JP5121426B2 - Semiconductive copolymer polyimide belt, method for producing the same, and intermediate transfer belt - Google Patents

Description

  The present invention relates to a semiconductive copolymer polyimide belt used as an intermediate transfer belt for an electrophotographic copying machine, a printer, a facsimile, a composite machine thereof, and a digital printing machine equipped with a color image forming apparatus, and a method for producing the same. About. The present invention also relates to an intermediate transfer belt of an electrophotographic apparatus comprising a semiconductive copolymer polyimide belt obtained by the production method.

  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 charge is generated by a laser, light emitting diode light, or the like 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.

  In recent years, OA equipment has been designed not only for high speed and high image quality, but also for high durability of key parts, and material design required to obtain high-quality transfer images stably for a long period of time even on intermediate transfer belts. Is becoming indispensable. In the color image forming apparatus, accurate transfer can be realized, resistance change due to transfer voltage can be prevented, and high-quality transfer images can be obtained stably for a long period of time. Finish the intermediate transfer belt with excellent physical properties such as flatness deterioration due to plastic deformation due to the load in the width direction, excellent bending durability, and stable use even if it is run for a long time. Is positioned as an important technology.

  The material of the intermediate transfer member used in the image forming apparatus is a semiconductive material made of thermoplastic resin such as polycarbonate resin (PC), polyvinylidene fluoride (PVDF), PC / polyalkylene phthalate (PAT) blend material. An endless belt or the like has been proposed (see, for example, Patent Documents 1 to 3). Conductive materials composed of these thermoplastic resins are inferior in mechanical properties, with a tensile yield strength recorded by a stress-strain curve measured according to JIS K 7113 of 100 MPa or less. When the belt is plastically deformed by such stress and applied to an intermediate transfer belt, there is a problem that a high-quality transfer image cannot be stably obtained.

  Also, semiconductive polyimide using a high molecular weight polyamic acid solution obtained by reacting 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine as a raw material, and conductive filler dispersed therein. Resin belt (for example, refer to Patent Document 4), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, p-phenylenediamine and 4,4′-diaminodiphenyl ether copolymer belt production method (For example, refer to Patent Document 5).

  However, the belts described in these patent documents are very brittle because they are semiconductive belts containing carbon black in a rigid polyimide resin up to about 20% by weight, and the inherent toughness of the polyimide resin is lost. When used as an intermediate transfer belt, there is a problem that cracks and cracks are generated due to a load applied in the width direction. One reason for this is that the polyimide resin has a relatively high crystal structure, resulting in a non-uniform distribution of stress, that is, stress concentration, which causes local breakage of the polyimide resin molecular chain. It is.

  In patent document 4 or 5, the rotational molding method is performed as a manufacturing method of a polyimide resin intermediate transfer member. After applying a polyimide resin precursor solution to the inner peripheral surface of a cylindrical mold, forming a coating by centrifugal molding, after partially removing the solvent and partially converting the imide until the coating can support itself, 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.

Also disclosed is an intermediate transfer member formed of a polyimide resin having a glass transition point of 245 ° C. or lower in which a conductive agent is dispersed (see, for example, Patent Document 6), and the polyimide resin is biphenyltetracarboxylic dianhydride. And oxydianiline (4,4′-diaminodiphenyl ether) are obtained by a dehydration condensation reaction at a temperature of 300 ° C. or lower. However, biphenyltetracarboxylic dianhydride components including 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride are described. It was not done, and was not fully satisfactory in terms of physical properties, environmental characteristics, electrical characteristics, etc. of the conductive belt.
JP-A-6-095521 Japanese Patent Laid-Open No. 5-200904 Japanese Patent Laid-Open No. 6-149083 Japanese Patent Laid-Open No. 10-063115 JP 2003-266454 A JP 2000-231270 A

  The present invention can realize accurate transfer in a color image forming apparatus, prevents resistance change due to a transfer voltage, and has excellent electrical characteristics such as being able to obtain a high-quality transfer image stably over a long period of time. In addition, plastic deformation due to large tension and load in the width direction of the belt, and cracks at the belt end are difficult to occur, and even when tension is applied, the belt flatness can be maintained, even if it is run for a long time The present invention provides a semiconductive copolymer polyimide belt having excellent physical properties such as stable use. Moreover, the manufacturing method of such a semiconductive copolymerization polyimide belt and the intermediate transfer belt of the electrophotographic apparatus which consists of a semiconductive copolymerization polyimide belt obtained by this manufacturing method are provided.

The inventor paid attention to the composition of the polyimide resin from the viewpoint of mechanical properties and the filling amount of carbon black from the viewpoint of electrical properties, and as a result of earnest research to solve the above problems, the polyimide resin was changed to 70- A semiconductive copolymer polyimide belt comprising 80% by weight and 30-20% by weight of carbon black and having a surface resistivity of 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω / □,
The polyimide resin,
Biphenyl containing 15-50 mol% 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and 85-50 mol% 3,3', 4,4'-biphenyltetracarboxylic dianhydride An aromatic diamine component comprising a tetracarboxylic dianhydride component and two aromatic diamines, or
Biphenyltetracarboxylic acid diester containing 15-50 mol% 2,3,3 ', 4'-biphenyltetracarboxylic acid diester and 85-50 mol% 3,3', 4,4'-biphenyltetracarboxylic acid diester It discovered that said objective could be achieved by setting it as the semiconductive copolymerization polyimide belt made into the resin obtained from the aromatic diamine component containing a component and 2 types of aromatic diamine. Based on this knowledge, further studies have been made and the present invention has been completed.

  That is, the present invention is as follows.

Item 1. A semiconductive copolymer polyimide belt comprising 70 to 80% by weight of polyimide resin and 30 to 20% by weight of carbon black and having a surface resistivity of 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω / □,
15 to 50 mol% 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and 85 to 50 mol% 3,3', 4,4'-biphenyltetracarboxylic acid A semiconductive copolymer polyimide belt obtained from a biphenyltetracarboxylic dianhydride component containing an anhydride and an aromatic diamine component containing two types of aromatic diamines.

Item 2. A semiconductive copolymer polyimide belt comprising 70 to 80% by weight of polyimide resin and 30 to 20% by weight of carbon black and having a surface resistivity of 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω / □,
The polyimide resin contains 15-50 mol% 2,3,3 ′, 4′-biphenyltetracarboxylic acid diester and 85-50 mol% 3,3 ′, 4,4′-biphenyltetracarboxylic acid diester. A semiconductive copolymer polyimide belt obtained from an aromatic diamine component containing a biphenyltetracarboxylic acid diester component and two aromatic diamines.

  Item 3. Item 3. The semiconductive copolymer polyimide belt according to Item 1 or 2, wherein the aromatic diamine component contains 20 to 80 mol% 4,4'-diaminodiphenyl ether and 80 to 20 mol% p-phenylenediamine.

Item 4. 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 volatile content of 2 to 5% by weight, and a nitrogen adsorption specific surface area. Item 4. The semiconductive copolymer polyimide belt according to any one of Items 1 to 3, wherein 80 to 150 m ² / g, dibutyl phthalate absorption is 50 to 100 ml / 100 g, and the amount of undecomposed raw material hydrocarbon is 10 ppm or less.

Item 5. The tensile yield strength recorded in the stress-strain curve measured according to JIS K7113: σy is 140 MPa or more, and the relationship with the tensile rupture strength: σb is (tensile rupture strength: σb) / (tensile yield strength) S: σy) ≧ 1.1
The semiconductive copolymer polyimide belt in any one of claim | item 1-4 satisfy | filling.

  Item 6. Item 6. The semiconductive copolymer polyimide belt according to any one of Items 1 to 5, wherein the flatness in the belt width direction is 2 mm or less.

  Item 7. Item 7. The semiconductive copolymer polyimide belt according to any one of Items 1 to 6, having a glass transition point of 280 ° C or higher.

Term 8.15-50 mol% 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride and 85-50 mol% 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride A polyimide precursor having a weight average molecular weight of 25,000 or less by reacting an approximately equimolar amount of a biphenyltetracarboxylic dianhydride component containing 2 and an aromatic diamine component containing two kinds of aromatic diamines in an organic polar solvent. Producing a solution, preparing a polyimide precursor solution composition by dispersing carbon black in the polyimide precursor solution, molding the carbon black-dispersed polyimide precursor solution composition into a tubular product by a rotational molding method, A method for producing a semiconductive copolymer polyimide belt in which the molded body is heat-treated and imidized,
(1) A step of applying the carbon black-dispersed polyimide precursor solution composition to the inner peripheral surface of a cylindrical mold that rotates at a centrifugal acceleration of 0.5 to 10 times the gravitational acceleration.
(2) A step of forming a self-supporting film by heating the cylindrical mold at a temperature of 100 to 140 ° C. while rotating at a centrifugal acceleration of 0.5 to 10 times the gravitational acceleration, and (3) The step of imidizing by heating at a temperature of 300 ° C. or higher while the film is attached to the inner peripheral surface of the cylindrical mold,
The manufacturing method characterized by including.

9. Biphenyl tetra comprising 15 to 50 mol% 2,3,3 ', 4'-biphenyltetracarboxylic acid diester and 85 to 50 mol% 3,3', 4,4'-biphenyltetracarboxylic acid diester A substantially equal molar amount of a carboxylic acid diester component and an aromatic diamine component containing two kinds of aromatic diamines are dissolved in an organic polar solvent to prepare a nylon salt type monomer solution. A polyimide precursor solution composition is prepared by dispersing carbon black, the carbon black-dispersed polyimide precursor solution composition is formed into a tubular product by a rotational molding method, and the molded product is heat-treated and imidized. A method for producing a conductive copolymer polyimide belt,
(1) A step of applying the carbon black-dispersed polyimide precursor solution composition to the inner peripheral surface of a cylindrical mold that rotates at a centrifugal acceleration of 0.5 to 10 times the gravitational acceleration.
(2) A step of forming a self-supporting film by heating the cylindrical mold at a temperature of 100 to 140 ° C. while rotating at a centrifugal acceleration of 0.5 to 10 times the gravitational acceleration, and (3) The step of imidizing by heating at a temperature of 300 ° C. or higher while the film is attached to the inner peripheral surface of the cylindrical mold,
The manufacturing method characterized by including.

  Item 10. Item 10. The method for producing a semiconductive copolymer polyimide belt according to Item 8 or 9, wherein the aromatic diamine component contains 20 to 80 mol% 4,4'-diaminodiphenyl ether and 80 to 20 mol% p-phenylenediamine.

  Item 11. Item 15. An intermediate transfer belt for an electrophotographic apparatus comprising a semiconductive copolymer polyimide belt obtained by the production method according to any one of Items 8 to 10.

  Hereinafter, the present invention will be described in detail.

1. Semiconducting Copolymerized Polyimide Belt The present invention is a semiconducting material comprising 70 to 80% by weight of polyimide resin and 30 to 20% by weight of carbon black and having a surface resistivity of 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω / □. A copolymerizable polyimide belt, wherein the polyimide resin is
Biphenyl containing 15-50 mol% 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and 85-50 mol% 3,3', 4,4'-biphenyltetracarboxylic dianhydride A semiconductive copolymer polyimide belt obtained from an aromatic diamine component comprising a tetracarboxylic dianhydride component and two aromatic diamines, or
The polyimide resin contains 15-50 mol% 2,3,3 ′, 4′-biphenyltetracarboxylic acid diester and 85-50 mol% 3,3 ′, 4,4′-biphenyltetracarboxylic acid diester. The present invention relates to a semiconductive copolymer polyimide belt obtained from an aromatic diamine component containing a biphenyltetracarboxylic acid diester component and two types of aromatic diamines.

  The semiconductive copolymer polyimide belt of the present invention contains 70-80% by weight of polyimide resin and 30-20% by weight of carbon black, but 72-78% by weight of polyimide resin and 28-22% by weight of carbon black. It is preferable to include. When the blending amount of the polyimide resin and the carbon black is within the above range, for example, when used as an intermediate transfer belt or the like of a color image forming apparatus, charge charging stability and slow charging can be appropriately performed, and It is preferable because it can stably obtain a high-quality transfer image for a long period of time, and further maintains the strength as an intermediate transfer belt and does not cause problems such as damage to the intermediate transfer member even when used for a long period of time. .

1.1 Polyimide resin As a polyimide resin used in the present invention,
Biphenyl containing 15-50 mol% 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and 85-50 mol% 3,3', 4,4'-biphenyltetracarboxylic dianhydride A polyimide resin (1) obtained from an aromatic diamine component containing a tetracarboxylic dianhydride component and two aromatic diamines, or
Biphenyltetracarboxylic acid diester containing 15-50 mol% 2,3,3 ', 4'-biphenyltetracarboxylic acid diester and 85-50 mol% 3,3', 4,4'-biphenyltetracarboxylic acid diester Polyimide resin obtained from an aromatic diamine component containing a component and two types of aromatic diamines (2)
If it is, it will not specifically limit.

  Hereinafter, the polyimide resin (1) will be described.

  The blending ratio of 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride is 2,3,3 ′, 4 ′. -Biphenyltetracarboxylic dianhydride 15-50 mol% and 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride 85-50 mol%, 2,3,3', 4'-biphenyl It is preferable that they are 20-30 mol% of tetracarboxylic dianhydrides and 80-70 mol% of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydrides. The blending ratio is preferable because it makes it possible to manufacture a belt having a good balance between flexibility and rigidity and excellent flatness without warping of the belt end.

  Further, when the asymmetrical 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride is contained in an amount exceeding 50 mol%, the cohesive force in the higher-order structure is reduced, and the yield strength is reduced. It becomes easy to cause plastic deformation. As a result, it is not preferable because orientation hardening of molecular chains accompanying an increase in plastic deformation is not sufficiently obtained and tends to break.

  Moreover, as an aromatic diamine component, what is necessary is just to contain 2 types of aromatic diamine, Although it does not specifically limit, 4,4'- diamino diphenyl ether 20-80 mol% and p-phenylenediamine 80-20 mol% It is preferable that they are 4,4'- diamino diphenyl ether 40-60 mol% and p-phenylenediamine 60-40 mol% is more preferable. When the amount of 4,4′-diaminodiphenyl ether is less than 20 mol%, the volume shrinkage force or imidization reaction in solvent volatilization or imidization reaction may occur when imide conversion is to be completed in a state of being attached to the mold. Since it peels from the inner surface of the cylindrical mold due to the shrinkage stress due to strong plane orientation at, it is not preferable because it is necessary to peel from the cylindrical mold in the imide conversion step and replace it with the outer periphery of the tubular mold. When 4,4′-diaminodiphenyl ether is contained in an amount exceeding 80 mol%, the tensile yield strength: σy tends to be less than 140 MPa.

  In addition, when a semiconductive copolymer polyimide belt obtained from a composition containing a biphenyltetracarboxylic dianhydride component and an aromatic diamine component at such a blending ratio is used as an intermediate transfer belt, It is preferable because the intermediate transfer belt has excellent physical properties such as no deterioration in flatness due to plastic deformation due to such a load, excellent bending durability, and stable use even after running for a long period of time.

  The method for synthesizing the polyimide resin (1) is not particularly limited, and a commonly used method can be adopted. However, the biphenyltetracarboxylic dianhydride component and the aromatic diamine component are generally used. A method in which an equimolar amount is reacted in an organic polar solvent to produce a polyimide precursor solution and then imidized by heat treatment is preferable.

  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 higher, hardly volatilizes from the film during thermal imidization, and imidization easily proceeds due to the plasticizing effect of the residual solvent.

  Although the weight average molecular weight of the polyimide precursor obtained by reacting in an organic polar solvent is not particularly limited, it is preferably 25000 or less, more preferably 20000 or less. It is preferable for the weight average molecular weight to be in this range since the solubility in an organic polar solvent is increased and a high concentration can be realized. However, in the present invention, a polyimide precursor solution having a weight average molecular weight exceeding 25,000 can also be used.

  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 20 Pa · s, for example.

  Next, the polyimide resin (2) will be described.

  The blending ratio of 2,3,3 ′, 4′-biphenyltetracarboxylic acid diester and 3,3 ′, 4,4′-biphenyltetracarboxylic acid diester is 2,3,3 ′, 4′-biphenyltetracarboxylic acid. Acid diester 15-50 mol% and 3,3 ′, 4,4′-biphenyltetracarboxylic acid diester 85-50 mol%, 2,3,3 ′, 4′-biphenyltetracarboxylic acid diester 20-30 mol% % And 3,3 ′, 4,4′-biphenyltetracarboxylic acid diester is preferably 80 to 70 mol%. When the amount of 2,3,3 ′, 4′-biphenyltetracarboxylic acid diester exceeds 50 mol%, the yield strength and elastic modulus of the obtained belt are weak, and when used as an intermediate transfer belt, the drive response is low. Not only is it bad, but there is a tendency that plastic deformation occurs due to a load applied in the width direction at an early stage. On the other hand, when the amount is less than 15 mol%, a highly crystalline and rigid polyimide is produced. Therefore, a semiconductive belt containing carbon black up to about 15% by weight is very brittle and tends to lose its toughness. There is.

  The 2,3,3 ′, 4′-biphenyltetracarboxylic acid diester or the 3,3 ′, 4,4′-biphenyltetracarboxylic acid diester is commercially available or can be produced by a known method. it can.

As a production method, for example, it is easily performed by a known method such as reacting 2 mol of the corresponding alcohol (lower alcohol, preferably C _1-3 alcohol) with 1 mol of the corresponding biphenyltetracarboxylic dianhydride. Can be manufactured. As a result, the raw acid anhydride reacts with the alcohol to open the ring to produce diesters (half-esters) each having an ester group and a carboxyl group on adjacent carbons on the two benzene rings.

  Moreover, as an aromatic diamine component, the thing similar to what was described by the said polyimide resin (1) is mentioned.

  The method for synthesizing the polyimide resin (2) is not particularly limited, and a commonly used method can be adopted, but approximately equimolar amounts of the biphenyltetracarboxylic acid diester component and the aromatic diamine component. Is preferably dissolved in an organic polar solvent to prepare a nylon salt type monomer solution, and the nylon salt type monomer solution is then heated to imidize.

  As an organic polar solvent, the thing similar to what was mentioned by the polyimide resin (1) can be mentioned.

  The biphenyltetracarboxylic acid diester component and the aromatic diamine component in the nylon salt type monomer solution have an ion pair of a carboxylate ion of the biphenyltetracarboxylic acid diester and an ammonium ion of the aromatic diamine as shown below in an organic polar solvent. It is considered that a substantial monomer state is taken.

(In the formula, Ar is a tetravalent residue obtained by removing two carboxyl groups and two ester groups from a biphenyltetracarboxylic acid diester, Ar ′ is a divalent residue obtained by removing two amino groups from an aromatic diamine, R represents an alkyl group (1 to 3 carbon atoms)
As described above, in the nylon salt type monomer solution, the biphenyltetracarboxylic acid diester component and the aromatic diamine component are present in a substantially monomer state, so that they are very easily dissolved in the above organic polar solvent, and the amount of the solvent to be used is minimized. There is an advantage that it can be reduced.

  The viscosity of the nylon salt monomer solution at 30 ° C. is not particularly limited, but is preferably 0.1 to 20 Pa · s, and more preferably 0.3 to 10 Pa · s, for example. .

  The solid content concentration of the polyimide precursor solution or the nylon salt monomer solution of the polyimide resin (1) or (2) is preferably 25% by weight or more, and more preferably 30 to 50% by weight. When the solid content concentration is within the above range, a belt having a film thickness of 90 μm or more can be easily produced. Since the amount of the solvent used is small, the cost can be reduced and the solvent can be easily removed by evaporation. In the present invention, since it contains an asymmetric biphenyltetracarboxylic dianhydride, it becomes possible to increase the solubility of the polyimide precursor in an organic polar solvent, and it is possible to adjust to a high solid content concentration as described above. It can be done.

  Also, when there are many solvents to evaporate, the buoyancy and surface tension that cause temperature convection and evaporation convection in the drying process, viscosity change due to solvent evaporation, density change, etc. are large, and the dispersion state of carbon black is caused by non-uniform dispersion A mottled phenomenon occurs. However, since the polyimide precursor solution composition of the present invention has a small solvent content, such a problem can be suppressed as much as possible.

  As described above, the polyimide resin used in the present invention is a polyimide resin molecule obtained by copolymerizing a predetermined amount of a biphenyltetracarboxylic anhydride component or a biphenyltetracarboxylic acid diester component with an aromatic diamine component. The structure is bent and flexibility is born in the polyimide resin belt.

  In general, when a polyimide is made from 3,3 ′, 4,4′-biphenyltetracarboxylic anhydride or 3,3 ′, 4,4′-biphenyltetracarboxylic acid diester, it is easily derived from its high symmetry. A crystal structure is formed. In the crystalline resin, since carbon black is excluded from the crystallized portion, the same surface resistivity tends to be obtained with a small amount of carbon black as compared with the amorphous resin. However, when 2,3,3 ′, 4′-biphenyltetracarboxylic anhydride or 2,3,3 ′, 4′-biphenyltetracarboxylic acid diester is added and copolymerized, the regularity of the molecular chain is inhibited. Therefore, the formation of crystals is suppressed and the amorphous structure becomes dominant. Therefore, the affinity with carbon black is increased, and the carbon black concentration in the polyimide resin can be increased. The carbon black concentration can be adjusted to a high concentration of, for example, 20 to 30% by weight (particularly 22 to 28% by weight).

  In the present invention, carbon black is mixed with a polyimide precursor solution or a nylon salt monomer solution to produce a carbon black-dispersed polyimide precursor solution composition. As a mixing method, carbon black is contained in a polyimide precursor solution or There is no particular limitation as long as it is a method of uniformly mixing and dispersing in the nylon salt type monomer solution, and examples thereof include a method using a sand mill, a bead mill, an ultrasonic mill, a three-roll mill or the like.

  The carbon black content in the carbon black-dispersed polyimide precursor solution composition is preferably 20 to 30% by weight in the total solid content of the carbon black-dispersed polyimide precursor solution composition, and is 22 to 28% by weight. It is more preferable.

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

  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 carbon black-dispersed polyimide precursor solution composition in which carbon black is uniformly dispersed can be produced.

  The average particle size of the carbon black dispersed in the solution 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 adjusted to a volatile content of 2 to 5% by weight (more preferably 2.5 to 5% by weight) by oxidation treatment.

  Hereinafter, carbon black produced by the oil furnace method and further adjusted to a volatile content of 2 to 5% by weight by oxidation treatment 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.

  The surface of carbon black adjusted to 2-5% by weight by oxidation treatment contains oxygen functional groups (particularly carboxyl groups) such as phenolic hydroxyl groups, carbonyl groups, and carboxyl groups, so in the polyimide precursor solution The fluidity and dispersion stability of the resin 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 polyimide resin belt is set within a desired range (10 ⁸ to 10 ¹⁴ Ω / □), the polyimide resin is highly filled with the carbon black (polyimide resin belt (of polyimide resin and carbon black). The total weight) can be 20-30 wt% carbon black). Thereby, the electroconductivity by the chain | linkage of carbon black is provided and the polyimide resin belt which has the stable electrical property which is hard to be influenced by an external environment and an applied voltage can be obtained. In other words, carbon black can be controlled to a high content of 20 to 30% by weight in the semiconductive copolymer polyimide 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.

The carbon black used in the present invention preferably has a nitrogen adsorption specific surface area (JIS K6217) of 80 to 150 m ² / g, and more preferably 100 to 130 m ² / g.

  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 80 m ² / g, there is a tendency that affinity with the polyimide precursor solution or the nylon salt type monomer solution cannot be obtained and the powder resistance does not have 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 20% 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.

  Moreover, it is preferable that the dibutyl phthalate (DBP) absorption amount of carbon black used by this invention is 50-100 ml / 100g, and it is more preferable that it is 60-80 ml / 100g. If the DBP absorption exceeds 100 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 20% by weight or more is obtained. There is a tendency to disappear. When the DBP absorption amount is less than 50 ml / 100 g, the powder resistance becomes too high. Therefore, unless the carbon black concentration in the solid content exceeds 30% by weight, a semiconductive polyimide resin belt cannot be obtained.

The surface resistivity of the semiconductive copolymer polyimide belt of the present invention is 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω / □, and preferably 1 × 10 ¹⁰ to 1 × 10 ¹³ Ω / □. The surface resistivity within this range is preferable because the transfer electric field acting on the toner layer becomes strong and both the primary transfer efficiency and the secondary transfer efficiency increase.

  In the material design of the semiconductive copolymer polyimide belt of the present invention, in particular, the intermediate transfer belt of an electrophotographic apparatus comprising a semiconductive copolymer polyimide belt, the tensile yield strength: σy and the tensile break strength: σb are belts Is an important strength factor of the material design, and at least the tensile yield strength: σy is preferably 140 MPa, and more preferably 150 MPa. It is preferable that the tensile yield strength: σy is in this range because plastic deformation (dimensional change due to elongation) does not occur due to stress applied during mounting.

  Further, the tensile breaking strength: σb needs to be larger than the tensile yield strength: σy, which contributes to the life (toughness) of belt rotation. Therefore, σb / σy ≧ 1.10 is preferable, and σb / σy ≧ 1.15 is more preferable. If σb / σy is less than 1.10, the belt tends to break before plastic deformation. Further, the upper limit value of σb / σy is not particularly limited.

  Here, the tensile breaking strength: σb and the tensile yield strength: σy are the tensile breaking strength and the tensile yield strength recorded by a stress-strain curve measured according to JIS K7113.

  The flatness in the belt width direction of the semiconductive copolymer polyimide belt of the present invention is preferably 2 mm or less, and more preferably 1.5 mm or less. When the flatness exceeds 2 mm, the adhesion between the driving roll for driving the belt and the intermediate transfer belt changes, and as a result, the moving speed of the belt changes. As a result, highly accurate image alignment is impossible, and image defects such as color misregistration occur. Further, if there is a warp or the like at the end of the intermediate transfer belt, it tends to come into contact with other members and cause a discharge, resulting in damage from the end and breaking. Here, flatness means a value measured by the method described in the examples.

  The glass transition point of the semiconductive copolymer polyimide belt of the present invention is preferably 280 ° C. or higher, and more preferably 300 ° C. or higher. When the glass transition point is within this range, dehydration imidization can be almost completed. Even if the imidization unreacted content is only a few percent, it does not affect the physical properties, environmental characteristics, electrical characteristics and the like of the semiconductive polyimide belt, and can be suitably used. The upper limit value of the glass transition point is not particularly limited. Here, the glass transition point is a value measured from the temperature dependence of dynamic viscoelasticity, and is measured by the method described in Examples.

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

2. The present invention relates to 15-50 mol% 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride and 85-50 mol% 3,3 ′, 4. A substantially equimolar amount of a biphenyltetracarboxylic dianhydride component including 4′-biphenyltetracarboxylic dianhydride and an aromatic diamine component including two aromatic diamines is reacted in an organic polar solvent. A polyimide precursor solution having a weight average molecular weight of 25,000 or less is produced, and carbon black is uniformly dispersed in the polyimide precursor solution to prepare a polyimide precursor solution composition. The carbon black dispersed polyimide precursor solution composition is A method for producing a semiconductive copolymer polyimide belt, which is formed into a tubular product by a rotational molding method and imidized by heat treatment of the molded product,
Biphenyl tetracarboxylic acid diester comprising 15-50 mol% 2,3,3 ', 4'-biphenyltetracarboxylic acid diester and 85-50 mol% 3,3', 4,4'-biphenyltetracarboxylic acid diester A nylon salt type monomer solution is prepared by dissolving approximately equimolar amounts of the component and an aromatic diamine component containing two types of aromatic diamines in an organic polar solvent, and carbon black is added to the nylon salt type monomer solution. Disperse to prepare a polyimide precursor solution composition, shape the carbon black-dispersed polyimide precursor solution composition into a tubular product by a rotational molding method, and heat-treat the molded body to imidize the semiconductive copolymer. A method for producing a polymerized polyimide belt,
(1) A step of coating the carbon black-dispersed polyimide precursor solution composition with a uniform thickness on the inner peripheral surface of a cylindrical mold rotating at a centrifugal acceleration of about 0.5 to 10 times the gravitational acceleration.
(2) A step of forming a self-supporting film by heating the cylindrical mold at a temperature of 100 to 140 ° C. while rotating at a centrifugal acceleration of 0.5 to 10 times the gravitational acceleration, and (3) The step of imidizing by heating at a temperature of 300 ° C. or higher while the film is attached to the inner peripheral surface of the cylindrical mold,
The manufacturing method of the semiconductive copolymerization polyimide belt characterized by including.

  Hereinafter, a method for producing a semiconductive polyimide belt using a carbon black-dispersed polyimide precursor solution composition (hereinafter simply referred to as “liquid raw material”) will be described.

  In addition, as said liquid raw material used with the said manufacturing method, the said carbon black dispersion | distribution polyimide precursor solution composition can be used conveniently.

  The liquid material is applied with a uniform thickness on the inner peripheral surface of a cylindrical mold that rotates at a low speed with a centrifugal acceleration of 0.5 to 10 times the acceleration of gravity. In other words, the shear force applied in the rotational direction is low when the liquid raw material is supplied at a low-speed rotation of 0.5-10 times the gravitational acceleration, and the orientation of molecular chains and the structure orientation of fillers such as carbon black are reduced. Can be suppressed.

  If the centrifugal acceleration is less than 0.5 times the gravitational acceleration, there is a risk that the supplied liquid raw material 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, not only the orientation of the molecular chain due to the shearing force in the rotational direction received during the supply and the structure orientation of the filler such as carbon black, but also the flow of the liquid raw material due to the centrifugal force occurs. Tend to affect the degree.

  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 liquid source supply means applies the liquid source to the inner peripheral surface of the cylindrical mold with a uniform thickness by moving the liquid source in the direction of the axis of rotation of the cylindrical mold rotating while being discharged by the nozzle method or the spray method. 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 liquid raw material, the liquid raw material is atomized so that the flow at the time of supply is as small as possible, and the liquid raw material can be instantaneously adhered to the inner peripheral surface of the rotating cylindrical mold. The spray method is preferred because the raw material can be supplied at the same rotational speed without being influenced, a thin coating film can be easily obtained, and the non-volatile concentration of the liquid raw material can be set high.

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

  When the liquid material is applied to the inner peripheral surface of the cylindrical mold with a uniform thickness in this way, it is necessary to make the film thickness uniform by flowing the liquid raw material by high-speed rotation of the cylindrical mold, that is, centrifugal force. There is no. In rotational molding using centrifugal force, after the raw material is supplied, the liquid raw material is uniformly cast on the inner surface of the cylindrical mold by the centrifugal force. Then, the carbon black particles are arranged as if the structure is 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. There is no limitation on the type of release material, but there is no particular limitation as long as it is not affected by the solvent of the liquid raw material or the water vapor generated from the resin during the heating reaction.

  In the liquid resin film forming step, the solvent is evaporated at a temperature of 100 to 140 ° C. while rotating at a low speed with a centrifugal acceleration of 0.5 to 10 times the weight acceleration to make the solid content concentration 40% by weight or more. This can be achieved by forming a self-supporting film 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 carbon black-dispersed polyimide 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 belt is usually adjusted to about 50 to 150 μm, preferably about 60 to 125 μm.

The surface resistivity is usually adjusted to be about 10 ⁸ to 10 ¹⁴ Ω / □, preferably about 10 ⁹ to 10 ¹⁴ Ω / □, and more preferably about 10 ¹⁰ to 10 ¹³ Ω / □.

  The semiconductive copolymerized polyimide belt of the present invention produced in this manner can appropriately perform charge charging stability and slow charging when used as an intermediate transfer belt in a color image forming apparatus of an electrophotographic apparatus, for example. In addition, accurate transfer can be realized in a color image forming apparatus, resistance change due to a transfer voltage can be prevented, and a high-quality transfer image can be obtained stably for a long period of time. Further, cracks and cracks due to the load applied in the width direction of the belt are unlikely to occur, and even when the belt is run for a long time, it has excellent durability and can be used stably. Furthermore, when the 2,3,3 ', 4'-biphenyltetracarboxylic acid component increases, the glass transition point shifts to the high temperature side. Therefore, it is also effective to use the transfer and fixing belt system as a belt base material in which transfer and fixing are performed simultaneously with a single belt.

  The color image forming apparatus is an electrophotographic image forming apparatus comprising at least one kind of the semiconductive polyimide belt of the present invention. By providing the semiconductive polyimide belt of the present invention as an intermediate transfer belt, a direct transfer belt or a transfer / fixing belt, a high-quality transfer image can be obtained. 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 copolymer polyimide belt of the present invention can realize accurate transfer in a color image forming apparatus, can prevent resistance change due to transfer voltage, and can stably obtain a high-quality transfer image for a long period of time. it can. Further, cracks and cracks due to the load applied in the width direction of the belt are unlikely to occur, and even when the belt is run for a long time, it has excellent durability and can be used stably. Furthermore, since it contains a 2,3,3 ', 4'-biphenyltetracarboxylic acid component, it has a high glass transition point. Therefore, it is also effective to use the transfer and fixing belt system as a belt base material capable of simultaneously performing transfer and fixing with a single belt.

  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)
30 mol% of 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and 3,3', 4,4'-biphenyltetracarboxylic dianhydride with respect to the total biphenyltetracarboxylic dianhydride component A polyimide precursor solution (weight average molecular weight 32) synthesized in an NMP solution with 20 mol% of 4,4′-diaminodiphenyl ether and 80 mol% of p-phenylenediamine with respect to 70 mol% of the product and the total aromatic diamine component. , 000) was prepared. This solution had a viscosity of 5.3 Pa · s (30 ° C.) and a solid content concentration of 18.5% by weight.

Oil furnace carbon black (CB1: pH 2.3, volatile content 3.3 wt%, nitrogen adsorption specific surface area 110 m ² / g, DBP absorption 65 ml / 100 g, undecomposed raw material hydrocarbon (PAH) Extraction amount 1.5 ppm) was added 0.28 kg and NMP 1.5 kg, and carbon black was uniformly dispersed by a ball mill to prepare a carbon black-dispersed polyimide precursor solution (hereinafter, liquid raw material) A. The liquid raw material A had a nonvolatile content concentration of 17.8% by weight, and the carbon black content in the nonvolatile content weight was 23.2% by weight. The average particle size of carbon black in the solution was 0.23 μm, and the maximum particle size was 0.38 μm.

(Production of carbon black filled polyimide seamless belt)
The liquid raw material A is 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 231.7 rpm) about 9.0 times the weight acceleration. ) To obtain a uniform spread film having a length of 480 mm 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 determined so that the thickness of the polyimide resin belt was 90 μm. After that, while rotating at a centrifugal acceleration of 9.0 times the weight acceleration (about 231.7 rpm), the temperature was raised to 120 ° C. over 30 minutes, and then maintained at 120 ° C. for 90 minutes. Was volatilized.

  Next, this tubular material 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 120 minutes (temperature increase rate: about 1.67 ° 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 90 micrometers.

Example 2
(Preparation of carbon black-dispersed polyimide precursor solution composition)
2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride 20 mol% and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride with respect to the total biphenyltetracarboxylic dianhydride component A polyimide precursor solution (weight average molecular weight 20) synthesized in an NMP solution with 50 mol% of 4,4′-diaminodiphenyl ether and 50 mol% of p-phenylenediamine with respect to 80 mol% of the product and the total aromatic diamine component. , 000) was prepared. This solution had a viscosity of 10 Pa · s (30 ° C.) and a solid content concentration of 30% by weight.

Oil furnace carbon black (CB2: pH 3.5, volatile content 4.8 wt%, nitrogen adsorption specific surface area 130 m ² / g, DBP absorption 60 ml / 100 g, undecomposed raw material hydrocarbon (PAH) 0.52 kg of extraction amount 0.8 ppm) and 2 kg of NMP were added, and carbon black was uniformly dispersed by a ball mill to prepare a carbon black-dispersed polyimide precursor solution (hereinafter, liquid raw material) B.

  The liquid material B had a non-volatile content concentration of 26.9% by weight, and of the non-volatile content, the carbon black content was 25.7% by weight. The average particle size of carbon black in the solution was 0.24 μm, and the maximum particle size was 0.41 μm.

(Production of carbon black filled polyimide seamless belt)
The liquid raw material B is 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 172.7 rpm) about 5 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 determined so that the thickness of the polyimide resin belt was 90 μm. After that, while rotating at a centrifugal acceleration (about 172.7 rpm) of 5.0 times the weight acceleration, the temperature was raised to 120 ° C. over 30 minutes, and then kept at 120 ° C. for 80 minutes. Was volatilized.

  Next, this tubular product was put into a high-temperature heating furnace while adhering to the inner peripheral surface of the cylindrical mold, and the polyimide conversion was completed under the same temperature conditions as in Example 1 to obtain a carbon black filled polyimide seamless belt (average film thickness: 90 μm).

Example 3
(Preparation of carbon black-dispersed polyimide precursor solution composition)
In a mixed solvent of NMP solution and methanol (NMP: methanol = 100: 22 (weight ratio)), 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride 50 mol% and 3,3 ′, 4,4 50 mol% of '-biphenyltetracarboxylic dianhydride is added, and the acid anhydride reacts with alcohol to open a ring, and each diester having an ester group and a carboxyl group on the adjacent carbon on the aromatic ring (half Ester), 50 mol% of 4,4′-diaminodiphenyl ether and 50 mol% of p-phenylenediamine were added to the solution, and the mixture was stirred at 50 ° C. for 3 hours. By removing over time, 5 kg of a nylon salt monomer solution was prepared. This solution had a viscosity of 0.2 Pa · s (30 ° C.) and a solid content concentration of 40.0% by weight.

  To this solution, 0.52 kg of CB2 same as Example 2 and 1.5 kg of NMP were added, and carbon black was uniformly dispersed by a ball mill to prepare a liquid raw material C. The liquid raw material C had a nonvolatile content concentration of 35.9% by weight, and the carbon black content in the nonvolatile component weight was 20.6% by weight. The average particle size of carbon black in the solution was 0.27 μm, and the maximum particle size was 0.67 μm.

(Production of carbon black filled polyimide seamless belt)
The liquid raw material C is 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 77.2 rpm) about one time 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 determined so that the thickness of the polyimide resin belt was 90 μm. Thereafter, while rotating at a centrifugal acceleration (about 77.2 rpm) of 1.0 times the weight acceleration, the temperature was raised to 120 ° C. over 30 minutes, and then maintained at 120 ° C. for 60 minutes to maintain the solvent. Was volatilized.

  Next, this tubular product was put into a high-temperature heating furnace while adhering to the inner peripheral surface of the cylindrical mold, and the polyimide conversion was completed under the same temperature conditions as in Example 1 to obtain a carbon black filled polyimide seamless belt (average film thickness: 90 μm).

Example 4
(Preparation of carbon black-dispersed polyimide precursor solution composition)
2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride 20 mol% and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride with respect to the total biphenyltetracarboxylic dianhydride component A polyimide precursor solution (weight average molecular weight 22) synthesized in an NMP solution with 80 mol% of a product, 80 mol% of 4,4'-diaminodiphenyl ether and 20 mol% of p-phenylenediamine with respect to the total aromatic diamine component. , 000) was prepared. This solution had a viscosity of 10 Pa · s (30 ° C.) and a solid content concentration of 28% by weight.

  To this solution, 0.45 kg of CB1 same as in Example 1 and 2.0 kg of NMP were added, and carbon black was uniformly dispersed by a ball mill to prepare a liquid raw material D. The non-volatile content concentration of the liquid raw material D was 24.8% by weight, and the carbon black content in the non-volatile content was 24.3% by weight. The average particle size of carbon black in the solution was 0.24 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: 90 μm) was produced in the same manner as in Example 1 except that the liquid raw material D was used.

Comparative Example 1
(Preparation of carbon black-dispersed polyimide precursor solution composition)
5 kg of a polyimide precursor solution (weight average molecular weight 33,000) prepared by synthesizing 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine in an NMP solution was prepared. This solution had a viscosity of 5.0 Pa · s (30 ° C.) and a solid content concentration of 18.0% by weight.

  To this solution, 0.27 kg of CB1 as in Example 1 and 1.5 kg of NMP were added, and carbon black was uniformly dispersed by a ball mill to prepare a liquid raw material E. The liquid raw material E had a non-volatile content of 17.3% by weight, and the carbon black content in the non-volatile content was 23.1% by weight. The average particle size of carbon black in the solution was 0.26 μm, and the maximum particle size was 0.51 μm.

(Production of carbon black filled polyimide seamless belt)
A specified amount of the liquid raw material E was introduced into 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 using a nozzle-type discharge device. Next, the charged liquid raw material was cast on the inner peripheral surface with a uniform coating thickness at a centrifugal acceleration (about 772.3 rpm) that is 100 times the gravitational acceleration. When the centrifugal acceleration is small, the liquid raw material does not flow sufficiently, and the film is formed while the coating film thickness at the portion charged into the cylindrical mold remains large. For this reason, in the rotational molding method using centrifugal force, it is necessary to uniformly cast the liquid material on the inner peripheral surface of the cylindrical mold with a large centrifugal acceleration.

  Thereafter, the rotation is changed to a centrifugal acceleration (approximately 172.7 rpm) that is 5.0 times the gravitational acceleration, the temperature is raised to 120 ° C. over 30 minutes, and then maintained at 120 ° C. for 90 minutes. Was volatilized. Next, the formed belt was removed from the inner peripheral surface of the cylindrical mold, and an aluminum tubular mold having an outer diameter of 295 mm and a length of 420 mm was inserted into the removed belt. 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. The reason why it was once removed from the cylindrical mold for molding was that the belt was peeled off or damaged from the inner peripheral surface of the cylindrical mold due to reaction shrinkage in the in-plane direction accompanying imide conversion at 150 to 250 ° C. is there. 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 90 micrometers.

Comparative Example 2
(Preparation of carbon black-dispersed polyimide precursor solution composition)
A polyimide precursor solution prepared by synthesizing 100 mol% of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 100 mol% of p-phenylenediamine in an NMP solution (weight average molecular weight of about 30,000) 5 kg was prepared. This solution had a viscosity of 5 Pa · s (30 ° C.) and a solid content concentration of 18.5% by weight.

Degussa carbon black “Special Black 4 (SB4)” (pH 3.0, volatile content 14.5 wt%, nitrogen adsorption specific surface area 180 m ² / g, DBP absorption 230 ml / 100 g, 0.17 kg of undecomposed raw material hydrocarbon (PAH) extraction amount 20 ppm) and 2 kg of NMP were added, and carbon black was uniformly dispersed by a ball mill to prepare liquid raw material F. The non-volatile content concentration of the liquid raw material F was 15.3% by weight, and the carbon black content in the non-volatile content was 15.5% by weight. The average particle size of carbon black in the solution was 0.27 μm, and the maximum particle size was 0.51 μm.

(Production of carbon black filled polyimide seamless belt)
A specified amount of the liquid raw material F was introduced into 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 using a nozzle-type discharge device. Next, the charged liquid raw material was cast on the inner peripheral surface with a uniform coating thickness at a centrifugal acceleration (about 423 rpm) 30 times the gravitational acceleration. Thereafter, polyimide conversion was completed in the same manner as in Comparative Example 1, and a carbon black filled polyimide seamless belt (average film thickness: 90 μm) was produced.

Comparative Example 3
(Preparation of carbon black-dispersed polyimide precursor solution composition)
Polyimide precursor solution prepared by synthesizing 100 mol% of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 100 mol% of 4,4′-diaminodiphenyl ether as a diamine component in an NMP solution (weight) 5 kg of an average molecular weight of about 30,000 was prepared. This solution had a viscosity of 5 Pa · s (30 ° C.) and a solid content concentration of 18.5% by weight.

  To this solution, 0.17 kg of Degussa carbon black “Special Black 4 (SB4)” used in Comparative Example 2 and 2 kg of NMP were added, and the carbon black was uniformly dispersed in a ball mill. G was prepared. The liquid raw material G had a nonvolatile content concentration of 15.3% by weight, and the carbon black content in the nonvolatile content weight was 15.5% by weight. The average particle size of carbon black in the solution was 0.27 μm, and the maximum particle size was 0.58 μm.

(Production of carbon black filled polyimide seamless belt)
The liquid raw material G is 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 11 times the gravitational acceleration (about 256.1 rpm) The liquid raw material was cast on the inner peripheral surface to a uniform coating thickness. After that, while rotating at a centrifugal acceleration of 11 times the weight acceleration (about 256.1 rpm), the temperature was raised to 120 ° C. over 30 minutes, and then kept at 120 ° C. for 90 minutes to volatilize the solvent. I let you.

  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 280 ° C. over 120 minutes (heating rate: about 1.33 ° C./min), 280 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 90 micrometers.

Comparative Example 4
(Preparation of carbon black-dispersed polyimide precursor solution composition)
Polyimide precursor solution prepared by synthesizing 100 mol% of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 100 mol% of 4,4′-diaminodiphenyl ether as a diamine component in an NMP solution (weight) 5 kg of an average molecular weight of about 20,000 was prepared. This solution had a viscosity of 1.4 Pa · s (30 ° C.) and a solid content concentration of 19.5% by weight.

  To this solution, 0.33 kg of CB2 same as that of Example 2 and 1.5 kg of NMP were added, and carbon black was uniformly dispersed by a ball mill to prepare a liquid raw material H. The non-volatile content concentration of the liquid raw material H was 19.1% by weight, and the carbon black content in the non-volatile content was 25.3% by weight. The average particle size of carbon black in the solution was 0.26 μm, and the maximum particle size was 0.51 μm.

(Production of carbon black filled polyimide seamless belt)
A carbon black-filled polyimide seamless belt (average film thickness: 90 μm) was produced in the same manner as in Example 2 except that the liquid raw material H was used.

Comparative Example 5
(Preparation of carbon black-dispersed polyimide precursor solution composition)
100 mol% of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride is added to a mixed solvent of NMP solution and methanol (NMP: methanol = 100: 22 (weight ratio)), and the acid anhydride is alcohol. To form a diester (half ester) having an ester group and a carboxyl group on adjacent carbons on the aromatic ring, respectively, and then, to this solution, 50 mol% of 4,4′-diaminodiphenyl ether After adding 50 mol% of p-phenylenediamine and stirring at 50 ° C. for 3 hours, excess methanol was removed at 60 ° C. over 1 hour to prepare 5 kg of a nylon salt monomer solution. This solution had a viscosity of 0.2 Pa · s (30 ° C.) and a solid content concentration of 40.0% by weight.

  To this solution, 0.52 kg of CB2 and 1.5 kg of NMP were added, and carbon black was uniformly dispersed by a ball mill to prepare a liquid raw material I. The liquid raw material I had a non-volatile content concentration of 35.9% by weight, and the carbon black content in the non-volatile content was 20.6% by weight. The average particle size of carbon black in the solution was 0.27 μm, and the maximum particle size was 0.67 μm.

(Production of carbon black filled polyimide seamless belt)
An attempt was made to produce a carbon black filled polyimide seamless belt (average film thickness: 90 μm) in the same manner as in Example 3 except that the liquid raw material I was used. Innumerable cracks began to enter the coating film, and finally it was broken into powder.

  Since the molecular weight of the amic acid produced from the nylon salt type monomer solution is very small, it is thought that the film became brittle due to solvent volatilization and was broken into powder.

Comparative Example 6
(Preparation of carbon black-dispersed polyimide precursor solution composition)
3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride 100 mol% with respect to the total biphenyltetracarboxylic dianhydride component, and 4,4′-diaminodiphenyl ether with respect to the total aromatic diamine component 5 kg of a polyimide precursor solution (weight average molecular weight 22,000) prepared by synthesizing 50 mol% and p-phenylenediamine 50 mol% in an NMP solution was prepared. This solution had a viscosity of 1.8 Pa · s (30 ° C.) and a solid content concentration of 19.5% by weight.

  To this solution, 0.31 kg of CB1 and 1.5 kg of NMP were added, and carbon black was uniformly dispersed by a ball mill to prepare a liquid raw material J. The liquid raw material J had a non-volatile concentration of 18.9% by weight, and the carbon black content in the non-volatile content was 24.1% by weight. The average particle size of carbon black in the solution was 0.27 μm, and the maximum particle size was 0.58 μm.

(Production of carbon black filled polyimide seamless belt)
An attempt was made to produce a carbon black filled polyimide seamless belt (average film thickness: 90 μm) in the same manner as in Example 1 except that the liquid raw material J was used. After raising the temperature and heating at 320 ° C. for 60 minutes, the solution was cooled to room temperature and was broken into powder.

  Since the polyamic acid solution has a weight average molecular weight of 22,000 and carbon black is 24.1% by weight, the film becomes mechanically fragile due to a decrease in molecular weight due to depolymerization during the drying process at 120 to 200 ° C. As a result, it is considered that cracking occurred due to inability to withstand reaction shrinkage in the in-plane direction of the film during thermal imidization.

  It describes in Table 1 about the carbon black dispersion | distribution polyimide precursor solution composition and liquid raw material which were obtained in the above Examples 1-4 and Comparative Examples 1-6.

Measurement of each physical property value described in this specification was performed as follows.
(1) 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.

(2) DBP absorption The DBP absorption was measured according to JIS K6217. Alternatively, reference was made to characteristic data of commercially available carbon.

(3) Volatile content of carbon black The volatile content is measured in accordance with JIS K6221 by measuring the weight loss when the carbon black is heated at 950 ° C. for 7 minutes, and the weight loss with respect to the carbon black weight before heating is measured. It was expressed as a percentage (% by weight).

(4) pH of carbon black
The pH value was a value based on ASTM D1512.

(5) Extraction amount of undecomposed raw material hydrocarbon (PAH) of carbon black 5 g of carbon black dried at 80 ° C. for 24 hours is placed in a cylindrical glass filter paper, and Soxhlet extraction is performed for 48 hours using 180 cc of monochlorobenzene as a solvent. The extract was concentrated, and the extract amount was quantified by liquid chromatogram, and the content was divided by the weight of carbon black. The LC-6A flow controller manufactured by Shimadzu Corp. SCL-6A detector manufactured by Shimadzu Corp. Detector The Watra 490E type manufactured by Millipore Corp. was used for the injection of 5 μl.

(6) Particle Size of Carbon Black in Solution 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.

(7) Solid content and concentration in polyimide precursor solution composition The solid content concentration of 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). Put the heat-resistant container containing the sample in an electric oven, heat and dry while heating up in order of 120 ℃ × 15min, 180 ℃ × 15min, 260 ℃ × 30min, and 300 ℃ × 30min. The weight of the solid content (solid content weight) is defined as 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 adopted as the solid content concentration.
Solid content concentration (%) = B / A × 100

(8) Weight average molecular weight of polyimide precursor The weight average molecular weight is a value measured by GPC method (solvent: NMP, converted to polyethylene oxide).

(9) Surface resistivity and volume resistivity of semiconductive belt Sample obtained by cutting the obtained semiconductive belt into a length of 400 mm was used as a resistance tester “Hiresta IP • UR Pro” manufactured by Mitsubishi Chemical Corporation. Using "-", measurements were made at a total of twelve places, three places at equal pitches in the width direction and four places in the longitudinal (circumferential) direction, and indicated as the average value of the whole. It was measured after 10 seconds had elapsed under the application of a voltage of 100V.

(10) Evaluation of mechanical properties The belt obtained in each example was cut into a width of 5 mm and a length of 100 mm, and this was used as a test piece with a uniaxial tensile testing machine (manufactured by Shimadzu Corp., Autograph) with a tensile span of 40 mm. The strain rate was measured at 50 mm / min. The yield strength and breaking strength were read from the recorded SS curve.

(11) 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 in the width direction of the belt was read with a laser displacement meter (product number: type KL080) (2) manufactured by Keyence Corporation. 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.

(12) Glass transition point (tan δ peak)
Using the Rheometrics Solids Analyzer RSAII manufactured by Rheometrics, the belts obtained in each Example and Comparative Example were cut into a width of 6 mm and a length of 27 mm, and this was evaluated as a test piece. Measurement conditions were as follows: temperature increase rate: 2 ° C./min, temperature range: 60-400 ° C., frequency: 10 Hz, dynamic strain: 0.02%.

(13) High voltage application test and idling durability test The evaluation was carried out with an energization system shown in FIG. 3 in an environment of 10 ° C. and 30% RH. Changes in the surface resistivity after the belt (1) obtained in the examples and comparative examples was operated for 50 hours at an applied voltage of 5.0 kV (conducting current of about 55 to 80 μA) by the voltage application roller (5). Was measured. Thereafter, idling durability evaluation was performed at a running speed of 280 mm / s without applying voltage, and durability was cleared for 300 consecutive hours.

  Comparative Examples 1 and 2 are methods in which a liquid material is introduced into a cylindrical mold and the liquid material is uniformly cast on the inner surface of the cylindrical mold by centrifugal force. The liquid material flows by centrifugal force, and the thickness of the coating film of the liquid material is determined by this flow. Since the belt solution is formed by casting the raw material solution on the inner surface of the mold by centrifugal force, the coating thickness is determined by the magnitude of the centrifugal force at each part of the cylindrical mold, that is, the radius of rotation. It is considered that the roundness (inner diameter waviness) had an effect on the thickness accuracy.

Test Examples The semiconductive belts produced in Examples 1 to 4 and Comparative Examples 1 to 4 were evaluated for SS curve, flatness, and glass transition point. The results are shown in Table 3.

  From Table 3, since the ratio of the breaking strength to the yield strength is high in the belts obtained in Examples 1 to 4, brittle fracture can be avoided.

  About the semiconductive belt manufactured in Examples 1-4 and Comparative Examples 1-4, the high voltage application test and the idling durability test were done. The results are shown in Table 4.

  From Table 4, the belts of Examples 1 to 4 showed almost no change (decrease) in surface resistivity even in the high voltage application test. This is considered because carbon black is in a uniformly dispersed state as continuous as possible in the plane direction. Furthermore, the belt was damaged even after 300 hours in the idling durability evaluation, and the flatness was hardly deteriorated by the durability evaluation. These results show that, for example, when used as an intermediate transfer belt, even if an excessive current is repeatedly applied, the surface resistivity does not change and a high-quality transfer image is obtained, and it is not damaged even after long-term use. Means.

The schematic of the flatness measuring method is shown. FIG. 2 shows a cross-sectional view along AA of FIG. 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 (9)

A semiconductive copolymer polyimide belt comprising 70 to 80% by weight of polyimide resin and 30 to 20% by weight of carbon black and having a surface resistivity of 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω / □,
15 to 50 mol% 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and 85 to 50 mol% 3,3', 4,4'-biphenyltetracarboxylic acid Semiconductive , obtained from a biphenyltetracarboxylic dianhydride component containing an anhydride and an aromatic diamine component containing 20 to 80 mol% 4,4'-diaminodiphenyl ether and 80 to 20 mol% p-phenylenediamine Copolymer polyimide belt. A semiconductive copolymer polyimide belt comprising 70 to 80% by weight of polyimide resin and 30 to 20% by weight of carbon black and having a surface resistivity of 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω / □,
The polyimide resin contains 15-50 mol% 2,3,3 ′, 4′-biphenyltetracarboxylic acid diester and 85-50 mol% 3,3 ′, 4,4′-biphenyltetracarboxylic acid diester. biphenyl tetracarboxylic acid diester components, obtained from an aromatic diamine component comprising 20 to 80 mole% of 4,4'-diaminodiphenyl ether and 80 to 20 mole% of p- phenylenediamine, semiconductive copolymerized polyimide belt. 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 volatile content of 2 to 5% by weight, and a nitrogen adsorption specific surface area. 80~150m ² / g, semiconductive copolymerized polyimide belt according to claim 1 or 2 dibutyl phthalate absorption of 50-100 ml / 100 g, and the amount of extracted undecomposed feedstock hydrocarbons is 10ppm or less. The tensile yield strength recorded in the stress-strain curve measured according to JIS K7113: σy is 140 MPa or more, and the relationship with the tensile rupture strength: σb is (tensile rupture strength: σb) / (tensile yield strength) S: σy) ≧ 1.1
The semiconductive copolymer polyimide belt according to any one of claims 1 to 3 , wherein: The semiconductive copolymer polyimide belt according to any one of claims 1 to 4 , wherein the flatness in the belt width direction is 2 mm or less. The semiconductive copolymer polyimide belt according to any one of claims 1 to 5 , which has a glass transition point of 280 ° C or higher. Biphenyl containing 15-50 mol% 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and 85-50 mol% 3,3', 4,4'-biphenyltetracarboxylic dianhydride A substantially equimolar amount of a tetracarboxylic dianhydride component, an aromatic diamine component containing 20 to 80 mol% of 4,4'-diaminodiphenyl ether and 80 to 20 mol% of p-phenylenediamine , and an organic polarity A polyimide precursor solution having a weight average molecular weight of 25,000 or less is produced by reacting in a solvent, and carbon black is dispersed in the polyimide precursor solution to prepare a polyimide precursor solution composition. The carbon black-dispersed polyimide precursor A method for producing a semiconductive copolymer polyimide belt in which a body solution composition is formed into a tubular product by a rotational molding method, and the molded body is heat-treated and imidized. ,
(1) A step of applying the carbon black-dispersed polyimide precursor solution composition to the inner peripheral surface of a cylindrical mold that rotates at a centrifugal acceleration of 0.5 to 10 times the gravitational acceleration.
(2) A step of forming a self-supporting film by heating the cylindrical mold at a temperature of 100 to 140 ° C. while rotating at a centrifugal acceleration of 0.5 to 10 times the gravitational acceleration, and (3) The step of imidizing by heating at a temperature of 300 ° C. or higher while the film is attached to the inner peripheral surface of the cylindrical mold,
The manufacturing method characterized by including. Biphenyl tetracarboxylic acid diester comprising 15-50 mol% 2,3,3 ', 4'-biphenyltetracarboxylic acid diester and 85-50 mol% 3,3', 4,4'-biphenyltetracarboxylic acid diester Nylon is prepared by dissolving a component and an approximately equimolar amount of an aromatic diamine component containing 20 to 80 mol% of 4,4′-diaminodiphenyl ether and 80 to 20 mol% of p-phenylenediamine in an organic polar solvent. A salt-type monomer solution is prepared, carbon black is dispersed in the nylon salt-type monomer solution to prepare a polyimide precursor solution composition, and the carbon black-dispersed polyimide precursor solution composition is formed into a tubular product by a rotational molding method. A semiconductive copolymerized polyimide belt that is molded into an imidized product by heat treatment,
(1) A step of applying the carbon black-dispersed polyimide precursor solution composition to the inner peripheral surface of a cylindrical mold that rotates at a centrifugal acceleration of 0.5 to 10 times the gravitational acceleration.
(2) A step of forming a self-supporting film by heating the cylindrical mold at a temperature of 100 to 140 ° C. while rotating at a centrifugal acceleration of 0.5 to 10 times the gravitational acceleration, and (3) The step of imidizing by heating at a temperature of 300 ° C. or higher while the film is attached to the inner peripheral surface of the cylindrical mold,
The manufacturing method characterized by including. An intermediate transfer belt for an electrophotographic apparatus comprising a semiconductive copolymer polyimide belt obtained by the production method according to claim 7 or 8 .

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