JPS62280240A - Conductive filler for synthetic resin - Google Patents

Abstract

PURPOSE:To obtain the title filler having excellent antistatic property and effect of shielding electromagnetic wave, by plating the surfaces of carbon fibers with a metal. CONSTITUTION:Metal-plated carbon fibers whose tensile strength, tensile elasticity and conductivity are 400-500kg/mm<2>, 20-30ton/mm<2> and 10<-4>-10<-5>OMEGA.cm, respectively, are obtained by treating the surface of carbon fiber 2 prepd. from polyacrylonitrile and whose diameter is 3-10mu with a metal plating consisting of Ni or Cu and whose thickness is 0.1-0.5mu. These carbon fibers are thereafter cut by 2-3mm in length with a cutter and then ground into about 0.5mm in length with a coarse grinder to obtain short fibers 3, which are then supplied in a fine grinder 6, where the fibers are introduced into a supersonic air flow 4 whose Mach no. is 2.5 or more and spouted from an air nozzle 5, finely ground thereby, and classified to obtain a conductive filler A whose length is 30mu or less. About 10wt% above-described filler is added to a synthetic resin.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention Conventionally, D
Composite materials containing LJ11 and metal powder have been commercialized for various uses (for example, their electromagnetic shielding effect, 'n
? n Focusing on the electrical protection effect, etc., I added wood 1 + clean room 1''l lightning 11 Ji + village (ko, prayer person) to the former.
It is used for the exterior of office or factory automation equipment, etc.). +'rf manufacturers have the drawbacks of not being able to color a single color of pond color due to the inclusion of conductive carbon, and not being able to support the colorization of current products, as well as the fact that it is in sheet form. It must be cut into a predetermined shape and glued to the adherend.
The disadvantage is that the shape that can be used is limited to almost flat shapes, which leads to poor productivity and limited applications.The disadvantage of this type of pond is that even if molding is applied, it costs a considerable amount of money for molding. There was a problem in that it required a lot of money, and unless it could be mass-produced, it would not suit the naked body, and its uses would be extremely limited. In addition, since the latter one is made of fibers and metal powder, the ground color is metallic, and coloring can be done relatively quickly with coloring pigments. Unless it is mixed in at around 40%, it is not possible to achieve the desired electromagnetic wave shielding effect or antistatic effect, and it is not possible to achieve the cost reduction as well as the weight reduction of the exterior material. A more important point is that metal IA fibers tend to get tangled when mixed in a large amount, and the fluidity of synthetic Q (fat) is easily inhibited during molding, and if the extrusion molding machine becomes clogged, it cannot be applied to products with complex shapes. There is a drawback that the particle size of the metal powder is 3 when mixed in.
When the roughness is 0 μ or more, the coarse metal powder or metal Iall appears on the surface and impairs surface smoothness, so there is also the drawback that it cannot be used in applications where surface smoothness is severe, such as mixing into paints.

The present invention has been made in view of the drawbacks of the conventional example, and the first objective is to reduce coloring, weight reduction, and cost, as well as to reduce the amount of mixing, and to reduce the synthesis quality after mixing.
(An object of the present invention is to provide a conductive filler for synthetic resins that has little effect on the fluidity of fat and surface smoothness and can be applied to paints.

The present invention will now be described in detail. The raw material carbon am used in the present invention is, for example, a poly-7-crylonitrile type material, and has a diameter of about 3 to 10 microns (7 microns is used in this embodiment). The surface of this carbon fiber is metal plated (1
), and its thickness is usually 0.1μ to 0.5μ
That's about it. Figure fjS3 shows the relationship between plating film thickness and specific resistance value. The metal to be plated is usually nickel or copper, but of course it is not limited to this, and if necessary, gold plating, silver plating, or other metal plating is also possible. The tensile strength of this metal-plated carbon fiber is 400 to 500 Kg/am2, the tensile modulus is 20 to 30)n/1m1112, and its electrical conductivity is 10-4 to 10-5 Ω・Qm, which is about the same as that of the conventional metal-plated carbon fiber. It has an electrical conductivity equivalent to that of metal fibers. Although it varies depending on the frequency of the electromagnetic wave, taking an electromagnetic wave of 500 MHz as an example, the strength of the radio wave with respect to an electric field is attenuated to 1/1,000,000, and with respect to a magnetic field, it is attenuated to 1/1.000,000.

The conductive filler (A) used in the present invention is made by finely pulverizing such raw material carbon KL & fiber into lengths of 30μ or less (preferably 20μ or less for r!!i materials).
The pulverized conductive filler (^) has a cylindrical shape as shown in FIG. The pulverization method is to first cut the long wire JIIl metal-plated carbon fiber to a length of about 2 to 3+ua with a cutter, then crush it to a length of about 0.5 mm with a coarse pulverizer, and finally with a fine pulverizer (6). Pulverize to a length of 30 to 20 microns or less. As shown in Fig. 2, the fine pulverization method involves continuously and automatically feeding metal-plated carbon a-fiber short fibers (3) into a supersonic swirling airflow (4) of Matsuha 2.5 or higher. A strong impact is applied to this IjrL splice (3) in an air flow (4) to promote pulverization, and at the same time, the pulverized metal-plated carbon fiber fine powder (i.e., the conductive filler (^)) is pulverized 811.
(6) The particles are introduced into a classification chamber provided in the chamber and classified into a predetermined particle size by high-speed swirling vortex flow.

The classified fine powder is introduced into a cyclone or a bag filter together with air, and is efficiently collected. On the other hand, the unpulverized short fibers (3) are collected by being brought to the outside of the high-speed swirling vortex by centrifugal force, and then passed through the air nozzle (5) and accelerated again into the ultra'ff continuous swirling airflow (4). Infused,
It's going to be crushed. At this time, when the short line MF, (3) is released from the air nozzle (5), ma speed turning
In addition to the pulverization by pulverization, the frequency of collisions between the short fibers and I(U(3) is increased by l\li, dramatically increasing the pulverization efficiency. In this way, the short fibers (3) are repeatedly pulverized until they are pulverized to a predetermined particle size. It circulates in the pulverizer (6).In addition, during the first to fine pulverization, the metal W gold short wire and the wire (3) may be pulverized while being heated or cooled, thereby increasing the pulverization efficiency. 01 1.-
li'i+ +--+ 1 The type of synthetic resin used in the present invention is not limited, and any type of synthetic resin can be mixed into it. The five-person method is not particularly limited. The amount of mixture will be described later. 'It can be used in various synthetic materials such as paints and adhesives (it can be mixed into pilgrimage materials.There are two types of paints: solvent-based and emulsion-based, but in the case of solvent-based paints, the type of plated metal does not matter. However, when the gold metal is copper, it is preferable to avoid mixing it into emulnolan-based paints, as it may cause discoloration due to oxidation.

When mixed into adhesives, it must be added in an amount that does not impair adhesive performance. When using IF+ in synthetic resin materials, the amount added is small due to its good conductivity, and therefore its fluidity is not impaired by mixing the conductive material (^), and it can be molded. Not only can it be used as a product, but it can also be used in the form of a sheet or film. In addition, when added to the rubber emulsion paint for use, a protein with high water content and excellent water retention, such as gelatin or glue, may be added. When using gelatin, first disperse the conductive filler (^) little by little in a warm gelatin solution (in some cases, a small amount of surfactant may be used), and completely dissolve the gelatin. When it becomes like a rubber emulnolan paint, stir it thoroughly, then coat the adherend by dipping, brushing or spraying (depending on the coating method, you may also add an appropriate amount of water). ) dries to form a conductive coating on the surface of the adherend.

The amount of conductive filler (^) mixed into the synthetic resin material is better as long as it does not impair the properties of the synthetic resin material or its applicability to the application, but it is usually about 10% by weight, and at most 20% by weight. Approximately % by weight is sufficient. Regarding the electromagnetic wave shielding effect of materials mixed with conductive filler (Δ), for example, if conductive filler (8) is mixed at a concentration of 10% heavy ffi into nylon resin, polycarbonate, ABS@l resin, etc. Electromagnetic waves are attenuated to 17100.000 to 1/40,000. Further, the specific gravity in that case is extremely small, 2.6 to 3.5.

In addition, the shape of the conductive filler (^) to be mixed is usually cylindrical as described in Aff, although it is made by crushing carbon fiber coated with metal M. When used for purposes, the diameter is generally 3 to 10μ, and the length after pulverization is 30μ or more (El' or 20μ or less). The ones used for soup have a diameter of 3 to 7μ,
The strength of the bow is 5 to 25μ (the best is 15 to 20μ). Looking at each application, materials with a fineness of 30μ or less are used for molded products and fillers such as putty, where surface smoothness is not of great importance, and are used for paints where surface smoothness and applicability are issues. In this case, it is preferable to use one whose length is 20μ or less.

As mentioned above, the interior of the present invention is composed of carbon Ia, #, and powder, and the surface of the carbon fiber powder is metal plated, so that the metal plated part is not only electrically conductive, but also carbon fiber. Since the fiber portion is also conductive, it exhibits conductivity equivalent to that of metal Ail fibers and metal powders, even though its specific gravity is lighter than conventional LK woven fiber metal powders, making it suitable for synthetic use. ) If this conductive filler is mixed into 11 as a material, it will have the same electromagnetic shielding effect as a metal fiber mixture. It can exhibit an anti-electrostatic effect.

In addition, since the interior is made of carbon fiber powder and the only metal part is the plating layer on the surface, the specific gravity is much lighter than conventional metal a-fibers and metal powders, contributing to the weight reduction of Ronin materials. There are some advantages as well. Furthermore, since carbon fiber powder with a size of 30μ or less is used as a conductive filler, the conductive fillers become entangled with each other during molding of the mixed synthetic resin 4N, impairing fluidity and impairing surface smoothness. Nothing happened,
It has the advantage that it can be handled in the same way as unmixed synthetic resin and is very easy to use. Incidentally, when the conductive filler has a thickness of 20 μm or less, the surface smoothness and applicability are not impaired and it is most suitable for use as a paint.

[Brief explanation of the drawing]

FIG. 1: An enlarged perspective view of the conductive filler according to the present invention,
Pt52 diagram: A schematic sectional view of a pulverizer according to the present invention. Pt53 diagram: A graph showing the relationship between the resistivity value and the metal plating film thickness of the conductive filler according to the present invention. (^)...Conductive filler, (1)...Metal plating, (
2)... Carbon fiber powder, (3)... Short fiber, /
A),,, petition; 1u oral faith
1- to t! F-J-1-(6)... Fine grinder. Inventor Other aspects Master inventor Ike 1) Katsushige patent applicant Kanebuchi Chemical Industry Co., Ltd. patent applicant Yuta Riki Kogyo Co., Ltd. Drawing number 1 (no change in content) Figure 3 0.6 0.+ 0.4 J, J O, Do 0
．． I N Komugi (μ) Procedural amendment (method) % formula % 2. Name of the invention: Synthetic lipid layer conductive filler 3. Person making the amendment: Relationship with the case (Patent applicant) Address: Kita, Osaka City Ward:=t=”;im 3-chome 2@4 Name Kanebuchi Chemical Y Gyomatsu Shiki Company Representative Takigi no h person Address Osaka Prefecture iiii yx-,,:,: 153-chome 1-4 Name Utah Riki Y Gyo Co., Ltd. Address: 9F Shin-Hanshin Building, 2-2-25 Umeda, Kita-ku, Osaka 530 5. Date of amendment order: July 29, 1985 6. Subject of amendment:・・・・・・・・・・・・Drawing 8
, the contents of the amendment are as shown in the attached sheet.

Claims (3)

[Claims] (1) A conductive filler for synthetic resins, which is carbon fiber whose surface is plated with metal and whose length is 30μ or less. (2) The conductive filler for synthetic resin according to claim 1, characterized in that the plating metal is nickel. (3) The conductive filler for synthetic resin according to claim 1, characterized in that the plated metal is copper.