JPH07186162A - Seamless resin film and its preparation - Google Patents

Abstract

PURPOSE:To obtain a seamless resin film wherein its strength is high by dispersing finely thermally conductive inorg. particles and the inner face of the seamless film is smoothly finished by dispersing uniformly the thermally conductive inorg. particles in a polyimide and making the inner surface of a polyimide film smooth. CONSTITUTION:As a thermally conductive inorg. particle, Si3N4 powder with a mean particle diameter of 0.6mum is dispersed in a solvent by using an ultrasonic cleaner to disperse secondarily aggregated particles into primary particles. Then, the particles are fed into a polyimide precursor soln. and the mixture is stirred by means of a mixer and a cylindrical mold is inserted therein and is pulled out and an outer mold is dropped by its own weight from the upper side and cast molding is performed on the outer surface of the cylindrical mold. Thereafter, it is primarily heat-treated to remove the solvent and to promote imidation reaction and as the result, a polyimide intermediate is obtd. Then, after the surface is coated with an electrically conductive primer 12 and it is dried, it is coated with a fluororesin 13 and it is calcined.

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 heat fixing belt 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. One example of their applications is heat fixing belts for copying machines and laser beam printers. .

Here, a polyimide tubular material used as a member for heat fixing of a copying machine or a laser beam printer will be described as an example. In a copying machine or a laser beam printer using an electrophotographic technique, a heat roller system is generally used as a fixing device for fixing a toner image formed on copy paper or transfer paper. That is, the copy paper on which the toner image is formed is sequentially fed between both the fixing roller having a heating mechanism and the pressure roller that is in pressure contact with the fixing roller, and the toner is heated and melted to fix the toner image on the copy paper. It is what makes me.

In recent years, technical development of this fixing device has progressed, and use of a polyimide tubular material in place of the above-mentioned heat fixing roller has been studied. An example of this fixing mechanism includes a driving roll, a tension roll, and a heater inside the thin film polyimide tubular material, and a backup roll outside, and forms a toner image between the polyimide tubular material and the backup roller via the heater. It is a mechanism that supplies the copied copy paper and sequentially fixes the toner images.

The characteristic of this fixing device is that the heat fixing is performed on the surface of the thin film polyimide tubular article through the heater.
Unlike the heat fixing roller, it does not require time to preheat the fixing roller in advance, and heat fixing can be started immediately after turning on the power switch (on-demand method). Also,
Compared to the roller method, the electric capacity of the heater is small and the overall power consumption is low.

The polyimide tubular products used for these applications are required to have heat resistance capable of withstanding the temperature at which the toner is melted by heat and mechanical properties such as tensile strength, tear strength or rigidity. As described above, the heater installed inside the tubular article instantly fuses 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 as ordinary resins. Therefore, in order to improve the thermal conductivity of the polyimide, after pouring the polyimide acid solution on the inner surface of a molded tube such as a glass tube or a stainless steel tube with a smooth inner surface, hold this molded tube vertically and make a bullet on this inner surface. By using a method of dropping a running body such as a spherical body or a spherical body by its own weight to form a certain thickness, and then drying and imidizing by heating to form a tubular product, an inorganic filler is contained in the inner layer, and the outer layer is made of polyimide. Has been proposed (Japanese Patent 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-62-3980 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 to be smooth, 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 the inner surface may be abraded depending on the material of the particles to be filled, and the contact members such as the heater and the roller may be damaged when the particles that are difficult to wear are used. . Furthermore, since only a very thin film can be formed by one treatment, there is a problem that the molding-drying-heating treatment must be repeated a plurality of times to obtain a laminate having practical strength. Further, it is very difficult to remove the polyimide tubular material from the inner surface of the molded tube such as a glass tube or a stainless tube. Further, since the polyimide tubular product is taken out from the inside of the molded tube, it is difficult to produce a tubular product having a small inner diameter, and it is also very difficult to produce a long product.

The method proposed in JP-A-3-25478 also has a problem in that it is difficult to finely disperse the inorganic filler and the strength of the film is low as in the above case. Further, it is difficult to finish the inner surface of the seamless film to be smooth, and there is a problem in contact friction with a member such as a roller.

In order to solve the above-mentioned conventional problems, the present invention finely disperses thermally conductive inorganic particles to maintain high strength, and a seamless resin film in which the inner surface of the seamless film is finished smooth, and its production. The purpose is to provide a method.

[0011]

In order to achieve the above object, the seamless resin film of the present invention is a seamless resin film having a substantially polyimide base material,
The polyimide is characterized in that the thermally conductive inorganic particles are substantially uniformly dispersed in the polyimide, and the inner surface of the polyimide film is smooth.

In the above-mentioned constitution, it is preferable that the abundance of the heat conductive inorganic particles is in the range of 1 to 50% by weight because the heat conductivity of the film can be kept high. Further, in the above constitution, it is preferable that 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 because the film strength can be kept high.

In the above structure, the thermally conductive inorganic particles are made of Si ₃ N ₄ , BN, SiC, AlN, alumina,
At least one selected from copper, nickel, gold, silver, platinum, beryllium oxide, magnesium, and magnesium oxide is preferable because the film can keep high thermal conductivity.

Further, in the above construction, when 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 to be smooth and comes into contact with a member such as a roller. It does not cause any problems when you drive.

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

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

In the above structure, the fluororesin is selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). It is preferable that it is at least one because the releasing property of the toner is high.

In the above construction, it is practically preferable that the conductive primer layer contains 1 to 40 wt% of carbon powder. Of course, in addition to carbon powder, gold powder, silver powder,
Powders having excellent conductivity such as aluminum powder and stainless steel powder can be used. Further, a metal vapor 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 for discharging the charged electric charge.

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

Further, in the above-mentioned constitution, when the thermally conductive inorganic particles are substantially primary particles uniformly dispersed in the polymer, it is possible to suppress a decrease in tear strength or tensile strength to a low level.

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 the polyimide precursor solution and mixed, and then the polyimide precursor solution is added to the cylindrical gold solution. It is characterized in that it is cast on the surface of the mold and then heated to complete the imide conversion reaction.

In the above-mentioned structure, after the polyimide precursor solution is cast on the surface of the cylindrical mold, the polyimide semi-cured tubular material is electrically conductive on the surface of the polyimide semi-cured tube during the reaction until the imide conversion reaction is completed by heating. When the imide conversion reaction is completed and the fluororesin is fired at the same time by applying heat-resistant primer components, drying, and then coating the fluororesin, then heat treatment to complete the imide conversion reaction and the fluororesin baking treatment. The thermal efficiency can be increased and the processing time can be shortened as compared with the case where the steps are performed separately. Furthermore, it is preferable because the polyimide and the fluororesin can be firmly integrated.

In the above-mentioned constitution, when the intermediate stage of the imide conversion reaction is a stage where the thickness reduction rate of the polyimide precursor is 50 to 95% in the above formula (Formula 1), it is easier to handle, more efficient and rational. Can be manufactured. When a polyimide precursor having a solid content of about 20% by weight is used, 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%.
The degree is practical.

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

Further, according to the preferable constitution that the coating thickness of the polyimide precursor solution is in the range of 10 to 1000 μm, the thickness can be made preferable for the seamless tubular product made of the polyimide resin which is the final molded product. .

Further, means for molding the polyimide precursor solution to a substantially uniform thickness on the outer surface of the cylindrical mold is to arrange an outer mold having a certain clearance outside the cylindrical mold, With the method of moving at least one of the cylindrical mold and the outer mold, a seamless tubular product made of a polyimide resin having a uniform thickness can be efficiently formed.

Further, according to a preferable construction in which the surface of the cylindrical mold is covered with the inorganic coating film layer,
The composite seamless tubular product of the final product can be easily peeled from the cylindrical mold, and the cylindrical mold can be repeatedly used by simple cleaning.

Further, a method of dispersing the heat conductive inorganic particles substantially in the primary particles is a method in which the heat conductive inorganic particles are added to the solution, ultrasonically treated, and then mixed with the polyimide precursor solution. According to the preferred configuration that there is, compared to the method of adding inorganic particles from the stage before synthesizing the polyimide precursor, it becomes easier to manufacture a small lot, and the time from adjusting the polyimide precursor composition solution to casting Since it can be shortened, it can be cast in a state of being dispersed in primary particles.

[0029]

According to the structure of the seamless resin film of the present invention described above, the thermally conductive inorganic particles are present in the polyimide in a substantially uniformly dispersed state, and the inner surface of the polyimide film is smooth. As a result, it is possible to realize a seamless resin film in which the thermally conductive inorganic particles are finely dispersed to maintain high strength, and the inner surface of the seamless film is finished to be smooth.

In the above structure, the fluororesin is selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). At least one compound polytetrafluoroethylene,
It is preferable because the toner has high releasability. The fluororesin is preferably baked in a smooth state. In order to obtain such a fluororesin layer in a smooth state, it is preferable to adopt a method of immersing the polyimide semi-cured tubular product in an aqueous dispersion of the fluororesin layer and performing heating and firing.

In the above construction, it is preferable that the thickness of the fluororesin layer is in the range of 2 to 30 μm from the viewpoint of durability. Further, in the above structure, it is preferable that the fluororesin layer contains the carbon powder in an amount of 0.1 to 3.0 wt% because 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 polyimide precursor solution as primary particles and mixed, and then the polyimide precursor solution is mixed with a cylindrical mold. A seamless resin film in which the heat-conductive inorganic particles are finely dispersed to maintain high strength and the inner surface of the seamless film is finished smooth by cast molding on the surface of the film and then heating to complete the imide conversion reaction. Can be realized efficiently and rationally.

When the surface of the cylindrical mold is coated with a fluororesin while the polyimide semi-cured tubular material is still attached, the surface of the polyimide semi-cured tubular material is easy to handle in mass production and dust and the like are also deposited. It is difficult and the yield can be improved.

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

Further, when the coating thickness of the polyimide precursor solution is in the range of 10 to 1000 μm, the thickness can be made preferable for the seamless tubular product made of the polyimide resin which is the final molded product.

Further, means for molding the polyimide precursor solution on the outer surface of the cylindrical mold to a substantially uniform thickness is to arrange an outer mold having a certain clearance outside the cylindrical mold, With the method of moving at least one of the cylindrical mold and the outer mold, a seamless tubular product 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 coated, it is possible to obtain excellent integrity without delamination.

[0038]

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

Next, FIG. 2 is a process diagram showing a process for coating the surface of the polyimide seamless film of the present invention with a fluororesin. 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 completion treatment of an imide conversion reaction and a firing treatment of the fluororesin at the same time. This is the 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 metal mold (core body) 1 having an outer diameter of 40 mm is washed with water a in advance, and then dried air b is applied thereto. You may add the process of drying. This preparation step is useful when the cylindrical mold 1 is continuously recycled and used. Next, the cylindrical mold 1 is dipped in the polyimide precursor solution 3, and then the outer mold 2 having a certain clearance is placed outside the cylindrical mold 1 to obtain the cylindrical mold or the outer mold. At least one of them was moved (preferably free fall due to the own weight of the outer mold) to cast the polyimide precursor solution 3 on the surface of the cylindrical mold 1 with a constant thickness. The polyimide precursor solution includes 3,3 ′, 4,4
Using a polyimide precursor solution (solution viscosity: about 1000 poise) obtained by reacting ′ -biphenyltetracarboxylic dianhydride and an aromatic diamine in N-methyl-2-pyrrolidone, a thickness of 600 μm Was applied.

Next, in a drying step B, the polyimide precursor solution P ₁ cast in the dryer 4 is heated at a temperature of 12
Dry at 0 ° C., time: 60 minutes. At this time, since it was not affected by hot air, the drying treatment was carried out in a substantially windless state.

Next, in the first heating step C, the imide conversion reaction was carried out in the oven 5 to an intermediate stage to obtain a polyimide semi-cured tubular product P ₂ . The conditions were as follows: oven temperature: 200 ° C., time: 20 minutes of semi-curing treatment.
As a result, the thickness reduction rate of the polyimide precursor represented by the formula (Formula 1) was about 85%.

Then, in cooling step D, cold air c was applied to cool to room temperature. The polyimide semi-cured tubular product P ₂ is a cylindrical mold 1
The cylindrical mold 1 was continuously supplied together with the cylindrical mold 1 to the next step without being removed from the surface. Further, in the steps up to this point, the cylindrical molds are gripped and processed by the gripping means one by one, but in the subsequent steps, a plurality of, preferably 10 to 1 are used.
In mass production, it is preferable to store about 100 pieces in a pallet or the like having a gripping means for processing.

Next, in the coating step E, the primer is applied.
About 10 to 100 pieces are simultaneously gripped by the gripping means 6, and an ordinary fluororesin primer (for example, DuPont product name: 855-001 or 855-300, as another example, for example, Japanese Patent Publication No. 53-33972). The disclosed composition and the like can also be used), and the semi-cured polyimide tubular product P ₂ is dip-coated on the composition solution 7 in which about 12 wt% of carbon black powder is added. In the dip coating, each of the cylindrical molds 1 was rotated at 1 rpm so that the composition solution 7 was uniformly attached. In addition to rotation, you may vibrate up and down. Then, after soaking, it was pulled up. 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 the cooling step G, cold air d was applied to cool to room temperature. P ₃ is a tubular article in which the surface of the polyimide semi-cured tubular article on the cylindrical mold 1 is coated with a primer.

Next, in the fluororesin coating step H, for example, polytetrafluoroethylene (45 wt%)
The composition liquid 9 in which about 0.6 wt% of Ketchin black was added to the water dispersion liquid (dispersion) of was applied to the surface of the primer by a dipping method so that the thickness after drying was about 10 μm. At this time, the cylindrical mold was set to 1 r. p. When the fluororesin was coated while rotating about m, a fluororesin solution having a uniform composition could be applied. In addition, when the coating is performed by the dipping method, a fluororesin layer having a uniform thickness and having a smooth film can be obtained, and the primer or the fluororesin can be coated only on a necessary portion without the need for treatment such as masking.

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

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

A cross-sectional view of the polyimide seamless composite tubular article obtained as described above is shown in FIG. In FIG. 3, (a) is a cross-sectional view in the length direction, and (b) is a cross-sectional view in a direction (II) orthogonal to the length direction. 3 (a), 3 (b)
In the above, 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 product obtained as described above. The primer layer 12 is present on the surface of the polyimide base material 11, and the polytetrafluoroethylene layer 13 is present on the surface thereof. The primer layer 12 has, for example, about 1 at one end side.
It is exposed about 0 mm. By bringing a conductive brush or the like into contact with the exposed portion 14, it is possible to easily discharge the electric charge charged during traveling.

Specific examples will be described below. (Example 1) The surface of an aluminum cylindrical 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 the coating was performed at 150 ° C. for 30 minutes.
Min, heated at 350 ° C. for 30 minutes and baked to coat silicon oxide. The surface of this cylindrical mold had a glass-like mirror surface, and the surface roughness (Rz) according to JIS-B0601 was 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) is a solvent N
A polyimide precursor solution obtained by reacting in -methyl-2-pyrrolidone (NMP) was prepared.

Next, as a heat conductive inorganic filler, Si ₃ N ₄ having an average particle diameter of 0.6 μm (manufactured by Shin-Etsu Chemical Co., Ltd., silicon nitride, thermal conductivity: 0.06 to 0.09 cal / cm · sec)・
C) powder was used. 40 g of the Si ₃ N ₄ powder 10 g
l NMP and dispersed by using an ultrasonic cleaner to disperse the secondary agglomerated particles into primary particles, then put into the polyimide precursor solution and stir with a mixer to homogenize 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 After that, the cylindrical mold is inserted into the polyimide precursor solution to a length of 600 mm and pulled up, and then the inner diameter is 31 m from the uppermost part of the cylindrical mold.
A ring-shaped outer mold of m was dropped by its own weight, and a film of a polyimide precursor solution having a thickness of about 500 μm was cast-molded on the outer surface of the cylindrical mold. Then, the cylindrical mold covered with this 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 remove the solvent and proceed the imide conversion reaction. The thickness of the polyimide film in this state (polyimide intermediate) was about 70 μm, and the reduction rate of the thickness was 86%. Next, a conventional fluororesin primer (for example, DuPont product name: Teflon 855-) 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, etc. In this example, Teflon 855-001 or Teflon 855-300, a product name of DuPont, was used. ), A semi-cured polyimide tubular material was applied by dip coating to a composition solution containing about 12 wt% of carbon black powder. The dip coating is performed by applying 1 to each of the cylindrical molds 1 so that the composition solution is uniformly attached.
r. p. It was rotated at m. Then, after soaking, it was pulled up. The thickness of the primer layer after drying was 4 μm.

Next, the primer is heated at a temperature of 180 ° C. for a time of:
Heat treatment was performed for 30 minutes. Next, in the fluororesin coating step, polytetrafluoroethylene 70w
A composition liquid obtained by adding about 0.6 wt% of Ketchin black (Carbon black manufactured by Akzo Co., Ltd.) to an aqueous dispersion (dispersion) of a fluororesin composition (solid content: 45 wt%) composed of t% and PFA of 30 wt%, The surface of the primer was applied by a dipping method to a thickness of about 10 μm after drying. At this time, the cylindrical mold was set to 1 r. p. When the fluororesin was coated while rotating about m, a fluororesin solution having a uniform composition could be applied.

Next, in order to carry out the completion treatment of the imide conversion reaction and the baking treatment of the fluororesin at the same time, heat treatment is carried out at a temperature of 250 ° C. for a time of 80 minutes, and then at a temperature of 380 ° C. for a time of 70 minutes. went. The surface of the polyimide-cured tubular product on the cylindrical mold was coated with a primer and polytetrafluoroethylene resin and baked, and the composite tubular product having a laminated structure was cooled to separate the cylindrical mold and the tubular product to a thickness of 65 μm ( The polyimide itself had a thickness of 50 μm), the outer diameter was 30 mm, and the length was 500 mm. The variation in thickness in the length direction was ± 5 μm. The thermal conductivity was also excellent.

The tear strength of the laminated polyimide composite tubular material 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 the polyimide composite tubular product having a laminated structure without adding Si ₃ N ₄ which is a heat conductive inorganic filler is 22.58 kgf / mm, and the tensile strength is 26.21.
It was kgf / mm. Therefore, the laminated polyimide composite tubular article of this example had practically sufficient tear strength and tensile strength.

The polyimide seamless composite tubular article was cut open and the surface roughness of the inner and outer surfaces was measured. 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 simple substance portion where the primer and the fluororesin layer are not coated on the outer surface of the tubular object 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 product is smooth and glossy because the inner surface is in contact with the glassy mirror surface of the mold coated with silicon oxide, and the filler is embedded in the polyimide resin. It was like that. on the other hand,
The polyimide resin surface not coated with the primer or the fluororesin on the outer side of the tubular material had fine irregularities of the filler on the surface and had a ground glass-like surface. Inside the polyimide resin, the filler was evenly dispersed in the state of primary particles or near them. The pencil hardness of the outermost layer of this tubular article, that is, the fluororesin coating surface was 2H or more, and the polyimide resin layer and the fluororesin layer were firmly bonded. This result is considered to be because the outer surface of the polyimide tubular material became a fine uneven surface due to the addition of the inorganic filler, and the adhesive force between the polyimide layer and the fluororesin layer was increased due to the effect.

The polyimide seamless film composite tubular article obtained in this example was used in the electrophotographic fixing device shown in FIG. That is, the fixing device is provided with a driving roll 22, a tension roll 23, and a heater 24 inside the polyimide composite tubular body 21 and a backup roll 25 outside, and the polyimide tubular body 21 and the backup via the heater 24. Toner image 2 between rollers 25
The copy paper 26 on which No. 7 was formed was supplied and the toner images were sequentially fixed by heating to obtain a fixed image 28. Then, the above tubular product was attached to a fixing device of a printer and a durability test was carried out. As a result, it was found that abrasion powder on the inner surface of the polyimide tubular product was extremely small and could be used for a long period of time. Also, heat resistance,
It was practically sufficient such as strength and slipperiness, and could be used for about 100,000 sheets with a laser printer.

The polyimide precursor which can be used in the present invention is
For example, it is obtained by reacting an aromatic tetracarboxylic acid component and an aromatic diamine component in an organic polar solvent. The aromatic tetracarboxylic acid component is not particularly limited and includes, for example, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 2,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride. , Pyromellitic dianhydride, etc., 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 type diamines such as 3,3′-dimethoxy-4,4′-diaminodiphenyl ether and 4,4′-diaminophenyl ether, dipheniene such as 3,3′-diphenylthioether and 4,4′-diaminodiphenylthioether Thioether type diamine, 4,4'-
Examples thereof include benzophenone-based diamines such as diaminobenzophenone, diphenylmethane-based diamines paraphenylenediamine, and metaphenylenediamine. Further, as the organic polar solvent, N-methylpyrrolidone, dimethylformamide, dimethylacetamide,
Examples thereof include phenol, o-cresol, m-cresol, p-cresol, dimethyl oxide and the like, but are not particularly limited thereto.

As the fluororesin, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA), tetrafluoroethylene-hexafluoropropylene copolymer resin (PFEP), ethylene-tetra Fluoroethylene copolymer resin (PETFE), ethylene-chlorotrifluoroethylene copolymer resin (PECTFE), polyvinylidene fluoride (PVdF) and the like can be used.

[0060]

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

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

[Brief description of drawings]

FIG. 1 is a process drawing showing a manufacturing process of a polyimide precursor tubular article according to an embodiment of the present invention.

FIG. 2 is a process drawing showing a manufacturing process of a polyimide composite tubular article according to an embodiment of the present invention.

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

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

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Metal core 2 External mold 3 Polyimide precursor solution in which thermally conductive inorganic particles are dispersed 4,8 Dryer 5,10 Oven 6 Gripping tool 7 Primer solution 9 Polytetrafluoroethylene aqueous dispersion 11 Thermal conductivity Polyimide base material in which inorganic particles are dispersed 12 Conductive primer layer 13 Polytetrafluoroethylene layer 14 Exposed part of conductive primer layer 21 Polyimide composite tubular material 22 Drive roll 23 Tension roll 24 Heater 25 Backup roll 26 Copy paper 27 Toner image 28 Fixing Image a Water b Dry Air c, d Cooling Air P ₁ Cast Molded Polyimide Precursor Solution P ₂ Polyimide Semi-cured Tubular Product P ₃ Polyimide Semi-cured Tubular Product with Primer Coated P ₄ Polyimide Compound tubular

Claims (20)

[Claims] 1. A seamless resin film having a polyimide as a base material, wherein the thermally conductive inorganic particles are substantially uniformly dispersed in the polyimide film, and the polyimide film. A seamless resin film whose inner surface is smooth. 2. The seamless resin film according to claim 1, wherein the amount of the thermally conductive inorganic particles present is in the range of 1 to 50% by weight. 3. The seamless resin film according to claim 1, wherein the primary particles of the thermally conductive inorganic particles have an average particle diameter of 0.01 to 5.0 μm. 4. The thermally conductive inorganic particles are Si ₃ N ₄ , B.
N, SiC, AlN, alumina, copper, nickel, gold,
The seamless resin film according to claim 1, which is at least one selected from silver, platinum, beryllium oxide, magnesium, and magnesium oxide. 5. The seamless resin film according to claim 1, wherein the inner surface of the polyimide film has a surface roughness Rz 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, which is in a range of 0 μm. 7. The seamless resin film according to claim 1, wherein the outer surface of the polyimide film is coated with a fluororesin. 8. A conductive layer is present between the polyimide film and the fluororesin coating layer.
The seamless resin film described in. 9. The fluororesin is at least one selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). The seamless resin film according to claim 7, which is one. 10. The seamless resin film according to claim 7, wherein carbon black is mixed with the fluororesin. 11. The conductive layer contains 1 to 40 w of carbon powder.
The seamless resin film according to claim 8, containing t%. 12. The seamless resin film according to claim 1, wherein the thermally conductive inorganic particles are substantially primary particles uniformly dispersed in the polymer. 13. Heat-conductive inorganic particles are dispersed and mixed into primary particles in a polyimide precursor solution, and then the polyimide precursor solution is cast on the surface of a cylindrical mold and then heated. A method for producing a seamless resin film, characterized in that the imide conversion reaction is completed. 14. A conductive primer is applied to the surface of a semi-cured polyimide tubular product in the middle of the reaction after the polyimide precursor solution is cast on the surface of a cylindrical mold and then heated to complete the imide conversion reaction. The method for producing a seamless resin film according to claim 13, wherein the components are applied, dried, and then coated with a fluororesin, and then heat treatment is performed to simultaneously complete the imide conversion reaction and perform the firing treatment on the fluororesin. 15. A polyimide precursor thickness reduction ratio of 50 to 95 is in the middle of the reaction until the imide conversion reaction is completed.
The method for producing a seamless resin film according to claim 13, which is a step of%. However, the thickness reduction rate is calculated by the following formula (Equation 1). [Equation 1] 16. The method for producing a seamless resin film according to claim 13, wherein the polyimide precursor solution is an aromatic polyimide precursor, and the viscosity thereof is 50 to 10,000 poise. 17. The coating thickness of the polyimide precursor solution is:
The method for producing a seamless resin film according to claim 13 or 14, wherein the range is 10 to 1000 μm. 18. A means for casting a polyimide precursor solution on the outer surface of a cylindrical mold to a substantially uniform thickness,
The seamless resin according to claim 13 or 14, which is a method of arranging an outer mold having a certain clearance outside the cylindrical mold and moving at least one of the cylindrical mold and the outer mold. Film manufacturing method. 19. The method for producing a seamless resin film according to claim 13, wherein the surface of the cylindrical mold is covered with an inorganic coating film layer. 20. A method of substantially dispersing primary particles of thermally conductive inorganic particles is a method of adding thermally conductive inorganic particles to a solution, performing ultrasonic treatment, and then mixing with a polyimide precursor solution. 15. The method for producing a seamless resin film according to claim 13 or 14.