JPS59221342A - Electrically conductive resin composition - Google Patents

Abstract

PURPOSE:To provide a composition composed of a thermoplastic resin and a finely pulverized coke, and giving a light-weight sheet or container, etc. having excellent mechanical strength and fluidity and uniform electrical conductivity. CONSTITUTION:100pts.wt. of a thermoplastic resin is compounded with 30- 120pts.wt. of finely pulverized coke (having a 50% weight diameter of 8-60mu). The resin is e.g. a polyolefin, an olefinvinyl acetate copolymer, etc. The volume resistivity and its lot-to-lot variability of the composition are extremely low and the uniform electrical conductivity can be maintained even if the kneading time is varied.

Description

Detailed Description of the Invention The present invention is an electrically conductive resin composition used in the form of sheets, plates, storage containers, etc., which maintains uniform electrical conductivity, is lightweight, and has excellent mechanical strength and fluidity. This invention relates to an excellent conductive resin composition.

It is well known that conductivity (2) is superior to resin compositions by kneading thermoplastic resins such as polyolefins and polyvinyl chloride with gold powder or carbon black such as silver and copper.

Combining the electrical conductivity 11 with the advantages of easy workability, corrosion resistance, and light weight inherent in fat assembly Ebimonoke 111M resin, it has good electrical conductivity, so it is used for static electricity countermeasures (engineering magazines, parts cabinets, etc.) such as 101L81. There is.

The carbon black contained in this conductive resin composition is
Although it has the advantage of not increasing the specific gravity of the conductive resin composition, when mixing it with a thermoplastic resin, the conductivity of the conductive resin composition changes sensitively due to changes in the kneading time, kneading torque, etc. However, it also has the disadvantage that as the amount added increases, the fluidity properties represented by the melt index (hereinafter abbreviated as II) become markedly lowered. In addition, when using a composite powder of silver, copper, etc., it has the advantage of having high conductivity itself compared to carbon black, but due to the oxidation of the composite powder surface, the particles of the gold threshold The contact resistance tends to increase, the specific gravity of the product increases, the mechanical strength decreases, and the overall properties are inferior.

The present inventors have improved the 0 drawbacks of conventional conductive m-lipid compositions,
As a result of intensive research to solve the problem, we found that if fine coke is used as a conductive additive, the coke will have appropriate conductivity, and the characteristics of the resulting conductive (2) fat composition will be amount of coke and 50% of coke
The weight-to-plate correlation is large, and the coke 5
The present invention was completed based on the finding that a conductive W composition with excellent properties can be obtained when the thickness is 0% weight to 60μ.

The conductive 11 fat composition of the present invention is characterized in that 30 to 120 parts by weight of fine coke is added to 100 parts by weight of thermoplastic resin.

The amount of coke added and the volume resistivity (Ω
The relationship between F) and R depends on the type and particle size of coke, and one embodiment of this is shown in FIG.

As shown in Figure 1, if the amount of coke added is less than 30 parts by weight, the volume resistivity will be more than lQ''l,Q-cy++, and no effect in terms of conductivity can be expected, and if the amount is more than 120 parts by weight. If so, the mechanical strength will decrease and it will not be put to practical use.

General-purpose thermoplastics III include, for example, polyolefins, co-electrolyte combinations of olefins and vinyl acetate, polyvinyl chloride, polystyrene, polyand, and the like.

The coke may be petroleum coke, pick coke, sashimi coke, or a mixture thereof. To crush this, the raw material coke is crushed using a stamp mill, hammer mill, or ball mill, and then passed through a sieve.
Separate into those below the sieve of about 250 μm or less and those above the sieve, and those above the sieve K are crushed again and passed through the sieve according to the method described above, and this process is repeated thereafter. The mass of subsieve particles collected in this way usually has the smallest particle size, approximately 10 μm, and is about 40 μm in size on a 50% weight plate.
This corresponds to a distribution of ~90μ. Therefore, if necessary, perform further classification using an air separator, etc.
Obtain a population of 8-60μ in N weight diameter. Incidentally, coke in this state exists as grains with extremely good fluidity without sharp protrusions, so it is easy to handle.

If the particle size of the coke is 50% of the diameter of 60% or more, the tensile strength of the product resin, bending, and t! It is undesirable that mechanical strength such as iJ impact strength tends to decrease and variations tend to increase significantly, and the amplitude of fluctuation between electric fields is large. on the other hand,
When the weight of the plate is less than 50% μ, the decreasing tendency of Ktlj, II is not steep, and it takes a long time to uniformly disperse coke during crosstalk.

The conductive resin composition of the present invention has extremely small volume resistivity and intra-metal fluctuations in volume resistivity even if the kneading time changes during production, and maintains uniform conductivity for -Km. As a K11-composition, it has the advantage that there is little reduction in mechanical strength and mechanical strength due to additives, and it has various properties not found in conventional additives.

Next, we will explain in detail the practical example of the non-inventive field.
The present invention is not limited to these.

Example 1-3 For each of the thermoplastic 11# fats shown in Table 1, coke with the particle size shown in Table 1 was mixed in the proportion shown in the table, and kneaded for the time shown in the table. .

Seishi coke containing 0.91% coke HF was pulverized in a stamp mill and milled to have the particle size shown in Table 1, that is, a 50% large particle size by weight.

A pressurized double-arm kneader is used for kneading, and the kneading humidity is 155°C for medium density polyethylene and 14°C for ethylene-vinyl acetate copolymer (shown as EV in Table 1).
The temperature was set at 5°C.

The conductivity of each submerged 1 [volume resistivity of the composition, I
I. The tensile yield point strength was determined by a conventional method and the excellent results are shown in Table 1. Regarding the volume resistivity, the same sample was measured three times and the minimum to maximum values were determined.

Comparative Examples 1 to 5 For each of the thermoplastics 1 shown in Table 1, the conductive additives shown in the table were mixed in the proportions shown in the table, and the mixture was kneaded and conductive according to Examples 1 to 3. Sex t! An IWI composition was prepared.

The properties of the obtained conductive resin composition were measured according to Examples 1 to 3, and the results are shown in Table 1.

As is clear from Table 1, when the carbon blacks shown in Comparative Examples 3 and 4 were used, the change in volume resistivity due to kneading time and the intra-lot variation in volume resistivity were extremely large, whereas in the case of the examples It was recognized that the case was extremely small.

Comparing Examples 1 and 2.3 and Comparative Example 3.4, Comparative Example 3.4 using carbon black has a lower volume resistivity (Ω・
It was criticized that the time required for crosstalk to become stable was long.

In addition, when determining the decrease in XI between Example 2 and Comparative Example 4, where the volume resistivity is the same as rgl-a, the former's II
was 10, and tsuba was 5. It was observed that Comparative Example 4 had a large decrease in M-work.

[Brief explanation of the drawing]

Figure 1 shows the amount of coke added to #it resin composition (Tree 11).
00*1 (weight part of coke added to isK) and volume resistivity (Ω·crn) are shown. Patent applicant Nippon Oil & Fats Co., Ltd. Representative patent attorney Isino II Tsukasa II! ! 30 50 +00 Procedures Amendment Written on June 28, 1981 Kazuo Wakasugi, Director General of the Patent Office 1. Indication of the case 1982 Patent Application No. 94843 2. Name of invention Conductive resin composition 8. Amendment Patent applicant address: 1-10-1 Yurakucho, Chiyoda-ku, Tokyo Name (434) Nippon Oil Ishi Co., Ltd. 4□ Agent 103 Address: 1-chome Muromachi, Nihonbashi, Chuo-ku, Tokyo 2 Yonachi voluntary amendment 6, subject of amendment (1) Detailed explanation of the invention in the specification (2) Drawings (1) "Vinyl acetate" in line 5 of page 4 of the specification is corrected to "vinyl acetate." (2) Line 8 on page 4 of the statement “Big coke” is replaced with “
Pitch coke,” he corrected. (3) Replace Figure 1 with the attached one. Corrections are indicated in red on the copied drawing.

Claims (2)

[Claims] (1) A conductive resin composition comprising 1100 parts by weight of thermoplastic sphere 1Ii and 30 to 120 Mm parts of finely pulverized coke. (2) The 50% weight diameter of the finely pulverized coke is 8 to 6.
The conductive resin composition according to claim 1, wherein the conductive resin composition has a particle diameter of 0μ.