JP3305467B2 - Seamless resin film and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seamless resin film having improved thermal conductivity and a method for producing the same. More specifically, the present invention relates to a seamless resin film suitable for a belt for heat fixing such as a copying machine or a laser beam printer, and a method for producing the same.

[0002]

2. Description of the Related Art Polyimide resins have excellent heat resistance, dimensional stability, mechanical properties, and chemical properties, and examples of their use include belts for heat fixing such as copying machines and laser beam printers. .

Here, a polyimide tubular material used as a heat fixing member of a copying machine, a laser beam printer or the like will be described as an example. 2. Description of the Related Art In a copying machine or a laser beam printer using an electrophotographic technique, a heat roller method is generally used as a fixing device for fixing a toner image formed on copy paper or transfer paper. That is, the toner is heated and melted while sequentially feeding the copy paper on which the toner image is formed between the fixing roller having the heating mechanism and the pressing roller pressed against the fixing roller, and the toner image is fixed on the copy paper. It is to let.

In recent years, the technical development of this fixing device has progressed, and the use of a polyimide tubular material instead of the above-mentioned heat fixing roller has been studied. An example of this fixing mechanism includes a drive roll, a tension roll, and a heater inside a thin film polyimide tubular article, a backup roll outside, and forms a toner image between the polyimide tubular article and the backup roller via a heater. This is a mechanism for supplying the copied paper and fixing the toner image sequentially.

[0005] The feature of this fixing device is that heat fixing is performed on the surface of the thin film polyimide tube through a heater.
Unlike the heat fixing roller, it does not require pre-heating time for the fixing roller in advance, and the heat fixing can be started as soon as the power switch is turned on (on-demand method). Also,
There is an advantage that the electric capacity of the heater is small and the overall power consumption is small as compared with the roller system.

[0006] Polyimide tubular articles used in these applications are required to have heat resistance and mechanical properties such as tensile strength, tear strength or rigidity that can withstand the temperature at which the toner is melted by heat. As described above, the heater installed inside the tubular article has a mechanism for instantaneously fusing the toner image on the copy paper passing through the outer surface of the polyimide tubular article. However, polyimide itself is not so high in thermal conductivity like ordinary resin. Therefore, in order to improve the thermal conductivity of the polyimide, after pouring the polyimide acid solution into the inner surface of a molded tube such as a glass tube or a stainless steel tube having a smooth inner surface, the molded tube is held vertically, and a bullet is formed on the inner surface. Dropping a running body such as a body or a sphere by its own weight, forming it to a certain thickness, then drying and imidating it by heating to form a tubular material, containing an inorganic filler in the inner layer, and forming the outer layer of polyimide (Japanese Patent Application Laid-Open No. 62-3980).

As another known example, it has been proposed to add an inorganic filler such as carbon, silica or metal to polyimide or the like (JP-A-3-25478).

[0008]

However, the method disclosed in JP-A-62-2980 has a problem that it is difficult to finely disperse the inorganic filler and the strength of the film is low. Further, it is difficult to finish the inner surface of the seamless film smoothly, and there is a problem in contact friction with a member such as a roller. In addition, since the inner surface of the film becomes uneven, there is a problem that, depending on the material of the particles to be filled, the inner surface is severely worn, and when particles that are hard to wear are used, contact members such as heaters and rollers are damaged. . Furthermore, since only a very thin film can be formed by one treatment, there is a problem that the molding, drying and heating treatment must be repeated a plurality of times and laminated in order to obtain a film having practical strength. In addition, it is very difficult to extract a polyimide tube from the inner surface of a formed tube such as a glass tube or a stainless steel tube. Further, there is a problem that it is difficult to produce a tube having a small inner diameter, and it is also very difficult to produce a long tube because the method is a method of taking out a polyimide tube from the inside of a molded tube.

[0009] Also in way that is proposed in Japanese Patent Laid-Open No. 3-25478, there is a problem that the same intensity of finely dispersed is difficult film of the inorganic filler is low. Further, it is difficult to finish the inner surface of the seamless film smoothly, and there is a problem in contact friction with a member such as a roller.

[0010] In order to solve the above-mentioned conventional problems, the present invention provides a seamless resin film in which the heat conductive inorganic particles are finely dispersed to maintain a high strength, and the inner surface of the seamless film is finished smoothly. The aim is to provide a method.

[0011]

In order to achieve the above object, a seamless resin film of the present invention is a seamless resin film substantially comprising a polyimide as a base material,
Heat conductive inorganic particles are mixed with the polyimide precursor solution,
The polyimide precursor solution has a glassy mirror surface.
Surface of cylindrical mold covered with coating layer
Imide conversion reaction is completed after heating and drying
In the middle of the reaction until
Conductive primer with fluororesin primer on the surface
Component and a fluororesin component on top of it
And heated and sintered, the polyimide fill
The heat conductive inorganic particles are present in the film substantially uniformly dispersed therein, and the inner surface of the polyimide film is smooth and glossy, and the outer surface is fine due to the heat conductive inorganic particles. A conductive layer containing a fluororesin primer on the surface of the polyimide substrate having irregularities, and a fluororesin layer thereon is formed; the fluororesin layer has a pencil hardness of 2H or more; Is characterized by being exposed in the length direction at the end.

In the above structure, the content of the thermally conductive inorganic particles is preferably in the range of 1 to 50% by weight, because the thermal conductivity of the film can be kept high. Further, in the above configuration, it is preferable that the average particle diameter of the primary particles of the thermally conductive inorganic particles be in the range of 0.01 to 5.0 μm because the film strength can be kept high.

[0013] In the above structure, the thermally conductive inorganic particles may be composed of Si ₃ N ₄ , BN, SiC, AlN, alumina,
It is preferable to use at least one selected from copper, nickel, gold, silver, platinum, beryllium oxide, magnesium, and magnesium oxide because the thermal conductivity of the film can be kept high.

In the above structure, if the surface roughness Rz of the inner surface of the polyimide film is in the range of 0.01 to 10 μm, the inner surface of the seamless film is finished smoothly, and the inner surface of the seamless film comes into contact with a member such as a roller. No problem when driving.

In the above structure, it is preferable that the thickness of the polyimide film is in the range of 3 to 300 μm because the mechanical strength is high and practical. In the above structure, it is preferable that the outer surface of the polyimide film be coated with a fluorine-based resin, since the frictional resistance of the surface is small and slippage can be prevented, and offset can be prevented.

In the above structure, it is preferable that a conductive layer is present between the polyimide film and the fluororesin coating layer, because it is difficult to be charged, the charge can be easily removed, the offset can be prevented, and a clear image can be fixed. .

In the above structure, the fluororesin is selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). It is preferable that at least one of them be used because the toner has high releasability.

In the above structure, it is practically preferable that the conductive primer layer contains 1 to 40% by weight of carbon powder. Of course, besides carbon powder, gold powder, silver powder,
Powder having excellent conductivity such as aluminum powder and stainless steel powder can be used. Further, a metal deposition layer, a metal sputtering layer, or the like may be interposed. In addition, when the conductive primer layer is exposed on at least one end side of the seamless tubular article, it is convenient to discharge the charged electric charge.

In the above-mentioned structure, it is preferable that the conductive layer contains 1 to 40% by weight of carbon powder, because it is harder to be charged, the charge can be easily removed, the offset can be prevented, and a clear image can be fixed.

In the above-mentioned structure, when the thermally conductive inorganic particles are substantially primary particles and are uniformly dispersed in the polymer, the decrease in tear strength and tensile strength can be suppressed low.

Next, in the method for producing a seamless resin film of the present invention, the thermally conductive inorganic particles are substantially dispersed in primary particles in a solution serving as a solvent for the polyimide precursor, and the dispersion is added to the polyimide precursor solution. After mixing, the polyimide precursor solution is cast into a surface of a cylindrical mold whose surface is covered with a glass-like mirror-like inorganic coating film layer, and after heating and drying, is further heated to complete the imide conversion reaction. In the middle of the reaction, the conductive primer component including a fluororesin primer is applied to the surface of the polyimide semi-cured tubular article and dried, then coated with a fluororesin, and at that time the conductive layer including the primer is By exposing in the length direction at the end, then, by performing a heat treatment, the completion treatment of the imide conversion reaction and the baking treatment of the fluororesin are performed simultaneously. In said polyimide is present thermally conductive inorganic particles are substantially uniformly dispersed, and the inner surface of the polyimide film has a glossy smooth,
The outer surface has fine irregularities due to the thermally conductive inorganic particles, and a laminated film having a pencil hardness of the fluororesin layer of 2H or more is formed.

In the above structure, after the polyimide precursor solution is cast on the surface of the cylindrical mold, the polyimide precursor solution is heated and heated to form a conductive film on the surface of the polyimide semi-cured tubular article during the reaction until the imide conversion reaction is completed. Applying and drying a functional primer component, then coating with a fluororesin, and then performing a heat treatment to simultaneously perform the imidization conversion reaction completion treatment and the fluororesin baking treatment, the imidization conversion reaction completion treatment and the fluororesin baking treatment , The thermal efficiency can be increased and the processing time can be reduced as compared with the case where the steps are performed separately. Further, it is preferable because strong integration of polyimide and fluororesin can be achieved.

In the above structure, if the intermediate step of the imide conversion reaction is a step in which the thickness reduction ratio of the polyimide precursor is 50 to 95% in the above formula (Equation 1), the handling is easier, more efficient and more rational. Can be manufactured. When using a polyimide precursor having a solid content of about 20% by weight, the thickness reduction rate is preferably about 70 to 95%,
When using a polyimide precursor having a higher solid content, for example, about 30 to 40% by weight, the thickness and reduction rate are 50 to 95%.
Even practical.

Further, according to the preferred structure in which the polyimide precursor solution is an aromatic polyimide precursor, a polyimide seamless film having excellent heat resistance can be obtained. When the viscosity is 50 to 10,000 poise, molding (cast molding) with a uniform thickness can be performed.

Further, according to a preferred configuration in which the applied thickness of the polyimide precursor solution is in the range of 10 to 1000 μm, it is possible to obtain a preferred thickness for a seamless tubular article made of a polyimide resin as a final molded article. .

The means for molding the polyimide precursor solution to a substantially uniform thickness on the outer surface of the cylindrical mold includes disposing an outer mold having a certain clearance outside the cylindrical mold, When at least one of the cylindrical mold and the outer mold is moved, a seamless tubular article made of a polyimide resin having a uniform thickness can be efficiently formed.

Further, the surface of the cylindrical mold is covered with the inorganic coating film layer, the peeling of the composite seamless tubular article of the final product from the cylindrical metal mold is easy, yet the simple cylindrical mold Can be used repeatedly by washing.

The method of dispersing the thermally conductive inorganic particles substantially in the primary particles is a method of adding the thermally conductive inorganic particles to a solution, performing ultrasonic treatment, and then mixing the resulting solution with the polyimide precursor solution. According to the preferred configuration, compared to the method of adding the inorganic particles from the stage before the synthesis of the polyimide precursor, the production of a small lot is easier, and the time from the preparation of the polyimide precursor composition solution to cast molding Can be cast, and can be cast in a state of being dispersed in primary particles.

[0029]

According to the above-described structure of the seamless resin film of the present invention, the heat conductive inorganic particles are substantially uniformly dispersed in the polyimide, and the inner surface of the polyimide film is smooth. This makes it possible to realize a seamless resin film in which the heat conductive inorganic particles are finely dispersed to maintain a high strength and the inner surface of the seamless film is finished smoothly.

In the above structure, the fluororesin is selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). When at least one compound polytetrafluoroethylene,
This is preferable because the toner has high releasability. Preferably, the fluororesin is fired in a smooth state. In order to obtain such a smooth fluororesin layer, it is preferable to adopt a method in which a polyimide semi-cured tubular article is immersed in an aqueous dispersion of the fluororesin layer and heated and fired.

In the above structure, the thickness of the fluororesin layer is preferably in the range of 2 to 30 μm from the viewpoint of durability. In the above-described configuration, it is preferable that the fluororesin layer contains 0.1 to 3.0% by weight of carbon powder since no electrostatic offset occurs.

Next, according to the constitution of the method of the present invention, the thermally conductive inorganic particles are substantially dispersed in the primary particles and mixed in the polyimide precursor solution, and then the polyimide precursor solution is placed in a cylindrical mold. A seamless resin film that is cast on the surface of the film and then heated to complete the imide conversion reaction, thereby finely dispersing the thermally conductive inorganic particles to maintain a high strength and smooth the inner surface of the seamless film. Can be efficiently and rationally realized.

Further, if the surface of the semi-cured polyimide material is coated with a fluororesin while the semi-cured polyimide material is adhered to the surface of the cylindrical mold, it is easy to handle in mass production, and dust and the like adhere. And yield can be improved.

Further, when the fluororesin is coated while rotating the cylindrical mold, a fluororesin solution having a uniform composition can be applied. When the polyimide precursor solution is an aromatic polyimide precursor, a polyimide seamless film having excellent heat resistance is obtained. Moreover, the viscosity is 50-1.
If it is 0000 poise, molding of a uniform thickness (cast molding) can be performed.

When the coating thickness of the polyimide precursor solution is in the range of 10 to 1000 μm, it is possible to obtain a preferable thickness for a seamless tubular article made of polyimide resin, which is a final molded article.

The means for forming the polyimide precursor solution to a substantially uniform thickness on the outer surface of the cylindrical mold includes disposing an outer mold having a predetermined clearance outside the cylindrical mold, When at least one of the cylindrical mold and the outer mold is moved, a seamless tubular article made of a polyimide resin having a uniform thickness can be efficiently formed.

Further, when the polyimide precursor solution is semi-cured, a primer is applied, and then a fluororesin is applied, so that excellent integrity without delamination can be obtained.

[0038]

The present invention will be described more specifically with reference to the following examples. FIG. 1 is a process diagram showing a step of forming a semi-cured polyimide film according to one embodiment of the present invention. First, A
Is a step (casting step) of applying and molding a polyimide precursor solution to a surface of a cylindrical mold at a constant thickness. B is a drying step for drying the cast polyimide precursor solution, C is a first heating step for performing an imide conversion reaction to an intermediate stage, and D is a cooling step. In the step A, a material prepared by dispersing and mixing thermally conductive inorganic particles substantially in primary particles in a polyimide precursor solution is used.

Next, FIG. 2 is a process diagram showing a process for coating a surface of a polyimide seamless film with a fluororesin according to one embodiment of the present invention. First, E is a step of applying a primer, F is a step of drying the applied primer, G is a cooling step, H is a step of coating a fluororesin, and I is a step of simultaneously completing the imide conversion reaction and firing the fluororesin. This is a second heating step to be performed. The step of removing the polyimide seamless tubular article from the cylindrical mold is not shown.

In the casting step A, as shown in FIG. 1, a metal cylindrical mold (core body) 1 having an outer diameter of 40 mm is washed with water a in advance and then dried with air b. A drying step may be added. This preparation step is useful when the cylindrical mold 1 is continuously recycled and used. Next, the cylindrical mold 1 is immersed in the polyimide precursor solution 3, and then the outer mold 2 having a certain clearance is arranged outside the cylindrical mold 1. At least one of them was moved (preferably naturally dropped by the weight of the outer mold), and the polyimide precursor solution 3 was cast on the surface of the cylindrical mold 1 with a constant thickness. As the polyimide precursor solution, 3,3 ', 4,4
A polyimide precursor solution (solution viscosity: about 1000 poise) obtained by reacting '-biphenyltetracarboxylic dianhydride with an aromatic diamine in N-methyl-2-pyrrolidone, and the like, and having a thickness of 600 µm Was applied.

Next, in the drying step B, the polyimide precursor solution P ₁ cast in the dryer 4 is heated to a temperature of 12
0 ° C, time: dried for 60 minutes. At this time, the drying treatment was performed in a substantially windless state so as not to affect the hot air.

Next in the first heating step C, subjected to intermediate stage an imide conversion reaction in an oven 5 to obtain a polyimide semi cured tubular article P _2. The conditions were a semi-curing treatment at an oven temperature of 200 ° C. and a time of 20 minutes.
As a result, the thickness reduction ratio of the polyimide precursor of the formula (Equation 1) was about 85%.

Next, in a cooling step D, the substrate was cooled to room temperature by blowing cold air c. The polyimide semi-cured tubular material P ₂ is a cylindrical mold 1
Without removing it from the surface, and the cylindrical mold 1 was continuously supplied to the next step. In the steps so far, the cylindrical molds have been gripped and processed one by one by the gripping means.
It is preferable for mass production to store about 00 pieces in a pallet or the like having gripping means for processing.

Next, in the coating step E of the primer,
About 10 to 100 pieces are simultaneously grasped by the grasping means 6, and a usual fluororesin primer (for example, DuPont product name: 855-001 or 855-300; for example, see Japanese Patent Publication No. 53-33972). etc. may also be used) those disclosed, the carbon black powder composition solution 7 was added about 12 wt%, and dip coating the polyimide semi cured tubular article P _2. In the dip coating, each of the cylindrical molds 1 was rotated at 1 rpm so that the composition solution 7 adhered uniformly. In addition to the rotation, it may be vibrated up and down. Then, it was raised after immersion. The thickness of the primer layer after drying was 4 μm.

Next, in the primer drying step F, a heat treatment was performed in the dryer 8 at a temperature of 180 ° C. for a time of 30 minutes. After the heat treatment, in a cooling step G, the substrate was cooled to room temperature by blowing cold air d. P ₃ is a tubular article in which a primer is coated on the surface of a polyimide semi-cured tubular article on the cylindrical mold 1.

Next, in the fluororesin coating step H, for example, polytetrafluoroethylene (45 wt%)
Composition 9 in which about 0.6 wt% of ketchin black was added to an aqueous dispersion (dispersion) was applied to the surface of the primer to a thickness of about 10 μm after drying by a dipping method. At this time, the cylindrical mold was set to 1r. p. When the fluororesin was coated while being rotated by about m, a fluororesin solution having a uniform composition could be applied. Further, by coating by a dipping method, it is possible to obtain a fluororesin layer of a smooth film having a uniform thickness and to coat only a necessary portion of the primer or the fluororesin without a treatment such as masking.

Next, in the second heating step I for simultaneously performing the completion of the imide conversion reaction and the baking of the fluororesin, a heat treatment was performed in the oven 10 at a temperature of 250 ° C. for a time of 80 minutes. : 380 ° C, time: 70 minutes. P ₄ is a composite tubular article obtained by coating the surface of the polyimide cured tubular article on the cylindrical mold 1 with a primer and polytetrafluoroethylene and firing the resultant. Then, it cooled in the cooling process J.

Finally, in the step of removing the polyimide seamless composite tubular article from the cylindrical mold, a thickness of 65 μm
A polyimide seamless composite tubular article having an outer diameter of 40 mm and a length of 300 mm was taken out. The variation in the thickness in the length direction was ± 1 μm.

FIG. 3 shows a cross-sectional view of the polyimide seamless composite tubular article obtained as described above. 3A is a cross-sectional view in the length direction, and FIG. 3B is a cross-sectional view in a direction (II) orthogonal to the length direction. FIG. 3 (a), (b)
In the figure, 11 is a polyimide base material mixed with thermally conductive inorganic particles, 12 is a primer layer, 13 is a polytetrafluoroethylene layer, and 14 is an exposed portion of the primer layer.

Next, FIG. 4 is a perspective view of the polyimide seamless composite tubular article obtained as described above. A primer layer 12 is present on the surface of a polyimide substrate 11, and a polytetrafluoroethylene layer 13 is present on the surface. The primer layer 12 has, for example, about 1 at one end.
It is exposed about 0 mm. By bringing a conductive brush or the like into contact with the exposed portion 14, electric charges charged during traveling can be easily discharged.

Hereinafter, specific embodiments will be described. (Example 1) The surface of a cylindrical aluminum mold having an outer diameter of 30 mm and a length of 700 mm was coated with a silicon oxide coating agent by a dipping method.
And baked for 30 minutes at 350 ° C. to cover the silicon oxide. The surface of this cylindrical mold had a glass-like mirror surface, and the surface roughness according to JIS-B0601 was (Rz) 0.2 μm. Next, as a polyimide precursor solution, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride having a viscosity of 2000 poise and an aromatic diamine (4,
4'-diaminodiphenyl ether) with N
A polyimide precursor solution obtained by reacting in -methyl-2-pyrrolidone (NMP) was prepared.

Next, Si ₃ N ₄ having an average particle diameter of 0.6 μm (silicon nitride manufactured by Shin-Etsu Chemical Co., Ltd., thermal conductivity: 0.06 to 0.09 cal / cm · sec) was used as a thermally conductive inorganic filler.・
° C) Powder was used. 10 g of the above Si ₃ N ₄ powder is 40 m
l of NMP, and using an ultrasonic cleaner, disperse the secondary agglomerated particles into primary particles, then put into the polyimide precursor solution, stir with a mixer and uniformly mix. Si ₃ N ₄ was dispersed. The mixing ratio of Si ₃ N ₄ to the solid content concentration of the polyimide precursor solution is 15 wt%
And Thereafter, the cylindrical mold was inserted into the polyimide precursor solution to a length of 600 mm and pulled up, and then the inner diameter was 31 m from the top of the cylindrical mold.
m was dropped by its own weight, and a coating of a polyimide precursor solution having a thickness of about 500 μm was cast on the outer surface of the cylindrical mold. Thereafter, the cylindrical mold covered with the polyimide precursor solution was heated at a temperature of 120 ° C. for 40 minutes and at a temperature of 200 ° C. for 15 minutes to allow the solvent to be removed and the imide conversion reaction to proceed. The thickness of the polyimide film in this state (polyimide intermediate) was about 70 μm, and the reduction ratio of the thickness was 86%. Next, a primer for ordinary fluororesin (for example, Teflon 855-product name, manufactured by DuPont) is added to the polyimide intermediate.
001, Teflon 855-300, Daikin Industries, Ltd. Product name: Polyflon EK-1700, Polyflon EK-18
00, polyflon EK-1900 and the like. In this example, Du Pont product name: Teflon 855-001 or Teflon 855-300 was used. ), A semi-cured polyimide tube was applied by dip coating to a composition solution containing about 12 wt% of carbon black powder. In the dip coating, each of the cylindrical molds 1 is placed one by one so that the composition solution adheres uniformly.
r. p. m. Then, it was raised after immersion. The thickness of the primer layer after drying was 4 μm.

Next, the primer was heated at a temperature of 180 ° C. for a time of:
Heat treatment was performed for 30 minutes. Next, in a fluororesin coating step, polytetrafluoroethylene 70w
An aqueous dispersion (dispersion) of a fluororesin composition (solid content: 45 wt%) consisting of t% and 30 wt% of PFA was added with about 0.6 wt% of Ketchin Black (carbon black manufactured by Akzo Corporation). The primer was applied to the surface of the primer by a dipping method to a thickness of about 10 μm after drying. At this time, the cylindrical mold was set to 1r. p. When the fluororesin was coated while being rotated by about m, a fluororesin solution having a uniform composition could be applied.

Next, a heat treatment at a temperature of 250 ° C. for a time of 80 minutes is performed to simultaneously carry out the imide conversion reaction completion treatment and a calcination treatment of the fluororesin. went. A polyimide-cured tubular article on a cylindrical mold is coated with a primer and a polytetrafluoroethylene resin on a surface thereof, and the laminated composite tubular article which is baked is cooled to separate the cylindrical mold and the tubular article, and a thickness of 65 μm ( A polyimide seamless composite tubular article having a thickness of 50 μm, an outer diameter of 30 mm, and a length of 500 mm was taken out. The variation in the thickness in the length direction was ± 5 μm. The thermal conductivity was also excellent.

The tear strength of the polyimide composite tubular article having a laminated structure obtained as described above was 17.91 kgf / mm.
And the tensile strength was 18.77 kgf / mm.
On the other hand, the tear strength of a polyimide composite tubular article having a laminated structure without adding Si ₃ N ₄ as a heat conductive inorganic filler is 22.58 kgf / mm, and the tensile strength is 26.21.
kgf / mm. Therefore, the polyimide composite tubular article of the laminated structure of this example had practically sufficient tear strength and tensile strength.

The polyimide seamless composite tubular article was cut open, and the inner and outer surfaces were measured for surface roughness. As a result, the inner surface Rz of the tubular article was 1.36 μm. In addition, the surface roughness Rz of the polyimide resin alone portion where the outer surface of the tubular material is not coated with the primer and the fluororesin layer is 3.0.
The surface roughness Rz of the outermost layer coated with the primer and the fluororesin layer was 1.33 μm. The appearance of the tubular article was smooth and glossy because the inner surface was in contact with the glass-like mirror surface of the silicon oxide-coated mold, and the filler was embedded in the polyimide resin. It was like that. on the other hand,
The surface of the polyimide resin not coated with a primer or a fluororesin outside the tubular material had a ground glass-like surface with fine irregularities of the filler appearing on the surface. In the inside of the polyimide resin, the filler was uniformly dispersed in the state of primary particles or a state close thereto. Further, the pencil hardness of the outermost layer, that is, the fluororesin-coated surface of this tubular article was 2H or more, and the polyimide resin layer and the fluororesin layer were firmly bonded. This result is considered to be due to the fact that the outer surface of the polyimide tube became a fine uneven surface due to the addition of the inorganic filler, and the effect increased the adhesion between the polyimide layer and the fluororesin layer.

The polyimide seamless film composite tubular article obtained in this example was used in an electrophotographic fixing device shown in FIG. That is, the fixing device includes a drive roll 22, a tension roll 23, and a heater 24 inside the polyimide composite tubular article 21, and a backup roll 25 on the outside. Toner image 2 between rollers 25
7 was formed, and the toner images were sequentially fixed by heating to obtain a fixed image 28. And attaching said tubing of the fixing device of the printer, as a result of the endurance test, the occurrence of abrasion powder of polyimide tubing inner surface was achieved withstand extremely small long-term use. Also, heat resistance,
It was practically sufficient, such as high-strength lubricity, and was able to withstand the use of about 100,000 sheets with a laser printer.

The polyimide precursor that can be used in the present invention is:
For example, it is obtained by reacting an aromatic tetracarboxylic acid component with an aromatic diamine component in an organic polar solvent. The aromatic tetracarboxylic acid component is not particularly limited. For example, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride , Pyromellitic dianhydride and the like, and a mixture of these tetracarboxylic acids may be used. The aromatic diamine component is not particularly limited and includes, for example, 3,3′-diaminophenyl ether,
Diphenyl ether diamines such as 3,3'-dimethoxy-4,4'-diaminodiphenyl ether and 4,4'-diaminophenyl ether; diphenyls such as 3,3'-diphenylthioether and 4,4'-diaminodiphenylthioate Thioether-based diamine, 4,4'-
Examples thereof include benzophenone-based diamines such as diaminobenzophenone, and other diphenylmethane-based diamines such as paraphenylenediamine and metaphenylenediamine. As the organic polar solvent, N-methylpyrrolidone, dimethylformamide, dimethylacetamide,
Examples include phenol, o-cresol, m-cresol, p-cresol, dimethyl oxide, and the like, but are not particularly limited thereto.

Examples of the fluorine resin include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA), tetrafluoroethylene-hexafluoropropylene copolymer resin (PFEP), and ethylene-tetrafluoroethylene. Fluoroethylene copolymer resin (PETFE), ethylene-chlorotrifluoroethylene copolymer resin (PECTFE), polyvinylidene fluoride (PVdF), or the like can be used.

[0060]

As described above, according to the present invention, the heat conductive inorganic particles are substantially dispersed in the primary particles in the polyimide, and the inner surface of the polyimide film is smooth. This makes it possible to realize a seamless resin film in which the heat conductive inorganic particles are finely dispersed and the strength is maintained high, and the inner surface of the seamless film is finished smoothly.

Next, according to the method of the present invention, the thermally conductive inorganic particles are substantially dispersed and mixed into the primary particles in the polyimide precursor solution, and then the polyimide precursor solution is applied to the surface of the cylindrical mold. By casting, then heating to complete the imide conversion reaction, the heat conductive inorganic particles are finely dispersed to maintain a high strength, and efficiently produce a seamless resin film in which the inner surface of the seamless film is finished smoothly. It can be realized reasonably.

[Brief description of the drawings]

FIG. 1 is a process chart showing a manufacturing process of a tube precursor of a poimide precursor according to one embodiment of the present invention.

FIG. 2 is a process diagram showing a production process of a polyimide composite tubular article according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view of a polyimide composite tubular article obtained according to one embodiment of the present invention.

FIG. 4 is a perspective view of a polyimide composite tubular article obtained according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view of a fixing mechanism of an electrophotographic apparatus using a polyimide tubular article obtained according to one embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 metal core 2 outer mold 3 polyimide precursor solution in which thermally conductive inorganic particles are dispersed 4, 8 dryer 5, 10 oven 6 gripper 7 primer solution 9 polytetrafluoroethylene aqueous dispersion 11 thermal conductivity Polyimide substrate in which inorganic particles are dispersed 12 Conductive primer layer 13 Polytetrafluoroethylene layer 14 Exposed portion of conductive primer layer 21 Polyimide composite tube 22 Drive roll 23 Tension roll 24 Heater 25 Backup roll 26 Copy paper 27 Toner image 28 fixed image a water b dry air c, d cooling air P ₁ cast polyimide precursor solution P ₂ polyimide half cured tubular article P ₃ polyimide semi cured tubular article tubing P ₄ polyimide primer is coated on the surface of Composite tubular object

Continuation of front page (56) References JP-A-3-25478 (JP, A) JP-A-62-2980 (JP, A) JP-A-3-25475 (JP, A) JP-A-5-273879 (JP JP-A-3-241381 (JP, A) JP-A-64-22514 (JP, A) JP-A-3-261518 (JP, A) JP-A-3-180309 (JP, A) JP-A-3-12268 (JP, A) JP-A-63-108038 (JP, A) JP-A-60-139755 (JP, A) JP-A-5-96558 (JP, A) A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 41/14 B29C 41/46 G03G 15/20 103

Claims (16)

(57) [Claims] 1. A seamless resin film substantially comprising a polyimide as a base material, wherein thermally conductive inorganic particles are mixed with a polyimide precursor solution,
The polyimide precursor solution has a glassy mirror surface.
Surface of cylindrical mold covered with coating layer
Imide conversion reaction is completed after heating and drying
In the middle of the reaction until
Conductive primer with fluororesin primer on the surface
Component and a fluororesin component on top of it
And heated and sintered, the polyimide fill
The heat conductive inorganic particles are present in the film substantially uniformly dispersed therein, and the inner surface of the polyimide film is smooth and glossy, and the outer surface is fine due to the heat conductive inorganic particles. A conductive layer containing a fluororesin primer on the surface of the polyimide substrate, and a fluororesin layer formed thereon, wherein the pencil hardness of the fluororesin layer is 2H or more; The seamless resin film characterized in that the conductive layer containing is exposed in the length direction at the end. 2. The seamless resin film according to claim 1, wherein the amount of the thermally conductive inorganic particles is in the range of 1 to 50% by weight. 3. The seamless resin film according to claim 1, wherein the average particle diameter of the primary particles of the thermally conductive inorganic particles is in the range of 0.01 to 5.0 μm. 4. The heat conductive inorganic particles are made of Si ₃ N ₄ , BN,
The seamless resin film according to claim 1, which is at least one selected from SiC, AlN, alumina, copper, nickel, gold, silver, platinum, beryllium oxide, magnesium, and magnesium oxide. 5. The seamless resin film according to claim 1, wherein the surface roughness Rz of the inner surface of the polyimide film is in the range of 0.01 to 10 μm. 6. The polyimide film has a thickness of 3 to 30.
The seamless resin film according to claim 1, wherein the thickness is in a range of 0 µm. 7. The at least one fluororesin selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). The seamless resin film according to claim 1, wherein 8. The seamless resin film according to claim 1, wherein carbon black is mixed with the fluororesin. 9. The conductive layer contains carbon powder in an amount of 1 to 40 wt.
2. The seamless resin film according to claim 1. 10. The seamless resin film according to claim 1, wherein the thermally conductive inorganic particles are substantially primary particles and are uniformly dispersed in the polymer. 11. A method for dispersing thermally conductive inorganic particles substantially in primary particles in a solution serving as a solvent for a polyimide precursor, mixing the dispersion with a polyimide precursor solution, and then, Cast-molded on the surface of a cylindrical mold whose surface is covered with a glass-like mirror-like inorganic coating film layer.After heating and drying, the polyimide is semi-cured in the middle of the reaction until heating to complete the imide conversion reaction. A conductive primer component including a fluororesin primer is applied to the surface of the tubular article and dried, and then coated with a fluororesin. At this time, the conductive layer including the primer is exposed in the length direction at the end. Then, by performing a heat treatment to simultaneously perform the imide conversion reaction completion treatment and the calcination treatment of the fluororesin, the heat conductive inorganic particles are contained in the polyimide. Being present are qualitatively uniformly dispersed, and the inner surface of the polyimide film has a glossy smooth outside surface having fine irregularities by the thermally conductive inorganic particles, a pencil of the fluorine resin layer A method for producing a seamless resin film, comprising forming a laminated film having a hardness of 2H or more. 12. A step in the course of the reaction until the imide conversion reaction is completed, the thickness reduction ratio of the polyimide precursor is 50 to 95.
%. The method for producing a seamless resin film according to claim 11, wherein the step is a percentage. However, the thickness reduction rate is obtained by the following equation (Equation 1). [Number _{1] x = {(V 0} -V a) / V 0} × 100 x: The polyimide precursor thickness reduction ratio V _0: the first coating molded thickness of the polyimide precursor V _a: imide polyimide precursor Thickness in the middle of the conversion reaction 13. The method for producing a seamless resin film according to claim 11, wherein the polyimide precursor solution is an aromatic polyimide precursor and has a viscosity of 50 to 10,000 poise. 14. A coating thickness of a polyimide precursor solution,
The thickness is in the range of 10 to 1000 μm.
3. The method for producing a seamless resin film according to item 1. 15. A means for casting a polyimide precursor solution to a substantially uniform thickness on the outer surface of a cylindrical mold,
13. The seamless resin according to claim 11, wherein an outer mold having a predetermined clearance is arranged outside the cylindrical mold, and at least one of the cylindrical mold and the outer mold is moved. Film production method. 16. The seamless method according to claim 11, wherein the method of substantially dispersing the thermally conductive inorganic particles into the primary particles is a method of adding the thermally conductive inorganic particles to a solution and then performing an ultrasonic treatment. A method for manufacturing a resin film.