JPS58218703A - Conductive resin composition - 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] This invention is applicable to electric wire-related applications such as high-voltage cables and communication cables, plastic-related applications such as fuel tanks, electronic parts, packaging materials, and automobile parts, hoses, belts, safety shoes, and flooring materials. , switching elements, ignition cables,
Rubber-related applications such as static elimination rolls, electrode-related applications, etc. (=Related to electrically conductive resin compositions that are widely used today.)

Conventionally, as this type of conductive resin composition, one prepared by kneading conductive solid powder such as carbon black or graphite in a resin is known, but it has a volume resistivity of 10.
5Ω. In the following applications, for example, polyethylene mixed with carbon black is difficult to mold as is during extrusion molding or injection molding, so rubber-like substances are added to improve its kneading and moldability. , a decrease in physical properties is inevitable.

In recent years, Ketjenblack, a type of carbon black, has been developed as a solid powder material to be incorporated into such conductive resin composition C2, and it has extremely superior conductivity compared to other carbon blacks such as acetylene black. It is possible to obtain excellent conductive side slopes with a low additive amount, and there is little decrease in conductivity during kneading. It has come to occupy the mainstream as a conductive solid powder used in conductive resin compositions.

However, this Ketjenblack is similar to other carbon blacks, such as □acetylene black,
black, lamp black, thermal black, channel black, roll black, disc black,
There is a problem that the production cost is extremely high for conductive resin compositions with a high blending ratio of conductive solid powder. In the case where only Bonblack is used (Second), sufficient performance cannot be obtained in terms of wire crosstalk and moldability of the obtained conductive resin composition. The maximum amount of polyethylene resin C that can be added using a mixer is approximately 25% by weight. As a conductive resin composition, its conductivity was not satisfactory.

The present inventors have developed a conductive resin composition that is excellent in both kneading properties and moldability, and is also inexpensive. As a result of extensive research, we have discovered that the objective can be achieved by combining polyolefin resin (--carbon black and graphite as conductive solid powder in a predetermined ratio), and have arrived at the present invention. It is something.

That is, the present invention uses polyolefin resins of 30 to 80
Weight%, carbon black 1 to 30 weight percentage, graphite 10
The object of the present invention is to provide a conductive resin composition containing a conductive resin composition containing .about.50 conductive resin compositions, and a preferred embodiment includes a solid-resin composite powder in which carbon black and/or graphite is coated on the solid surface with a resin. The carbon black is Ketjenblack.

As the polyolefin resin used in the present invention, high-pressure method C, which is carried out under high pressure of polymerization pressure of 1000 atmospheres or more, is used.
High-pressure polyethylene produced from 2, 20-70kg
, /Crn2 and 10 kg/cm2, copolymers made by copolymerizing a small amount of propylene, butene-1, hexene-1, vinyl acetate, acrylic acid, etc. Examples include alkyl acrylates, vinyl acetate-vinyl chloride, copolymers with lower α-olefins, and polypropylene, polyisobutylene, polyenes, and various copolymers thereof. In particular, the present invention exhibits its effects on polyethylene, polypropylene, or various copolymers thereof. These polyolefin resins may be blended with various additives such as lubricants, plasticizers, stabilizers, etc. in advance.

Examples of the carbon black used in the present invention include conventionally known Ketjen black, acetylene black, fire black, lamp black, surf black, channel black, roll black, disk black, and the like. Among these carbon blacks, preferred ones have electrical conductivity (-excellent,
It has excellent conductive side slopes with a low additive amount, and when kneading (-
Ketjen black has a small decrease in conductivity when exposed to heat.

Furthermore, the graphite used in combination with carbon black as a conductive solid powder may be natural graphite p or artificial graphite. The particle size of carbon black is 15-600m.
On the other hand, graphite is a particle and has higher conductivity than carbon black. In the present invention, by using both in combination, a highly conductive resin composition with good moldability that cannot be expected when used alone can be obtained.

The carbon black and graphite used as the conductive solid powder in the present invention are prepared by blending and kneading the polyolefin resin (two to form a conductive resin composition) without treating the solid surface of the carbon black and graphite. However, it is preferable to use a solid whose surface is coated with a resin.
It is blended as a resin composite powder. Conventional methods for coating this solid surface with resin include two known interfacial polymerization methods, in-situ polymerization methods, in-liquid curing coating methods, phase separation methods from aqueous solutions, phase separation methods from organic solutions, There are submerged drying methods, melt dispersion cooling methods, inclusion exchange methods, powder bed methods, air suspension coating methods, spray drying methods, vacuum evaporation methods, electrostatic coalescence methods, etc., but it is preferable to Either by graft polymerizing the vinyl resin, or by adsorbing a metal salt that can impart two charges on the solid surface, and then polymerizing the oligomer and/or polymer 5 with the opposite charge to the metal salt.
This is a method in which one or both of the following are brought into contact with a resin solution or dispersion containing one or more of the following.

As a method for graft polymerizing the above-mentioned solid surface of carbon black and/or graphite (-vinyl resin), various polymerization methods such as bulk polymerization method, solution polymerization method, etc. can be used in the presence of a radical polymerization initiator. However, a method in which a conductive solid powder and a vinyl monomer are subjected to suspension polymerization in an aqueous medium in the presence of a compound that generates sulfite ions is particularly preferred, and water is generally used as the medium for suspension polymerization. An aqueous medium such as, but not limited to, a mixture of water and methanol can be used.Also, as a polymerization initiator in suspension polymerization (two), compounds that generate sulfite ions in an aqueous medium, such as Blowing sulfur dioxide gas, sulfite aqueous solution, sulfites such as sodium bisulfite and ammonium bisulfite, and persulfates such as potassium persulfate, sodium chloride, ammonium persulfate, etc. alone or in combination. Can be used.

The solid-resin composite powder obtained in this way has free radicals (a pair of active sites (-1 polymerization reaction) on the surface of the solid powder).
A part of the vinyl resin produced from the second step is chemically gelaft bonded.

Vinyl monopolymers used for this purpose include A'l
Ionically dissociable vinyl monomers such as unsaturated carboxylic acids such as lylic acid, methacrylic acid, α-chloroacrylic acid, iconic acid, maleic anhydride, maleic acid, and somaric acid, vinyl chloride, and vinyl fluoride. Vinyl halides such as
Non-ionically dissociable vinyl compounds such as styrene, styrene compounds such as α-methylstyrene, aliphatic vinyl esters such as vinyl acetate and vinyl propionate, and unsaturated carboxylic acid esters such as methyl acrylate and lauryl methacrylate. Monomers can be mentioned. Among these vinyl monomers, particularly preferred are those that form vinyl resins that are compatible with polyolefin resins, and such vinyl monomers can be graft-polymerized. . When the surface of this conductive solid powder is coated with resin by graft polymerization, the amount of resin is 01 to 30% by weight, preferably 05 to 30% by weight based on the solid powder (2% by weight).
15 layers = S.

Further, after adsorbing a metal salt capable of imparting a C dielectric charge to the solid surface of carbon black and/or graphite, the solid surface contains one or more oricomers and/or polymers having an opposite charge to that of the metal salt. In the resin solution or dispersion (method C2 of making two contacts), the metal salt used is Ag.
I + Fe C/! 3 + Fe2O3+ MgC
:A2+ MCA3. Fe(OH)3. Fe SO
4, Positive charge 1;1 donor substance such as Na25o4 or Ba
We can list the negative charge f′N1 as CA2, etc.
In addition, the resin solution or dispersion containing one or more types of oligomers and/or polymers to be used includes:
Examples include acrylic or methacrylic polymer or copolymer emulsions, acrylic-styrene copolymer emulsions, ethylene-acrylic copolymer aqueous solutions, epoxy resin aqueous solutions, phenolic resin aqueous solutions, and the like. Particularly preferred as these resin aqueous solutions or resin dispersions are aqueous solutions or dispersions of resins that are compatible with polyolefin resins, such as ethylene-acrylic copolymer aqueous solutions and ,
Examples include acrylic copolymer emulsions having ester groups such as butyl, lauryl, and stearyl. like this(
- Solid-resin composite powder obtained by washing (the amount of resin in the second step is 0.1 to 30% by weight, preferably 0.1 to 30% by weight, based on the solid powder)
．． It is 5 to 15 years old.

Note that the conductive solid powder may be coated with a resin using both carbon black and graphite, or either one of them may be used.

The blending ratio of the polyolefin resin, carbon black, and graphite constituting the conductive resin composition of the present invention is determined depending on the physical properties such as conductivity, kneadability, and moldability required for the conductive resin composition. However, in order to achieve the purpose of the present invention, the content is usually 30 to 80% by weight of polyolefin resin, 1 to 30% by weight of carbon black, and 10 to 50% by weight of graphite, preferably polyolefin resin. 45-70% by weight, carbon black 10-
25% by weight and graphite 15-405-40% by weight If the polyolefin resin is less than 30% by weight, although satisfactory physical properties can be obtained for conductivity C2, moldability and properties (extrusion molding properties) deteriorate, In addition, if the content of graphite is 80% by weight or more, satisfactory physical properties cannot be obtained in terms of conductivity C2.In addition, if the graphite content is 10% by weight or less, ``expensive Ketjen black (alternatively, graphite may be used in combination)'' The economic effect is poor, and if it exceeds 50% by weight, the deterioration of extrudability is more noticeable than the effect of improving conductivity (
Two. Furthermore, if the amount of carbon black added is as low as ~11 parts by weight, it will be difficult to improve conductivity.
Moreover, if the amount is more than 30% by weight, two problems will arise in moldability.

From the standpoint of conductivity, when acetylene black is used as carbon black (- is preferably 5% by weight or more, and when furnace black or thermal black is used, it is preferably 10% by weight or more).

In the present invention (2), carbon black or graphite is coated with a resin.C2: solid-resin composite powder as a polyolefin resin In addition, the amount of carbon black and graphite (for two, the amount of resin was subtracted from the added solid-resin composite powder) was calculated.

The conductive resin composition containing the polyolefin resin, carbon black, and graphite is prepared using a conventional method using an appropriate black such as a co-kneader, Banbury mixer, mixing roll, or pressure kneader within the range of the above-mentioned mixing ratio. It is preferable to mix and knead the mixture uniformly and form it into pellets, and these pellets can be transformed into a desired product (two-molded, one
do.

In addition, in the preparation of this conductive resin composition, polyolefin resins (usually added flame retardants, pigments, plasticizers, stabilizers, antioxidants, ultraviolet absorbers, crosslinking agents, wetting agents) are used. In addition, carbon black, a modifier for improving the adhesion between the graphite and the polyolefin resin, etc. can be used.

According to present invention C2, when only carbon black is used as the conductive solid powder, the conductivity can be improved without deteriorating the kneading property or the moldability, and furthermore, the conductivity can be improved. A resin composition can be provided at a low price.

Hereinafter, the present invention will be specifically explained based on Examples and Comparative Examples.

[Examples 1 to 11 and Comparative Examples 1 and 2] Average particle size 30/
Add 100 parts by weight of Ketjen Black from No. 7 to 1200 parts by weight of water and add it to this! 07 parts by weight of sodium inric acid, a part of lauryl methacrylate polymer, and Fe
CA3 ・6 0.3 parts by weight of H2O and 0.7 parts by weight of potassium persulfate
5 parts by weight and 30.7 parts by weight of NaH5o.
The mixture was reacted at 5°C for 5 hours with stirring, then filtered, washed with water, and dried to obtain 107 parts by weight of Ketjen black-lauryl methacrylate polymer composite powder in which the surface of Ketjen black was coated with lauryl methacrylate polymer. . The amount of resin in this powder was 65% by weight.

In addition, 4 parts by weight of natural graphite powder with an average particle size of 6 μm was added to 4 parts by weight in water.
00 parts by weight, and add 0.00 parts by weight of sodium oleate to this.
2 parts by weight, 1.75 parts by weight of lauryl methacrylate,
By adding 11.7 parts by weight of a 6% by weight H2S03 aqueous solution and reacting at 60'C with stirring for 3 hours, graphite-lauryl methacrylate polymer composite powder 1
068 parts by weight were obtained. The amount of #I fat in this powder was 644 parts by weight.

Next, polyethylene (manufactured by Showa Denko K.K., product name: SHOLEX F 6050 C), the Ketjen blank-lauryl methacrylate polymer composite powder, and the graphite-lauryl methacrylate polymer composite powder were mixed into a first powder.
The conductive resin compositions of Examples 1 to 11 and Comparative Examples 1 and 2 were prepared by blending them in the proportions shown in the table and kneading them at 150°C using a kneading roll. The resulting resin compositions of Examples and Comparative Examples were molded into sheets with a thickness of 1 mm using a hot press at a press temperature of 200° C. and a press pressure of 40 kg/cm2, and their volume resistivity was determined. It was measured.

The resin compositions of the above Examples and Comparative Examples were tested using a twin-screw extruder (PCM-30) manufactured by Ikegai Tekko Co., Ltd. at a temperature of 200 m at screw rotation speeds of approximately 50 r, p, and m.
Extrusion molding was carried out under the molding conditions of 1230 °C and 260 °C, and the extrusion formability was investigated (-1 using Tanabe Plastic sheet manufacturing equipment (VS-50), screw rotation speed 20 to 40 r , p, m. and temperature 250
The sheet moldability was investigated by counting under the molding conditions of ℃.

[Example 12] Add 100 parts of Ketjenblack or graphite to 1 part of water.
000 parts by weight, and while stirring, add 200.5 parts by weight of FeC/!3.6H as a dielectric charge imparting substance, and then add an ethylene-acrylic copolymer aqueous solution (Steel Chemical Co., Ltd., cleavage product name: Deixen). 5 parts by weight was added and left in contact for 1 hour, filtered and dried to give a resin amount of 488 parts by weight solids.
105 parts by weight of resin composite powder was obtained. Regarding the conductive resin composition obtained using this solid-resin composite powder, the volume resistivity value, kneading property, moldability, etc. determined in the same manner as in each of the above examples are shown in Table 1.

[Example 13] Solid-resin composite powders obtained in Examples 1 to 11 above Table 1 to (Sho) ○...Good, and the properties of the molded product are also good.

Δ: Possible, but the properties of the molded product are poor.

×...It's impossible.

A conductive resin composition obtained using polypropylene (Ube Industries, Ltd., grade name F 109 T) as the polyolefin resin (one volume specific The resistance value, kneadability and moldability are shown in Table 1 (-).

The results are shown in Table 1.
r mountain IF writing (spontaneous) 11/rice 11, f? Brush 12 II 2 n Director-General of the Japan Patent Office Kazuo Wakasugi 1 Naka ('l Indication Show (1+ 57 <l Patent Application No. 99989 Li 2 Title of the invention Conductive resin composition 3 Relationship with the amended party case Patent applicant , 7. II 4+ , jl 6-17-2, Ginza, Chuo-ku, Tokyo 1% Name (6'4) Nippon Steel Chemical Industry Co., Ltd. 4 Deputy Director 104
Phone 0R (ls48) 16? fi Address 8th floor, Ebara Building, 7-14-2 Senza, Chuo-ku, Tokyo Name (827B)
) Patent attorney Katsuo Naruse (1 other person) 7 "Detailed explanation of the invention" column 8 of the specification subject to amendment 8 R807tJ stated in page 14, line 8 of the specification of the amendment
Correct it to 0 w J.

Claims (5)

[Claims] (1) A conductive resin composition characterized by containing 30 to 80 parts by weight of a polyolefin resin, 1 to 30 parts by weight of carbon black, and 10 to 50 parts by weight of graphite. (2) Polyolefin resin 45-70% by weight, carbon black 10-25% by weight and graphite 15-40% by weight
The conductive resin composition according to claim 1. (3) The conductivity according to claim 1 or 2, wherein the carbon black and/or graphite is blended as a solid-resin composite powder obtained by graft polymerizing a vinyl monomer on the solid surface. Resin composition. (4) Carbon black and/or graphite adsorbs a metal salt capable of imparting an electric charge onto its solid surface, and then adsorbs one or more oligomers and/or polymers having an opposite charge to that of the metal salt. The conductive resin composition according to claim 1 or 2, which is blended as a solid-resin composite powder whose solid surface is coated with a resin by contacting with a resin solution or dispersion containing H. . (5) The conductive resin composition according to any one of claims 1 to 4, C2, wherein the carbon black is Ketjen black.