JPH01230655A - Conductive resin composition - Google Patents

Abstract

PURPOSE:To obtain the title resin composition improved in the balance between conductivity and viscosity, by mixing a PS resin with a mineral oil, a butadiene rubber and a specified carbon black. CONSTITUTION:A PS resin (a) containing 100 pts.wt. PS component is mixed with 1-15 pts.wt. mineral oil (b) of a viscosity (25 deg.C) of 100-400cP, 1-10 pts.wt. butadiene rubber (c) of a butadiene content >=50% and 10-20 pts.wt. carbon black (d) of a DBP absorption >=100ml/100g, desirably, 150-400ml/100g, and the obtained mixture is kneaded at 130-250 deg.C to obtain the title composition of a volume resistivity >=1X10<10>OMEGA.cm and an MI >=5g/10min.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a conductive resin composition, and more particularly to a conductive resin composition having a low viscosity and using carbon black. .

(Prior Art) Generally, conductive resin compositions using carbon black as a conductive material are known. In order to obtain the desired conductivity, it is possible to increase the amount of carbon black blended, but if too much carbon black is blended, the softening fluidity of the resin composition will decrease, making molding difficult. The resulting molded product becomes brittle.

Conventionally, methods such as modifying carbon black and adding surfactants have been used to deal with this problem.

(Problems to be Solved by the Invention) However, in these conventional methods, there is a problem in that conductivity must be sacrificed in order to obtain the desired viscosity. Since it is preferable to use carbon black as the material, a resin composition using carbon black with a good balance between conductivity and viscosity has been desired.

(Means to Solve the Problems) Therefore, as a result of intensive studies to solve these problems, the inventors of the present invention found that by adding a rubber component to the resin, it was possible to reduce the blend i of carbon black and at the same time obtain an advantage. The present inventors have discovered that flexibility can be imparted to a resin composition, and that the viscosity of the resin composition can be optimized by adding a specific amount of mineral oil, and the present invention has been completed.

That is, an object of the present invention is to provide a conductive resin composition that exhibits high conductivity, has a viscosity suitable for various moldings, and has an excellent balance between conductivity and viscosity.

This purpose is to add 100 parts by weight of the polystyrene component in the polystyrene resin, 1 to 10 parts by weight of mineral oil, 1 to 10 parts by weight of butadiene rubber, and 70 to 2 parts of carbon black with a DBP oil absorption of ioomtiiooy or more.
The volume resistivity value obtained by blending 0 parts by weight is /
010Ω・α or less and melt index flow! ;
This can be easily achieved by using a conductive resin composition characterized in that it has a conductive resin composition of at least g/10 minutes.

This is a polystyrene resin mainly composed of carbon black, rubber, and mineral oil, which has a volume resistivity of / 0.
”It is less than Ω・α and is a softening flow conductive resin.

The polystyrene resin used in the present invention is not particularly limited, but for example, "Dialex" HT-gg manufactured by Mitsubishi Monsanto Chemicals.

HT-7A, YH-9! ;/, Asahi Kasei Kogyo ■-8t
Examples include yron"I10'l, ll0g, II9ko, etc.

In addition, mineral oils that can be used as food additives are good, such as "RAMBUS M" manufactured by Matsuzai Oil Research Institute.
-26o'', especially when the viscosity at 2S℃ is /00
-II 00 cps is preferable from the viewpoint of kneading with the resin and improving fluidity after mixing.

The butadiene rubber is not particularly limited, but preferably has a butadiene content of 0% or more,
Preferably more than go%, for example, manufactured by Asahi Kasei Corporation.
It is preferable to use Toughprene A" and "Toughprene-0'12" from the viewpoint of imparting conductivity and flexibility.

Carbon black is commonly used as a conductivity imparting agent, and for example, DBP oil absorption is ioomt.
/ioog or more, preferably /jtO~! l00d! /
/θO1 is preferably used. Examples of such carbon black include "430!;O" manufactured by Mitsubishi Chemical Corporation.
E3", -*3isoB", ≠3'1SOE3゜豐39
! ;OB, Japan Easy ■ 1 Ketch Enblack EC
”, “DJ-600”, manufactured by Tokai Carbon Co., Ltd.≠ysoo
, ≠5500, and acetylene black manufactured by Denki Kagaku Kogyo ■.

The resin composition of the present invention is made by uniformly kneading these components, and the blending ratio is usually 70 to 70 parts by weight of carbon black to 10 parts by weight of the polystyrene component in the polystyrene resin. Preferably 10-75
Parts by weight, butadiene rubber is usually 2 to 70 parts by weight, preferably 5 to 8 parts by weight, and mineral oil is usually 1 to 15 parts by weight, preferably 2 to 10 parts by weight. Manufacturing the resin composition of the present invention For kneading, mix these in appropriate proportions, pre-mix using a "Henshil mixer" or an appropriate mixer, and then heat to 30-250°C to melt and mix. This is carried out using a roll, a Banbury mixer, a single-screw or twin-screw extruder, a Busco kneader, or the like.

The resin composition of the present invention thus obtained has a volume resistivity value of 7×10 10 Ω·α or less, preferably /×10
8Ω・α or less and melt index flow (M
The conductive resin composition has a good balance between conductivity and viscosity, with I) of 31/10 minutes or more, preferably 19710 minutes or more.

(Examples) Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

Comparative Example/~7 and Example/~// Table 7 shows comparative examples and examples.

Polystyrene resin (Mitsubishi Monsanto Kasei's "Yarex" YH-15/) was blended with Butadier/Go AJ, mineral oil, and carbon black (Hikari-2 below), and a mixer was attached to the measuring head. The mixture was kneaded at 760° C. using a new “Labo Plastomill” manufactured by Seiki Seiki.

After kneading, the obtained resin composition was heated with a q-inch heating type roll at iso to /AO°C to obtain a sheet-like composition, and this was
It was molded into a square flat plate with a thickness of 2 mm and a side of 70 by a hot press at 40 to 7 gO<0>C and 50 to 200 Ki/cm2.

The molded plate was a test piece cut out with a diamond cutter to have a width of 2 crn and a length of iocm, and electrodes were attached to the molded plate so that the electrode spacing was 7, and the volume resistivity was measured.

In addition, the volume resistivity of the composition is such that the sample resistance is /o6~1
When it is in the range of 0.016Ω, the resistance meter is HIGHRESIST.
Use a TANCE METER tI32qA (manufactured by Yokogawa Hulett Paracard ■), and when the resistance of the sample is 10'Ω or less, use a resistance meter "DEG I TAL".
MULTMETERTR-A g! The resistance of the test piece was measured in an atmosphere with a temperature of 25° C. and a humidity of 60% using a test piece “1” (manufactured by Takeda Riken ■).

S: Area of resistance measuring electrode (cm2) t: Distance between electrodes (,) Melt index (MI value) is determined by grinding the remaining part of the test piece into a pulverizer with a diameter of 0. ! The powder was ground into granules having a size of less than 100 ml, and this was used as a sample to measure the Ml value using a Melt Indexer MX/0/type (manufactured by Zen Kogyo ■).

The crushed sample was heated to 220℃! ;, Apply a load of gKy,
The weight of the resin discharged for a predetermined period of time from the nozzle with the inner diameter C was measured, and this was converted to the weight of the resin discharged in 10 minutes, which was defined as the MI value.

P! The weight parts of the diene rubber, mineral oil, and carbon black are based on 100 parts by weight of the polystyrene component in the polystyrene resin.

The amount of styrene component and butadiene component in polystyrene resin and butadiene rubber can be determined by dissolving an appropriate amount of resin or rubber with deuterated chloroporm, and using an 'H-NMR analyzer to determine the resonance frequency of the styrene component from 6.5 to ? ,/p
Regarding pm and butadiene ingredients! , the weight ratio was determined by converting the intensity ratio at the 41 ppm position into molecular weight.

The amount of mineral oil in the polystyrene resin was extracted with methanol and then separated using thin layer chromatography. The components were confirmed by infrared absorption spectroscopy, separated and collected, and determined by gravimetric method.

(Effects of the Invention) According to the present invention, it is possible to obtain a conductive resin composition that exhibits high conductivity, has a viscosity suitable for various moldings, and has an excellent balance between conductivity and viscosity.

Sender: Mitsubishi Chemical Industries, Ltd. Representative Patent Attorney Hase - Others/names

Claims (1)

[Claims] (1) Polystyrene component 100 in polystyrene resin
Parts by weight include 1 to 15 parts by weight of mineral oil, 1 to 10 parts by weight of butadiene rubber, and 100 ml/1 DBP oil absorption.
A conductive resin containing 10 to 20 parts by weight of carbon black of 0.00 g or more and having a volume resistivity of 1×10^1^0 Ω・cm or less and a melt index flow of 5 g/10 min or more. Composition.