JPS62226505A - Conductive resin board material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to shielding plates for preventing electromagnetic interference, synthetic resin planar heating plates, electrode plates for dust collectors, electrode plates for batteries, etc. Let's take a look at the conductive resin plate material being used.

[Conventional technology 1] Conventionally, this type of conductive resin plate material has been produced by kneading solid powder such as carbon black or graphite that improves conductivity into the resin, and then molding the resulting kneaded product by compression molding or extrusion molding. It is known to be molded into a plate shape.

:For applications where the volume resistivity value is 10α or less, for example, it is difficult to mold polyethylene with carbon black mixed in it by extrusion molding or injection molding, so saturated s1-rene thermoplastics are used. Elastomers or saturated olefin-based thermoplastic elastomers are added to improve kneading and moldability (JP-A-60-8).
362 (Japanese Unexamined Patent Publication No. 1987-4.8 Ωcm), and one in which carbon black is adsorbed onto synthetic resin fibers is added to a synthetic resin to improve conductivity (Japanese Patent Application Laid-Open No. 1983-4.8 Ωcm).

However, for the former, it is necessary to add a considerable amount of saturated styrene-based elastomer or saturated olefin-based lath I-mer to improve kneadability and moldability, resulting in a decrease in physical properties. In addition, although the conductivity of the latter is improved compared to that obtained by adding carbon black alone to a synthetic resin, compression is required because the direction of the fibers needs to be uniform. There are problems in that it is limited to molding methods that do not generate shearing force, such as molding, and is not economical.

Therefore, in order to solve the various problems that these conventional conductive resin compositions have, first, a polyolefin resin and
We proposed a conductive resin composition containing carbon black and graphite in a predetermined ratio, and achieved certain results in terms of musical composition and moldability (Japanese Patent Publication No. U11 1982-218.703).

[Problem to be Solved by the Invention 1] However, although it is possible to mold a plate with a relatively narrow product width using this conductive resin composition, it becomes difficult to form a large plate with a product width of 500 mrm or more. Heat melting F! when molding by extrusion molding or other methods. There were problems in that AI+7 had a high viscosity and lacked fluidity, making it difficult to mold.

Furthermore, in extrusion molding or compression molding of conductive resin compositions containing a large amount of carbon fiber powder, the mechanical strength of the manufactured plate material is lowered due to the influence of the filler, making it difficult to commercialize it in large sizes. It is difficult to manufacture conductive resin plates with strength that can withstand the There is a need for the development of large-sized conductive resin plates.

[Means for Solving the Problems] The present invention has been devised in view of this point of view, and therefore it not only has excellent conductivity but also has better mechanical strength than conventional extrusion molding or compression molding plate materials. This covers a conductive resin plate material that has a high level of strength.

That is, the present invention uses polyolefin resins of 35 to 75
1i1n%, carbon black 10 to 30% by weight, and graphite 5 to 50% by weight. A plate material formed by rolling between at least a pair of rolls an original plate made of a conductive resin composition containing 10 to 30% by weight of carbon black and 5 to 50% by weight of graphite, the volume resistivity of which is is a conductive resin plate material with a resistance of 1ΩcIR or less.

The polyolefin resin used in J3 in the present invention includes high-pressure polyethylene produced under high pressure of polymerization pressure of 1000 atm or more, under a pressure of about 20 to 70:9/d, or under a pressure of about 10:9/ci. Examples include medium- and low-pressure polyethylene, polypropylene, polypropylene, and various copolymers thereof, which are produced below, and polyethylene, polypropylene, and various copolymers thereof are preferable. These polyolefin resins may be blended with various additives such as lubricants, plasticizers, stabilizers, etc. in advance.

Further, a mixture of these polyolefin resins may be used.

Examples of carbon black include conventionally known Ketjen black, acetylene black, furnace black, lamp black, thermal black, channel black,
Examples include roll black and disc black. Particularly preferred among these carbon blacks is one that has excellent conductivity, provides an excellent conductive material with a low addition ω, and is suitable for kneading 11. 'i' is Ketjen black with little decrease in conductivity.

Further, the graphite used together with carbon black as the conductive solid powder may be natural graphite or artificial graphite. This graphite itself has higher conductivity than carbon black, and has a particle size of 1 to 600.
From the viewpoint of moldability, the average particle size is preferably 2 to 100 μm, more preferably 4 to 80 μm.

Furthermore, the above-mentioned carbon black and/or graphite used as a conductive solid powder can be blended with a polyolefin resin and kneaded without any treatment on the solid surface, or kneaded with the addition of an appropriate dispersion aid. Alternatively, the surface of the solid may be coated with a suitable resin, and the solid-resin composite powder may be blended with a polyolefin resin and kneaded. As a method of coating this solid surface with a resin, the interfacial polymerization method, which is generally known in the past, and the in
5itu width method, liquid curing coating method, phase fraction N from aqueous solution
1 method, phase separation method from organic solution, in-liquid drying method, melt-dispersion cold IJl method, inclusion exchange method, powder bed method, in-liquid suspension coating method,
There are spray drying methods, vacuum evaporation methods, electrostatic coalescence methods, etc., and the preferred method is to graft-polymerize a vinyl resin onto the solid surface, or to adsorb a metal salt that imparts an electric charge to the solid surface. 1+ of oligomers and/or polymers having an opposite charge to this metal salt.
A method of contacting with a resin solution or dispersion containing If+ or two or more thereof can be mentioned.

The blending ratio of the polyolefin resin, carbon black, and graphite constituting the 3# electrically conductive resin composition of the present invention is usually 35 to 75 fflf1% of the polyolefin resin, 10 to 30% by weight of carbon black, and 5 to 50% by weight of graphite.
and preferably 45 to 70% by weight of polyolefin resin, 15 to 25% by weight of carbon black, and 5 to 5% by weight of graphite.
It is 40% by weight. If the blending ratio of polyolefin resin is less than 35 wt ω%, satisfactory physical properties can be obtained in terms of electrical conductivity, but the moldability, especially rolling formability, deteriorates, and if it exceeds 75 wt 16%. It is not possible to obtain satisfactory physical properties regarding conductive performance. Yo Iζ,
If the blending ratio of graphite is less than 5% by weight, the economic effect of using carbon black and graphite together will be poor, and if it exceeds 5Ωcmff1%, the effect of improving formability, especially rolling The deterioration of moldability becomes noticeable. Furthermore, if the blending ratio of carbon black is less than 10% by weight, it becomes difficult to improve the conductivity, and if it exceeds 30% by weight, problems arise in moldability.

The conductive resin plate material of the present invention is produced by mixing the polyolefin resin, carbon black, and graphite within the above blending ratio using a suitable blender such as a co-kneader, a Banbury mixer, a mixing roll, or a pressurized blender using a conventional method. The mixture is uniformly mixed and kneaded, preferably formed into a pellet shape, and then formed by extrusion molding, press molding, etc. to a thickness of 0.5 to 25 #11. The original plate is preferably 1 to 10 m long, and the original plate is rolled between at least one pair of rolls whose gap distance is adjusted to 1/2 to 1/10, preferably 1/2.5 to 115 of the original plate thickness. . The original plate to be supplied to the roll may be supplied by preheating a cold plate, or may be continuously supplied as a hot plate via a heat retaining means using an extruder, a press machine, or the like.

Regarding the temperature of the original sheet during the above rolling, it is best to keep the temperature within the crystal melting point of the polyolefin resin used as the matrix ±40°C.By rolling within this temperature range, the polyolefin resin is reoriented and the product sheet material is formed. It is possible to improve brittleness and to mold a conductive resin plate material with toughness without significantly reducing the inherent conductivity of the conductive resin. If the temperature of the original sheet during this rolling is higher than the crystal melting point of the polyolefin resin +40°C, the orientation of the polyolefin resin will be incomplete and the toughness of the rolled product sheet will not be improved. If the temperature of the original sheet during rolling is lower than the crystal melting point of −40° C., peeling occurs at the interface between the polyolefin resin and the carbonaceous material, resulting in a decrease in electrical conductivity.

Further, the rolling may be performed only on the -axis, but orthogonal biaxial rolling may be performed when the strength in the biaxial directions is desired to be similar or when the product width is desired to be widened. Further, the rolling ratio (thickness before rolling/thickness after rolling) is 2 to 10, preferably 2.5 to 5. If the rolling ratio is less than 2, the improvement in mechanical strength will not be maintained at 1], and if the rolling ratio is greater than 10, the conductivity will decrease too much.

・The conductive resin plate material of the present invention has a volume resistivity value of 1
It is a thin conductive resin plate material with a particularly wide width and a thickness of 341II+ or less, which exhibits excellent conductive performance of Ωcrm or less, and which could not be molded by conventional extrusion or pressing methods. If b is higher than 1Ωcryt, it is easy to mold and the drop in strong electric current is not large. There is no reason why it must be manufactured by rolling.

[Example] Hereinafter, the conductive resin plate material of the present invention will be described based on Examples and Comparative Examples.

Examples 1 to G and Comparative Examples 1 to 9 Ketjenblack, natural graphite with an average particle size of 6μ, and high density polyethylene with a crystal melting point of 130°C were blended in the proportions shown in Table 1, and using a Pan Bali mixer. 150-18
Mix at 0°C for 5 minutes, then roll at 140°C using two wooden rolls.
The pellets were kneaded at ~170°C, made into pellets using a sheet cutter, and the pellets were made into pellets using a 40#111 extruder at a cylinder temperature of 200-260°C and a die temperature of 23°C.
Thickness 2-8#l11 and width 200 under the condition of 0-260℃
It was molded into a M sheet.

The (-) sheet was supplied between a pair of rolls having a diameter of 170+ m and a rolling blade of 20 tons, and rolled under the rolling conditions shown in Table 1. At this time, the gap between the pair of rolling rolls is
0.5 mm only in Comparative Example 3, 1.0 in other cases.
II! It became an IR.

The tensile strength (JIS K 7113), elongation (JIS K 7113), and volume resistivity (four-probe method) of the conductive resin plates of each of the obtained Examples and Comparative Examples were measured. The results are shown in Table 1.

As is clear from the results in Table 1, the elongation rate of the sheets of Comparative Examples 6 to 9 manufactured by extrusion was in the 1% range, whereas that of the plate materials manufactured by extrusion molding was in the 1% range. The elongation rate of the formed plate material is 2% or more, and
Significant improvement in tensile strength.

[Effects of the Invention] The conductive resin plate material of the present invention not only exhibits excellent conductivity with a volume resistivity of 10 crs or less, but also exhibits excellent performance in terms of mechanical strength. It can be made into a large plate material, which could not be achieved with materials with conductive performance of 1 Ωcm or less.

Patent applicant Nippon Steel Chemical Co., Ltd. Same as above
Representative of Shin E1 Steel Corporation
Patent attorney Katsuo Naruse (2 others) Procedural notice (spontaneous) June 1985 Near Japan Patent Office Commissioner Uga Torubu 1, Indication of case Patent application No. 67184 of 1988 2, Invention Relationship with the name case Patent applicant address 5-13-16 Ginza, Chuo-ku, Tokyo Name (6
64) Nippon Steel Chemical Co., Ltd. (1 other person) 4. Agent 105 Phone: 03 (433) 4420
Address: 8@, 7, 3-8 Fr Bridge, Minato-ku, Tokyo. The "Nida" written on page 8, line 14 of the statement of contents of the amendment is amended to "Nida".

that's all

Claims (3)

[Claims] (1) A plate material formed by rolling an original plate made of a conductive resin composition containing 35 to 75% by weight of polyolefin resin, 10 to 30% by weight of carbon black, and 5 to 50% by weight of graphite between at least a pair of rolls. A conductive resin plate material having a volume resistivity of 1 Ωcm or less. (2) The conductive resin plate material according to item 1, which is obtained by rolling an original plate made of a conductive resin composition using rolls in a temperature range of ±40° C. of the crystalline melting point of the polyolefin resin. (3) The conductive resin plate material according to claim 1 or 2, having a rolling ratio of 2 to 10.