JP2009139646A - Semiconductive polyimide resin belt and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductive polyimide resin belt which, when used as an intermediate transfer belt or the like in a color image forming apparatus, ensures less dimensional change and less change in electric properties (electric resistance and dielectric constant) due to moisture, can optimally achieve charge stability and charge elimination, and enables to stably obtain high-quality transferred images over a long period of time, and in particular, to provide an intermediate transfer belt comprising the semiconductive polyimide resin belt. <P>SOLUTION: The semiconductive polyimide resin belt contains a carbon black and a polyimide resin, wherein the polyimide resin is prepared by imidizing a biphenyltetracarboxylic acid dianhydride and an aromatic diamine, and the aromatic diamine component contains 50-80 mol% of 4,4'-diamino-p-terphenyl based on the total amount of the aromatic diamine. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductive polyimide resin belt used in an electrophotographic apparatus including a color image forming apparatus, a printer, a facsimile machine, a multifunction machine of these, and a digital printing machine, and a method for manufacturing the same. More specifically, when used as an intermediate transfer belt of a color image forming apparatus, there is little change in dimensions and electrical characteristics (electrical resistance and dielectric constant) due to humidity, and charge charging stability and slow charging are optimally performed. The present invention relates to a semiconductive polyimide resin belt capable of obtaining a high-quality transfer image stably for a long period of time and a method for producing the same.

  In an image forming apparatus using an electrophotographic method, first, a uniform charge is formed on a latent image carrier made of an inorganic or organic photoconductive photosensitive member, and electrostatic charges are generated by a laser or light emitting diode light that modulates an image signal. After the latent image is formed, the electrostatic latent image is developed with charged toner to obtain a visualized toner image. Then, the toner image is electrostatically primary transferred onto the intermediate transfer belt, and the toner image on the intermediate transfer belt is electrostatically secondary transferred onto the recording paper and fixed by heating or pressing. Thus, an intermediate transfer method for obtaining a required reproduced image is known.

  As a semiconductive belt that can be used for an intermediate transfer belt, a polyimide resin film excellent in mechanical properties and heat resistance is blended with a conductive filler.

  As such a semiconductive belt, there is known a conductive polyimide seamless belt obtained by adding conductive carbon black such as acetylene black and ketjen black to polyimide resin having high mechanical strength (see, for example, Patent Document 1). ).

  Also, semi-conductivity in which a high molecular weight polyamic acid solution obtained by reacting 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine is used as a raw material, and a conductive filler is dispersed therein. A polyimide resin belt is known (see, for example, Patent Documents 2 to 4).

  However, since the semiconductive polyimide resin belt described in these patent documents uses a rigid polyimide resin, the rigidity is sufficient, but since it is not flexible, from the end of the belt in long-term use. There is a problem that cracking is likely to occur.

  Furthermore, a high molecular weight polyamic acid solution obtained by reacting 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and flexible 4,4′-diaminodiphenyl ether is used as a raw material, and this is added to pH 2-4. A semiconductive polyimide resin belt in which carbon black is dispersed is known (see, for example, Patent Document 5).

  Also, a method for producing a semiconductive belt comprising a copolymer of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, p-phenylenediamine and 4,4′-diaminodiphenyl ether (for example, a patent Reference 6), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride as tetracarboxylic dianhydrides, p-phenylenediamine and diaminodiphenylsulfone as aromatic diamines And a method for producing a copolymer belt (see, for example, Patent Document 7).

  In Patent Documents 2 to 7, after a polyimide resin precursor solution is applied to the inner peripheral surface of a cylindrical mold and formed by centrifugation, a part of the solvent is removed and part of the imide is formed until the film can support itself. After the conversion, it is manufactured by a method of peeling from the mold and replacing the outer periphery of the tubular mold to remove the solvent and complete the imide conversion reaction.

  When a polyamic acid solution containing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride as a main component is used, after the rotational molding method, the imide conversion will be completed in a state of being attached to the mold. Then, since it peels from the inner surface of the cylindrical mold due to the volume shrinkage force in the solvent volatilization or imidization reaction and the contraction stress due to the strong surface orientation in the imidization reaction, it peels off from the cylindrical mold in the imide conversion process. It is performed by replacing the outer periphery of the tubular mold.

However, when the imide conversion is performed using the tubular mold as described above, the evaporation cannot be completely removed due to the evaporation of the solvent remaining in the peeling belt, and the belt swells by being accumulated between the belt and the tubular mold. Due to the contraction of the belt that occurs during the conversion reaction, there have been problems such as deterioration of belt flatness and waviness.
Japanese Patent Application Laid-Open No. H0577252 JP 7-156287 A Japanese Patent Laid-Open No. 10-63115 JP-A-10-83122 JP 2000-281902 A JP 2003-266454 A JP 2006-206778 A

  The object of the present invention is that, when used as an intermediate transfer belt of a color image forming apparatus, there is little change in dimensions and electrical characteristics (electrical resistance and dielectric constant) due to humidity, and optimal charge stability and slow charging of electric charge. It is also possible to provide a semiconductive polyimide resin belt, particularly an intermediate transfer belt made of the semiconductive polyimide resin belt, which can be used for a long time and can stably obtain a high-quality transfer image for a long period of time.

  As a result of intensive studies to solve the above problems, the present inventor has obtained a semiconductive polyimide resin belt containing carbon black and a polyimide resin, and the polyimide resin has a biphenyltetracarboxylic dianhydride and a fragrance. And the aromatic diamine component contains 4,4′-diamino-para-terphenyl in an amount of 50 to 80 mol% based on the total amount of the aromatic diamine. It has been found that the characteristic semiconductive polyimide resin belt can achieve the above object. Based on this knowledge, further studies have been made and the present invention has been completed.

  That is, this invention provides the following semiconductive polyimide resin belt and its manufacturing method.

Item 1. A semiconductive polyimide resin belt containing carbon black and polyimide resin,
The polyimide resin is obtained by imidizing biphenyltetracarboxylic dianhydride and an aromatic diamine, and the aromatic diamine component converts 4,4′-diamino-para-terphenyl to an aromatic diamine. A semiconductive polyimide resin belt containing 50 to 80 mol% based on the total amount.

  Item 2. The aromatic diamine component is further selected from the group consisting of 4,4′-diaminodiphenyl ether, 4,4′-bis (4-aminophenoxy) biphenyl and bis [4- (4-aminophenoxy) phenyl] ether. Item 2. The semiconductive polyimide resin belt according to Item 1, comprising at least one aromatic diamine.

Item 3. The carbon black is obtained by oxidizing carbon black produced by an oil furnace method. After oxidation, the carbon black has a pH of 2 to 5, a nitrogen adsorption specific surface area of 60 to 150 m ² / g, and a dibutyl phthalate absorption amount. The semiconductive polyimide resin belt according to Item 1 or 2, wherein is 40 to 120 ml / 100 g.

Item 4. Item 4. The intermediate transfer belt of an electrophotographic apparatus comprising the semiconductive polyimide resin belt according to any one of Items 1 to 3, wherein the surface resistivity is 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω / □.

Item 5. A carbon black-dispersed polyamic acid solution composition is prepared by dispersing carbon black in a polyamic acid solution obtained by reacting biphenyltetracarboxylic dianhydride or a derivative thereof and an aromatic diamine in an organic polar solvent, The carbon black-dispersed polyamic acid solution composition is molded into a tubular product by a rotational molding method, and the molded body is heated to imidize by a heat treatment method,
(1) A step of applying the carbon black-dispersed polyamic acid solution composition to the inner peripheral surface of a rotating cylindrical mold,
(2) A process of forming a self-supporting film by heating at a temperature of 80 to 150 ° C. while rotating the cylindrical mold, and (3) attaching the film to the inner peripheral surface of the cylindrical mold. The process of imidating by heating at a temperature of 300 to 350 ° C. in the state,
The manufacturing method characterized by including.

  Hereinafter, the present invention will be described in detail.

1. TECHNICAL FIELD The present invention is a semiconductive polyimide resin belt containing carbon black and a polyimide resin, and the polyimide resin is obtained by imidizing biphenyltetracarboxylic dianhydride and an aromatic diamine. And a semiconductive polyimide resin belt characterized in that the aromatic diamine component contains 50 to 80 mol% of 4,4'-diamino-para-terphenyl with respect to the total amount of the aromatic diamine. .

1.1 Polyimide resin As the biphenyltetracarboxylic dianhydride used in the present invention, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic Acid dianhydrides, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydrides, and derivatives thereof can be mentioned, and these may be used alone or in combination of two or more. Can do. Among these, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride having a highly symmetric molecular chain is likely to have a structure in which several molecular chains are bundled, so that local bending ( This is preferable from the viewpoint that the thickness of the molecular chain increases when the kink occurs, and the yield stress increases.

  The carboxylic dianhydride component used in the present invention preferably contains 50 mol% or more of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride with respect to the total amount of the carboxylic dianhydride component. It is more preferable to contain 80 mol% or more. Moreover, although an upper limit is not specifically limited, It is preferable that it is 100 mol% or less.

  The carboxylic dianhydride component used in the present invention may be any component as long as the biphenyltetracarboxylic dianhydride is a main component, and other than biphenyltetracarboxylic dianhydride as long as the effects of the present invention are not impaired. The carboxylic dianhydride may be included.

  Here, a main component means containing 70 mol% or more with respect to carboxylic dianhydride component whole quantity.

  As an aromatic diamine component used in the present invention, 4,4′-diamino-para-terphenyl is contained in an amount of 50 to 80 mol% with respect to the total amount of aromatic diamine, and 65 to 80 mol% is contained. More preferred. By containing 4,4′-diamino-para-terphenyl in the above range, the concentration of imide groups (rings) in the repeating unit of the polyimide resin can be reduced, the amount of dehydration during imide conversion is reduced, and volume shrinkage Since the force can be reduced, the imidization reaction can be carried out while attached to the mold.

  Other aromatic diamine components include 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 4 , 4′-bis (3-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ether, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, paraphenylenediamine, 2,2 -Bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (para-aminophenoxy) phenyl] hexafluoropropane, etc. Among these, 4,4′-bis (4-aminophenoxy) biphenyl, bis [ - (4-aminophenoxy) phenyl] ether, 4,4'-diaminodiphenyl ether is preferred.

  The method for synthesizing the polyimide resin is not particularly limited, and a commonly used method can be adopted. However, an approximately equimolar amount of the carboxylic dianhydride component and the aromatic diamine component, A method of producing a polyimide precursor solution by reacting in an organic polar solvent and then imidizing by heat treatment is preferred.

  The organic polar solvent is not particularly limited, but an aprotic organic polar solvent is preferable. For example, N-methyl-2-pyrrolidone (hereinafter sometimes referred to as “NMP”), N, N— Dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoamide, 1,3-dimethyl-2-imidazolidinone, and the like, Two or more mixed solvents may be used. Among these, NMP is particularly preferable because it has a boiling point as high as 200 ° C. or more, hardly volatilizes from the film during thermal imidization, and imidization easily proceeds due to the plasticizing effect of the residual solvent.

  The viscosity at 30 ° C. of the polyimide precursor solution is not particularly limited, but is preferably 3.0 to 50 Pa · s, and more preferably 5.0 to 30 Pa · s, for example.

  The non-volatile content of the polyimide precursor solution of the polyimide resin is preferably 15 to 25% by weight.

  As described above, by using a polyimide resin obtained by imidizing biphenyltetracarboxylic dianhydride and aromatic diamine, the balance of rigidity and toughness of the obtained semiconductive polyimide resin belt is good. The belt is preferable because it has excellent durability and the flatness of the belt does not deteriorate even when the belt is run for a long time.

  In the present invention, carbon black is mixed with a polyimide precursor solution to produce a carbon black-dispersed polyimide precursor solution composition (hereinafter referred to as a precursor solution composition). The method is not particularly limited as long as it is a method of uniformly mixing and dispersing in the precursor solution, and examples thereof include a method using a sand mill, a bead mill, an ultrasonic mill, a three rolls, and the like.

  The carbon black content in the precursor solution composition is preferably 15 to 30% by weight, and more preferably 18 to 26% by weight, based on the total solid content in the precursor solution composition.

  Here, the carbon black content in the precursor solution composition is the same as the carbon black content in the semiconductive polyimide resin belt obtained from the solution.

  Therefore, the semiconductive polyimide resin belt of the present invention preferably contains 70 to 85% by weight of polyimide resin, more preferably 74 to 82% by weight.

  It should be noted that an imidazole compound (2-methylimidazole, 1,2-dimethylimidazole, 2-methyl-4-methylimidazole, 2-ethyl-4-methyl) is contained in the composition as long as the effect of the present invention is not adversely affected. Additives such as ethyl imidazole, 2-phenylimidazole) and surfactants (fluorine surfactants, etc.) may be added.

  By the above method, a precursor solution composition in which carbon black is uniformly dispersed can be produced.

  The average particle size of the carbon black dispersed in the precursor solution composition is preferably 0.1 to 0.5 μm, and more preferably 0.3 μm or less. The maximum particle size of the dispersed carbon black is preferably 1 μm or less, and more preferably 0.6 μm or less.

1.2 Carbon Black The carbon black used in the present invention is not particularly limited. For example, the conductive properties were controlled by grafting a polymer on the surface of the carbon black particles or coating an insulating material. Carbon black may be used, and carbon black or the like obtained by oxidizing the surface of the carbon black particles may be used. Among these, carbon black of the oil furnace method is produced by thermally decomposing hydrocarbons in a reducing atmosphere in a high-temperature gas at 1400 ° C or higher where fuel is burned, so that the oxygen content and impurities inside the particles and on the surface are extremely low. It is preferable because crystallites develop. Furthermore, carbon black produced by the oil furnace method is preferably further oxidized, in particular, produced by the oil furnace method, pH 2-5, nitrogen adsorption specific surface area 60-150 m ² / g, And what has a dibutyl phthalate (DBP) absorption amount of 40-120 ml / 100g is preferable. By using such carbon black, it is possible to prevent the occurrence of electric field concentration due to the application of a high voltage. As a result, resistance change due to transfer voltage is prevented, voltage dependence is low, and resistance change due to the environment. A conductive belt with a small amount can be obtained.

  Hereinafter, carbon black produced by further oxidizing the carbon black produced by the oil furnace method will be described.

  Examples of the oxidizing agent used in the oxidation treatment include oxidizing agents such as nitrogen oxides containing nitric acid, ozone, hypochlorous acid, and sulfuric acid gas. Among these, an oxidizing agent containing ozone is preferable, and ozone is particularly preferable from the viewpoint that carbon black after oxidation treatment has little remaining oxidizing agent and undecomposed raw material hydrocarbon (PAH) is decomposed. The undecomposed raw material hydrocarbon (PAH) should be as small as possible, specifically 10 ppm or less.

  Moreover, what adjusted the volatile content of carbon black to 2 to 5 weight% by the oxidation process is preferable, and 2.5 to 5 weight% is more preferable. The surface of carbon black adjusted to 2 to 5% by weight by oxidation treatment contains oxygen functional groups (particularly carboxyl groups) such as phenolic hydroxyl groups, carbonyl groups, and carboxyl groups, so the polyimide precursor solution composition The fluidity and dispersion stability in the product are improved, and the affinity for the polyimide resin is also improved.

  In addition, if the carbon black has the same specific surface area and dibutyl phthalate (DBP) absorption produced by the oil furnace method, the amount of volatile matter and the powder resistance are approximately proportional. Since the oxygen functional group, which is a volatile component on the surface of the carbon black, acts as an insulator that inhibits the flow of π electrons, the powder resistance is higher than that of the carbon black produced by the oil furnace method that has not been oxidized. By setting to this range, the powder resistance of carbon black can be controlled at a high value of about 3 to 30 Ω · cm.

Therefore, when the surface resistivity of the semiconductive polyimide resin belt is set to a desired range (10 ⁸ to 10 ¹⁴ Ω / □), the carbon black is highly filled in the polyimide resin (semiconductive polyimide resin belt ( The total weight of the polyimide resin and carbon black) can be 15 to 30% by weight of carbon black. Thereby, the electroconductivity by the chain | linkage of carbon black is provided and the semiconductive polyimide resin belt which has the stable electrical property which is hard to be influenced by an external environment or an applied voltage can be obtained. In other words, carbon black can be controlled to a high content of 15 to 30% by weight in the semiconductive polyimide resin belt of the present invention.

  The volatile content of carbon black is measured by the method described in the examples.

  Carbon black having a volatile content of less than 2% (for example, Mitsubishi Carbon Black “MA11” “MA100” manufactured by Mitsubishi Chemical Corporation, “Printex 95”, “Printex L6” manufactured by Dexa, etc.) has a high affinity for the polyimide precursor solution. There is a problem and tends to form secondary aggregates by van der Waals force after dispersion.

Carbon blacks with a volatile content exceeding 6% (for example, “Color Black FW200”, “Special Black 5”, “Special Black 4”, “Printex 150T”, etc., manufactured by Dexa) are mostly carbon black of the channel method. In addition to oxygen and oxygen, there are many impurities such as sulfur and undecomposed raw material hydrocarbons (PAH), and these impurities tend to degrade the original mechanical properties of binder resins such as polyimide resins. In addition, when it is an oil furnace carbon black that is oxidized at a volatile content exceeding 6%, the powder resistance is greatly increased (because it becomes insulating carbon black), so the surface resistivity required as an intermediate transfer belt is required. There is a tendency that 10 ⁸ to 10 ¹⁴ Ω / □ cannot be realized.

Carbon black used in the present invention preferably has a nitrogen adsorption specific surface area (JIS K6217) is 60~150m ² / g, more preferably 80~150m ² / g, in 90~130m ² / g More preferably.

  Generally, when carbon black is oxidized by various methods, more oxygen functional groups are imparted as the specific surface area increases. However, the powder resistance of carbon black and the physical properties when blended with various materials are correlated with the number of oxygen functional groups imparted to the unit surface, not the absolute amount of oxygen functional groups.

When the nitrogen adsorption specific surface area is less than 60 m ² / g, there is a tendency that affinity with the polyimide precursor solution cannot be obtained and the powder resistance does not become a sufficiently high value. Further, if it exceeds 150 m ² / g, carbon black with a high specific surface area, that is, carbon black with primary particles being small or having pores even at the same particle diameter, and even when oxygen functional groups are added, carbon is eventually obtained. Since the powder resistance of black does not increase, there is a tendency that a semiconductive polyimide resin belt having a high carbon black content (for example, filled at a high concentration of 15% by weight or more) cannot be obtained. That is, there is a tendency that only a semiconductive polyimide resin belt having a low carbon black filling amount can be obtained.

  The pH of the carbon black used in the present invention is preferably 2 to 5, more preferably 2 to 4, and still more preferably 2 to 3.

  The carbon black used in the present invention has a dibutyl phthalate (DBP) absorption amount of preferably 40 to 120 ml / 100 g, more preferably 40 to 100 ml / 100 g, and 50 to 90 ml / 100 g. Is more preferable. If the DBP absorption exceeds 120 ml / 100 g, the powder resistance of carbon black does not increase even when oxidation treatment is performed, so a semiconductive polyimide resin belt filled with carbon black at a high concentration of 15% by weight or more is obtained. There is no tendency. When the DBP absorption amount is less than 40 ml / 100 g, the powder resistance becomes too high, so that the semiconductive polyimide resin belt cannot be obtained unless the carbon black concentration in the solid content exceeds 30% by weight.

The surface resistivity of the semiconductive copolymer polyimide belt of the present invention is preferably 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω / □, and preferably 1 × 10 ⁹ to 1 × 10 ¹⁴ Ω / □. More preferably, it is 1 × 10 ¹⁰ to 1 × 10 ¹³ Ω / □. It is preferable for the surface resistivity to be in this range, since charges are not accumulated on the intermediate transfer belt, and it is possible to achieve both suppression of toner scattering that occurs during transfer and the self-discharge function of the intermediate transfer belt.

  The flatness in the belt width direction of the semiconductive polyimide resin belt of the present invention is preferably 2 mm or less, and more preferably 1.5 mm or less. When the flatness is within this range, the adhesion between the driving roll for driving the belt and the intermediate transfer belt is maintained, and high-precision image alignment is possible. Here, flatness means a value measured by the method described in the examples.

  Moreover, the manufacturing method of the semiconductive polyimide resin belt of the present invention is not particularly limited, but is preferably manufactured by the following method.

2. The present invention relates to a method for producing a conductive polyimide resin belt. In the present invention, carbon black is dispersed in a polyamic acid solution obtained by reacting biphenyltetracarboxylic dianhydride or a derivative thereof and an aromatic diamine in an organic polar solvent. A semiconductive polyimide resin belt prepared by preparing a carbon black-dispersed polyamic acid solution composition, molding the carbon black-dispersed polyamic acid solution composition into a tubular product by a rotational molding method, and imidizing the molded body by heat treatment A manufacturing method of
(1) A step of applying the carbon black-dispersed polyamic acid solution composition to the inner peripheral surface of a rotating cylindrical mold,
(2) A process of forming a self-supporting film by heating at a temperature of 80 to 150 ° C. while rotating the cylindrical mold, and (3) attaching the film to the inner peripheral surface of the cylindrical mold. The process of imidating by heating at a temperature of 300 to 350 ° C. in the state,
It is related with the manufacturing method characterized by including.

  Hereinafter, a method for producing a semiconductive polyimide resin belt using a carbon black-dispersed polyimide precursor solution composition (hereinafter referred to as a precursor solution composition) will be described.

  In addition, as a precursor solution composition used with the said manufacturing method, any precursor solution composition described in this specification can be used conveniently.

  The precursor solution composition is applied to the inner peripheral surface of a rotating cylindrical mold with a uniform thickness. The rotational speed of the cylindrical mold is not particularly limited, but it is preferable to rotate at a low speed with a centrifugal acceleration of 0.5 to 10 times the gravitational acceleration. With low-speed rotation of 0.5-10 times the acceleration of gravity and low-speed rotation of the precursor solution composition, the shear force applied in the rotation direction is small, and the orientation of molecular chains and the structure orientation of fillers such as carbon black Can be suppressed.

  If the centrifugal acceleration is less than 0.5 times the gravitational acceleration, there is a risk that the supplied precursor solution composition may flow down (sag) without being in close contact with the inner peripheral surface of the cylindrical mold. On the other hand, if the acceleration is greater than 10 times the gravitational acceleration, the flow of the precursor solution composition due to centrifugal force occurs in addition to the orientation of molecular chains due to the shearing force in the rotational direction received during supply and the structure orientation of fillers such as carbon black. However, it tends to affect the flatness.

  The centrifugal acceleration (G) used in the present invention is derived from the following equation.

G (m / s ² ) = r · ω ² = r · (2 · π · n) ²
Here, r is the radius (m) of the cylindrical mold, ω is the angular velocity (rad / s), and n is the number of rotations in one second (the number of rotations in 60 seconds is r.p.m.). The gravitational acceleration (g) to be compared is 9.8 (m / s ² ).

  The precursor solution composition supply means is configured to uniformly distribute the precursor solution composition on the inner peripheral surface of the cylindrical mold by moving it in the direction of the axis of rotation of the cylindrical mold rotating while being discharged by a nozzle method or a spray method. Apply by thickness. Here, the uniform thickness refers to coating on the inner peripheral surface of the cylindrical mold in a range of ± 5% with respect to the coating average thickness.

  As a means for supplying the precursor solution composition, the precursor solution composition is atomized so that the flow during supply is as small as possible and can be instantaneously adhered to the inner peripheral surface of the rotating cylindrical mold. The material can be supplied at the same rotational speed without being greatly affected by the viscosity of the body solution composition, a thin coating film can be easily obtained, and the concentration of the non-volatile content of the precursor solution composition can be set high. The spray method is preferable because it is possible.

  The shape of the coating head is not particularly limited, and can be used as appropriate, such as a circle or a rectangle. Further, the size thereof is not particularly limited, and it can be designed to have an appropriate discharge pressure depending on the combination with the viscosity of the precursor solution composition to be discharged.

  The distance between the spray head and the cylindrical mold may be arbitrary, and is preferably about 5 to 200 mm. There is no particular limitation on the discharge pressure method, but a compressed air or a high viscosity liquid-compatible MONO pump, gear pump, or the like is used.

  In this way, when the precursor solution composition is applied to the inner peripheral surface of the cylindrical mold with a uniform thickness, the precursor solution composition is flowed by high-speed rotation of the cylindrical mold, that is, centrifugal force. It is not necessary to make the thickness uniform. In rotational molding using centrifugal force, after the raw material is supplied, the precursor solution composition is uniformly cast on the inner surface of the cylindrical mold by centrifugal force. Then, the carbon black particles are lined up as if the structure was formed in the flow direction by the flow caused by the centrifugal force. Therefore, this may cause an adverse effect on the electrical characteristics of the polyimide intermediate transfer belt. On the other hand, according to the method of the present invention which does not rotate at high speed, such a problem hardly occurs.

  It is preferable to apply a release agent to the inner peripheral surface of the cylindrical mold so that the polyimide resin does not adhere. Although there is no restriction | limiting in the kind of mold release material, there will be no limitation in particular if it is not attacked by the solvent of a precursor solution composition, the water vapor | steam generated from resin at the time of a heating reaction, etc.

  In the liquid resin film forming step, the solvent is volatilized and solidified at a temperature of 80 to 150 ° C. (preferably 100 to 140 ° C.) while rotating at a low speed with a centrifugal acceleration of 0.5 to 10 times the weight acceleration. By setting the partial concentration to 40% by weight or more, it can be achieved by forming a film having self-supporting property on the inner peripheral surface of the cylindrical mold.

  In the polyimide resin film forming step, the temperature rises to about 250 ° C. in 60 to 120 minutes while remaining attached to the inner peripheral surface of the cylindrical mold, although it varies depending on the type of polyimide resin. Next, the polyimide resin film can be formed by heating the film at a temperature at which the polyimide is completely converted, for example, at 300 to 350 ° C. for 30 to 90 minutes. By performing the film formation while adhering to the inner peripheral surface of the cylindrical mold, it is possible to suppress the shrinkage caused by the imidization reaction or solvent volatilization and to uniformly align the polymer chains in the in-plane direction with the stress.

  As described above, the precursor solution composition used in the present invention has a high solid content concentration, and further contains carbon black at a high content. Furthermore, the semiconductive polyimide resin belt molded using this has a high carbon black concentration, and the original mechanical properties (toughness, etc.) of the polyimide resin are sufficiently retained.

  The average film thickness of the obtained semiconductive polyimide resin belt is usually adjusted to about 50 to 150 μm, preferably about 60 to 125 μm.

  When the semiconductive polyimide resin belt of the present invention thus manufactured is used as, for example, an intermediate transfer belt of a color image forming apparatus of an electrophotographic apparatus, cracks and cracks due to a load applied in the width direction of the belt are hardly generated. It is excellent in durability and can exhibit excellent mechanical properties that can be used stably even after running for a long time.

  The semiconductive polyimide resin belt of the present invention is effective as a belt base material for an intermediate transfer belt of an electrophotographic apparatus, and a transfer and fixing belt that combines transfer and fixing with a single belt. When used as a transfer and fixing belt, it is effective to form a non-adhesive resin film on the surface in order to improve the releasability of the toner adhering to the surface. Examples of the non-adhesive resin film material include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). A fluorine-based resin or the like is preferable. Further, an elastic silicone resin, a fluororubber resin, an elastic fluorosilicone resin, an elastic polysiloxane, or the like may be used.

  The semiconductive polyimide resin belt of the present invention has little dimensional change due to humidity and changes in electrical characteristics (electrical resistance and dielectric constant) when used as an intermediate transfer belt of a color image forming apparatus, and charge charging stability. Can be optimally performed, and a high-quality transfer image can be obtained stably over a long period of time. Further, it is effective as a belt base material for an intermediate transfer belt and a transfer / fixing belt in which a single belt has both transfer and fixing.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example with a comparative example, this invention is not limited to these Examples.

Example 1
(Preparation of carbon black-dispersed polyimide precursor solution composition)
100 mol% of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) based on the total carboxylic dianhydride component and 4,4'- based on the total aromatic diamine component 70 mol% of diamino-para-terphenyl and 30 mol% of 4,4′-diaminodiphenyl ether (DADE) were added in an approximately equimolar amount of carboxylic dianhydride component and aromatic diamine component to N-methyl-2- Polymerization in pyrrolidone was performed to prepare 2 kg of a polyimide precursor polyamic acid solution. This solution had a viscosity of 6.0 Pa · s (30 ° C.) and a nonvolatile content concentration of 18% by weight.

To this solution, 0.1 kg of oil furnace carbon black (CB1: pH 4.1, nitrogen adsorption specific surface area 95 m ² / g, DBP absorption 65 ml / 100 g, volatile content 2.1 wt%) and N-methyl- 2-pyrrolidone 0.8 kg was added, and carbon black was uniformly dispersed by a ball mill to prepare a carbon black-dispersed polyimide precursor solution A (hereinafter referred to as precursor solution composition A). The solid content concentration of this solution was 15.9% by weight, and the carbon black content in the solid content weight was 21.7% by weight. The average particle size of carbon black in the solution was 0.28 μm, and the maximum particle size was 0.51 μm.

(Production of carbon black filled polyimide seamless belt)
The precursor solution composition A was applied to the inner peripheral surface of a cylindrical mold having an outer diameter of 324 mm, an inner diameter of 300 mm, and a length of 500 mm by a spray method, and a centrifugal acceleration (about 154 rpm) of 4.0 times the weight acceleration. , A uniform developed film having a length of 480 mm was obtained on the inner peripheral surface of a cylindrical mold having a length of 500 mm. The coating thickness was calculated from the nonvolatile content concentration, and was determined so that the thickness of the polyimide resin belt was 70 μm. Thereafter, while rotating at a centrifugal acceleration (about 154 rpm) of 4.0 times the weight acceleration, the temperature was raised to 120 ° C. over 30 minutes, and then kept at 120 ° C. for 100 minutes to volatilize the solvent.

  Next, this tubular product is put into a high-temperature heating furnace while adhering to the inner peripheral surface of the cylindrical mold, and the temperature is raised to 320 ° C. over 150 minutes (temperature increase rate: about 1.3 ° C./min). Polyimide conversion was completed by heating at 60 ° C. for 60 minutes. Then, it cooled to room temperature and peeled from the metal mold | die inner surface, and obtained the carbon black filling polyimide seamless belt with an average thickness of 70 micrometers.

Example 2
(Preparation of carbon black-dispersed polyimide precursor solution)
100 mol% of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) based on the total carboxylic dianhydride component and 4,4'- based on the total aromatic diamine component 50% by mole of diamino-para-terphenyl and 50% by mole of 4,4′-bis (4-aminophenoxy) biphenyl are mixed with N-methyl in an approximately equimolar amount of a carboxylic dianhydride component and an aromatic diamine component. Polymerization in -2-pyrrolidone was performed to prepare 2 kg of a polyamic acid solution of a polyimide precursor. This solution had a viscosity of 7.0 Pa · s (30 ° C.) and a nonvolatile content concentration of 18% by weight.

To this solution, 0.09 kg of oil furnace carbon black (CB2: pH 2.5, nitrogen adsorption specific surface area 120 m ² / g, DBP absorption 105 ml / 100 g, volatile content 3.9 wt%) and N-methyl- 2-pyrrolidone 0.8 kg was added, and carbon black was uniformly dispersed by a ball mill to prepare a carbon black-dispersed polyimide precursor solution composition B (hereinafter referred to as precursor solution composition B). The solid content concentration of this solution was 15.6% by weight, and the carbon black content in the solid content weight was 20.0% by weight. The average particle size of carbon black in the solution was 0.26 μm, and the maximum particle size was 0.44 μm.

(Production of carbon black filled polyimide seamless belt)
A carbon black-filled polyimide seamless belt (average film thickness: 70 μm) was produced in the same manner as in Example 1 except that the precursor solution composition B was used.

Example 3
(Preparation of carbon black-dispersed polyimide precursor solution)
100 mol% of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) based on the total carboxylic dianhydride component and 4,4'- based on the total aromatic diamine component 80 mol% of diamino-para-terphenyl and 20 mol% of bis [4- (4-aminophenoxy) phenyl] ether are mixed with N-methyl in an approximately equimolar amount of the carboxylic dianhydride component and the aromatic diamine component. Polymerization in -2-pyrrolidone was performed to prepare 2 kg of a polyamic acid solution of a polyimide precursor. This solution had a viscosity of 5.0 Pa · s (30 ° C.) and a nonvolatile content concentration of 18% by weight.

In this solution, 0.11 kg of oil furnace carbon black (CB3: pH 2.3, nitrogen adsorption specific surface area 120 m ² / g, DBP absorption 75 ml / 100 g, volatile content 3.3 wt%) and N-methyl- 2-pyrrolidone 0.8 kg was added, and carbon black was uniformly dispersed by a ball mill to prepare a carbon black-dispersed polyimide precursor solution composition C (hereinafter referred to as precursor solution composition C). The solid content concentration of this solution was 16.2% by weight, and the carbon black content in the solid content weight was 23.4% by weight. The average particle size of carbon black in the solution was 0.26 μm, and the maximum particle size was 0.44 μm.

(Production of carbon black filled polyimide seamless belt)
A carbon black filled polyimide seamless belt (average film thickness: 70 μm) was produced in the same manner as in Example 1 except that the precursor solution composition C was used.

Comparative Example 1
(Preparation of carbon black-dispersed polyimide precursor solution)
100 mol% of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) with respect to the total carboxylic dianhydride component and paraphenylenediamine (PPD) with respect to the total aromatic diamine component ) 100 mol% was polymerized in N-methyl-2-pyrrolidone in approximately equimolar amounts of a carboxylic dianhydride component and an aromatic diamine component to prepare 2 kg of a polyamic acid solution of a polyimide precursor. This solution had a viscosity of 5.5 Pa · s (30 ° C.) and a nonvolatile content concentration of 18.5% by weight.

Degussa carbon black “Special Black 4 (SB4)” (pH 3.0, nitrogen adsorption specific surface area 180 m ² / g, DBP absorption 230 ml / 100 g, volatile content 14.5 wt. %) 0.06 kg and N-methyl-2-pyrrolidone 0.6 kg were added, and carbon black was uniformly dispersed by a ball mill, and carbon black-dispersed polyimide precursor solution composition D (hereinafter referred to as precursor solution composition). D). The solid content concentration of this solution was 16.2% by weight, and the carbon black content in the solid content weight was 14.0% by weight. The average particle size of carbon black in the solution was 0.30 μm, and the maximum particle size was 0.55 μm.

(Production of carbon black filled polyimide seamless belt)
An attempt was made to produce a carbon black-filled polyimide seamless belt (film thickness: 70 μm) using the precursor solution composition D in the same manner as in Example 1, but the centrifugal acceleration (about 154 r) was 4.0 times the weight acceleration. .pm), the temperature was raised to 120 ° C. over 30 minutes, and then the solvent was volatilized by holding at 120 ° C. for 100 minutes. As a result, a self-supporting film (polyimide precursor) was removed from the cylindrical mold. The belt) has come off naturally.

  Therefore, an aluminum tubular mold having an outer diameter of 295 mm and a length of 420 mm was inserted inside the self-supporting film peeled off from the cylindrical mold. Thereafter, the temperature was raised to 350 ° C. over 180 minutes, and the polyimide conversion was completed by heating at 350 ° C. for 60 minutes at a high temperature. Then, it cooled to room temperature, removed from the tubular metal mold | die, and obtained the carbon black filling polyimide seamless belt with an average thickness of 71 micrometers.

Comparative Example 2
(Preparation of carbon black-dispersed polyimide precursor solution)
100 mol% of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) based on the total carboxylic dianhydride component and 4,4'- based on the total aromatic diamine component 30 mol% of diaminodiphenyl ether (DADE) and 70 mol% of paraphenylenediamine (PPD) were polymerized in N-methyl-2-pyrrolidone in approximately equimolar amounts of a carboxylic dianhydride component and an aromatic diamine component. 2 kg of a polyamic acid solution of a polyimide precursor was prepared. This solution had a viscosity of 5.0 Pa · s (30 ° C.) and a nonvolatile content concentration of 18% by weight.

  To this solution, 0.07 kg of Degussa carbon black “Special Black 4 (SB4)”, which is the channel carbon black used in Comparative Example 1, and 0.6 kg of N-methyl-2-pyrrolidone were added. Black was uniformly dispersed to prepare a carbon black-dispersed polyimide precursor solution composition E (hereinafter referred to as precursor solution composition E). The solid content concentration of this solution was 16.1% by weight, and the carbon black content in the solid content weight was 16.3% by weight. The average particle size of carbon black in the solution was 0.29 μm, and the maximum particle size was 0.55 μm.

(Production of carbon black filled polyimide seamless belt)
A carbon black filled polyimide seamless belt (film thickness: 71 μm) was prepared in the same manner as in Comparative Example 1 except that the precursor solution E was used.

Comparative Example 3
(Preparation of carbon black-dispersed polyimide precursor solution)
100 mol% of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) based on the total carboxylic dianhydride component and 4,4'- based on the total aromatic diamine component A polyamic acid solution of a polyimide precursor is obtained by polymerizing 100 mol% of diamino-para-terphenyl in N-methyl-2-pyrrolidone in approximately equimolar amounts of a carboxylic dianhydride component and an aromatic diamine component. 2 kg was prepared. This solution had a viscosity of 6.0 Pa · s (30 ° C.) and a nonvolatile content concentration of 18% by weight.

  To this solution, 0.06 kg of Degussa carbon black “Special Black 4 (SB4)” used in Comparative Example 1 and 0.6 kg of N-methyl-2-pyrrolidone were added. Black was uniformly dispersed to prepare a carbon black-dispersed polyimide precursor solution composition F (hereinafter referred to as precursor solution composition F). The solid content concentration of this solution was 15.8% by weight, and the carbon black content in the solid content weight was 14.3% by weight. The average particle size of carbon black in the solution was 0.26 μm, and the maximum particle size was 0.55 μm.

(Production of carbon black filled polyimide seamless belt)
A carbon black-filled polyimide seamless belt (film thickness: 70 μm) was prepared in the same manner as in Example 1 except that the precursor solution composition F was used, but the centrifugal acceleration (4.0 times the weight acceleration) While rotating at about 154 rpm, the temperature was raised to 120 ° C. over 30 minutes, and then the solvent was evaporated by holding at 120 ° C. for 100 minutes. As a result, a self-supporting film (polyimide) was obtained from the cylindrical mold. The precursor belt) was peeled off naturally and was broken into powder.

Comparative Example 4
(Preparation of carbon black-dispersed polyimide precursor solution)
100 mol% of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) based on the total carboxylic dianhydride component and 4,4'- based on the total aromatic diamine component 90 mol% of diamino-para-terphenyl and 10 mol% of 4,4'-diaminodiphenyl ether (DADE) are mixed with N-methyl-2-pyrrolidone in approximately equimolar amounts of a carboxylic dianhydride component and an aromatic diamine component. Polymerization was conducted in 2 kg of a polyamic acid solution of a polyimide precursor. This solution had a viscosity of 6.0 Pa · s (30 ° C.) and a nonvolatile content concentration of 18% by weight.

  To this solution, 0.1 kg of CB1 used in Example 1 and 0.8 kg of N-methyl-2-pyrrolidone were added, and carbon black was uniformly dispersed by a ball mill. And a precursor solution composition G). The solid content concentration of this solution was 15.9% by weight, and the carbon black content in the solid content weight was 21.7% by weight. The average particle size of carbon black in the solution was 0.27 μm, and the maximum particle size was 0.55 μm.

(Production of carbon black filled polyimide seamless belt)
A carbon black-filled polyimide seamless belt (film thickness: 70 μm) was prepared in the same manner as in Example 1 except that the precursor solution composition G was used, but the centrifugal acceleration (4.0 times the weight acceleration) While rotating at about 154 rpm, the temperature was raised to 120 ° C. over 30 minutes, and then the solvent was evaporated by holding at 120 ° C. for 100 minutes. As a result, a self-supporting film (polyimide) was obtained from the cylindrical mold. The precursor belt was peeled off naturally and was damaged.

Comparative Example 5
(Preparation of carbon black-dispersed polyimide precursor solution)
100 mol% of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) based on the total carboxylic dianhydride component and 4,4'- based on the total aromatic diamine component 20 mol% of diamino-para-terphenyl and 80 mol% of 4,4′-diaminodiphenyl ether (DADE) were added in an approximately equimolar amount of a carboxylic dianhydride component and an aromatic diamine component to N-methyl-2- Polymerization in pyrrolidone was performed to prepare 2 kg of a polyimide precursor polyamic acid solution. This solution had a viscosity of 5.0 Pa · s (30 ° C.) and a nonvolatile content concentration of 18% by weight.

  To this solution, 0.06 kg of Degussa carbon black “Special Black 4 (SB4)” used in Comparative Example 1 and 0.6 kg of N-methyl-2-pyrrolidone were added. Black was uniformly dispersed to prepare a carbon black-dispersed polyimide precursor solution composition H (hereinafter referred to as precursor solution composition H). The solid content concentration of this solution was 15.8% by weight, and the carbon black content in the solid content weight was 14.3% by weight. The average particle size of carbon black in the solution was 0.26 μm, and the maximum particle size was 0.55 μm.

(Production of carbon black filled polyimide seamless belt)
A carbon black filled polyimide seamless belt (film thickness: 70 μm) was prepared in the same manner as in Comparative Example 1 except that the precursor solution H was used.

Comparative Example 6
(Preparation of carbon black-dispersed polyimide precursor solution)
100 mol% of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) based on the total carboxylic dianhydride component and 4,4'- based on the total aromatic diamine component 40 mol% of diamino-para-terphenyl and 60 mol% of 4,4′-diaminodiphenyl ether (DADE) were added in an approximately equimolar amount of a carboxylic dianhydride component and an aromatic diamine component, and N-methyl-2- Polymerization in pyrrolidone was performed to prepare 2 kg of a polyimide precursor polyamic acid solution. This solution had a viscosity of 5.0 Pa · s (30 ° C.) and a nonvolatile content concentration of 18% by weight.

  To this solution, 0.1 kg of CB1 used in Example 1 and 0.8 kg of N-methyl-2-pyrrolidone were added, and carbon black was uniformly dispersed by a ball mill. Precursor solution composition I) was prepared. The solid content concentration of this solution was 15.9% by weight, and the carbon black content in the solid content weight was 21.7% by weight. The average particle size of carbon black in the solution was 0.27 μm, and the maximum particle size was 0.55 μm.

(Production of carbon black filled polyimide seamless belt)
A carbon black filled polyimide seamless belt (average film thickness: 70 μm) was prepared in the same manner as in Example 1 except that the liquid raw material I was used.

  The following characteristics were evaluated about the polyimide seamless belt obtained from the above Examples 1-3 and Comparative Examples 1-6. The results are shown in Tables 1-3.

  Measurement of each physical property value described in this specification was performed as follows.

<Measurement of solid content concentration in carbon black-dispersed polyimide precursor solution composition>
The solid content concentration in the carbon black-dispersed polyimide precursor solution composition is a value calculated as follows. The sample is precisely weighed in a heat-resistant container such as a metal cup, and the weight of the sample at this time is defined as A (g). The heat-resistant container containing the sample is put in an electric oven, heated and dried while sequentially heating at 120 ° C. × 15 minutes, 180 ° C. × 15 minutes, and 300 ° C. × 30 minutes. The weight (nonvolatile content) is B (g). The values of A and B of five samples for the same sample were measured (n = 5) and applied to the following equation to determine the solid content concentration. The average value of the five samples was defined as the solid content concentration.
Solid content concentration = B / A × 100 (%)

<Nitrogen adsorption surface area>
The nitrogen adsorption surface area was measured according to JIS K6217 (low temperature nitrogen adsorption method). Alternatively, reference was made to characteristic data of commercially available carbon.

<DBP absorption>
DBP absorption was measured according to JIS K6217. Alternatively, reference was made to characteristic data of commercially available carbon.

<Carbon black volatile content>
The volatile content was determined by measuring the weight loss when the carbon black was heated at 950 ° C. for 7 minutes in accordance with JIS K6221 and expressing the weight loss with respect to the weight of the carbon black before heating as a percentage (% by weight).

<PH of carbon black>
The pH value was a value based on ASTM D1512.

<Particle size of carbon black>
The particle size of carbon black in the solution is a value measured using a LA-920 type laser diffraction / scattering particle size distribution analyzer manufactured by HORIBA.

<Evaluation of mechanical properties>
(Tensile modulus)
From each carbon black-filled polyimide seamless belt obtained, a test piece (20 mm × 250 mm) was cut out, and this test piece was autographed (AGS, manufactured by Shimadzu Corporation) based on the tensile conditions described in JIS K7127. −5 kNG), the tensile modulus (GPa) of the test piece was measured under the conditions of a tensile speed of 25 mm / min and a measurement temperature of 23 ° C. In addition, the tensile elasticity modulus cut out five test pieces from each said carbon black filling polyimide seamless belt, and calculated | required it as an average value of the value measured about each test piece.
(Tensile yield strength, tensile breaking strength, tensile elongation)
A test piece (5 mm × 40 mm) was cut out from each carbon black-filled polyimide seamless belt, and the autograph (manufactured by Shimadzu Corporation, AGS-5kNG) was obtained based on the tensile conditions described in JIS K7127. ), The tensile yield strength (MPa), tensile breaking strength (MPa), and tensile elongation (%) of the test piece were measured under the conditions of a tensile speed of 50 mm / min and a measurement temperature of 23 ° C. In addition, each characteristic value was calculated | required as an average value of the value measured about each test piece, cutting out each 5 test pieces from each said carbon black filling polyimide seamless belt.

<Surface resistivity of semiconductive polyimide resin belt>
The surface resistivity (SR) is measured using a sample of the obtained semiconductive polyimide resin belt cut to a length of 400 mm as a sample, a resistance measuring instrument “HIRESTA IP / UR probe” manufactured by Mitsubishi Chemical Corporation. Was used to measure a total of 12 locations, 3 at regular intervals in the width direction and 4 in the longitudinal (circumferential) direction, and indicated the average value of the whole. The surface resistivity (SR) was measured after 10 seconds had elapsed while applying a voltage of 500V.

<Flatness measurement>
Each carbon black-filled polyimide seamless belt obtained was cut to a width of 350 mm, and stretched on two rollers (3) with a diameter of 30 mm as shown in FIG. The displacement amount of the belt surface was read in the width direction of the belt with a laser displacement meter (product number: type KL080) (2). Then, as shown in FIG. 2, the value obtained by subtracting the minimum value from the maximum value is defined as the flatness in the width direction.

<High voltage application test and idling durability test>
Evaluation was carried out with an energization system shown in FIG. The belt resistivity (1) obtained in the examples and comparative examples was measured for fluctuations in surface resistivity after operating for 50 hours at an applied voltage of 4.0 kV (applied current of about 50 μA) by a voltage application roller (5). . Then, idling durability evaluation of continuous 300 hours was implemented at the speed of 280 mm / s without the applied voltage. Durability was cleared for 300 consecutive hours.

  In Comparative Examples 3 and 4, due to the rigid molecular structure, the film spontaneously contracted with the solvent volatilization, and the film peeled off from the mold and was damaged. In order to form a film without breakage, it is considered necessary that the amount of 4,4'-diamino-para-terphenyl is 80 mol% or less based on the total aromatic diamine component.

  From Table 3, the belts of Examples 1 to 3 showed little change (decrease) in surface resistivity even in the high voltage application test. This is considered because it is a uniform dispersion state as continuous as possible in the plane direction. Further, the belt was not damaged even after 300 consecutive hours in the idling durability evaluation, and the flatness was hardly deteriorated. In Comparative Examples 5 and 6, the belt did not break, but the rigidity (Young's modulus, yield strength) was small, so the belt was partially stretched by creep (plastic deformation) in the width direction, and the flatness deteriorated. It is thought that.

  From these results, when the semiconductive polyimide resin belt of the present invention is used as, for example, an intermediate transfer belt, a high-quality transfer image can be obtained with no change in surface resistivity even when an excessive current is repeatedly applied. It means that it will not be damaged even after long-term use.

The schematic of the flatness measuring method is shown. FIG. 2 shows a cross-sectional view along AA in FIG. 1. The schematic diagram of the electricity supply system used for a high voltage application test and an idling durability test is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Endless tubular film 2 Laser displacement meter 3 Roller 4 Scanning direction of laser displacement meter 5 Voltage application roller 6 Traveling direction

Claims (5)

A semiconductive polyimide resin belt containing carbon black and polyimide resin,
The polyimide resin is obtained by imidizing biphenyltetracarboxylic dianhydride and an aromatic diamine, and the aromatic diamine component converts 4,4′-diamino-para-terphenyl to an aromatic diamine. A semiconductive polyimide resin belt containing 50 to 80 mol% based on the total amount.   The aromatic diamine component is further selected from the group consisting of 4,4′-diaminodiphenyl ether, 4,4′-bis (4-aminophenoxy) biphenyl and bis [4- (4-aminophenoxy) phenyl] ether. The semiconductive polyimide resin belt according to claim 1, comprising at least one aromatic diamine. The carbon black is obtained by oxidizing carbon black produced by an oil furnace method. After oxidation, the carbon black has a pH of 2 to 5, a nitrogen adsorption specific surface area of 60 to 150 m ² / g, and a dibutyl phthalate absorption amount. The semiconductive polyimide resin belt according to claim 1 or 2, wherein is 40 to 120 ml / 100 g. The intermediate transfer belt of an electrophotographic apparatus comprising a semiconductive polyimide resin belt according to any one of claims 1 to 3, wherein the surface resistivity is 1 x 10 ⁸ to 1 x 10 ¹⁴ Ω / □. A carbon black-dispersed polyamic acid solution composition is prepared by dispersing carbon black in a polyamic acid solution obtained by reacting biphenyltetracarboxylic dianhydride or a derivative thereof and an aromatic diamine in an organic polar solvent, The carbon black-dispersed polyamic acid solution composition is molded into a tubular product by a rotational molding method, and the molded body is heated to imidize by a heat treatment method,
(1) A step of applying the carbon black-dispersed polyamic acid solution composition to the inner peripheral surface of a rotating cylindrical mold,
(2) A process of forming a self-supporting film by heating at a temperature of 80 to 150 ° C. while rotating the cylindrical mold, and (3) attaching the film to the inner peripheral surface of the cylindrical mold. The process of imidating by heating at a temperature of 300 to 350 ° C. in the state,
The manufacturing method characterized by including.

Images