JP2005249952A - Semiconductive film and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductive seamless belt having good flexibility by suppressing the aggregation of a conductive filler with respect to a semiconductive film. <P>SOLUTION: A method for manufacturing a semiconductive film comprises a step of obtaining a homogeneous solution by preparing a semiconductive polyamide acid solution by mixing a dispersion prepared by dispersing a conductive filler in an organic polar solvent in the presence of a polymer dispersant with a polyamide acid or polymerizing the polyamide acid in the dispersion, adding predetermined amounts of an imidation catalyst and a dehydrating agent based on the amount of the polyamide acid to the semiconductive polyamide acid solution, and carrying out blending/stirring/defoaming; a step of forming a polyamide acid coating film of a uniform thickness by applying the homogeneous solution on a metallic thin film; a step of uniformly gelatinizing the coating film; and a step of heating the coating film under conditions of a sufficient temperature and time to thoroughly convert the polyamide acid to a polyimide. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a semiconductive film, and is particularly useful, for example, as an original film of a semiconductive seamless belt used in an electrophotographic image forming apparatus and a method for producing the same.

  In an electrophotographic image forming apparatus such as a copying machine, a laser beam printer, a facsimile, and a composite device thereof, generally, an electrostatic image corresponding to an image obtained by an image reading apparatus is formed on the surface of a charged photoreceptor. A latent image is formed and converted into a toner image by a developing device, and then electrostatically transferred (primary transfer) to an intermediate transfer member made of film, and then transferred again from the intermediate transfer member to paper or the like (secondary transfer). Heat fixing with a fixing belt. In addition to the intermediate transfer member, the use of a film is being studied not only for the photosensitive member and fixing that also serves as a transfer.

Conventionally, a plastic material is used as a film material for reasons such as good moldability and light weight, and this plastic material has excellent heat resistance, mechanical strength, and environmental resistance characteristics. A polyimide film using a polyimide resin has been studied. Moreover, as a characteristic requested | required of the belt material used for an electrostatic transfer system, it has a so-called medium resistance whose surface resistance value is about 10 ⁸ to 10 ¹³ Ω · cm. Therefore, a technique of incorporating a large amount of carbon black in the polyimide resin is generally used (see, for example, Patent Document 1 or 2).
JP-A-5-77252 Japanese Patent Laid-Open No. 10-63115

  However, since the synthesis and film formation of polyimide resin go through complicated processes, there is a problem due to the aggregation of carbon black, that is, there is a problem that the electrical resistance value is lowered due to variations in resistivity and an electric load during use. Such a decrease in the electric resistance value causes an excessive current to flow through the belt during transfer. Therefore, when the belt is used as an intermediate transfer belt, problems such as retransfer of toner once transferred may occur. Such a decrease in resistance leads to shortening of the life of the semiconductive belt in the electrophotographic image forming apparatus, leading to an increase in maintenance labor such as belt replacement and running cost.

  In addition, the large amount of carbon black present in the resin significantly reduces the flexibility of the resin, and when such a belt is incorporated in the apparatus, the life until a component breakage such as a crack occurs is shortened. That is, as described above, the life of the semiconductive belt in the electrophotographic image forming apparatus is shortened, leading to an increase in maintenance labor such as belt replacement and running cost.

  Therefore, the object of the present invention is to synthesize and form polyimide resin, which suppresses the aggregation of carbon black even through complicated processes, and has good flexibility even when filled with a large amount of carbon black. To provide a film.

  In order to achieve the above object, the present inventors have conducted intensive research on a semiconductive film, and can provide a semiconductive film having good flexibility by the following semiconductive film and its manufacturing method. As a result, the present invention has been completed.

  The present invention relates to a method for producing a semiconductive film, wherein (1) a conductive filler is dispersed in an organic polar solvent in the presence of a polymer dispersant to form a conductive filler dispersion, and the dispersion and the polyamic acid are combined. To the mixed semiconductive polyamic acid solution, 0.1 to 1.5 molar equivalent of an imidization catalyst with respect to amic acid and 0.1 to 3.0 molar equivalent of dehydrating agent with respect to amic acid are added. A step of obtaining a uniform solution by mixing, stirring and defoaming, (2) a step of forming a polyamic acid coating film having a uniform thickness by coating on a metal thin film, and (3) substantially And a step of uniformly gelling the coating film at a low temperature at which imidization does not occur, and (4) a step of heating at a temperature and time sufficient to completely convert the polyamic acid into polyimide. It is characterized by that. By such a manufacturing method, until the uniformly dispersed conductive filler is formed into a belt, it does not cause significant aggregation and can be rapidly chemically imidized and immobilized by using an imidization catalyst and a dehydrating agent. Therefore, it is possible to provide a semiconductive film excellent in flexibility in which variation in resistivity and reduction in electric resistance value are suppressed. Accordingly, the life of the belt can be extended, and maintenance work such as belt replacement and the running cost can be reduced.

  (1) A conductive filler is dispersed in an organic polar solvent in the presence of a polymer dispersant to form a conductive filler dispersion, and a semiconductive polyamic acid solution obtained by polymerizing polyamic acid in the dispersion is used. By adding 0.1 to 1.5 molar equivalent of an imidization catalyst with respect to amic acid and 0.1 to 3.0 molar equivalent of a dehydrating agent with respect to amic acid, mixing, stirring, and defoaming A step of obtaining a uniform solution, (2) a step of coating on a metal thin film to form a polyamic acid coating film having a uniform thickness, and (3) a low temperature at which substantially no imidization occurs, And (4) a step of heating at a temperature and a time sufficient to completely convert the polyamic acid into a polyimide. This manufacturing method prevents the aggregation of evenly dispersed conductive fillers and allows rapid chemical imidization and immobilization, thereby reducing the variation in resistivity and the decrease in electrical resistance. It is possible to provide a semiconductive film excellent in the above.

  At this time, it is preferable that the conductive filler is carbon black and the polymer dispersant contains at least poly (N-vinyl-2-pyrrolidone). Carbon black is preferable for causing the desired surface resistivity to appear with a small amount of addition, and a polymer dispersant containing poly (N-vinyl-2-pyrrolidone) is used, and the solubility in the polyamic acid solution is excellent. The dispersibility of carbon black is further enhanced by the combination with the organic polar solvent.

  The organic polar solvent is preferably composed of N, N-dimethylacetamide, N, N-dimethylformamide and N-methyl-2-pyrrolidone. Such an organic polar solvent has a low molecular weight, can be easily removed from a molded product, and has excellent characteristics of carbon black dispersibility.

  Furthermore, it is preferable that the imidization catalyst contains a tertiary amine. It can be said that the catalyst itself is suitable for the present invention in that the stability of the catalyst itself is high, the imidization can be easily controlled, and a rapid reaction does not occur.

  Further, it is preferable that the dehydrating agent contains acetic anhydride. The chemical imidization can be performed in a relatively short time, and the excellent molecular strength and dimensional stability can be obtained by the strong molecular chain formed during film formation.

  Furthermore, it is preferable that the viscosity at 5 ° C. of a resin solution composition comprising the semiconductive polyamic acid solution containing an imidization catalyst and a dehydrating agent is 70 Pa · s or less. While preventing gel-like defects, it is possible to suppress film thickness variation and bubble entrainment phenomenon and stably form a film.

  The present invention is a semiconductive film produced by any of the production methods described above, wherein the common logarithmic value of the surface resistivity of the belt is 8 to 13 (log Ω / □). To do. When used in an electrophotographic image forming apparatus, it is possible to supply an excellent seamless belt capable of suppressing the residual potential and charging variation of the photosensitive layer and obtaining an undisturbed electrostatic latent image.

  A semiconductive seamless belt produced by any one of the manufacturing methods described above, wherein the difference in surface resistivity before and after the discharge deterioration test is 2.0 (log Ω) as a common logarithmic value. / □) It is preferable that With the belt having such characteristics, it is possible to prevent a decrease in resistance due to the occurrence of partial discharge during use and a decrease in the life of the belt due to overcurrent.

  Furthermore, it is a semiconductive film produced by any one of the manufacturing methods described above, and it is preferable that the belt has a tensile elastic modulus of 4000 MPa and a folding strength of 100 times or more. With the semiconductive film having such characteristics, it is possible to provide a semiconductive film that satisfies the mechanical strength and elasticity required for a belt material used in a transfer method and the like and has excellent flexibility.

  According to the method for producing a semiconductive film of the present invention, since the uniformly dispersed conductive filler is not formed into a belt until the belt is formed, variation in resistivity and a decrease in electric resistance value are suppressed. In addition, the use of an imidization catalyst and a dehydrating agent enables rapid chemical imidization and immobilization, so that a seamless belt excellent in flexibility can be provided. If the semiconductive film of the present invention is used as a photoreceptor belt substrate or an intermediate transfer member, stable images and a long life of the belt can be achieved, and maintenance labor such as belt replacement and running cost can be reduced. By polymerizing the polyamic acid when preparing the precursor solution, it is possible to further disperse and homogenize the filler, and to produce a semiconductive film without any further variation in resistivity or reduction in electrical resistance. Can do.

  At this time, the conductive filler is carbon black, and the polymer dispersant contains at least poly (N-vinyl-2-pyrrolidone), so that a desired surface resistivity can be obtained by adding a small amount of the conductive filler. And the dispersibility of the filler is further increased.

  Moreover, when it consists of the said organic polar solvent specific substance, it has the low molecular weight, the removal from a molded article is easy, and it has the characteristic excellent in the dispersibility of carbon black.

  Furthermore, when the imidization catalyst contains a tertiary amine, the catalyst itself has high stability, is easy to control imidization, and does not cause a rapid reaction. It can be said that it is a suitable catalyst.

  Further, when the dehydrating agent contains acetic anhydride, it can be chemically imidized in a relatively short time, and can have excellent mechanical strength and dimensional stability due to a strong molecular chain formed during film formation. .

  Furthermore, when the viscosity of the resin solution composition containing the imidization catalyst and the dehydrating agent is within a predetermined range, it is possible to prevent the gel-like defects and suppress the variation in the film thickness and the bubble entrainment phenomenon, thereby stabilizing Thus, it is possible to form a film.

  For a semiconductive film having a predetermined surface resistivity produced by any one of the manufacturing methods described above, when used in an electrophotographic image forming apparatus, the residual potential of the photosensitive layer and variations in charging are suppressed. Therefore, it is possible to supply an excellent seamless belt capable of obtaining an electrostatic latent image without disturbance.

  In addition, for semiconductive films produced by any of the manufacturing methods described above and having a predetermined range of surface resistivity difference before and after the discharge deterioration test, partial discharge during use It is possible to prevent a decrease in resistance value due to the above and a decrease in the life of the belt due to overcurrent.

  Further, a mechanical material required for a belt material used in a transfer method or the like by a semiconductive film having a tensile elastic modulus and bending strength within a predetermined range, which is manufactured by any of the manufacturing methods described above. A seamless belt satisfying strength and elasticity and having excellent flexibility can be provided.

Embodiments of the present invention will be described below.
That is, the present inventors protect and disperse the conductive filler in a specific organic solvent with a specific dispersant, thereby causing the filler to agglomerate during mixing with the polyamic acid or during polymerization in the polyamic acid. I found that there was nothing. Thereby, variation in resistivity and a decrease in electric resistance value can be suppressed, and a flexible film can be produced even when a large amount of conductive filler is filled. Moreover, it discovered that the movement of the filler in the middle of film formation can be suppressed by making the precursor solution which disperse | distributed the filler uniformly chemically imidized and fix | immobilized rapidly as it is. In other words, when a semiconductive polyamic acid solution containing the conductive filler is formed, the gel is rapidly gelled at a low temperature in the presence of an imidization catalyst and a dehydrating agent. The point of the present invention is that a synergistic effect can be obtained in which the movement of the filler in the precursor solution layer can be suppressed and the dispersion can be fixed while maintaining the uniformity of the dispersed filler.

Specifically, the present invention provides a method for producing a semiconductive film,
(1) A conductive filler is dispersed in an organic solvent in the presence of a polymer dispersant to form a conductive filler dispersion, and the semiconductive polyamic acid solution obtained by mixing the dispersion and polyamic acid is mixed with amic acid. On the other hand, 0.1 to 1.5 molar equivalent of an imidization catalyst and 0.1 to 3.0 molar equivalent of a dehydrating agent with respect to amic acid are added, and a uniform solution is obtained by mixing, stirring and defoaming. Obtaining a step;
(2) A step of coating on a metal thin film to form a polyamic acid coating film having a uniform thickness;
(3) a step of uniformly gelling the coating film at a low temperature at which imidization does not substantially occur;
(4) heating at a temperature and time sufficient to completely convert the polyamic acid to polyimide;
It is characterized by comprising.

  According to the method for producing a semiconductive film comprising the above steps, significant aggregation does not occur until the uniformly dispersed conductive filler is formed into a film. For this reason, it is possible to provide a semiconductive film with excellent flexibility by suppressing variations in resistivity and a decrease in electric resistance, and by using an imidization catalyst and a dehydrating agent. Thus, maintenance work such as belt replacement and running costs can be reduced. That is, it is possible to prevent aggregation due to the imidization catalyst and the dehydrating agent by dispersing the conductive filler in advance before mixing the imidization catalyst and the dehydrating agent. Further, by mixing the dispersion and the polyamic acid, the occurrence of aggregation can be further prevented, and an excellent flexible semiconductive film can be produced.

  Furthermore, in order to imidize and fix the precursor solution having such high uniformity as it is, (2) it is applied onto a metal thin film to form a polyamic acid coating film having a uniform thickness ( 3) Gelation at low temperature, (4) Rapid chemical imidization in that state. By such a film forming method, it is possible to produce a film while maintaining the uniformity of the filler in the solution. That is, immobilization can be realized under conditions where there is no movement of the filler in the precursor solution layer due to gravity such as convection and rotational molding in thermal imidization.

Further, the present invention is a method for producing a semiconductive film,
(1) A conductive filler is dispersed in an organic solvent in the presence of a polymer dispersant to obtain a conductive filler dispersion, and a semiconductive polyamic acid solution obtained by polymerizing polyamic acid in the dispersion is mixed with amic acid. A homogeneous solution by adding 0.1 to 1.5 molar equivalents of an imidization catalyst to 0.15 molar equivalents and 0.1 to 3.0 molar equivalents of dehydrating agent to amic acid, mixing, stirring and defoaming Obtaining
(2) A step of coating on a metal thin film to form a polyamic acid coating film having a uniform thickness;
(3) a step of uniformly gelling the coating film at a low temperature at which imidization does not substantially occur;
(4) heating at a temperature and time sufficient to completely convert the polyamic acid to polyimide;
It is characterized by comprising.

  As described above, the method for producing a semiconductive film comprising the above steps can suppress a variation in resistivity and a decrease in electric resistance value, and can provide a semiconductive film excellent in flexibility. Long service life is achieved, and maintenance work such as belt replacement and running costs can be reduced. In particular, by polymerizing the polyamic acid in the dispersion, the state in which the conductive filler is dispersed can be fixed to some extent, so that it is possible to obtain a specific effect that the occurrence of aggregation can be further prevented. A more excellent flexible semiconductive film can be produced. Furthermore, in the present invention, as described above, by moving the filler as much as possible and chemically imidizing, the state of being dispersed and fixed to some extent by polymerization can be maintained as it is, and complete fixing can be achieved. A semiconductive film having excellent dispersibility and uniformity in a solution state can be obtained.

  At this time, it is preferable that the conductive filler is carbon black and the polymer dispersant contains at least poly (N-vinyl-2-pyrrolidone). That is, examples of the conductive filler include carbon black such as ketjen black and acetylene black, metal such as aluminum and nickel, metal oxide compound such as tin oxide, and conductive powder such as potassium titanate, or polyaniline and polyacetylene. 1 type (s) or 2 or more types of appropriate things, such as a conductive polymer like, can be used. Among them, carbon black such as ketjen black is preferable in order to adjust the surface resistivity and cause a desired value to appear with a small amount of addition. As for the polymer dispersant, various polymers can be used as will be described later, but by including at least poly (N-vinyl-2-pyrrolidone), it has excellent solubility in a polyamic acid solution. The dispersibility of carbon black is further enhanced by the combination with the organic polar solvent.

  The organic polar solvent is preferably composed of N, N-dimethylacetamide, N, N-dimethylformamide and N-methyl-2-pyrrolidone. That is, for the organic polar solvent, various solvents can be used as described later. In particular, the organic polar solvent as described above has a low molecular weight and can be easily removed from the molded product, and the conductive filler. In particular, the carbon black has excellent dispersibility. Therefore, by using such an organic polar solvent, a belt with little variation in surface resistivity and no reduction in electrical resistance value can be easily produced.

  Furthermore, it is preferable that the imidization catalyst contains a tertiary amine. That is, regarding the chemical imidation catalyst in the present invention, it is preferable that the stability of the catalyst itself is high, the imidization control is easy, and a rapid reaction is not caused. It can be said that it is preferable. Specific compounds of the tertiary amine will be described later.

  The present invention also provides a method for producing a semiconductive film, wherein the dehydrating agent contains acetic anhydride. Although specific compounds will be described later, chemical imidization can be performed in a relatively short time by adding an appropriate amount of a dehydrating agent, and excellent mechanical properties can be obtained by a strong molecular chain formed during film formation. Can have strength and dimensional stability. In particular, in the present invention, a dehydrating agent containing acetic anhydride is preferable.

  Furthermore, the present invention provides a semiconductive film characterized in that a resin solution composition comprising an imidization catalyst and a dehydrating agent in a semiconductive polyamic acid solution has a viscosity at 5 ° C. of 70 Pa · s or less. Provide a method. When the viscosity exceeds 70 Pa · s, the variation in the film thickness becomes remarkably high, which may cause a gel-like defect or a bubble entrainment phenomenon. Therefore, it is possible to stably form a film by controlling the viscosity before chemical imidization as described above, particularly before the coating film is produced. The viscosity here is based on the value measured using a B-type viscometer.

  Moreover, it is suitable for this invention that the common logarithm value of the surface resistivity of a semiconductive film is 8-13 (logohm / square). When the surface resistivity exceeds 13 (log Ω / □), the residual potential of the photosensitive layer increases when used in an electrophotographic image forming apparatus and the like, causing variation in charging, and electrostatic latent images tend to be disturbed. It is not preferable. Further, if the surface resistivity is less than 8 (log Ω / □), toner dust (scattering) may occur and the image quality may become coarse. The above manufacturing method is optimal for ensuring such characteristics in a seamless belt, which has been difficult with conventional methods, and easily provides a seamless belt having flexibility and stable semiconductivity. Can do. The surface resistivity referred to here is based on the value measured using the method described in <Evaluation method> described later.

  Furthermore, in the semiconductive film according to the present invention, it is preferable that the difference in surface resistivity before and after the discharge deterioration test is 2.0 (logΩ / □) or less as a common logarithmic value. If the conductive filler or the like is not uniformly dispersed in the film, in some cases, such as when used in an electrophotographic image forming apparatus, a discharge may occur, and conversely, by conducting a discharge test, Such defects can be detected. Specifically, if the difference in surface resistivity before and after the discharge deterioration test exceeds 2.0 (log Ω / □), the resistance value decreases due to the occurrence of partial discharge during use and the belt life decreases due to overcurrent. By supplying a belt that has been confirmed and selected in advance by such a test, stable transfer or the like can be performed for a long period of time. In addition, the discharge deterioration test here shall be performed on the basis of the method described in <Evaluation method> described later.

The semiconductive film according to the present invention preferably has a tensile modulus of 4000 MPa and a bending strength of 100 times or more. That is, the belt material used for the transfer method or the like is required to have a certain mechanical strength and elasticity, and if the tensile elastic modulus or the bending resistance is smaller than the above, the belt is liable to break, which is not preferable. Providing a semiconductive film excellent in strength and flexibility produced by the above production method enables stable transfer for a long period of time in an electrophotographic image forming apparatus. In addition, the tensile elasticity modulus and bending strength here are based on values measured using the method described in <Evaluation method> described later.
Hereinafter, the present invention will be described in more detail.

  First, carbon black and a polymer dispersant are added and dispersed in the organic polar solvent to prepare a carbon black dispersion. The carbon black used in the present invention has an average particle size of 5 to 100 nm, preferably 10 to 70 nm, and more preferably 15 to 60 nm. Those having an average particle diameter of less than 5 nm are substantially difficult to obtain. When the average particle diameter exceeds 100 nm, the surface roughness, mechanical strength and electrical properties of the polyimide resin composition containing the carbon black This is because it is difficult to obtain a practically satisfactory one from the viewpoint of resistance controllability. The said average particle diameter shows the average particle diameter based on the primary particle diameter measured with the electron microscope etc. In addition, the carbon black may have its electric resistance controlled by grafting a polymer on the particle surface or coating an insulating material, or may oxidize the carbon black particle surface. Examples of the carbon black used in the present invention include furnace black and channel black. Specifically, “Special Black 550”, “Special Black 350”, “Special Black 250”, “Special Black 100”, “Printex 35”, “Printex 25” manufactured by Mitsubishi Chemical, manufactured by Degussa Hichols Co., Ltd. “MA7”, “MA77”, “MA8”, “MA11”, “MA100”, “MA100R”, “MA220”, “MA230”, manufactured by Cabot Corporation, “MONARCH 1300”, “MONARCH 1100”, “MONARCH 1000” , “MONARCH 900”, “MONARCH 880”, “MONARCH 800”, “MONARCH 700”, “MOGUL L”, “REGAL 400R”, “VULCAN” C-72R ”and the like, and“ Color B1ack FW200 ”,“ Color Black FW2 ”,“ Color Black FW2V ”,“ Color Black FW1 ”,“ Color Black FW18 ”,“ S Black Black FW18 ”,“ S ”, manufactured by Degussa Huls. Black 6 ”,“ Color Black S170 ”,“ Color Black S160 ”,“ Special Black 5 ”,“ Special Black 4 ”,“ Special Black 4A ”,“ Printex 150T ”,“ PrintV ”,“ PrintV ” “Printex 140U”, “Printex 140V”, and the like, and a single type or a plurality of types of carbon black may be used in combination.

  Examples of the polymer dispersant used in the present invention include poly (N-vinyl-2-pyrrolidone), poly (N, N′-diethylacrylazide), poly (N-vinylformamide), and poly (N-vinylacetamide). , Poly (N-vinylphthalamide), poly (N-vinylsuccinamide), poly (N-vinylurea), poly (N-vinylpiperidone), poly (N-vinylcaprolactam), poly (N-vinyloxazoline), etc. And a single or a plurality of polymer dispersants can be added. In addition to this, within the scope of the object of the present invention, a polymer material, a surfactant, and a dispersion stabilizer for inorganic salt damage can be used. In the present invention, it is preferable that poly (N-vinyl-2-pyrrolidone) is contained because the dispersibility of carbon black is further increased.

  The organic polar solvent used in the present invention is not particularly limited as long as it increases the dispersibility of the conductive filler, particularly carbon black, but N, N-dialkylamides are useful. N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and the like can be mentioned. They can be easily removed from the polyamic acid and the polyamic acid molded article by evaporation, displacement or diffusion. Other organic polar solvents include N, N-diethylformamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, hexamethylphosphoric triamide, pyridine, tetramethylene sulfone, dimethyltetramethylene. And sulfone. These may be used singly or a known method can be applied as a dispersion method, and examples thereof include a ball mill, a sand mill, a basket mill, and ultrasonic dispersion.

  Next, in order to prepare a semiconductive polyamic acid solution, diamine and acid dianhydride are dissolved in an organic polar solvent, and the carbon black dispersion is added to the polyamic acid solution obtained after the polymerization reaction. A method of mixing and stirring, a method of dissolving a diamine and an acid dianhydride in the carbon black dispersion, and a polymerization reaction, etc. are mentioned. In order to make the dispersibility of carbon black uniform, the latter method is used. preferable.

  As the acid dianhydride component, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride Perylene-3,4,9,10-tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, ethylenetetracarboxylic dianhydride and the like.

Examples of the diamine include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'- Diaminodiphenylsulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3′-dimethyl-4,4′-biphenyldiamine, benzidine, 3,3′-dimethylbenzidine, 3,3 ′ -Dimethoxybenzidine, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylpropane, 2,4-bis (β-amino-t-butyl) toluene, bis (p -Β-amino-t-butylphenyl) ether, bis (p-β-methyl-t-aminophenyl) Benzyl) benzene, bis-p- (1,1-dimethyl-5-fumino-pentyl) benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine, di ( p-aminocyclohexyl) methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2 , 11-diaminododecane, 1,2-bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 5-methylno Methylenediamine, 2,11-diaminododecane, 2,17-difuminoeicosadecane, 1,4-diaminosic hexane, 1,10-diamino-1,10-dimethyldecane, 1,12-diaminooctadecane, 2 , 2-bis [4- (4-aminophenoxy) phenyl] propane, piperazine, H ₂ N (CH ₂ ) ₃ O (CH ₂ ) ₂ OCH ₂ NH ₂ , H ₂ N (CH ₂ ) ₃ S (CH ₂ ) ₃ NH ₂ , H ₂ N (CH ₂ ) ₃ N (CH ₂ ) ₂ (CH ₂ ) ₃ NH _{2 and the} like.

  An appropriate solvent can be used for the polymerization reaction of these acid dianhydrides and diamines, but an organic polar solvent is preferably used from the viewpoint of solubility and the like, and for the dispersion of carbon black and the solvent for the polymerization reaction. Those that can also be used together are more preferred.

  Regarding the blending amount of each raw material, it is necessary to experimentally examine a composition suitable for the intended use of the finally obtained polyimide resin composition. For example, the addition amount of carbon black for obtaining a semiconductive film having a common logarithmic value of surface resistivity of 8 to 13 (log Ω / □) is preferably about 10 to 40% by weight based on the polyimide resin solid content, 10-30 weight% is more preferable. In order to develop the resistance region, it is necessary to use highly conductive carbon black. When such highly conductive carbon black is added at a low addition amount of less than 10% by weight, stable resistance can be produced with good reproducibility. May be difficult. On the other hand, if it exceeds 40% by weight, the inherent high mechanical properties of the polyimide resin are impaired, brittleness is developed, and the belt end face may be cracked when the belt is driven by a plurality of drive rollers or the like.

  The monomer concentration (concentration of acid dianhydride component and diamine component in the solvent) of the semiconductive polyamic acid solution is set according to various conditions, but is preferably 5 to 30% by weight. The polymerization reaction is carried out in a nitrogen atmosphere, the reaction temperature is preferably set to 60 ° C. or less, and the reaction time is preferably about 0.5 to 10 hours. The semiconductive polyamic acid solution can be adjusted in viscosity because the solution viscosity increases as the polymerization reaction proceeds. Also, the viscosity can be adjusted by lowering the monomer concentration by adding a solvent or the like. The viscosity of the semiconductive polyamic acid solution in the present invention is usually 1 to 1000 Pa · s.

  Next, an imidization catalyst and a dehydrating agent are added to the semiconductive polyamic acid solution and mixed uniformly, and then formed on a metal thin film and converted into polyimide.

  The chemical imidation catalyst added to the polyamic acid solution according to the present invention is preferably a tertiary amine, for example, an aliphatic tertiary amine such as triethylamine, an aromatic tertiary amine such as N-dimethylaniline, And heterocyclic tertiary amines such as pyridine, picoline, quinoline and isoquinoline. These are added in an amount of 0.1 to 1.5 molar equivalents, preferably 0.4 to 1.0 molar equivalents relative to the amic acid.

  Furthermore, the dehydrating agent added to the polyamic acid solution according to the present invention includes, for example, aliphatic acid anhydrides, aromatic acid anhydrides, N, N′-dialkylcarbodiimides, lower aliphatic halides, halogenated lower aliphatic halides. , Halogenated lower fatty acid anhydrides, arylphosphonic acid dihalides, thionyl halides, or mixtures of two or more thereof. Of these, aliphatic anhydrides such as acetic anhydride, propionic anhydride, and lactic acid anhydride, or a mixture of two or more thereof are preferably used. The amount of the dehydrating agent is 0.1 to 3.0 molar equivalent, preferably 1.5 to 2.4 molar equivalent. If it is out of this range, the chemical imidation rate falls below the preferred range, or the releasability from the support is deteriorated.

  A semiconductive polyamic acid solution to which an imidization catalyst and a dehydrating agent are added is cast on a metal thin film to obtain a resin layer having a uniform thickness and high accuracy. The semiconductive polyamic acid solution to which the imidization catalyst and the dehydrating agent are added reacts at or near room temperature to convert the polyamic acid into polyimide. This chemical conversion reaction takes place at temperatures between 10 ° C. and 120 ° C., and the reaction is very rapid at higher temperatures and slower at lower temperatures. Below about 10 ° C., the chemical conversion of the polyamic acid is said to actually stop, and the temperature of the semiconductive polyamic acid solution is from before the addition of the imidization catalyst and dehydrating agent until a uniform coating is formed. Must be maintained below 10 ° C. The semiconductive polyamic acid formed into a uniform coating on a metal thin film is heated to 80 ° C. to 120 ° C. while slowly moving in a drying furnace, and the carbon black is dispersed in 1 to 5 minutes. It becomes a self-supporting gel. In order to completely remove the organic solvent and completely convert the remaining polyamic acid to polyimide, the gel is treated at a high temperature of 300 ° C. to 450 ° C. It is preferable to heat at a temperature of 320 ° C. to 420 ° C. for 5 to 60 minutes, preferably 10 to 30 minutes.

The completely imidized product is then cooled to room temperature and then released from the metal thin film to obtain the desired semiconductive film. The semiconductive film thus obtained has good flexibility, which is the object of the present invention, and is a transfer conveyance belt, an intermediate transfer belt, a transfer fixing belt, a photoreceptor belt, etc. for copying machines and printers. As a functional belt, it can exhibit excellent characteristics. At the same time, it can be used in a wide range of other fields.
Moreover, the manufacturing method of this invention is applicable to the belt used for not only the semiconductive film of the said use but every field | area.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. Evaluation items in Examples and the like were measured as follows. In addition, it cannot be overemphasized that this invention is not limited to this Example and evaluation method.

<Evaluation method>
(1) Surface resistivity and its variation With Hiresta UP, MCP-HTP16 (manufactured by Mitsubishi Chemical Co., Ltd., probe: UR-100), an applied voltage of 100 V, 10 seconds later, a surface resistivity at a measurement condition of 25 ° C. and 60% RH The surface resistivity was shown as a common logarithm value. Measurement was performed every 1000 mm, and the variation in surface resistivity was evaluated based on the fluctuation range.
(2) Discharge deterioration test By subjecting the sample to corona discharge treatment to cause discharge deterioration, the same effect as a decrease in surface resistivity due to voltage concentration can be obtained. Using the corona discharge tester, each sample obtained in Examples and Comparative Examples was subjected to voltage: 70 V, current: 3 A, electrode length 0.3 m, electrode-sample distance: 3 mm, sample moving speed: 0.45 m / Corona discharge treatment was performed under the condition of min, and the surface resistivity before treatment and after treatment was measured to determine the amount of decrease in surface resistivity (Δρs).
(3) Tensile modulus According to JIS K6301, a dumbbell No. 3 punched specimen (width 5 mm) was examined.
(4) Folding strength
According to JIS P8110, the number of reciprocal bendings until the test piece (total length 110 mm / width 15 mm) broke was measured.

<Example 1>
200 g of carbon black (MA100, manufactured by Mitsubishi Chemical Corporation, furnace black, average particle diameter 22 nm based on primary particles) and 100 g of poly (N-vinyl-2-pyrrolidone) are added to 1700 g of N-methyl-2-pyrrolidone (NMP). did. After being dispersed by stirring at room temperature for 12 hours in a pole mill, it was filtered through # 400 stainless steel mesh to obtain a carbon dispersion having a carbon concentration of 10%. 192.39 g of this carbon liquid was transferred to a 5000 mL four-necked flask, charged with 20.0.13 g of N-methyl-2-pyrrolidone and 227.09 g (2.1 mol) of p-phenylenediamine, and dissolved while stirring at room temperature. . Next, 617.86 g (2.1 mol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was added, reacted at 20 ° C. for 1 hour, and then heated at 75 ° C. for 20 hours. By stirring the solution, a carbon black-containing polyimide precursor solution having a solution viscosity of 160 Pa · s as measured by a B-type viscometer (solid content concentration: 20 wt%, carbon black addition amount resin: 25 parts) was obtained. The carbon black-containing polyimide precursor solution was filtered using a # 800 stainless mesh to obtain a varnish for forming a semiconductive film.

  Next, 0.5 molar equivalent of isoquinoline and 2.0 molar equivalent of acetic anhydride are added to the amic acid of the semiconductive film-forming varnish cooled to 5 ° C., and after uniform stirring and defoaming, A dispenser was applied to a thin film made of aluminum (100 μm) having a width of 200 mm and a length of 10 m so as to have a thickness of 600 μm. The varnish viscosity at this time was 50 Pa · s at 5 ° C. So far, the solution temperature has been maintained at 5 ° C. Next, hot air at 100 ° C. was blown from the aluminum thin film surface for 5 minutes to cause gelation, followed by continuous heat treatment at 300 ° C. for 2 minutes and 380 ° C. for 10 minutes to complete solvent removal and imidization. It was. Then, it cooled and peeled from the metal mold | die and obtained a 75 micrometer semiconductive film.

<Example 2>
144.93 g of the carbon liquid obtained in Example 1 was transferred to a 5000 mL four-necked flask, 153.22 g of N-methyl-2-pyrrolidone, 129.77 g (1.2 mol) of p-phenylenediamine, and 4,4 '-Diaminodiphenyl ether (6006 g, 0.3 mol) was charged and dissolved while stirring at room temperature. Next, 441.33 g (1.5 mol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was added, reacted at a temperature of 20 ° C. for 1 hour, and then heated at 75 ° C. for 20 hours. By stirring the solution, a carbon black-containing polyimide precursor solution having a solution viscosity of 130 Pa · s as determined by a B-type viscometer (solid content concentration 20 wt%, carbon black addition amount resin 25 parts) was obtained. The carbon black-containing polyimide precursor solution was filtered using a # 800 stainless mesh to obtain a varnish for forming a semiconductive film.

  Next, 0.2 molar equivalents of isoquinoline and 2.0 molar equivalents of acetic anhydride are added to the amic acid of the varnish for forming a semiconductive film cooled to 5 ° C., followed by uniform stirring and defoaming. The film was applied to a thickness of 600 μm on a thin film made of aluminum (100 μm) having a width of 200 mm and a length of 10 m using a dispenser. The varnish viscosity at this time was 50 Pa · s at 5 ° C. So far, the solution temperature has been maintained at 5 ° C. Next, hot air at 100 ° C. was blown from the aluminum thin film surface for 5 minutes to cause gelation, followed by continuous heat treatment at 300 ° C. for 5 minutes and 380 ° C. for 10 minutes to complete solvent removal and imidization. It was. Then, it cooled and peeled from the metal mold | die and obtained a 75 micrometer semiconductive film.

<Comparative Example 1>
A film having an average thickness of 75 μm was obtained in the same manner as in Example 1 except that the imidization catalyst was changed to 0.1 molar equivalent relative to the amic acid.

<Comparative example 2>
A film having an average thickness of 76 μm was obtained in the same manner as in Example 1 except that the imidization catalyst and the dehydrating agent were not used.

<Comparative Example 3>
A film having an average thickness of 76 μm was obtained in the same manner as in Example 2 except that the imidization catalyst and the dehydrating agent were not used.

<Comparative example 4>
A film having an average thickness of 75 μm was obtained in the same manner as in Example 1 except that the dispersant was not used.

<Comparative Example 5>
A film having an average thickness of 76 μm was obtained in the same manner as in Example 1 except that the dispersant, the imidization catalyst, and the dehydrating agent were not used.

<Evaluation results>
The evaluation results of the above examples and comparative examples are summarized in Table 1.

表１の結果より、本発明の分散剤を用い、イミド化触媒及び脱水剤の存在下で製膜すれば、表面抵抗のばらつきが小さくかつ可撓性のあるフィルムが得られることは明らかである。

From the results in Table 1, it is clear that if the dispersant of the present invention is used and film formation is performed in the presence of an imidization catalyst and a dehydrating agent, a flexible film having a small variation in surface resistance can be obtained. .

The foregoing has mainly described the polyimide resin, but it goes without saying that the same technique can be applied to other resins. For example, polyamide imide, polybenzimidazole, etc. are mentioned.

Claims (10)

  (1) A conductive filler is dispersed in an organic polar solvent in the presence of a polymer dispersant to form a conductive filler dispersion, and the semiconductive polyamic acid solution obtained by mixing the dispersion and polyamic acid is mixed with amic acid. A homogeneous solution by adding 0.1 to 1.5 molar equivalents of an imidization catalyst to 0.15 molar equivalents and 0.1 to 3.0 molar equivalents of dehydrating agent to amic acid, and mixing, stirring, and defoaming (2) a step of forming a polyamic acid coating film having a uniform thickness by coating on a metal thin film, and (3) a coating film at a low temperature at which substantially no imidization occurs. A method for producing a semiconductive film, comprising: a step of uniformly gelling; and (4) a step of heating at a temperature and time sufficient to completely convert the polyamic acid into a polyimide.   (1) A conductive filler is dispersed in an organic polar solvent in the presence of a polymer dispersant to form a conductive filler dispersion, and the amide is added to the semiconductive polyamic acid solution obtained by polymerizing the polyamic acid in the dispersion. Uniform by adding 0.1 to 1.5 molar equivalent of imidization catalyst to acid and 0.1 to 3.0 molar equivalent of dehydrating agent to amic acid, mixing, stirring and degassing A step of obtaining a solution; (2) a step of forming a polyamic acid coating film having a uniform thickness by coating on a metal thin film; and (3) a coating film at a low temperature at which substantially no imidization occurs. And (4) a step of heating at a temperature and a time sufficient to completely convert the polyamic acid into a polyimide, and a method for producing a semiconductive film comprising the steps of: .   The method for producing a semiconductive film according to claim 1 or 2, wherein the conductive filler is carbon black, and the polymer dispersant contains at least poly (N-vinyl-2-pyrrolidone).   The semiconductive film according to any one of claims 1 to 3, wherein the organic polar solvent comprises N, N-dimethylacetamide, N, N-dimethylformamide and N-methyl-2 monopyrrolidone. Production method.   The method for producing a semiconductive film according to claim 1, wherein the imidization catalyst contains a tertiary amine.   The method for producing a semiconductive film according to any one of claims 1 to 5, wherein the dehydrating agent contains acetic anhydride.   The viscosity at 5 ° C of a resin solution composition comprising an imidization catalyst and a dehydrating agent in the semiconductive polyamic acid solution is 70 Pa · s or less. A method for producing a semiconductive film.   A semiconductive film produced by the production method according to claim 1, wherein the common logarithm of the surface resistivity of the film is 8 to 13 (log Ω / □). Semiconductive film.   It is a semiconductive film produced by the manufacturing method in any one of Claims 1-7, Comprising: The difference of the surface resistivity before a discharge deterioration test and a discharge deterioration test is 2.0 (normal logarithm value). logΩ / □) or less, a semiconductive film.   A semiconductive film produced by the production method according to claim 1, wherein the film has a tensile elastic modulus of 4000 MPa and a folding strength of 100 times or more. Conductive film.