fiber, aluminum flake, aluminum powder, barium ferrite, strontium ferrite, etc. can be used as the organic filler. Wood flour, aromatic polyamide fiber, etc. can be used. The combination of these fillers can be expected to improve not only physical properties and appearance but also conductivity. The composition of the present invention can be used in Banbury mixers, rolls,
In addition to a batch-type kneader such as a Brabender plastogram, it can be obtained using a continuous extruder such as a single-screw extruder or a twin-screw extruder. The order of compounding is not particularly limited, and in addition to mixing and kneading the compound at once, it is also possible to first mix a part of the synthetic resin or synthetic rubber and carbon black in a batch or continuous extruder. It is also possible to knead the mixture and then knead the kneaded product with the remainder of the synthetic resin or synthetic rubber. Example 1 The properties of the raw material liquid hydrocarbon are initial distillation temperature 180-190°C 10% distillation temperature 205-215°C 50% distillation temperature 250-260°C 97% distillation temperature 320-340°C Viscosity (80°C) Approx. Ethylene heavy end with a carbon atom/hydrogen atom (weight ratio) of 12.5 was used in the furnace of the shell gasification process. The reactor was reacted with the amount of steam supplied into the furnace at a temperature of 1400℃ and an internal pressure of 30Kg/cm ² with respect to the raw material hydrocarbon, and the DBP oil absorption was 490ml/100g. Carbon black with an ash content of 0.04% by weight was obtained. This high-performance carbon black or ketschen black (a special furnace black made by AKZO) was kneaded with various synthetic resins and synthetic rubbers in various proportions using a Brabender plastogram, and the conductivity of the composition was measured. The results are shown in Table 1. Incidentally, the volume resistivity was measured on a compression molded sheet having a thickness of 2 mm by the Wheatstone bridge method according to SRIS standard 2301-1969.

[Table] Example 2 12 parts by weight of the same high-performance carbon used in Example ¹ and 2,2 parts by weight of 0.05 parts by weight for 100 parts by weight of low-density polyethylene with a density of 0.920 g/cm 2 and an MFR of 4 g/10 minutes. '-Methylenebis(6-tert-butyl-3-
methylphenol) and 0.5 parts by weight of zinc stearate were mixed and kneaded for 5 minutes at 200°C in a Brabender plastogram. The volume resistivity and heat aging resistance of a 2 mm thick sheet obtained by compression molding this kneaded product were measured. Example 1 instead of high performance carbon for comparison
A similar experiment was conducted using the same ketchen black used in . The results are shown in Table 2. In addition, heat aging resistance is
Evaluation was made based on the time taken until the tensile elongation retention rate decreased to 50% or less in a gear oven at 150°C.

【table】

Claims (1)

[Claims] 1 (a) 30 to 97% by weight of synthetic resin or synthetic rubber,
(b) When liquid hydrocarbons are subjected to a partial oxidation reaction with molecular oxygen and water vapor in a furnace to produce highly conductive carbon black at the same time as synthesis gasification, the weight ratio of carbon atoms/hydrogen atoms of the hydrocarbons is is 9 or more and the furnace has an internal temperature range of 1300
~1450℃, furnace pressure 25~80Kg/ ^cm2 , amount of steam supplied to the furnace 400~800 per ton of hydrocarbon.
Highly conductive carbon black obtained by operation under Kg conditions and with a DBP oil absorption of 350ml/100g or more
A highly conductive carbon black composition comprising 70 to 3% by weight.