JP2009241403A - Manufacturing process and manufacturing equipment of seamless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing process and equipment of seamless belt comprising mainly a polyimide which can reduce a poor appearance and increase accuracy of a thickness. <P>SOLUTION: A manufacturing process of manufacturing a seamless belt comprises extruding at the same time a first polyamide acid solution (11) and a second polyamide acid solution (12) through a cyclic multi-layered die (20) into the inner part of a cylindrical die (30), whereby a multi-layered cylindrical body (18) comprising a first cylindrical layer (16) composed of the first polyamide solution (11) and a second cylindrical layer (17) covering an outer periphery of the first cylindrical layer (16) and comprising the second polyamide acid solution (12) is formed on the inner surface of the cylindrical die (30), wherein gas is introduced in an intermediate hollow part of a multi-cylindrical film (15) containing the first and the second polyamide solutions (11, 12), which is extruded through the cyclic multi-layered die (20). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a multilayer seamless belt mainly composed of polyimide, and a manufacturing apparatus.

  In recent years, fixing belts, transfer conveyance belts, intermediate transfer belts, transfer fixing belts, and photoreceptor belts used in various image forming apparatuses have been required to have high speed and high image quality. Is desired. Materials for seamless belts used in image forming apparatuses include polycarbonate (PC), polyvinylidene fluoride (PVDF), polyalkylene phthalate (PAT), PC / PAT blend materials, ethylene tetrafluoroethylene copolymer (ETFE), etc. These thermoplastic resins are used. Moreover, as a manufacturing method of a seamless belt, the method disclosed by patent documents 1-6 etc. is proposed, for example.

  However, in the methods disclosed in Patent Documents 1 to 6, depending on the manufacturing conditions such as the material application conditions, there is a possibility that appearance defects such as waving and warping may occur on the surface of the seamless belt.

  On the other hand, polyimide is usually used as a material for a seamless belt excellent in mechanical properties and heat resistance. For a seamless belt mainly composed of polyimide, for example, a polyamic acid solution (polyimide resin precursor) in which polyamic acid and a conductive material are dissolved (or dispersed) in a solvent is prepared, and this solution is used as a cylindrical mold. After being applied to the inner surface of the film, it is obtained by drying and curing.

  When the above-described seamless belt mainly composed of polyimide is configured as a single layer type, there is a possibility that the balance between flexibility and rigidity may be deteriorated when applied to an intermediate transfer belt or a transfer conveyance belt. Also, depending on the application of the seamless belt, it was necessary to change the surface resistance, wear resistance, linear expansion coefficient, etc. between the inner and outer peripheral sides of the seamless belt. It was difficult to change the characteristics of the peripheral side and the outer peripheral side.

  In order to solve the above problem, in Patent Document 7, a polyamic acid solution for forming an inner layer is applied to the outer peripheral surface of a metal core, and then a polyamic acid solution for forming an outer layer is applied, There has been proposed a method of forming a multilayer seamless belt by forming a multilayer cylindrical body made of a polyimide resin precursor and then heating and drying the multilayer cylindrical body. However, in this method, since the polyamic acid solution is applied in two steps, the manufacturing process may be complicated.

  On the other hand, Patent Document 8 proposes a method of forming a multilayer seamless tube made of a polyvinylidene fluoride resin by coextrusion molding using an annular multilayer die. According to this method, since it is multilayered by coextrusion molding, the manufacturing process can be shortened.

JP-A-3-89357 Japanese Patent Laid-Open No. 62-019437 Japanese Patent Laid-Open No. 3-180309 JP 2002-18872 A JP 2000-094461 A JP 2000-263568 A JP 2005-24873 A JP 2007-72240 A

  However, when the method of the above-mentioned Patent Document 8 is adopted as a method for producing a multilayer seamless belt mainly composed of polyimide, there is a risk that the thickness accuracy is lowered because the viscosity of the polyamic acid solution as a material is high.

  The present invention provides a method and an apparatus for manufacturing a multilayer seamless belt mainly composed of polyimide, which can reduce the appearance defect and improve the thickness accuracy.

  The method for producing a seamless belt according to the present invention includes simultaneously extruding a first polyamic acid solution and a second polyamic acid solution from an annular multilayer die into the inside of a cylindrical mold, and forming the first polyamide on the inner surface of the cylindrical mold. A seamless belt manufacturing method for forming a multilayered cylindrical body including a first cylindrical layer made of an acid solution and a second cylindrical layer covering the outer periphery of the first cylindrical layer and made of the second polyamic acid solution The gas is injected into the hollow portion of the multilayered tubular membrane containing the first and second polyamic acid solutions extruded from the annular multilayer die.

  According to the seamless belt manufacturing method of the present invention, the polyamic acid is maintained while maintaining the cylindrical shape of the multilayer tubular membrane by injecting gas into the hollow portion of the multilayer tubular membrane containing the first and second polyamic acid solutions. The solution can be extruded. Therefore, since a multilayer cylindrical body having a uniform thickness can be formed on the inner surface of the cylindrical mold, it is possible to reduce the appearance defect and improve the thickness accuracy.

  In the seamless belt manufacturing method of the present invention, before extruding the first and second polyamic acid solutions, the annular multilayer die is disposed inside the cylindrical mold opened vertically upward, and the first and second 2 When extruding the polyamic acid solution, it is preferable to extrude the annular multilayer die while moving the annular multilayer die relative to the cylindrical mold in the vertical direction. By such a method, a uniform thickness can be ensured by using the fall of the polyamic acid solution due to its own weight, and the axial length of the formed multilayer cylindrical body can be controlled by the stop position of the annular multilayer die.

  In the seamless belt manufacturing method of the present invention, it is preferable that an inner diameter of the cylindrical mold is 1.07 times or less of an outer peripheral die lip diameter of the annular multilayer die. In this case, since the expansion of the multilayer cylindrical film is limited, the pressurizing effect by the gas injection works more effectively for the uniform rolling of the multilayer cylindrical film than the expansion of the multilayer cylindrical film. As a result, the thickness accuracy can be easily improved, and variations in characteristics such as surface resistance can be suppressed.

  The first and second polyamic acid solutions preferably each have a viscosity of 200 to 1000 Pa · s as measured by a Brookfield viscometer (B type viscometer) at 25 ° C. When the viscosity is within this range, the thickness accuracy can be easily improved.

  The seamless belt manufacturing apparatus of the present invention includes a cylindrical mold and an annular multilayer die for simultaneously extruding the first polyamic acid solution and the second polyamic acid solution into the cylindrical mold, On the inner surface of the cylindrical mold, a first cylindrical layer made of the first polyamic acid solution and a second cylindrical layer covering the outer periphery of the first cylindrical layer and made of the second polyamic acid solution A seamless belt manufacturing apparatus for forming a multi-layered cylindrical body including gas that injects gas into a hollow portion of a multi-layered cylindrical film that is extruded from the annular multi-layer die and includes the first and second polyamic acid solutions. Injecting means is provided.

  According to the seamless belt manufacturing apparatus of the present invention, since the gas injection means for injecting gas into the hollow portion of the multilayer tubular membrane containing the first and second polyamic acid solutions is provided, the cylindrical shape of the multilayer tubular membrane is maintained. While the polyamic acid solution can be extruded. Therefore, since a multilayer cylindrical body having a uniform thickness can be formed on the inner surface of the cylindrical mold, it is possible to reduce the appearance defect and improve the thickness accuracy.

  When the seamless belt manufacturing apparatus of the present invention further includes a control means, the control means inserts the first and second polyamic acid solutions into the cylindrical mold opened vertically upward before pushing out the first and second polyamic acid solutions. When the annular multilayer die is disposed and the first and second polyamic acid solutions are pushed out, it is preferable that the annular multilayer die is controlled to move in the vertical direction relative to the cylindrical mold. With this configuration, it is possible to secure a uniform thickness by utilizing the fall of the polyamic acid solution due to its own weight, and to control the axial length of the formed multilayer cylindrical body by the stop position of the annular multilayer die.

  In the seamless belt manufacturing apparatus of the present invention, the inner diameter of the cylindrical mold is preferably 1.07 times or less of the outer peripheral die lip diameter of the annular multilayer die. In this case, since the expansion of the multilayer cylindrical film is limited, the pressurizing effect by the gas injection works more effectively for the uniform rolling of the multilayer cylindrical film than the expansion of the multilayer cylindrical film. As a result, the thickness accuracy can be easily improved, and variations in characteristics such as surface resistance can be suppressed.

  Hereinafter, embodiments of the present invention will be described.

  In the production method and production apparatus of the present invention, at least two types of polyamic acid solutions (first and second polyamic acid solutions) are used. Examples of the preparation method include a method obtained by reacting acid dianhydride or a derivative thereof and diamine in approximately equimolar amounts and reacting them in an organic solvent. The material composition of the first polyamic acid solution and the second polyamic acid solution can be appropriately selected according to the required performance. In the case of producing a multilayer seamless belt having three or more layers, three or more types of polyamic acid solutions may be used.

  Examples of suitable acid dianhydrides include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic acid Dianhydride, 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride Anhydrides, 1,4,5,8-naphthalenetetracarboxylic dianhydride and the like can be mentioned.

  Examples of suitable diamines 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′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenylpropane and the like can be mentioned.

  Examples of suitable organic solvents include acetone, chloroform, methyl ethyl ketone, tetrahydrofuran, dioxane, acetonitrile, alcohol solvents (methanol, ethanol, isopropanol, etc.), N, N-dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone. (NMP) or the like can be used, but N, N-dimethylacetamide, NMP, and dimethylformamide, which are polar amide solvents, are preferable.

  Moreover, additives such as a conductive material may be added to the polyamic acid solution used in the present invention. For example, when the seamless belt manufactured in the present invention is used for an intermediate transfer member, a transfer carrier, a transfer fixing member, etc., various carbon, aluminum, nickel, tin oxide, potassium titanate are used to obtain semiconductivity. An electrically conductive material such as an inorganic compound such as polyaniline or polypyrrole is added to the polyamic acid solution. In this case, in order to suppress variation in the surface resistance of the seamless belt, it is preferable to uniformly disperse the conductive material in the polyamic acid solution.

  The content of these conductive materials can be appropriately selected according to the type of the conductive material, but is preferably 5 to 50% by weight, more preferably 7 to 40% by weight with respect to the polyamic acid. When this content is 5% by weight or more, the uniformity of the surface resistance can be improved. On the other hand, when it is 50% by weight or less, the mechanical strength of the seamless belt can be ensured. Note that the content of the conductive material may be changed between the first polyamic acid solution and the second polyamic acid solution.

  The plural polyamic acid solutions used in the present invention can be appropriately selected in material composition according to the required performance. From the viewpoint of improving the thickness accuracy, a B-type viscometer at 25 ° C. It is preferable to adjust the concentration of each material so that the viscosity is 200 to 1000 Pa · s.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an example of the manufacturing apparatus of the present invention. FIG. 2 is a schematic sectional view of an annular multilayer die used in the manufacturing apparatus of FIG.

  As shown in FIG. 1, the manufacturing apparatus 1 includes a control means 10, an annular multilayer die 20, a hydraulic cylinder mechanism 28, a cylindrical mold 30, supply machines 40 a and 40 b, hoppers 50 a and 50 b, a gas injection means 60, and a pneumatic cylinder. It has a mechanism 61, a compressor 70, and other components not shown. A specific manufacturing procedure by the manufacturing apparatus 1 will be described later. In the manufacturing apparatus 1, gas injection means is provided in the hollow portion of the multilayer cylindrical film 15 (see FIGS. 3A to 3C described later) extruded from the annular multilayer die 20. Since gas is injected using 60, the polyamic acid solution can be extruded while maintaining the cylindrical shape of the multilayered cylindrical film 15. Therefore, since the smoothness of the surface of the multilayer cylindrical film 15 can be ensured, the multilayer cylindrical body 18 (see FIG. 3D described later) having a uniform thickness can be formed on the inner surface of the cylindrical mold 30. Thereby, the appearance defect of the seamless belt can be reduced and the thickness accuracy can be improved.

  The control means 10 operates the feeders 40a and 40b based on the set values of the manufacturing conditions input by the user via an input means (not shown) such as a touch panel or buttons, or stored in advance in the memory. The operation of the annular multilayer die 20 in the vertical direction, the operation of the gas injection means 60, and the like are controlled. The control means 10 can be usually realized by a CPU, a memory or the like.

  As shown in FIG. 2, the annular multilayer die 20 includes a first flow path 21 through which the first polyamic acid solution 11 flows, a second flow path 22 through which the second polyamic acid solution 12 flows, An annular discharge port 23 communicating with the first and second flow paths 21 and 22 is formed. Each of the first and second flow paths 21 and 22 has an annular cut surface in a direction orthogonal to the flow direction, and the second flow path 22 is disposed on the outer peripheral side of the first flow path 21. The first polyamic acid solution 11 is supplied from the feeder 40 a (see FIG. 1) to the annular multilayer die 20 and flows through the first flow path 21. On the other hand, the second polyamic acid solution 12 is supplied from the feeder 40 b (see FIG. 1) to the annular multilayer die 20 and flows through the second flow path 22. Then, the first polyamic acid solution 11 and the second polyamic acid solution 12 merge at the connection portion 24 where the first flow path 21 and the second flow path 22 are connected, and are pushed out from the annular discharge port 23. Here, since the first and second polyamic acid solutions 11 and 12 are high in viscosity, the first and second polyamic acid solutions 11 and 12 are extruded from the annular discharge port 23 as a multilayered cylindrical film 15 having two layers without being compatible. In addition, 1-20 mm is preferable and, as for the space | interval L of the annular discharge port 23 and the connection part 24, 1-10 mm is more preferable. Within this range, the thickness of each layer of the multilayer cylindrical film 15 can be prevented from varying due to the influence of the discharge pressure. Further, when changing the thickness of each layer in the obtained multilayer cylindrical body 18, the first and second flow paths 21 and 22 are changed in cross-sectional area so that the desired thickness ratio is obtained. What is necessary is just to adjust the discharge amount of 2 polyamic-acid solutions 11 and 12. The discharge amount of the first and second polyamic acid solutions 11 and 12 can also be adjusted by changing the discharge pressure of the first and second polyamic acid solutions 11 and 12.

The inner diameter D ₁ (see FIG. 1) of the cylindrical mold 30 is preferably 1.07 times or less, and 1.04 times or less of the outer peripheral die lip diameter D ₂ (see FIG. 2) of the annular multilayer die 20. It is more preferable. In this case, since the expansion of the multilayer cylindrical film 15 is limited, the pressurizing effect by the gas injection is more effective for the uniform rolling of the multilayer cylindrical film 15 than the expansion of the multilayer cylindrical film 15. work. As a result, the thickness accuracy can be easily improved, and variations in characteristics such as surface resistance can be suppressed. On the other hand, in order to easily maintain the cylindrical shape of the multilayer cylindrical film 15, the inner diameter D ₁ of the cylindrical mold 30 should be 1.02 times or more the outer peripheral die lip diameter D ₂ of the annular multilayer die 20. Preferably, it is 1.03 times or more. In order to obtain a seamless belt applied to the intermediate transfer belt or the transfer conveyance belt, the inner diameter D ₁ of the cylindrical mold 30, the outer peripheral die lip diameter D ₂ of the annular multilayer die 20, and the inner peripheral die lip diameter D of the annular multilayer die 20. ₃ (see FIG. 2) may be, for example, about 80 to 500 mm, 70 to 467 mm, and 69 to 466 mm, respectively.

  Moreover, as shown in FIG. 1, the cylindrical mold 30 is opened vertically upward. The annular multilayer die 20 is configured to be insertable into the cylindrical mold 30 by a hydraulic cylinder mechanism 28. When the annular multilayer die 20 is inserted into the cylindrical mold 30, the gap between the annular multilayer die 20 and the inner surface of the cylindrical mold 30 is preferably set in the range of 1 mm to 100 mm. Within this range, the inner surface of the cylindrical mold 30 is not damaged, and the expansion ratio of the multilayer cylindrical film 15 can be regulated within a range in which the thickness accuracy can be improved. The hydraulic cylinder mechanism 28 is controlled by the control means 10.

  The material of the annular multilayer die 20 and the cylindrical mold 30 is preferably a heat-resistant material such as stainless steel, aluminum, or glass. For example, when the inner wall 30a of the cylindrical mold 30 is coated with an organosilicon acid compound such as a silicone resin, polyimide resin, or the like, releasability can be imparted to the inner wall 30a of the cylindrical mold 30. . When the inner wall 30a of the cylindrical mold 30 has releasability, the seamless belt can be easily removed from the cylindrical mold 30 in the manufacturing method described later.

  The cylindrical mold 30 of the present embodiment has a bottom portion, and a hole 31 for injecting gas is formed in the bottom portion. In addition, although the diameter of this hole 31 is not specifically limited, 1-10 mm is preferable from a viewpoint of an improvement of thickness precision, and 2-5 mm is more preferable.

  The feeder 40a receives the first polyamic acid solution 11 from the hopper 50a, and supplies (pumps) the first polyamic acid solution 11 to the annular multilayer die 20 based on a command from the control means 10. Similarly, the feeder 40b receives the second polyamic acid solution 12 from the hopper 50b, and supplies (pumps) the second polyamic acid solution 12 to the annular multilayer die 20 based on a command from the control means 10. Although supply machine 40a, 40b is not specifically limited, For example, the extruder which mainly has a gear pump, a monono pump, or a screw, a cylinder, and a drive device is preferable.

  The gas injection means 60 has a function of injecting the gas supplied from the compressor 70 into the cylindrical mold 30 through the injection nozzle 62. As this gas injection means 60, a mass flow meter (mass flow flow meter), a float area type flow meter, etc. can be used, for example. It is preferable to use air as the gas to be injected because it is readily available. However, if the reactivity during resin molding or the heat capacity of the gas is affected, other highly stable gases such as nitrogen, argon, or helium Can also be used. The gas injection means 60 may be fixed to the hole 31 without using the injection nozzle 62.

  When injecting gas by the gas injection means 60, it is desirable to inject so that the internal pressure of the hollow part of the multilayer cylindrical membrane 15 becomes substantially constant. Even when the annular multilayer die 20 moves relative to the cylindrical mold 30, the expansion ratio of the multilayer cylindrical film 15 is maintained substantially constant and the thickness is maintained by making the internal pressure substantially constant. It is possible to prevent the variation of.

  In the present embodiment, the gas injection means 60 is configured to be operable in the vertical direction by the atmospheric pressure cylinder mechanism 61. Therefore, it is also possible to insert the injection nozzle 62 from the hole 31 and inject the gas while raising the injection nozzle 62 as the annular multilayer die 20 moves upward.

  The nozzle opening of the injection nozzle 62 is usually preferably opened vertically upward, but may be opened horizontally. It is also possible to provide a plurality of injection nozzles 62.

  In the present embodiment, the case where the gas injection means 60 injects gas from the bottom side of the cylindrical mold 30 is illustrated, but the present invention is not limited thereto, and the annular multilayer die 20 is provided with gas injection means, It is good also as a structure which inject | pours gas, pushing out a polyamic-acid solution.

  The compressor 70 supplies gas (not shown) to the gas injection means 60. The compressor 70 supplies gas (not shown) to the atmospheric pressure cylinder mechanism 61 to control the vertical operation of the gas injection means 60. The compressor 70 is controlled by the control means 10.

  In the present embodiment, the entire operation of the manufacturing apparatus 1 is controlled by the control means 10, but the present invention is not limited to this, and may be configured to operate each element manually, for example. .

  Next, an example of the manufacturing method of the present invention will be described with reference to FIGS. 1 and 2 and FIGS. 3A to 3D are schematic process diagrams showing an example of the manufacturing method of the present invention. In addition, in the following description, although demonstrated using the component of the manufacturing apparatus 1 demonstrated above, the manufacturing method of this invention is not limited to the method manufactured with the manufacturing apparatus 1, It applies to other apparatuses. Applicable.

  The present embodiment described below mainly includes a step of forming a multilayered cylindrical body 18 composed of the first and second polyamic acid solutions 11 and 12, which is a characteristic part of the present invention, and drying performed subsequently thereto. A process and an imidization process.

  First, first and second polyamic acid solutions 11 and 12 are prepared and poured into hoppers 50a and 50b, respectively. At this time, when the control means 10 detects that the first and second polyamic acid solutions 11 and 12 are more than a predetermined amount, the control means 10 opens the ball valves (not shown) at the bottoms of the hoppers 50a and 50b, and supplies the feeder 40a. , 40b is controlled to supply the first and second polyamic acid solutions 11, 12 respectively.

  Next, the annular multilayer die 20 is inserted into a predetermined position in the vertical lower part of the cylindrical mold 30 by the hydraulic cylinder mechanism 28. Here, the position where the annular multilayer die 20 is inserted can be arbitrarily set, but is preferably in the range of 1 mm to 100 mm from the bottom surface of the cylindrical mold 30, and more preferably in the range of 2 mm to 50 mm. Within this range, the control of the hydraulic cylinder mechanism 28 can be facilitated, and the first and second polyamic acid solutions 11 and 12 can be prevented from being bent or drawn down.

  Further, the gas injection means 60 is disposed in the hole 31 through the injection nozzle 62 by the atmospheric pressure cylinder mechanism 61. This arranging operation may be performed before or after the inserting operation of the annular multilayer die 20 or may be performed simultaneously. The injection nozzle 62 may be fixed to the hole 31 in advance.

  Next, the feeders 40 a and 40 b apply pressure to the first and second polyamic acid solutions 11 and 12, respectively, and send them to the annular multilayer die 20. The fed first and second polyamic acid solutions 11 and 12 flow through the first and second flow paths 21 and 22, respectively, and are pushed out from the annular discharge port 23 as a multilayer cylindrical film 15. Then, as shown in FIGS. 3A to 3C, along with this extrusion, the hydraulic cylinder mechanism 28 moves the annular multilayer die 20 vertically upward. Further, the gas is injected into the hollow portion of the multilayer cylindrical film 15 by the gas injection means 60 together with the extrusion of the first and second polyamic acid solutions 11 and 12. As a result, the multilayer cylindrical film 15 expands toward the inner surface side of the cylindrical mold 30 and contacts the inner surface of the cylindrical mold 30. At this stage, the multilayer cylindrical film 15 may not be in contact with the inner surface of the cylindrical mold 30.

  When the annular multilayer die 20 is raised, the first and second polyamic acid solutions 11 and 12 are dropped so that the lower ends of the first and second polyamic acid solutions 11 and 12 are always in contact with the bottom surface of the cylindrical mold 30. It is preferable to increase in accordance with the speed. By supporting the lower ends of the first and second polyamic acid solutions 11 and 12 by the bottom surface of the cylindrical mold 30 and reducing the falling speed of these, a pool of the solution is generated in the lower part of the cylindrical mold 30. This is because it is possible to prevent the occurrence of uneven thickness of the multilayer cylindrical film 15.

  The pressure of the gas injected into the hollow portion of the multilayer cylindrical film 15 (hereinafter also referred to as blow pressure) is not particularly limited, but is preferably 4 to 6 MPa, and preferably 5 to 5.5 MPa from the viewpoint of improving the thickness accuracy. More preferred.

  When the length of the multilayer cylindrical film 15 in the axial direction reaches a predetermined length, the feeders 40a and 40b stop pumping the first and second polyamic acid solutions 11 and 12, respectively. The hydraulic cylinder mechanism 28 stops the raising operation of the annular multilayer die 20. In this way, as shown in FIG. 3D, the inner surface of the cylindrical mold 30 covers the first cylindrical layer 16 made of the first polyamic acid solution 11 and the outer periphery of the first cylindrical layer 16, and A multilayer cylindrical body 18 composed of the second cylindrical layer 17 composed of the 2 polyamic acid solution 12 is formed. According to this method, a uniform thickness is ensured by utilizing the falling weight of the first and second polyamic acid solutions 11 and 12, and the multilayer cylindrical body 18 is formed depending on the stop position of the annular multilayer die 20. The length in the axial direction can be controlled. If the multi-layered cylindrical film 15 is not in contact with the inner surface of the cylindrical mold 30 at the stage where the pumping of the first and second polyamic acid solutions 11 and 12 is stopped, the multilayer pressure can be increased by increasing the blow pressure. The tubular film 15 may be expanded to bring the multilayer tubular film 15 into contact with the inner surface of the tubular mold 30.

  In this method, when the annular multilayer die 20 is moved, the thickness of the multilayer cylindrical film 15 can be controlled by adjusting the moving speed. That is, when the annular multilayer die 20 is moved at the same speed as the falling speed of the first and second polyamic acid solutions 11 and 12, the thickness of the multilayer tubular film 15 pushed out from the annular multilayer die 20 can be maintained. On the other hand, if it is moved at a speed slower than the self-weight fall speed, the thickness of the multilayer tubular film 15 can be increased. Conversely, if it is moved at a speed faster than the self-weight drop speed, the multi-layer tubular film 15 Can be made thinner. Moreover, the thickness adjustment of the multilayer cylindrical film 15 can be performed by controlling the blow pressure and the extrusion amount of the first and second polyamic acid solutions 11 and 12, and by adjusting these together, More precise thickness control is possible. Of these, the method of controlling the thickness by adjusting the blow pressure is preferable because it enables very simple and quick response control.

  Next, the cylindrical mold 30 is rotated at a predetermined rotational speed (for example, about 1000 to 2000 rpm) around its axis to perform leveling and defoaming of the coating surface.

  Next, the multilayer cylindrical body 18 formed on the inner surface of the cylindrical mold 30 is heated. First, primary heating is performed until the multilayer cylindrical body 18 can be self-supported. The heating temperature at this time is not particularly limited as long as it can evaporate the solvent used, and can be appropriately set, but is usually about 80 to 230 ° C. The heating time is appropriately set according to the heating temperature, and is usually about 10 to 60 minutes.

  Next, by secondary heating, imidation reaction, removal of residual solvent, and removal of ring-closing water are performed. The temperature of the secondary heating is not particularly limited as long as it is a temperature suitable for this purpose, but is usually about 250 ° C to 400 ° C. The heating time is appropriately set according to the heating temperature, and is usually about 10 to 60 minutes.

  Note that the primary and secondary heating are preferably performed while rotating the cylindrical mold 30 as described above. This is because variations in characteristics of the seamless belt can be reduced by heating and fixing while rotating at a predetermined rotation speed.

  Thereafter, the seamless belt formed by cooling to room temperature and curing the multilayer cylindrical body 18 is peeled off from the cylindrical mold 30. In addition, it is preferable to apply a release agent such as a silicone resin to the inner surface of the cylindrical mold 30 in advance since the workability of the seamless belt can be improved.

  As mentioned above, although an example of embodiment of this invention was demonstrated, this invention is not limited to the said embodiment. For example, when extruding the first and second polyamic acid solutions 11 and 12, in the above embodiment, an example in which the cylindrical mold 30 is fixed and the annular multilayer die 20 is moved vertically upward has been described. 20 may be fixed and the cylindrical mold 30 may be moved vertically downward. As a device for moving the cylindrical mold 30 vertically downward, for example, a lifting device such as a hydraulic cylinder mechanism or a lifting device is preferable. In this case, when the cylindrical mold 30 having no bottom is used and the cylindrical mold 30 is installed on the lifting device, the installation surface of the cylindrical mold 30 in the lifting device is the first. It will serve to support the lower ends of the first and second polyamic acid solutions 11 and 12.

  The annular multilayer die 20 may be moved vertically upward and the cylindrical mold 30 may be moved vertically downward. In this case, since any one of the annular multilayer die 20 and the cylindrical mold 30 can be used for fine adjustment of the relative movement speed, film formation with higher definition is possible.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

  Evaluation examples and measurement methods thereof are shown below for Examples and Comparative Examples described later.

<Surface resistivity>
Using a surface resistivity measuring device (manufactured by Mitsubishi Yuka Co., Ltd., Hiresta IP MCP-HT260, probe: HR-100), obtained in each example and comparative example under the condition of a measurement temperature of 25 ° C. (60 ° C.% RH). A voltage of 500 V was applied to any 12 points on the surface of the outer layer of the seamless belt, and the surface resistivity was measured 1 minute after the start of the application. Here, the average value of 12 points measured was defined as the surface resistivity.

<Warpage amount>
First, the seamless belts obtained in each of the examples and comparative examples are cut so that the length in the axial direction (width direction) is 350 mm, and a belt 100 (see FIG. 4) serving as a measurement sample is prepared. did. Then, as shown in FIG. 4, the belt 100 is passed over the two rolls 2 and 2 (diameter 30 mm) arranged in parallel in the vertical direction without slack, and the end portion of the belt 100 in the central portion between the rolls 2 and 2 A distance a (mm) and a distance b (mm) were measured, and a value obtained by subtracting 30 from the average value was taken as the amount of warpage. When the warp amount is a positive value, the warp amount is outward, and when the warp amount is negative, the warp amount is inward. The load on the belt 100 at the time of measurement was 67N.

<Average thickness and thickness variation>
About the seamless belt obtained in each example and comparative example, five measurement points are provided at equal intervals in the width direction, and 10 points are measured at equal intervals in the circumferential direction for each measurement point, for a total of 50 points. The average value of the measured data was defined as the average thickness. The difference between the maximum value and the minimum value of the measurement data was defined as the thickness variation amount.

<Example 1>
In 1158.0 g of N-methyl-2-pyrrolidone (NMP), dry 33.3 g of carbon black (Ketjen Black manufactured by Lion) was added and stirred at room temperature for 12 hours using a ball mill. A dispersed NMP solution was obtained. To this carbon black-dispersed NMP liquid (40 ° C.), 205.8 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 75.6 g of p-phenylenediamine (PDA) were added. It was dissolved in a nitrogen atmosphere to obtain a carbon black-dispersed NMP solution containing approximately equimolar amounts of BPDA and PDA. This was reacted with stirring in a nitrogen atmosphere at 70 ° C. for 15 hours to disperse the carbon black, and the outer layer polyamic acid solution (viscosity by B-type viscometer: 350 Pa · s, carbon black amount: polyimide solid content 100 weight) 13 parts by weight) was obtained.

  Similarly, 35.0 g of dried carbon black (Ketjen Black manufactured by Lion Corporation) was added to 1216.2 g of NMP, and stirred at room temperature for 12 hours using a ball mill to obtain a carbon black-dispersed NMP liquid. . In this carbon black-dispersed NMP solution (40 ° C.), 205.8 g of BPDA, 60.5 g of PDA, and 28.0 g of 4,4′-diaminodiphenyl ether (DDE) are dissolved in a nitrogen atmosphere, and BPDA and PDA are dissolved. And DDE were obtained in a ratio of BPDA / PDA / DDE = 10/8/2 (molar ratio). This was reacted with stirring in a nitrogen atmosphere at 70 ° C. for 15 hours to disperse the carbon black, and the polyamic acid solution for the inner layer (viscosity by B-type viscometer: 450 Pa · s, carbon black amount: 100% by weight of polyimide solid content) 13 parts by weight) was obtained. Note that DDE is a molecule that imparts flexibility to the belt. By including DDE in the inner layer, followability to a fixed roller is improved, or an anti-spinning function due to friction with an appropriate roller is given. be able to.

Next, by using the manufacturing apparatus shown in FIGS. 1 and 2, the outer layer polyamic acid solution (equivalent to the second polyamic acid solution 12) and the inner layer polyamic acid solution (first phase) are produced by the method shown in FIGS. A multilayer cylindrical body 18 was prepared from the polyamic acid solution 11 and the like. At this time, as the tubular mold 30, the inner diameter _{D 1} is used as a 100 mm. Further, as the annular multi-layer die 20, one having an interval L between the annular discharge port 23 and the connecting portion 24 of 10 mm and an outer peripheral die lip diameter D ₂ and an inner peripheral die lip diameter D ₃ of 96 mm and 94 mm, respectively was used. Moreover, the discharge pressure of the polyamic acid solution for the outer layer and the discharge pressure of the polyamic acid solution for the inner layer were both 1.8 MPa, the blow pressure was 5 MPa, and the moving speed of the annular multilayer die 20 was 10 mm / second. And after forming the multilayered cylindrical body 18 in the inner surface of the cylindrical metal mold | die 30, the cylindrical metal mold | die 30 was rotated at 1500 rpm for 10 minutes, and it was set as the uniform application | coating surface. The thickness of each layer of the multilayer cylindrical body 18 at this time was about 400 μm. Next, the cylindrical mold 30 was heated at 150 ° C. for 15 minutes, further heated to 400 ° C. at a rate of 2 ° C./minute, and continued to be heated at 400 ° C. for 10 minutes to advance imide conversion. In addition, in the case of the said heat processing, all were performed, rotating the cylindrical metal mold | die 30 at 250 rpm. Then, it cooled to room temperature, the seamless belt was peeled from the cylindrical metal mold | die 30, and the 2 layer seamless belt of Example 1 was obtained. The surface resistivity of the belt of Example 1 was 1 × 10 ⁴ Ω / □, and the amount of warpage was −5 mm. Further, the average thickness of the belt of Example 1 was 80 μm, and the thickness variation amount was 5 μm. The belt of Example 1 showed no coating streaks or undulations.

<Example 2>
Outer peripheral lip diameter _{D 2} and an inner peripheral lip diameter _{D 3,} using a circular multi-layer die 20 is 91mm and 89mm, respectively, both of the discharge pressure of the discharge pressure and the inner layer for the polyamic acid solution of the outer layer polyamic acid solution 1.9MPa A two-layer seamless belt was obtained in the same manner as in Example 1 except that. The average thickness of the belt of Example 2 was 80 μm, and the thickness variation amount was 7 μm. The belt of Example 2 was slightly wavy.

<Comparative Example 1>
The above-mentioned polyamic acid solution for the outer layer is applied to the inner surface of a cylindrical mold similar to the cylindrical mold 30 used in Example 1 with a dispenser, and then the cylindrical mold is rotated at 1500 rpm for 10 minutes for uniform application. The surface. The thickness of the coating film at this time was about 400 μm. Next, the cylindrical mold was heated at 150 ° C. for 15 minutes, and then returned to room temperature over 40 minutes. Subsequently, the inner layer polyamic acid solution was applied to the inner surface of the obtained outer layer with a dispenser, and then the cylindrical mold was rotated at 1500 rpm for 10 minutes to obtain a uniform coated surface. At this time, the thickness of the inner layer coating film was about 400 μm. Subsequently, the cylindrical mold was heated at 150 ° C. for 15 minutes, further heated to 400 ° C. at a rate of 2 ° C./minute, and heated at 400 ° C. for 10 minutes to proceed imide conversion. In addition, in the case of the said heat processing, all performed, rotating a cylindrical metal mold | die at 250 rpm. Then, it cooled to room temperature, peeled the seamless belt from the cylindrical metal mold | die, and obtained the 2 layer seamless belt of the comparative example 1. The surface resistivity of the belt of Comparative Example 1 was 1 × 10 ⁴ Ω / □, and the amount of warpage was −6 mm. Moreover, the average thickness of the comparative example 1 was 80 micrometers, and the thickness variation amount was 10 micrometers. The belt of Comparative Example 1 showed many coating lines and undulations.

It is a schematic block diagram which shows an example of the manufacturing apparatus of this invention. It is a schematic sectional drawing of the cyclic | annular multilayer die used for the manufacturing apparatus of FIG. AD is a schematic process drawing which shows an example of the manufacturing method of this invention. It is a schematic perspective view for demonstrating the measuring method of curvature amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 10 Control means 11 1st polyamic-acid solution 12 2nd polyamic-acid solution 15 Multilayer cylindrical film | membrane 16 1st cylindrical layer 17 2nd cylindrical layer 18 Multilayer cylindrical body 20 Annular multilayer die 21 1st flow path 22 Second flow path 23 Annular discharge port 24 Connection 28 Hydraulic cylinder mechanism 30 Cylindrical mold 30a Inner wall 31 Holes 40a, 40b Feeders 50a, 50b Hopper 60 Gas injection means 61 Pneumatic cylinder mechanism 62 Injection nozzle 70 Compressor

Claims (7)

The first polyamic acid solution and the second polyamic acid solution are simultaneously extruded from the annular multilayer die into the cylindrical mold, and the first cylindrical layer made of the first polyamic acid solution is formed on the inner surface of the cylindrical mold. And a seamless belt manufacturing method for forming a multilayered cylindrical body that covers the outer periphery of the first cylindrical layer and includes the second cylindrical layer made of the second polyamic acid solution,
A method for producing a seamless belt, in which gas is injected into a hollow portion of a multilayered tubular membrane that is extruded from the annular multilayer die and includes the first and second polyamic acid solutions.   Prior to extruding the first and second polyamic acid solutions, the annular multilayer die is disposed inside the cylindrical mold opened vertically upward, and when the first and second polyamic acid solutions are extruded, The method for producing a seamless belt according to claim 1, wherein the multilayer die is extruded while being relatively moved in the vertical direction with respect to the cylindrical mold.   The seamless belt manufacturing method according to claim 1 or 2, wherein an inner diameter of the cylindrical mold is 1.07 times or less of an outer peripheral die lip diameter of the annular multilayer die.   The method for producing a seamless belt according to any one of claims 1 to 3, wherein each of the first and second polyamic acid solutions has a viscosity measured by a Brookfield viscometer at 25 ° C of 200 to 1000 Pa · s. . A cylindrical mold, and an annular multilayer die for simultaneously extruding the first polyamic acid solution and the second polyamic acid solution into the cylindrical mold, and the inner surface of the cylindrical mold has the first Manufacture of a seamless belt that forms a multi-layered cylindrical body including a first cylindrical layer made of a polyamic acid solution, and a second cylindrical layer covering the outer periphery of the first cylindrical layer and made of the second polyamic acid solution A device,
An apparatus for manufacturing a seamless belt, comprising gas injection means for injecting gas into a hollow portion of a multilayered tubular membrane containing the first and second polyamic acid solutions extruded from the annular multilayer die. The manufacturing apparatus further includes control means,
The control means arranges the annular multilayer die inside the cylindrical mold opened vertically upward before extruding the first and second polyamic acid solutions, and the first and second polyamic acid solutions The seamless belt manufacturing apparatus according to claim 5, wherein, when extruding, the annular multilayer die is relatively moved in a vertical direction with respect to the cylindrical mold.   The seamless belt manufacturing apparatus according to claim 5 or 6, wherein an inner diameter of the cylindrical mold is 1.07 times or less of an outer peripheral die lip diameter of the annular multilayer die.

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