JPS58112712A - Electrically conductive film or sheet - Google Patents

Abstract

PURPOSE:To obtain the titled film sheet having an excellent electric conductivity, a smooth surface and an excellent mechanical strength by a method wherein furnace black group carbon black with specific grain diameters is contained in tetrafluoroethylene-ethylene copolymer at a specific rate. CONSTITUTION:Three to twelve wt% of furnace black group carbon black with grain diameters 20-50mum is mixed by a Henschel mixer or the like with tetrafluoroethylene-ethylene copolymer, melted and extruded by a biaxial extruder or the like to obtain the desired film sheet. EFFECT:At the time of melting and extrusion melting viscosity does not increase, melting fracture and performation or the like do not occur.

Description

Detailed Description of the Invention The present invention relates to a tetrafluoroethylene-ethylene A polymer (hereinafter referred to as 1'-111
(abbreviated as "TvE") or V-).

Conventionally, most conductive films and V-) (hereinafter referred to as films) based on fluoropolymer have been made of tetrafluoroethylene resin, but this resin cannot be melt extruded and therefore Films were manufactured using special molding methods such as compression molding and paste extrusion. On the other hand, among fluoropolymers, tetrafluorinated polymers that can be melt-extruded are known, but when ordinary carbon black such as acetylene black is used as a conductive pigment in this polymer, high Melt-extruding a strong, smooth, and highly conductive film is extremely difficult from a processing standpoint. Therefore, in order to eliminate the above-mentioned drawbacks, the present inventors have conducted intensive research on the effects of carbon black on processing. Since we were able to obtain a film with good smoothness and excellent conductivity, the gist of the present invention is that
mμ furnace black type carbon black from 3 to 1
2 weight 91. The @ part consists of a tetrafluoroethylene-ethylene copolymer.

The present invention will be explained in detail below.

"ETv1" used in the present invention is a copolymer of tetrafluoroethylene and ethylene).

For example, Aflon C0P (product name: manufactured by Asahi Glass Co., Ltd.).

Examples include Hostaflon E.T (trade name: manufactured by Hoechst), Tefuse J'L/ (trade name: manufactured by DuPont), etc., and the shape thereof is preferably bead-shaped, powdered, etc.
Appropriate values can be selected for I, intrinsic viscosity, etc.

Next, in the present invention, carbon black produced by the furnace method is used. In general, carbon black is broadly classified into two types, the furnace method and the impact method. In the former, the decomposition raw materials are fed into a combustion furnace together with an appropriate amount of air, and are produced by incomplete combustion or thermal decomposition. In the latter case, the decomposed raw material is burned with an appropriate amount of air in a small free-diffusion flame under airtight conditions, and the flame is applied to a cold surface below the ignition point to collect the generated carbon black. . The former is further classified into systems such as Nyoshi Furnace Black, 9-Pook, Therma-Pook, Acetylene Black, etc. in terms of raw materials and manufacturing methods; however, in the present invention, the above-mentioned Toshi Furnace Black is particularly used, so 132
．． Other materials do not exhibit the desired effect, and are difficult to obtain because the WI melt viscosity is extremely high, they tend to melt and break, and small pores open even when carbon plastic is used.

The fur furnace black type carbon black used in the present invention has a particle size of 20 to 50#111, and a fine particle type called conductive furnace black (C1 type) is particularly preferable. For example, Ketjenblack MC (product name F113) manufactured by Lion Oil and Fats is used as carbon black belonging to the C1 series.Using this type of carbon black allows the present invention to exhibit its characteristics to the best of its ability. .

Here, in the present invention, although the particle size is specifically determined as described above, if the particle size is 50 mμ or more, the surface of the obtained film or sheet tends to be prone to spots or bulges, and the smoothness tends to be impaired, whereas if it is 20 mμ or less, This is because it is technically difficult to manufacture.

Next, the mixing ratio of carbon black is 3 to 12% by weight, more preferably 5 to 8% by weight, and 3% by weight in 1IiI.
If it is less than 12 weight X, it is difficult to form a preferable film.

]! The method of mixing iTF]c and carbon black is by a known method using a general mixer etc. At this time, the carbon black is surface treated in advance to make it easier to mix. This method can also be carried out (by known methods). A preferred method for pelletizing this mixed turtle is by a well-known melt extrusion method, but in particular, a twin screw extruder (manufactured by Ikegai Iron Works) with a special configuration is used. It is preferable to do so. As shown in Figures 1 to 4, this type of twin-screw extruder has a structure in which two screws (1) are meshed together, and the shape of the screw (1) is divided into three zones. The hopper zone has a normal shape as shown in Figure 4, the central zone has an eccentric shape as shown in Figure 3, and the tip zone has an intermittently divided convex part of the screw as shown in Figure 2. The screws (1) and (2) rotate in the same direction and at the same speed. By using a melt extruder having such a screw and extruding the resin into a strand shape through the narrow nozzle p and cutting the resin, pellets can be easily obtained. A well-known melt extrusion method is used to produce the film or sheet of the present invention using this pellet.

As described above, the present invention is made by mixing a specific amount of a specific carbon black with a specific diameter into a polyfluoroethylene-ethylene copolymer.
It has become possible to manufacture a K-based conductive film or sheet by melt extrusion, and it has become possible to provide a product that is strong and has excellent surface smoothness.

The use of the present invention is not particularly limited.

Widespread use is expected from an industrial perspective as well. For example, it can be used to remove static electricity from electrical equipment parts.
- For example, if the conductive film or sheet of the present invention is placed on the inner surface of a magnetic tape cassette half, static electricity from the tape can be removed and the tape can be rotated smoothly due to its smooth surface. The film or sheet of the present invention has great utility value when used as a sliding member of such a tape, and is expected to be used even more with the development of electronic engineering such as electromagnetic shielding.

Next, examples of the present invention and comparative examples will be given.

<Example> (Particle size: 30 mμ) Blending was carried out using Henshi A/l Kisa- with the above blending ratio. This turtle is put into a twin-screw extruder at about 300°C.
The pellet is extruded into a strand through a small-hole nozzle lWp to form a pellet, and the pellet is passed through a 40-
When the film was formed by melt extrusion at 10° C., a conductive film V-) having a thickness of 4011 mm was obtained. The volume resistivity of this sheet is 4.8
It had a conductivity of ~&4×10Ω/teeth, kana].

The surface was smooth and had excellent mechanical strength. These values are shown in Table 1.

Comparative Example> An attempt was made to perform melt extrusion in the same manner using the same amount of acetylene black with a particle size of 6 amμ produced by the pyrolysis method instead of Ketjen black EC with the composition of the example, but However, melt rupture occurred and film formation was impossible.

table

[Brief explanation of the drawing]

The drawing shows an example of the melt extruder screw used to produce the raw material for producing the film of the present invention. Figure 1 is the side view, Figures 2, 3 and 4 are the 1st side view.
They are cross-sectional views taken along lines A, B-B, and CC in the figure, respectively. (1) <2)...Screw, (3)...Protrusion. Procedural amendment (voluntary) 1. Indication of the incident 1981 Patent Application No. 2115222, Issued
Name of conductive film or sheet 3, Person making the amendment Relationship to the case %Pill-Person (133) Gu/Zemai type company 4 Agent 8577 5 Date of notice of reasons for refusal (date of amendment order) Attached sheet Article 7, Contents of the amendment (1) On page 4, line 19 of Book A, the words ``can be done'' have been replaced with ``difficult to do so,'' in which case, for example, lubricants, other appropriate additives, fillers, etc. may be required. There is no obligation to make any additions, and these are naturally within the scope of the present application.''

Claims (1)

[Claims] 1. Furnace platter carphone black with a particle size of 20~SO#ls! 1. A conductive film or sheet comprising S to 12% by weight and the balance consisting of a tetrafluoroethylene-ethylene copolymer.