JPH10338790A - Semiconductive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject resin composition having proper volume resistivity and free from fish eye by including a perfluoroalkyl group-containing cesium salt into a thermoplastic resin having a specific relative permittivity. SOLUTION: This resin composition is obtained by including (B) 0.01-5 pts.wt. perfluoroalkyl group-containing cesium salt into (A) 100 pts.wt. thermoplastic resin having >=2.5 relative permittivity measured in 1 kHz frequency at 23 deg.C. Preferably a fluororesin, especially preferably vinylidene fluoride resin is preferably used as the component A. The component B comprises preferably 5-20C, preferably 5-15C perfluoroalkyl group and the component B include e.g. cesium perfluoroalkyl sulfonate. Thereby, a resin composition having proper volume resistivity, uniform distribution of volume resistivity and small dispersion of volume resistivity and not causing change in volume resistivity even when high voltage is repeatedly applied and reduced in fish eye is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a semiconductive resin composition, and more particularly, to a semiconductive resin composition having a moderate volume resistivity,
The semi-conductive resin composition has a uniform volume resistivity distribution, a small variation, a small change in the volume resistivity even when a high voltage is repeatedly applied, a small humidity dependency of the volume resistivity, and a small fish eye. . The semiconductive resin composition of the present invention is suitable as a material for forming at least a surface layer such as a charging roll, a transfer roll, a developing roll, a charging belt, and a discharging belt in an electrophotographic image forming apparatus. Further, the semiconductive resin composition of the present invention is suitable for applications utilizing semiconductivity, antistatic properties, dust adsorption preventing properties, and the like, for example, films for electronic component packaging, wallpaper, exterior materials for OA equipment, and the like. .

[0002]

2. Description of the Related Art In the field of electric and electronic equipment, a resin material capable of precisely controlling static electricity is required. For example, in an image forming apparatus such as an electrophotographic copying machine, a facsimile, a laser beam printer, and the like, an image is formed through respective steps of charging, exposure, development, transfer, fixing, and static elimination. In each of these steps, it is necessary to precisely control static electricity. In an electrophotographic image forming apparatus, generally, a step of uniformly and uniformly charging the surface of a photosensitive drum, a step of forming an electrostatic latent image (electrostatic image) on the surface of the photosensitive drum by exposure, and a developer ( Developing the electrostatic latent image into a visible image (toner image) with toner, transferring the toner on the photosensitive drum onto a transfer material (for example, transfer paper), and pressing and heating the toner on the transfer material. An image is formed by various processes such as a fixing process of fusing and fusing and a cleaning process of cleaning toner remaining on the photosensitive drum.

A charging roll (or belt), a developing roll, a toner layer thickness regulating blade, a transfer roll (or belt), and the like mounted on such an image forming apparatus include:
That the surface layer is semiconductive, specifically 10 ⁵
It is required to have a volume resistivity of about 10 to 10 ¹¹ Ωm. For example, in a charging method using a charging roll, a charging roller to which a voltage is applied is brought into contact with the photosensitive drum to directly apply a charge to the surface of the photosensitive drum to uniformly and uniformly charge. In the developing method using a developing roll, the frictional force between the developing roll and the toner supply roll causes the toner to adhere to the surface of the developing roll in a charged state, and after uniformizing the toner with a toner layer thickness regulating blade, In addition, the electrostatic latent image on the surface of the photosensitive drum is developed by flying with an electric attraction force. In a transfer method using a transfer roll, an electric field is generated by applying a voltage having a polarity opposite to that of the toner to the transfer roll, and the toner on the photoconductor is transferred onto a transfer material by the electrostatic force of the electric field.

Therefore, each member such as a charging roll in an image forming apparatus is required to be semiconductive having a low volume resistivity in an appropriate range. It is necessary that the volume resistivity has a uniform distribution, and if the volume resistivity differs locally, a high-quality image cannot be obtained. For example, if the distribution of the volume resistivity of the charging roll is not uniform, the surface of the photosensitive drum cannot be charged uniformly and uniformly, and the quality of an image is degraded. In addition, high voltage is repeatedly applied to these members, but if the volume resistivity fluctuates significantly, high-quality images cannot be stably obtained. Due to changes in humidity and temperature,
If the volume resistivity of these members fluctuates significantly, high-quality images cannot be stably obtained. It is possible to cope with a change in temperature by warming the device, but it is difficult to cope with a change in humidity under a normal use environment.

Also, OA formed of a polymer material
The exterior materials and parts of the device absorb dust and toner and the like, thereby impairing the appearance and causing a failure. Films and containers for packaging electronic components such as ICs and LSIs are required to have antistatic properties. In order to impart anti-dust and anti-static properties, it is effective to lower the electrical resistivity of the polymer material or its molded product. Conventionally, methods for lowering the electrical resistivity of a polymer material or a molded article thereof include (1) a method of applying an organic antistatic agent to the surface of a molded article, and (2) a method of applying an organic antistatic agent to the polymer material. There are known a method of kneading, (3) a method of kneading a conductive filler such as carbon black or metal powder into a polymer material, and (4) a method of kneading an electrolyte into a polymer material.

However, in the method (1), since the antistatic agent is easily dropped off by wiping or cleaning the surface of the molded article, a long-term antistatic effect cannot be expected. In the method (2), as an organic antistatic agent,
Surfactants and hydrophilic resins are used. In the method using a surfactant, a mechanism that imparts antistatic properties by bleeding out the surfactant from the surface of the molded article is employed. The antistatic property changes greatly. In a method using a hydrophilic resin, it is necessary to mix a large amount of the hydrophilic resin in order to obtain a desired antistatic effect. In addition, there is a problem that the electrical resistivity and the antistatic property are largely dependent on humidity.

The method (3) is employed in many fields. For example, the charging roll is formed by coating a metal core with a semiconductive polymer composite material (composition) in which a conductive filler is kneaded into a polymer material. However, composite materials that are semiconductive by dispersing conductive fillers in a polymer material generally have a very non-uniform distribution of volume resistivity, and the variation is often several orders of magnitude. There was a problem in practical performance. Moreover, a composite material in which a conductive filler is dispersed in a polymer material generally has insufficient withstand voltage, and is not necessarily suitable for applications in which a high voltage is repeatedly applied. In addition, in order to achieve the required level of semi-conductivity by using a conductive filler, it is necessary to increase the filling amount, and therefore, the moldability and mechanical strength of the polymer composite material decrease. Or the hardness becomes too high. Polymer composite materials in which conductive fillers are dispersed are often colored by conductive fillers such as conductive carbon black. Improper.

In the method (4), an alkali metal salt (electrolyte) such as lithium chloride or potassium chloride is kneaded into a polymer material, and the electrical resistivity is reduced by metal ions such as Li ⁺ and K ⁺ . (Japanese Patent Publication No. 63-14017). However, the inorganic metal salt used as the alkali metal salt in this method has poor affinity with the resin,
There was a problem that fish eyes due to agglomerates and the like were easily generated. If the kneading temperature is increased or the kneading time is lengthened to dissolve the agglomerates in the resin, the resin or inorganic metal salt will decompose and impair the practical mechanical properties and appearance. Did not. In the case of a deliquescent metal salt such as a Li salt, if a large amount is filled, the polymer composite material becomes hygroscopic, so that the volume resistivity greatly changes due to a change in humidity, or the metal bleeds out. There is a problem that the surface of the molded article becomes sticky due to salt deliquescence.

On the other hand, polyvinylidene fluoride (PVDF)
Such fluororesins are excellent in heat resistance, weather resistance, chemical resistance, solvent resistance, ozone resistance, stain resistance, non-adhesion and the like. In an electrophotographic image forming apparatus, members that come into contact with toner, such as a charging roll and a developing roll, are likely to cause a phenomenon in which the toner is fused to form a film (filming phenomenon). This phenomenon is unlikely to occur. Therefore, fluororesins are expected to be suitable for applications such as a charging roll, a charging belt, a developing roll, and a transfer roll in an electrophotographic image forming apparatus.

However, fluororesins such as PVDF are:
Like many polymeric materials, it has high electrical resistivity and is not semiconductive. Fluororesins are easily charged by friction. The fluororesin member sucks dust, toner, and the like, thereby impairing the appearance and causing a failure. Conventionally, fluororesins have been used for the surface layer of a fixing roll (heating roll) in an image forming apparatus because they are non-adhesive and have excellent toner release properties, but they are used as a charging member such as a charging roll. There were many problems to be solved. In order to lower the electrical resistivity of the fluororesin such as PVDF to make it semiconductive, the above-mentioned methods (1) to (4) can be applied. However, applying these conventional methods to fluororesin has the following problems in addition to the above-mentioned problems.

Since the fluororesin is excellent in non-adhesiveness, even if the fluororesin molded article is coated with the organic antistatic agent by the method (1), the fluororesin easily falls off. According to the method (2), when a surfactant is kneaded into a fluororesin to form a composite material, the surfactant bleeds out, thereby impairing the stain resistance, which is an advantage of the fluororesin.
In addition, it contaminates other members that come into contact with the fluororesin molded product, and adversely affects the charging characteristics of the toner. In the method of kneading a hydrophilic resin with a fluororesin, the electric resistivity cannot be sufficiently reduced unless a large amount of the hydrophilic resin is blended, so that the ozone resistance and the solvent resistance are reduced.

According to the method (3), the composite material in which the conductive filler is dispersed in the fluororesin has a small surface energy of the fluororesin, so that the conductive filler easily moves in the resin by applying a high voltage. As a result, there is a problem that the volume resistivity fluctuates, and the distribution of the distribution becomes severe. According to the method (4), for example, it has long been known that PVDF is a good conductor of ions (for example, JP-A-51-32330, JP-A-51-110658, 51-1
No. 11337, JP-A-54-127772)
In view of this, it is expected to be effective for imparting semiconductivity to fluororesin. However, when a resin composition obtained by kneading an inorganic metal salt such as lithium chloride or potassium chloride into a fluororesin is used as a charging member such as a charging roll or a belt, the volume resistivity is increased by repeatedly applying a high voltage. There was an inconvenience of doing it. This phenomenon is presumed to be due to the fact that metal ions such as Li ⁺ and K ⁺ gradually move to the negative electrode side due to the application of a high voltage, and the metal ions in the charging member are unevenly distributed.

Conventionally, the amount of the metal salt added is reduced, and
As a method of lowering the volume resistivity, a method of adding lithium perchlorate and a low molecular weight organic solvent as a third component to PVDF has been proposed (Japanese Patent Application Laid-Open Nos. 61-72061 and 61-162545). No.). However, this method cannot satisfy the appearance and mechanical strength of the molded product, and particularly the stickiness of the surface is further deteriorated by the bleed out of the organic solvent. Further, a method has been proposed in which a hygroscopic ionic good solvent solvent resin such as a polyalkylene oxide or an epihalohydrin polymer is added as the third component (JP-A-7-247397, JP-A-8-1).
65395, JP-A-8-176389).
However, in this method, since the hygroscopic resin is added, the humidity dependency of the volume resistivity is large, and the contamination resistance and the ozone resistance are deteriorated.

[0014]

SUMMARY OF THE INVENTION The object of the present invention is to
Has an appropriate volume resistivity of about ⁵ to 10 ¹¹ Ωm, and
It is an object of the present invention to provide a semiconductive resin composition having a uniform volume resistivity distribution, a small variation, and a small fish eye. Another object of the present invention is to have a volume resistivity of about 10 ⁵ to 10 ¹¹ Ωm, a small variation in the volume resistivity, a small change in the volume resistivity even when a high voltage is repeatedly applied, and a volume resistivity. Another object of the present invention is to provide a semiconductive resin composition having a small humidity dependence and a small fish eye. The present inventors have conducted intensive studies to overcome the above-mentioned problems of the prior art. As a result, a perfluoroalkyl sulfone was used as an electrolyte in a thermoplastic resin having a relative dielectric constant of 2.5 or more measured at 1 KHz and 23 ° C. When a perfluoroalkyl group-containing cesium salt such as cesium acid is blended, the above-mentioned properties are remarkably superior to those obtained when a conventional inorganic metal salt such as lithium chloride or potassium chloride is blended. I found what I could get.

The perfluoroalkyl group-containing cesium salt used in the present invention dissolves in a thermoplastic resin having a relative dielectric constant of 2.5 or more measured at 1 kHz and 23 ° C., and is dissolved at a temperature not lower than the glass transition temperature of the resin. It is a compound (electrolyte) exhibiting ion conductivity. It is presumed that the perfluoroalkyl group-containing cesium salt is uniformly dispersed when added to the thermoplastic resin, and that at least a part of the cesium salt is ionized into cations and anions in the resin. The resin composition of the present invention in which a perfluoroalkyl group-containing cesium salt is blended at a predetermined ratio, has a volume resistivity of a semiconductive region,
The characteristics are that the volume resistivity distribution is uniform and the dispersion is small, the volume resistivity does not change even when high voltage is repeatedly applied, the humidity dependency of the volume resistivity is small, the fish eye is small, and the bleed out is small. Have.

These characteristics brought about by the addition of the cesium salt containing a perfluoroalkyl group are unexpected and remarkable, and the thermoplastic resin having a specific dielectric constant and the cesium salt containing a perfluoroalkyl group have a high dielectric constant. It clearly shows the remarkable action and effect by the combination of. The present invention is effective in imparting semiconductivity to a thermoplastic resin having a relative dielectric constant of 2.5 or more, among which a fluororesin,
Furthermore, it is particularly effective when a vinylidene resin is used among the fluororesins. The present invention has been completed based on these findings.

[0017]

Thus, according to the present invention, a perfluoroalkyl group-containing cesium salt is added to 100 parts by weight of a thermoplastic resin having a dielectric constant of 2.5 or more measured at 1 KHz and 23 ° C. A semiconductive resin composition containing 0.01 to 5 parts by weight is provided.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

(Thermoplastic Resin) The thermoplastic resin used in the present invention has a relative dielectric constant at 1 kHz and 23 ° C. of 2.5 or more, preferably 3 or more, more preferably 4 or more. A thermoplastic resin having a relative dielectric constant of less than 2.5 has poor compatibility with a perfluoroalkyl group-containing cesium salt, and it is difficult to dissolve the cesium salt in the resin, and as a result, an appropriate volume It is difficult to obtain a semiconductive resin composition having a resistivity and a small variation in volume resistivity.

Examples of the thermoplastic resin having a relative dielectric constant of 2.5 or more at 1 kHz and 23 ° C. include fluororesin, polyamide resin, vinyl chloride resin, polycarbonate resin, polyester resin (polyethylene terephthalate and the like). Among these, a fluororesin is more preferable. 1
Examples of the fluororesin having a relative dielectric constant of 2.5 or more at 23 kHz at 23 kHz include vinylidene fluoride resin, vinyl fluoride resin, ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene ( PC
TFE), ethylene-chlorotrifluoroethylene (E
CTFE). Among these fluororesins, in terms of the remarkable effect of the moldability and semiconductivity imparting effect,
Vinylidene fluoride resin is particularly preferred.

Examples of the vinylidene fluoride resin include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene. And copolymers. These vinylidene fluoride resins are:
Each can be used alone or in combination of two or more. Among the vinylidene fluoride resins, PVDF, which is a homopolymer of vinylidene fluoride, is preferable from the viewpoints of stain resistance, ozone resistance, and solvent resistance. From the viewpoint of flexibility and tear strength, a vinylidene fluoride copolymer mainly containing vinylidene fluoride is used alone.
Alternatively, it is preferable to use it by blending with PVDF. For the purpose of improving the adhesion, a vinylidene fluoride copolymer having a functional group introduced is also preferably used. The vinylidene fluoride resin may be used by blending with another fluorine resin. Further, a thermoplastic resin other than a fluororesin may be blended as long as the stain resistance, ozone resistance, chemical resistance and the like of the vinylidene fluoride resin are not significantly reduced.

(Perfluoroalkyl Group-Containing Cesium Salt) In the present invention, in order to reduce the electric resistance (volume resistivity) of the thermoplastic resin having a predetermined relative dielectric constant such as a fluororesin, to make it semiconductive. A cesium salt containing a perfluoroalkyl group is blended as an electrolyte. The perfluoroalkyl group-containing cesium salt used in the present invention is a compound containing a perfluoroalkyl group and cesium in the molecule, and is an organic salt having properties as an electrolyte. Examples of the perfluoroalkyl group-containing cesium salt include cesium perfluoroalkylsulfonate, cesium perfluoroalkylcarboxylate, and cesium perfluoroalkylphosphate.

The perfluoroalkyl group-containing cesium salt has usually 5 to 20 carbon atoms, preferably 5 to 1 carbon atoms.
Those containing 5, more preferably 5 to 10 perfluoroalkyl groups are desirable. If the number of carbon atoms in the perfluoroalkyl group is too small, the perfluoroalkyl group-containing cesium salt tends to bleed out, and if it is too large, the effect of imparting conductivity is reduced. These cesium salts containing a perfluoroalkyl group can be used alone or in combination of two or more. In order to balance the effect of imparting conductivity and the suppression of bleed-out, two or more cesium salts containing a perfluoroalkyl group having different molecular weights may be used in combination.
These cesium salts containing a perfluoroalkyl group are
It has excellent compatibility with a thermoplastic resin having a relative dielectric constant of 2.5 or more at 23 kHz and at kHz, has a good effect of reducing volume resistivity, and does not cause coloring of the resin. Among these perfluoroalkyl group-containing cesium salts, cesium perfluoroalkyl sulfonate is particularly preferred.

The mixing ratio of the perfluoroalkyl group-containing cesium salt is based on 100 parts by weight of the thermoplastic resin.
0.01 to 5 parts by weight, preferably 0.05 to 1 part by weight,
More preferably, it is in the range of 0.1 to 0.5 parts by weight. If the proportion of the perfluoroalkyl group-containing cesium salt is too small, the effect of reducing the volume resistivity is small, and if it is too large, the cesium-containing electrolyte may bleed out or the molded article may become cloudy. In the case of a fluororesin such as vinylidene fluoride resin, if the mixing ratio of the perfluoroalkyl group-containing cesium salt is too large, precipitation of aggregates becomes severe, and depending on the type of the resin and processing conditions, decomposition or coloring may occur. is there. When the perfluoroalkyl group-containing cesium salt is cesium perfluoroalkyl sulfonate, a sufficient action and effect can usually be obtained even at a mixing ratio of about 0.1 to 0.5 part by weight.

(Other Additives) Various additives can be added to the semiconductive resin composition of the present invention, if necessary. Examples of the additive include powdery fillers such as talc, mica, silica, alumina, titanium oxide, zinc oxide, iron oxide, aluminum hydroxide, magnesium hydroxide, graphite, organic metal salts, and metal oxides; Fiber filler; and the like. These fillers
It is used within the range not hindering the object of the present invention. In addition, general-purpose additives such as antioxidants, lubricants, plasticizers, organic pigments, inorganic pigments, ultraviolet absorbers, surfactants, inorganic acids, organic acids, pH adjusters, crosslinking agents, coupling agents, etc. It can be used in a range that does not disturb the object of the invention.

(Semiconductive Resin Composition) The semiconductive resin composition of the present invention comprises a cesium salt containing a perfluoroalkyl group in a thermoplastic resin having a relative dielectric constant of 2.5 or more measured at 1 KHz and 23 ° C. Can be uniformly dispersed. The fact that the perfluoroalkyl group-containing cesium salt is uniformly dispersed in the thermoplastic resin can be determined by whether or not a resin composition having a volume resistivity of a desired semiconductive region is obtained. . According to the present invention, the volume resistivity is usually 10 ⁵ to 10 ¹¹ Ωm, preferably 10 ⁷ Ωm.
A semiconductive resin composition in the range of 10 to 10 ¹¹ Ωm, more preferably 10 ⁸ to 10 ¹¹ Ωm can be obtained. The mixing method of each component is not particularly limited. As a specific preferable mixing method, for example, a perfluoroalkyl group-containing cesium salt is dissolved in a mixed solvent of water and a water-soluble solvent, a resin powder is added thereto, and mixed with a mixer such as a mixer. Then, there is a method of drying (in some cases, drying under reduced pressure), and melt-extruding the obtained dried product to form pellets.

For example, when a vinylidene fluoride resin is used as the thermoplastic resin, a perfluoroalkyl group-containing cesium salt is dissolved in warm water to which acetone is added at a ratio of about 5% by volume, and the resin powder is added thereto. After mixing, drying, and then pelletizing the dried product by a melt extrusion method. In the case where the perfluoroalkyl group-containing cesium salt is cesium perfluoroalkyl sulfonate, the same effect can be obtained without directly dissolving in water and dry blending with a resin, but in that case, it is easy to mix as uniformly as possible. Preferably, cesium perfluoroalkylsulfonate is pulverized into a fine powder and then mixed with the resin. Various molding methods such as a melt extrusion method, an injection molding method, a solution casting method, and a coating method can be applied to the molding of the semiconductive resin composition. It is also possible to prepare pellets of a masterbatch containing a high concentration of a cesium salt containing a perfluoroalkyl group, and to process the resin after dilution with a resin as required during molding.

When extruding the semiconductive resin composition of the present invention into a sheet or a seamless belt, a continuous extrusion method is preferably employed. Desirable continuous extrusion of the sheet includes a single or twin screw extruder and T
A method in which a molten resin composition is extruded directly from a lip using a mold die, and cooled and solidified while being closely attached to a cooling drum by an air knife or the like. In particular, when a vinylidene fluoride resin is used, it is desirable to control the cooling temperature within a range of 0 to 100 ° C. As a desirable continuous melt extrusion molding method of a seamless belt,
A method in which a single-screw or twin-screw extruder and a spiral annular die are used to extrude the dies from directly below the lip of the dies, and to control the inner diameter by an internal cooling mandrel method to take out the inner diameter.

In order to form a roll-shaped molded article such as a charging roll using the semiconductive resin composition of the present invention, the semiconductive resin composition is formed into a tube in advance, and then directly formed on a cored bar. Or a method of coating through another layer (for example, another resin layer, an elastomer layer, a primer layer, or the like), or a method of coating a semiconductive resin composition directly on a cored bar or through another layer. A coating method or the like is employed. In addition, films, sheets, tubes, filaments, and other various molded products can be obtained by applying a general melt molding method such as injection molding or extrusion molding to the semiconductive resin composition of the present invention. it can.

The semiconductive resin composition of the present invention can be applied to various application fields requiring antistatic properties, antistatic properties, static elimination properties, semiconductive properties and the like. The semiconductive resin composition of the present invention may be used alone, or may be used in combination with another resin, elastomer, metal, or the like, if necessary. For example, a layer made of the semiconductive resin composition of the present invention and another resin layer can be combined to form a laminated sheet. Although all of the various molded articles may be molded with the semiconductive resin composition of the present invention, in order to impart semiconductivity to the surface of the molded article, only the surface layer of the semiconductive resin composition of the present invention is used. It may be formed of an object.

[0030]

The present invention will be described more specifically below with reference to examples and comparative examples. The method for measuring physical properties is
It is as follows. (1) Thickness The thickness of the molded product was measured using a dial gauge thickness gauge (trade name “DG-911” manufactured by Ono Sokki Co., Ltd.). (2) Volume resistivity The volume resistivity was measured according to JIS K6911. More specifically, a sample is sandwiched by a load of 7 kgf in a resiliency cell having a ring-shaped electrode (trade name “HP16008B” manufactured by Hewlett-Packard Co., Ltd.), and a voltage of 1 kV is applied between the inner electrode and the counter electrode. Was applied in the thickness direction for one minute, and the volume resistivity was measured. The outer diameter of the inner electrode is 26.0 mm, the inner diameter of the outer counter electrode is 38.0 mm, and the outer diameter of the counter electrode is 40.0 mm. The volume resistivity was determined by a measuring device (trade name “HP4339A High Resistance Meter”) manufactured by Hewlett-Packard Co., Ltd. The sample is at room temperature 23 ° C before measurement,
After being left for one day or more in an atmosphere of a humidity of 50%, the measurement was performed in this environment. (3) Calculation of average value The thickness and volume resistivity measurements described above were arbitrarily selected.
The measurement was performed on zero sheet samples, the arithmetic average value was obtained for the thickness, and the maximum value, the minimum value, and the arithmetic average value were obtained for the volume resistivity. (4) Volume resistivity at repeated voltage application The volume resistivity was measured in the same manner as the above-described method of measuring the volume resistivity. However, a cycle of a voltage application time of 10 seconds for a voltage of 100 V and a time period of 10 seconds for a non-electricity application is defined as one cycle,
And the volume resistivity at each voltage application was measured. The application and non-application of the voltage were controlled by a personal computer. (5) Humidity Dependence of Volume Resistivity A constant temperature and humidity chamber of 23 ° C. at a relative humidity of 30%, 50%, 70%, and 90% [manufactured by Nagano Chemical Machine Co., Ltd., trade name “LH30- 13M ”] for 24 hours, and then the volume resistivity was measured by the method described above. However, between the inner electrode and the counter electrode, not 1 kV but 1
A voltage of 0 V was applied for one minute in the thickness direction. (6) Bleed-out The sample was placed in an environment with a temperature of 23 ° C and a relative humidity of 50%.
After standing for days, the presence or absence of bleed-out of the additive was confirmed by visual observation and touch. (7) Fisheye For the sheet sample to be used for measuring the volume resistivity,
The presence or absence of fish eyes was visually observed.

Example 1 53.8 g of potassium perfluorooctanesulfonate [trade name: "F110" manufactured by Dainippon Ink and Chemicals, Incorporated; C ₈ F ₁₇ SO ₃ K] was 700 c.
C was dissolved at 50 ° C. in a mixed solution of acetone / water (mixing ratio = 70 cc / 630 cc) to obtain a solution A. On the other hand, 20 g of cesium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 300 cc of water (5
(0 ° C.). The solution A and the solution B were mixed and stirred to precipitate a white precipitate. After removing water-soluble components from this precipitate by filtration, 3000 cc
, And then dried under reduced pressure at 90 ° C to obtain cesium perfluorooctanesulfonate [C ₈ F
₁₇ SO ₃ Cs]. After dissolving cesium perfluorooctanesulfonate (hereinafter abbreviated as “PFSCs”) in hot water of about 90 ° C. so as to have a composition ratio shown in Table 1, slowly cooled to a temperature of 40 to 50 ° C. Then
Acetone was added in such an amount that the acetone concentration became 5% by volume.
In this solution, polyvinylidene fluoride (PVDF) [trade name “# 850” manufactured by Kureha Chemical Industry Co., Ltd .;
A powder having a relative dielectric constant at 23 ° C. of ε ′ = 10.0] was added. Using a mixer (trade name “Super Mixer” manufactured by Kawada Seisakusho Co., Ltd.), the mixture was stirred and mixed at a rotation speed of 1,000 rpm for about 5 minutes. The mixing ratio between the resin and the solvent is
120 cc of warm water at 40 to 50 ° C. and 10 cc of acetone were used per 0 g.

The obtained mixture was dried in an oven at 100 ° C. for 24 hours, then dried under reduced pressure at 90 ° C. for 5 hours, and then dies using a single screw extruder (Pla Giken Co., Ltd.). At a temperature of 230 ° C., the pellet was formed into a diameter of about 3 mm. The raw material thus pelletized is supplied to a spiral annular die having a lip outer diameter (diameter) of 50 mmφ, a lip clearance of 1 mm, and a die temperature of 230 ° C. using a single screw extruder (Pla Giken Co., Ltd.). It was extruded right below the lip of the die into an annular molten film. While controlling the inner diameter of the extruded annular molten film by an inner diameter sizing ring (40 ° C.), the molten film was pulled directly below by a nip roll. The obtained annular film was cut into a ring having a length of about 400 mm at right angles to the flow axis direction, and then cut open to form a sheet. The thickness of the obtained sheet was 150 μm. A sample was prepared using the sheet thus obtained, and the volume resistivity and the like were measured. Table 1 shows the results.

[Embodiments 2-3] In Embodiment 1, the PF
The procedure was performed in the same manner as in Example 1 except that the blending ratio of SCs was changed as shown in Table 1. Table 1 shows the results.

[Embodiment 4] In Embodiment 1, PVDF was used.
Instead of vinylidene fluoride-hexafluoropropylene copolymer (hereinafter abbreviated as “VDFP”) [trade name “# 2300” manufactured by Kureha Chemical Industry Co., Ltd .; 1 KHz, 23 ° C.
Ε '= 9.8] and PFSC
Example 1 was repeated except that the mixing ratio of s was changed as shown in Table 1. Table 1 shows the results.

[Comparative Examples 1 to 3]
Instead of SCs, an inorganic metal salt cesium chloride (Cs
Cl), lithium chloride (LiCl) or potassium chloride (KCl) were used in the respective proportions shown in Table 1 in the same manner as in Example 1. Table 1 shows the results.

[Comparative Examples 4 to 6]
Instead of SCs, potassium perfluorooctanesulfonate [trade name “F11” manufactured by Dainippon Ink and Chemicals, Inc.
0 "; C ₈ F ₁₇ SO ₃ K] (hereinafter abbreviated as“ PFSK ”)
Or lithium perfluorooctanesulfonate [manufactured by Dainippon Ink and Chemicals, Inc., trade name “F116”; C ₈
F ₁₇ SO ₃ Li] (hereinafter, abbreviated as “PFSLi”) was used in the same manner as in Example 1 except that the mixing ratios shown in Table 1 were used. Table 1 shows the results.

[0037]

[Table 1]

(Footnotes) (1) PVDF: polyvinylidene fluoride [manufactured by Kureha Chemical Industry Co., Ltd., trade name “# 850”, relative dielectric constant ε '= 10.
0] (2) VDFP: vinylidene fluoride-hexafluoropropylene copolymer [trade name “#” manufactured by Kureha Chemical Industry Co., Ltd.
2300 ", relative permittivity ε '= 9.8] (3) PFSCs: cesium perfluorooctanesulfonate (4) PFSK: potassium perfluorooctanesulfonate [trade name" F11 "manufactured by Dainippon Ink and Chemicals, Inc.
0 "] (5) PFSLi: lithium perfluorooctanesulfonate [F1 manufactured by Dainippon Ink and Chemicals, Incorporated.
16 ")

As is evident from the results in Table 1, when a cesium perfluoroalkyl sulfonate is used, a semiconductive resin having an appropriate volume resistivity, a uniform distribution of the volume resistivity, and a small variation. It can be seen that the composition was obtained (Examples 1 to 4). Moreover, the semiconductive resin compositions of Examples 1 to 4 had no fish eyes and no bleed-out of additives. On the other hand, when cesium chloride as an inorganic metal salt is used, a semiconductive resin composition having a uniform volume resistivity distribution and a small variation can be obtained, but the effect of reducing the volume resistivity is small, and fish eye Is observed (Comparative Example 1). When lithium chloride (Comparative Example 2) is used, a resin composition having a large variation in the distribution of volume resistivity is obtained, and when potassium chloride (Comparative Example 3) is used, the effect of reducing the volume resistivity is small. Moreover, fish eyes were observed in all of the resin compositions (Comparative Examples 2 to 3) containing these inorganic metal salts (LiCl, KCl). Furthermore, bleed-out was confirmed in the resin composition containing lithium chloride (Comparative Example 2). In addition, although the organic metal salt contains a perfluoroalkyl group, the use of a potassium salt (Comparative Examples 4 to 5) or a lithium salt (Comparative Example 6) has a small effect of reducing the volume resistivity.

Example 5 and Comparative Examples 7 to 10 In the same manner as in Example 1, samples having the components and composition ratios shown in Table 2 were prepared. For each sample, the volume resistivity at the time of repeated voltage application was measured, and the ratio of the 300th volume resistivity to the 1st cycle volume resistivity was calculated. Table 2 shows the results.

[0041]

[Table 2] (Footnote) (1) PVDF: polyvinylidene fluoride [Kureha Chemical Industry Co., Ltd., trade name "# 850", relative permittivity ε '= 10.
0] (2) PFSCs: cesium perfluorooctanesulfonate (3) PFSK: potassium perfluorooctanesulfonate [trade name “F11” manufactured by Dainippon Ink and Chemicals, Inc.
0 ")

As is evident from the results in Table 2, the use of a perfluoroalkyl group-containing cesium salt provides a semiconductive resin composition having a small change in volume resistivity even when a high voltage is repeatedly applied. (Example 5). In contrast, when the inorganic metal salt cesium chloride is used,
Even when a high voltage is repeatedly applied, a semiconductive resin composition having a relatively small change in volume resistivity is obtained, but fish eyes are observed (Comparative Example 7). When the inorganic metal salt lithium chloride (Comparative Example 8) or potassium chloride (Comparative Example 9) is used, the dependence of the volume resistivity on the number of times of voltage application is large, and fish eyes are observed. Although an organic metal salt containing a perfluoroalkyl group, when a potassium salt is used, the dependency of the volume resistivity on the number of times of voltage application is large, and the effect of reducing the volume resistivity is small (Comparative Example 10).

Example 6 and Comparative Examples 11 to 12 In the same manner as in Example 1, samples having the components and the composition ratios shown in Table 3 were prepared. For each sample, the humidity dependency of the volume resistivity was measured. Table 3 shows the results.

[0044]

[Table 3] (Footnote) (1) PVDF: polyvinylidene fluoride [Kureha Chemical Industry Co., Ltd., trade name "# 850", relative permittivity ε '= 10.
0] (2) PFSCs: cesium perfluorooctanesulfonate

As is evident from the results in Table 3, when a cesium salt containing a perfluoroalkyl group is used, a semiconductive resin composition having a small humidity dependency of volume resistivity can be obtained (Example 6). On the other hand, when the inorganic metal salt cesium chloride (Comparative Example 11) is used, the humidity dependency of the volume resistivity is slightly large, and when lithium chloride (Comparative Example 12) is used, the volume resistivity increases as the humidity increases. Fluctuates rapidly.

[0046]

According to the present invention, a semiconductive resin composition having a moderate volume resistivity of about 10 ⁵ to 10 ¹¹ Ωm, a uniform distribution of the volume resistivity, small variation, and no fish-eye. Things can be provided. The semiconductive resin composition of the present invention is superior in mechanical strength as compared with a conventional method of mixing a conductive filler. Further, a semiconductive resin composition using a fluororesin represented by vinylidene resin is excellent in ozone resistance, stain resistance, moldability, and the like, and is also excellent in the above-mentioned various properties. Therefore, a charging roll in an electrophotographic image forming apparatus,
It is suitable as a material for forming at least a surface layer such as a transfer roll, a developing roll, a charging belt, and a charge removing belt.
In addition, the semiconductive resin composition of the present invention is used for applications utilizing semiconductivity, antistatic properties, dust absorption preventing properties, for example, films for packaging electronic parts, wallpaper, OA equipment exterior materials,
It is suitable as a transfer tube for powder coating materials.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Masami Akatsu 18-13 Kamitamari, Tamari-mura, Niiji-gun, Ibaraki Pref.

Claims (5)

[Claims] 1. A semiconductive material containing 0.01 to 5 parts by weight of a perfluoroalkyl group-containing cesium salt per 100 parts by weight of a thermoplastic resin having a relative dielectric constant of 2.5 or more measured at 1 KHz and 23 ° C. Resin composition. 2. The semiconductive resin composition according to claim 1, wherein the perfluoroalkyl group-containing cesium salt is cesium perfluoroalkyl sulfonate. 3. The semiconductive resin composition according to claim 1, wherein the thermoplastic resin is a fluororesin. 4. The semiconductive resin composition according to claim 3, wherein the fluororesin is a vinylidene fluoride resin. 5. The semiconductive resin composition according to claim 2, wherein the cesium perfluoroalkyl sulfonate contains a perfluoroalkyl group having 5 to 20 carbon atoms.