CONDUCTIVE FLUORORESIN COMPOSITION

AND MOLDED PRODUCT THEREOF FIELD OF INVENTION

The present invention relates to a conductive fluororesin

composition of melt processible fluororesin and zinc oxide powder that is of utility in articles requiring electric conductivity or antistatic properties. The composition is white, can be melt-molded, exhibits stable electrostatic diffusivity, does not foam when melt processed resulting in a smooth extruded surface, and has excellent wear resistance. The composition has utility in pressure rolls for copying machines, printers, and the like, or pipes, wafer holding jigs, and the like used in semiconductor

manufacturing.

BACKGROUND OF INVENTION

Melt processible fluororesins such as tetrafluoroethylene- perfluoro(alkyl vinyl ether) copolymer (PFA), tetrafluoroethylene- hexafluoropropylene copolymer (FEP), and tetrafluoroethylene-ethylene copolymer (ETFE) have excellent heat resistance, chemical resistance, and non-tackiness, properties intrinsic to fluororesins. These fluororesins are excellent insulating materials, but when these fluororesins are used as parts for rolls, tubes or belts for office automation appliances such as copying machines and printers, or pipes, integrated circuit holding jigs or tubes in semiconductor manufacturing apparatus, then electric

conductivity or antistatic property suitable for each of them are required.

Addition of carbon black or graphite particles to fluororesin is known to impart electric conductivity and antistatic properties to fluororesins. For example, disclosed is a method that mixes Ketjenblack with very few impurities as a conductive carbon black with PFA by a Henschel mixer (see Japanese Kokai Patent Application No. Hei 2[1990]-60954), also disclosed is a method that puts conductive carbon black into PFA whose molecular ends have been fluorinated, then melt-mixes them to lower the electric resistance and to suppress the increase in the melt viscosity (see Japanese Kokai Patent Application No. Hei 6[1994]-1902). In addition, the idea that particles for rendering electric conductivity such as carbon, zinc oxide, tin oxide, and titanium oxide could be dispersed into the fluororesin (PFA) so that the volume resistance value reaches 10 ¹⁴ -10 ¹⁷ Qcm and used as a fixing roll of office automation appliances has been proposed (see for example Japanese Kokai Patent Application No. Hei 6[1994]- 169701 ).

As a filler used to render electric conductivity to fluororesins, carbon black has been well known. However, when a conductive PFA containing carbon black is used in an office automation appliance roll, it is said that the black paper back of carbon is stained or the electric conductivity is excessive in a roller fixing system, making the electrostatic control of a fixing process difficult. On the other hand, if the amount of carbon black, which is mixed to achieve the electric conductivity of the electrostatic diffusive material area (a material that is difficult to be charged, where electric charge is slowly diffused) suitable for many office automation appliance rolls, is decreased, the carbon black is not uniformly dispersed into the resin after molding. It is known that the electric resistance of the conductive fluororesin composition depends largely upon the dispersed state of the particles for rendering electric conductivity as well as the kind or amount of particles for rendering electric conductivity mixed as a filler (see for example Journal of Applied Polymer Science, v. 69, p. 193).

Particularly in a conductive fluororesin composition in an electrostatic diffusive material region where the amount of mixture of particles for rendering electric conductivity is small, if the particles for rendering electric conductivity are not uniformly dispersed, then the electrostatic diffusivity of the molded body is unstable and is sometimes deviated to an insulation area from a semiconductive area. Under this situation, in the fluororesin composition to which the carbon black was added, it is difficult to control the electric conductivity (for example, to finely adjust the electric

conductivity by the increase and decrease in the amount of addition of the carbon black) in the electrostatic diffusive material area or electrostatic insulating material area in accordance with the intended office automation appliance. In addition, for the lining of conductive resins that are used in the chemical industry or food industry, carbon black is preferably not detected as a black foreign matter. Also, if the resin wall is black, fluid in the lining is difficult to see, with the result that a white color is preferable.

Accordingly, the present inventors developed a conductive fluororesin composition, which is stable in electric conductivity of the molded body, has a smooth molding surface, and has a white color, through the search for particles for rendering electric conductivity which can exert stable electrostatic diffusivity and is easily adjusted.

SUMMARY OF INVENTION

The present inventors discovered zinc oxide powder as the material for rendering electric conductivity to solve the aforementioned problems. It was found that when the zinc oxide powder had a specific surface area of 10 m ² /g or smaller, it was uniformly and easily dispersed into a resin, although the amount in the mixture was small, the electric conductivity, specifically electrostatic diffusivity, could be stably rendered to the resin. In addition, it was found that the electrostatic dissipation property, which was rendered by the aforementioned zinc oxide, could be finely adjusted by changing the amount of addition, even if the surface resistance was in the vicinity of 10 ¹¹ Ω/α. A fine adjustment of the electric conductivity in such an electrostatic insulating region has not been achieved up until this invention.

Moreover, zinc oxide powder is generally known to be a material that undesirably causes foaming in the melt-mixing and melt-molding process with a melt processible resin. It was found that this problem could also be suppressed by using the aforementioned zinc oxide powder with a specific surface area of 10 m ² /g or smaller. Therefore, the composition composed of the melt processible fluororesin and the zinc oxide powder with a specific surface area of 10 m ² /g or smaller has stable electric conductivity, is excellent in wear resistance, and has a smooth molding surface due to less foaming when melt processed. Furthermore, it was found that even if the zinc oxide powder of the present invention was added and mixed with the melt processible fluororesin, since the influence (increase) on the melt flow rate (MFR) was small and the electric conductivity could be finely adjusted in accordance with its usage, this composition could be applied to a range of usages such as office automation appliance rolls or tubes represented by pressure rolls of copying machines, printers, and the like, and holding jigs, tubes and the like which are used in manufacturing apparatuses for semiconductors.

The present invention thus relates to a white conductive fluororesin composition characterized in that in a composition in which zinc oxide powder is included in a melt processible fluororesin, the specific surface area of the zinc oxide powder is 10 m ² /g or smaller; also, no substantial foaming is observed on the surface of a string-shaped extruded product (bead) at 372°C of said composition.

In one embodiment, the white conductive fluororesin composition of the present invention includes the zinc oxide powder at a ratio of 5-40 wt%.

In one embodiment, the melt processible fluororesin, which is included in the white conductive fluororesin composition of the present invention, is a copolymer of tetrafluoroethylene and perfluoro(alkyl vinyl ether).

In one embodiment, the present invention relates to a pressure roll for copying machines and printers molded of the aforementioned white conductive fluororesin composition.

According to the present invention, a conductive fluororesin composition, which exhibits a stable semiconductive property with a surface resistance of about 10 ^10~16 Ω/α, melt extrudes resulting in an article with a smooth surface, and can be used in OA rolls or tubes represented by pressure rolls of copying machines, printers, etc., as well as holding jigs and tubes which are used in manufacturing apparatuses for

semiconductors, can be produced.

In addition, this composition can also be applied to interior linings such as ignition prevention PFA pipes of flammable liquids and sanitary pipes such as foods and chemicals.

DETAILED DESCRIPTION OF INVENTION

The conductive fluororesin composition of the present invention includes zinc oxide powder in a melt processible fluororesin. In the present invention "melt processible fluororesin" means a fluororesin that can flow in the molten state and can be molded into products such as films, fibers, and tubes from a molten product by using a conventional well-known melt molding apparatus such as an extruder or injection molding machine, where the molded products can exhibit sufficient strength and durability (toughness) for their utility. The melt processible fluororesin of utility in the present invention, for example, is

tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and

tetrafluoroethylene-ethylene copolymer (ETFE). In particular, the melt processible fluororesin is preferably the tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (alternately referred to herein as PFA). In the tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer, the use of a copolymer with about 1 -10 wt%, especially about 3-8 wt%, of

perfluoro(alkyl vinyl ether) content is preferable, and it is preferable for the alkyl group of perfluoro(alkyl vinyl ether) to have 1 -5 carbons, especially 1 - 3 carbons. Such a PFA copolymer can be prepared based on a

conventional method (see for example, Japanese Kokoku Patent Nos. Sho 48[1973]-2223 and Sho 48[1973]-20788) and can also be commercially obtained. For example, this copolymer is commercialized under the trade names of Teflon (registered trademark) PFA (Du Pont-Mitsui

Fluorochemicals Co., Ltd.), Neoflon (registered trademark) PFA (Daikin Industries, Ltd.), and Fluon (registered trademark) PFA (Asahi Glass Co., Ltd.).

Although there is no particular limitation around the melt viscosity or molecular weight of these melt processible fluororesins, since the viscosity of the resin composition is raised by mixing the zinc oxide powder, a melt processible fluororesin with a melt flow rate (MFR) of about 2-50 g/10 min at 372°C and a load of 5,000 g is preferably used.

In addition, as the melt processible fluororesin to be mixed, an aggregated powder with an average particle diameter of 10 m or smaller, preferably 7 μιτι or smaller, and further preferably 5 μιτι or smaller in which colloidal particles with an average particle diameter of about 0.2 μιτι are aggregated is more preferably used. This aggregated powder, for example, can be obtained by adding an electrolytic substance to an aqueous dispersion of melt processible fluororesin, which is obtained by emulsion-polymerizing about 1 -75 wt% colloidal particles of a melt processible fluororesin with an average particle diameter of about 0.1 -0.3 μιτι into water, aggregating colloidal particles of the melt processible fluororesin while mechanically stirring, separating them from the aqueous medium, washing with water as needed, and drying.

Since the zinc oxide powder of the present invention is white, exhibits a semiconductive property by itself, and exhibits good electric conductivity (e.g., also by doping a conductive substance such as aluminum or gallium on the surface), although it is not as good as carbon black, it is broadly industrially used as a white semiconductive material that is substituted for carbon black. As the zinc oxide powder, there are indefinite particles, which are prepared from electrolytic zinc metallurgy by an indirect method (French process), and petal-shaped or aggregated particles which are prepared from electric furnace dust, etc., by a direct method (American process). The zinc oxide powder, which is used in the present invention, has a specific surface area of 10 m ² /g or smaller and can be prepared by a dry method-French process, so that a smooth surface is attained and impurities are very few. Here, the dry method- French process is a method that oxidizes zinc vapor, which is generated by heating molten metal zinc at about 1 ,000°C in air, thus being able to obtain high-purity zinc oxide. In mixing of zinc oxide and the thermoplastic fluororesin, foaming due to the zinc oxide powder generated by heating during extrusion molding is observed to be a problem. In the present invention, as for the aforementioned problem, it was found that foaming during the molding was suppressed by using indefinite particles prepared, for example, by the dry method-French process, especially using zinc oxide powder with a specific surface area of 10 m ² /g or smaller, thus being able to melt mold a tube or sleeve with a smooth surface. The specific surface area of the zinc oxide used in the present composition has a specific surface area of 10 m ² /g or smaller, for example, is 1 -10, 2-9, 3-8, 4-7, or 5-6 m ² /g, preferably the specific surface area of the zinc oxide used in the present composition is 6 m ² /g or smaller, for example, 1 -6, 2-6, 3-6, and 4-6 m ² /g. Where zinc oxide powder of specific surface area greater than 10 m ² /g is used, melt extrusion undesirably results in foaming at the surface of the extruded article, caused by air, etc., drawn into the zinc oxide powder. The particle diameter of the zinc oxide powder is preferably 0.5-10 μιτι, although it is not particularly limited, but a good product cannot be obtained from fine particles of 20-50 nm because undesirable foaming occurs. In the present invention, "specific surface area" of the zinc oxide powder is a quantity that is indicated by the total of the surface areas of the particles which are included in a unit amount of powder, and it is usually shown by the total surface area SW (m ² /g) of the powder in terms of unit mass. As methods for measuring the specific surface area, there are the known adsorption method, wet heating method, permeation method, and diffusion rate method. Of these known methods, the adsorption method utilizing the adsorption of a gas is most often used. In this method, molecules or ions with a known size are adsorbed to the powder particle surface, and the surface area is calculated from the amount of adsorption by applying a BET isothermal adsorption expression.

A product in which the zinc oxide powder is doped with a different kind of element such as aluminum or gallium to improve the electric conductivity is inappropriate for the molten fluororesin with a molding temperature of 300°C or higher, because foaming occurs during molding. If the zinc oxide of the present invention is mixed with the melt processible fluororesin powder with an average particle diameter of 10 m or smaller, the zinc oxide particles are finely and more uniformly dispersed into the melt processible resin powder. For this reason, the surface state of the molded body to be obtained is smooth and has no foaming, compared with mixtures with other particles for rendering electric conductivity. Even in case this composition is used in wafer holding jigs or solvent lines that are used in semiconductor manufacturing apparatuses, electric conductivity can be rendered. In addition, a conductive fluororesin composition suitable for office automation appliance rolls or tubes represented by fixing rolls of printers, etc., which require a very smooth surface, can be obtained, its wear resistance is also superior to that of conventional products. Although the amount of mixture of the zinc oxide powder depends upon the intended level of electric conductivity, the amount is about 5-40 wt%, preferably 5-30 wt%, more preferably 10-25 wt%, and especially 17- 23 wt% in the composition, based on the combined weight of fluororesin and zinc oxide.

In the conductive fluororesin composition of the present invention, since the zinc oxide powder is very uniformly dispersed into the melt processible fluororesin, the electric resistance is stable and the surface state of the molded body to be obtained is smoother and has good precision, so that this composition can be used to manufacture office automation appliance rolls or tubes represented by fixing rolls of copying machines, printers, and the like, or holding jigs or tubes which are used in manufacturing apparatuses for semiconductors.

To prepare the conductive fluororesin composition of the present invention, the melt processible fluororesin and the zinc oxide powder can be combined and mixed by a high-speed rotary blade. Commercially available mixers having the high-speed rotary blade for mixing these fluororesin powder and zinc oxide powder are for example, the Henschel mixer made by Mitsui Miike Works K.K., "cutter mixer" made by Aikosha Works K.K., "Airitsuhi intensive mixer" made by Nippon Airitsuhi K.K., etc.

In addition, the aforementioned mixing is preferably carried out so that the average particle diameter of the powder composition obtained is 0.5-8 μιτι, preferably about 1 -6 μιτι.

Moreover, since the molded body that is obtained from the conductive fluororesin powder composition into which the zinc oxide powder is uniformly dispersed has a small change in the electric

resistance in the molded body or between the molded bodies, additives for other purposes can be optionally mixed in the conductive fluororesin powder composition of the present invention. As these additives, a powder or fibrous powder such as glass, graphite, carbon black, alumina, mica, silicon carbide, boron nitride, titanium oxide, bismuth oxide, iron oxide, bronze, gold, silver, copper, nickel, stainless steel, and

molybdenum disulfide are of utility. Moreover, nanomaterials such as fullerene (C60) or carbon nanotube can also be mixed as additives. Furthermore, the conductive fluororesin powder composition of the present invention, which is obtained by mixing using a mixer of a highspeed rotary blade under specific conditions, is preferably pelletized through use of a melt extruder and used in extrusion molding, injection molding, transfer molding, and melt molding such as melt spinning. The non-pelletized conductive fluororesin powder composition can also be used as a direct molding raw material, or the powder composition can also be compacted by a compactor and melt-molded to facilitate processing of the powder composition through a molding machine hopper. In addition, the conductive fluororesin powder composition, which is obtained in the present invention, can also be granulated and used as a material for powder molding or coating.

Examples of molded bodies that can be made from the present composition include: pressure roll surfaces of copying machines, etc., which require the control of the electric conductivity, or hoses, tubes, containers, etc., for the transport of flammable substances, which require an antistatic property. In addition, since many usages that require electric conductivity or antistatic property are adopted, although the present invention is not particularly limited, for example, there are conductive jigs related to the semiconductor manufacture, lining of integrated circuit trays, work stands of integrated circuit assembly factories, antistatic mats, antistatic gloves, interior materials for automobiles, antistatic wallpaper, antistatic rollers, antistatic belts, and the like. For example, a pressure roll showing stable electrostatic diffusivity can be manufactured by coating the core metal, etc., of a pressure roll for copying machines and printers, with the conductive fluororesin composition of the present invention. Such a coating can be carried out by methods well known in this field, for example, a coating means such as coating, spraying, and immersion of tubes.

Although the thickness of the coating layer may be appropriately determined, if necessary, 1 μιτι or greater is preferable to exert a sufficient pressure roll performance. In addition, 500 μιτι or smaller is preferable in consideration of cost, heat conductivity, etc. The composition of the present invention can be further

characterized in that no substantial foaming is observed on a string- shaped extruded product (bead) surface at 372°C. In the present invention, "string-shaped extruded product (bead) surface at 372°C" means the surface of a bar-shaped resin product extruded from a cylinder described in Application Example 3.

EXAMPLES

Next, the present invention will be explained in detail by application examples and comparative examples. Here, as the tetrafluoroethylene- perfluoro(alkyl vinyl ether) copolymer (PFA), a tetrafluoroethylene- perfluoropropylvinyl ether (the carbon number of the alkyl group is 3, i.e., perfluoropropylvinyl ether (PPVE)) copolymer was used. Foaming and surface smoothness of molded beads with a conductive fluororesin composition, dispersed state of zinc oxide powder, and static attenuation property and surface resistance of compression molding sheets were measured by the methods described below.

Manufacture Example 1

60 kg of a 30 wt% aqueous PFA dispersion (average particle diameter: 0.2 μιτι, melting point: 309°C, perfluoro(propylvinyl ether) content = 3.5 wt%) obtained by emulsion polymerization was put into a stirring tank (100 L) having a stirring shaft with six sheets of blades of a down-flow type propeller and a drainage means; 500 g of 60% nitric acid was added to it while stirring at 300 rpm. In addition, this mixture was further stirred at 300 rpm for 10 min, after the aqueous dispersion was aggregated, the PFA aggregated particles were floated and lifted on the water layer by stirring at 450 rpm for 20 min to separate them from the water layer.

This water layer was discharged from the stirring tank. Next, water was put into the stirring tank, then the PFA aggregated particles were washed with water and passed through a screen (mesh: 100-150 μιτι) made of stainless steel. The PFA aggregated particles left on the screen were dried at 160°C for 24 h to obtain a fine PFA powder. When the average particle diameter of the fine PFA powder obtained was measured by a laser diffraction type of particle size distribution measurer (Sympatec

GmbH, HEROS & RODOS), it was 2-6 μηη.

This fine PFA powder and zinc oxide-A (ZnO-A) (average particle diameter: 1 μιτι, specific surface area: 4-6 m ² /g) were charged into a mixer (Henschel mixer made by Mitsui Miike Works K.K.) and mixed at the number of rotation of 3,400 rpm for 5 min. For its melt-kneading, this mixture was melt-mixed at 380°C and subjected to a screw rotation of 50 rotations by a melt kneader (25 mm biaxial extruder) made by Toyo Seiki

Co., Ltd., so that a conductive fluororesin powder composition (pellet shape) at each mixture ratio was obtained.

Manufacture Examples 2-6

Zinc oxide powder-B (ZnO-B)with a specific surface area of 10 m ² /g or smaller (average particle diameter: 0.3-1 μιτι, specific surface area : 2-6 m ² /g) was mixed with a melt processible fluororesin at the ratios shown in Table 1 , and conductive fluororesin powder compositions were prepared in the same sequence as that of Manufacture Example 1 .

Comparative Example 1

A melt processible fluororesin was obtained by the same process as that of Manufacture Example 1 and used without adding zinc oxide particles for rendering electric conductivity.

Comparative Example 2

7.5 wt% carbon black as particles for electric conductivity was mixed with a melt processible fluororesin, and a conductive fluororesin powder composition was prepared in the same sequence as that of Manufacture Example 1 . Its melt flow rate (MFR) was changed from 7.8

(g/10 min) to 2.5 (g/10 min) of the melt processible fluororesin; the carbon black having a large influence on the moldability.

Comparative Examples 3-4

Conductive fluororesin powder compositions were prepared in the same sequence as that of Manufacture Example 1 except for mixing zinc oxide powder with a specific surface area of greater than 10 m ² /g.

Application Example 1 - Measurement of electrostatic attenuation characteristic Using the following sequence and measuring appliances, sheets of 150 x 150 x 3 1 were manufactured from the compositions of Manufacture Examples 1 -6 and Comparative Examples 1 -4; the change in the potential generated by rubbing cotton cloth was measured at constant temperature and constant humidity up to a lapse of 600 sec.

Measuring appliances: Current collection type potential measurer KS-525 type + gauge box, made by Kasuga Denki K.K.

Measuring method:

(1 ) Manufacture of sheets of 150 x 150 x 3 t

(2) Cutting-out of 150 x 150 x 3 t (the measuring surfaces are the same)

(3) The sheets are dried at 200°C for 5 h by an oven.

(4) After cooling, the sheets are held for 3 days in an temperature- controlled room (23 ± 2°C, 30 ± 5%) and measured.

(5) The cap of a measuring nozzle in the gauge box is removed, and the power of a device for aligning the nozzle to a position of scale 5 KV is turned on (100 mm from the surfaces of samples) and adjusted to zero.

(6) A rubber hand and a vinyl hand are mounted.

(7) Contact area of gauze and the sample surfaces, 35 x 100 mm

(8) A Teflon (registered trademark) square bar is placed on the gauze, and a fixed load (90 g) is applied to the gauze.

(9) The sample surfaces are rubbed at a speed of one reciprocation (20 mm/s) for 1 sec with the gauze.

(10) After 1 min, the samples are immediately put into the gauze box and start to be measured (10 sec, 30 sec, up to 600 sec).

The results are shown in Table 1 . The compositions of

Manufacture Examples 1 -6 showed stable electrostatic dissipation property (0.37-1 .4 kv) of 1 .5 kv or lower suitable for the usage as a roll for office automation equipment. On the contrary, the composition of

Comparative Example 1 (only/neat PFA) exhibited too low of an electric conductivity (too high insulation), and in the compositions of Comparative Examples 2-4, the potential after 30 sec was already zero, showing too high of an electric conductivity. In addition, in the compositions of

Manufacture Examples 1 -6, it was shown that the electrostatic attenuation characteristic could be controlled within the aforementioned range by regulating the amount of addition of the zinc oxide. Application Example 2 - Measurennent of surface resistance

Similarly to Application Example 1 , sheets of 150 x 150 x 1 .5 t from the compositions of Manufacture Examples 1 -6 and Comparative

Examples 1 -4 were manufactured. When 10-500 V (DC) was applied for 10 sec to the obtained surfaces, a surface resistance measurer (HIRESTA IP) made by Mitsubishi Petrochemical Co., Ltd. was used to measure the surface resistance values (Ω/α) (according to JIS K6991 1 ).

The results are shown in Table 1 . Here, 9 x 10 ¹² Ω/α is the measurement limit, and if the surface resistance exceeds 9 x 10 ¹² Ω/α, "> 10 ¹³ " is indicated in Table 1 . In addition, five arbitrary positions were measured, and their average was adopted as the measured value.

Moreover, for samples with high surface resistance, since the resistance values sometimes exceed the measurement limit, the maximum value, the minimum value, and the average value were adopted as measured values (when the measurement was impossible, the value was excluded, and the average value was calculated).

All of the compositions of Manufacture Examples 1 -6 showed a value greater than the measurement limit (9 x 10 ¹² Ω/α), and it was confirmed that these compositions had electric resistance (generally 10 ¹¹ or greater) required for the usage as a roll for office automation articles. On the contrary, the values measured in Comparative Examples 2-4 were insufficient for the same usage. Simply by adding 7.5 wt% carbon black, the surface resistance value was largely changed 10 ⁴ -10 ⁵ Ω/α

(Comparative Example 2). For this reason, it was confirmed that a fine adjustment of the electric conductivity through the increase and decrease in the amount of addition was difficult.

Application Example 3 - Measurement of melt flow rate (MFR)

Using a melt indexer made by Toyo Seiki Co., Ltd., provided with a corrosion-resistant cylinder, die, and piston based on ASTM D-1238-95, each sample of 5 g was filled in the cylinder with an internal diameter of 9.53 mm held at 372±1°C, held for 5 min, and extruded through an orifice with an internal diameter of 2.1 mm and a length of 8 mm under a load of 5 kg (piston and weight). The extrusion rate (g/10 min) at that time was attained as MFR.

The results are shown in Table 1 . If the MFR is smaller than 1 .6, it is said that a molding inferiority is caused. All of the compositions of Manufacture Examples 1 -6 exceeds this value, and it was confirmed that sufficient moldability was maintained even by adding zinc oxide. Application Example 4 - Evaluation of surface smoothness

Each composition was heated at 275-300°C corresponding to the melting point of the PFA resin used before molding for 10 h, then extruded by about 50 mm under the MFR measurement condition of Application Example 3 of 372°C, so that beads were obtained. The smoothness of their surface state was evaluated with the naked eye.

The results are shown in Table 1 . In the table, O shows a state in which there are no substantial recesses and projections on the surface; X shows a state in which inappropriate recesses and projections exist in terms of molding. In the compositions of Manufacture Examples 1 -6, recesses and projections were not seen after molding, forming a smooth surface.

Tablel

O: No recesses and projections, X : Occurrence of recesses and projections

In the conducive fluororesin composition of the present invention, since conductive zinc oxide powder is dispersed into a melt processible fluororesin, the molded body obtained from the composition exhibits a stable electric resistance, even in a high electric resistance area that has been difficult up to now, and a conductive fluororesin composition molded product with a smoother surface state of the molded body and excellent wear resistance can be manufactured. In addition, even if this

composition is used in wafer holding jigs or solvent lines that are used in semiconductor manufacturing apparatuses, since the conductive particles are not isolated in a liquid of the apparatuses, a conductive fluororesin composition product that does not stain the apparatuses can be

manufactured.

Moreover, the composition of the present invention can be subjected to melt molding such as extrusion molding, injection molding, transfer molding, and melt spinning, thus being able to manufacture a final molded body with the required electric conductivity and electrostatic diffusivity. The type of molded body is not particularly limited in the present invention, for example: tubes, sheets, bars, fibers, packings, conductive jigs related to semiconductor manufacture and the like.