JP2001040102A - Tubular article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tubular article which has a high heat conductivity, an internal circumferential surface with a lowly restricted friction coefficient and an excellent performance as a fixed belt or the like. SOLUTION: This tubular article comprising a polyimide resin-based composition containing as the main component a polyimide resin, (A) a heat conductive inorganic filler and (B) a fluororesin powder, is characterized in that the article is composed of a tubular internal layer 11 in which a content ratio of component (A) is set to be 10-40 wt.% on the basis of the polyimide resin composition and that of component (B) is set to be 0.1-20 wt.% on the basis of the polyimide resin composition, and of a fluororesin coating layer 13 via an electrically conductive primer layer 12, formed on the external circumferential surface of the internal layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular member used for a fixing belt of an image forming apparatus such as a copying machine, a facsimile, and a printer.

[0002]

2. Description of the Related Art Conventionally, polyimide resins have been used for heat resistance,
It has excellent dimensional stability, mechanical characteristics and chemical characteristics, and is used as a fixing belt of an image forming apparatus such as a copying machine. 2. Description of the Related Art In recent years, as an example of a method of fixing an image on transfer paper in an electrophotographic fixing device, there is a belt fixing method using a tubular member of the above polyimide resin. In this belt fixing method, for example, in a method (surf method) shown in FIG. 2, an endless belt 10 made of a polyimide resin is stretched over two rollers 7 and 8 and a heater 9 which are separated from each other. The pressure roller 2 is disposed so as to face the endless roller. In the system shown in FIG. 3 (on-demand system), an endless belt 10 is wrapped around the heater 9 without using two rollers in an isolated state. The pressure roller 2 is disposed so as to be opposed to. Then, the transfer paper 3 on which the toner 5 is temporarily attached is fed between the endless belt 10 and the pressure roller 2, so that the toner 5 is melted and fixed to form the toner image 6. The endless belt 10 is formed by cutting a tubular object into an appropriate width, and its outer peripheral surface is used as a toner fixing surface.

In these belt fixing systems, by forming the endless belt 10 extremely thin, heat generated by the heater 9 can be immediately transmitted to the fixing belt, and the heat capacity can be reduced. Therefore, when the power is turned on, the surface temperature of the fixing belt immediately rises to a predetermined temperature, so that there is an advantage that the waiting time can be remarkably reduced and power can be saved.

However, the on-demand method has an advantage that the meandering control can be simplified. However, since the endless belt 10 itself is required to have higher strength against buckling, if the endless belt 10 is formed thin, the mechanical strength is reduced. Therefore, when it is incorporated in an image fixing device, wrinkles and meandering occur, so that it was not possible to easily form a thin film. However, if the thickness of the endless belt 10 is increased, the heat conduction performance of the polyimide resin is extremely poor by nature. As a result, the toner fixability also decreases.

Here, since the toner charging property is maintained at the same level as that of the surf system, as an endless belt used in the on-demand system, for example, by adding a heat conductive filler to a polyimide resin, the heat conduction performance is improved. An improved fixing belt has been proposed (JP-A-7-110).
632). In addition, a method has been proposed in which a heat conductive inorganic filler is added to a polyimide resin to prevent a decrease in mechanical strength and a deterioration in surface roughness by finely dispersing the heat conductive inorganic filler (Japanese Patent Laid-Open No. 7-1995). 186162).

[0006]

However, in the fixing belt described in JP-A-7-110632, if the heat conductive filler has a high hardness, it is present on the inner peripheral surface of the tubular article. There has been a problem that the heat conductive filler particles damage contact members such as a heater surface and a roller. Further, Japanese Patent Application Laid-Open No. Hei 7-18616
In the case where the heat conductive inorganic filler in JP-A No. 2 is finely dispersed, if the abrasion of the inner peripheral surface of the tubular article progresses and the abundance of hard particles increases on the inner peripheral surface, the heater surface is increased as described above. However, there was a problem that the friction was increased and the friction coefficient was increased. In order to solve the above-mentioned problem, a method of preventing abrasion by applying a lubricant such as silicone grease to the inner peripheral surface of the tubular article has been taken as a known technique, but since the lubricant has poor thermal conductivity, Invites a decrease in toner fixability,
It was not preferred.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is intended to provide a tubular article having high thermal conductivity, a low coefficient of friction on the inner peripheral surface, and excellent performance as a fixing belt and the like. Its purpose is to provide.

[0008]

Means for Solving the Problems To achieve the above object, a tubular article of the present invention comprises a polyimide resin composition containing a polyimide resin as a main component and the following components (A) and (B). The content of the component (A) is 10 to 40% by weight in the polyimide resin composition, and the content of the component (B) is 0.1 to 20 in the polyimide resin composition. In this case, the weight% is set. (A) Thermally conductive inorganic filler. (B) Fluororesin powder.

That is, the present inventors have intensively studied to obtain a tubular material having a high thermal conductivity and suitable as a fixing belt without damaging the heater surface due to friction of the inner peripheral surface. Was. As a result, a polyimide resin-based composition containing a polyimide resin as a main component, and a thermally conductive inorganic filler (component A) and a fluororesin powder (component B) dispersed therein, When a tubular material in which the content ratio of the filler (component A) and the content ratio of the fluororesin powder (component B) are set to specific ranges is used, the friction coefficient of the inner peripheral surface is 2/100 of the conventional one.
3 or less, finding that the intended purpose can be achieved,
The present invention has been reached.

In the tubular article of the present invention, if the tubular article has a three-layer structure in which a fluororesin coating layer is formed on the outer peripheral surface of the tubular article via a conductive primer layer, Since the conductivity is imparted, the tubular article and the fluororesin coating layer are hardly charged, easy to remove static electricity, can prevent offset, can fix a clear image, and have found that they are more preferable.

When the tubular article of the present invention is used as a fixing belt by forming the above-mentioned fluororesin coating layer, the above-mentioned fluororesin coating layer reduces the frictional resistance of the outer peripheral surface to make it slippery. It has been found that the toner is more preferable because it can enhance the releasability of the toner and prevent the offset.

[0012]

Next, an embodiment of the present invention will be described.

The tubular article of the present invention comprises a polyimide resin composition containing a polyimide resin as a main component and a heat conductive inorganic filler (component A) and a fluororesin powder (component B) at specific ratios. It is a tubular object.

The heat conductive inorganic filler (component A) is not particularly limited as long as it is an inorganic powder having a heat conductive function. For example, boron nitride, potassium titanate, mica,
Examples include titanium oxide, talc, calcium carbonate, aluminum nitride, alumina, silicon carbide, silicon, silicon nitride, silica, graphite, gold, silver, platinum, beryllium oxide, magnesium, and magnesium oxide. Above all, it has a high heat conduction function, exhibits a release effect, is chemically stable,
Boron nitride is preferred in that it is harmless.

The content of the heat conductive inorganic filler (component A) is 10 to 40% by weight in the polyimide resin composition.
Must be set in the range. Particularly preferably,
It is in the range of 20-35% by weight. It is preferable that the thickness be in such a range, since the thermal conductivity of the tubular article can be kept high. In addition, the said heat conductive inorganic filler (A component)
If the content is less than 10% by weight, a sufficient effect of improving thermal conductivity cannot be obtained, which is not preferable. Conversely, 40% by weight
If it exceeds, the resulting tubular article has low mechanical strength and is liable to cracks and cracks, which is not preferable.

Further, it is preferable that the average particle size of the primary particles of the heat conductive inorganic filler (component A) is set in a range of 0.01 to 5.0 μm. More preferably, it is in the range of 0.05 to 2.0 μm. When the content is within such a range, the particles are less likely to aggregate and are uniformly dispersed, so that there is no variation in thermal conductivity or strength, and strength as a fixing belt can be maintained, which is preferable. It is not preferable that the average particle diameter is less than 0.01 μm because irregularities easily occur on the inner and outer peripheral surfaces of the obtained tubular article due to aggregation of the particles. Conversely, if it exceeds 5.0 μm, the particles become large, so that irregularities due to the particles are likely to occur on the inner and outer peripheral surfaces of the obtained tubular article, which is not preferable. The average particle size of the primary particles of the heat conductive inorganic filler (component A) is determined, for example, by using a liquid obtained by ultrasonically dispersing in an organic solvent such as ethanol as a sample and using a light transmission centrifugal sedimentation method. It can be measured by a distribution meter.

On the other hand, as the fluororesin powder (component B), for example, polytetrafluoroethylene (PTF)
E), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PF
A), an ethylene-tetrafluoroethylene copolymer (E
TFE) and the like. Among them, PTFE is preferred because of its high heat resistance and small dynamic friction coefficient.

The content of the fluororesin powder (component B) must be set in the range of 0.1 to 20% by weight in the polyimide resin composition. Particularly preferably,
It is in the range of 0.5 to 10% by weight. If the content of the fluororesin powder (component B) is less than 0.1% by weight, the effect of reducing the friction coefficient cannot be obtained, which is not preferable. Conversely, if it exceeds 20% by weight, the resulting tubular article has low mechanical strength and is liable to cracks and cracks.

Further, the average particle size of the fluororesin powder (component B) is preferably set in the range of 0.01 to 5.0 μm. More preferably, 0.5 to 5.0.
It is in the range of μm. When the content is within such a range, the particles are less likely to aggregate and are uniformly dispersed, so that there is no variation in thermal conductivity or strength, and strength as a fixing belt can be maintained, which is preferable. In addition, the said average particle diameter is 0.1.
When the diameter is less than 01 μm, irregularities are likely to be formed on the inner peripheral surface and the outer peripheral surface of the obtained tubular article due to aggregation of particles, which is not preferable. Conversely, if it exceeds 5.0 μm, the particles become large, so that irregularities due to the particles are likely to occur on the inner and outer peripheral surfaces of the obtained tubular article, which is not preferable. The method for measuring the average particle size of the fluororesin powder (component B) is in accordance with the method for measuring the average particle size of the primary particles of the thermally conductive inorganic filler (component A).

Further, as described above, the tubular article of the present invention is a tubular article comprising a polyimide resin composition containing a polyimide resin as a main component. Here, the “main component” is a main component constituting the polyimide resin-based composition, and means that it has a significant effect on the properties of the composition. The polyimide resin is obtained by converting polyamic acid into imide. The polyamic acid, which is a precursor of a polyimide resin, can be obtained by reacting substantially equimolar amounts of tetracarboxylic dianhydride or a derivative thereof with a diamine in an organic solvent.

The above tetracarboxylic dianhydride includes:
A compound represented by the following general formula (1) is given.

[0022]

Embedded image

Specific examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ',
4,4'-benzophenonetetracarboxylic dianhydride,
3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,3,3', 4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2'-bis (3,4-dicarboxyphenyl) propane dianhydride Anhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, perylene-3,
4,9,10-tetracarboxylic dianhydride, bis (3,
4-dicarboxyphenyl) ether dianhydride, ethylene tetracarboxylic dianhydride and the like.

In addition, such tetracarboxylic dianhydrides
Specific examples of the diamine to be reacted with the product include 4,4'-
Diaminodiphenyl ether, 4,4'-diaminodiph
Phenylmethane, 3,3′-diaminodiphenylmethane,
3,3'-dichlorobenzidine, 4,4'-diaminodi
Phenyl sulfide-3,3'-diaminodiphenyls
Rufone, 1,5-diaminonaphthalene, m-phenylene
Diamine, p-phenylenediamine, 3,3'-dimethyl
-4,4'-biphenyldiamine, benzidine, 3,
3'-dimethylbenzidine, 3,3'-dimethoxyben
Dizine, 4,4'-diaminophenylsulfone, 4,
4'-diaminodiphenyl sulfide, 4,4'-dia
Minodiphenylpropane, 2,4-bis (β-amino-
Tert-butyl) toluene, bis (p-β-amino-tert-butyl)
Tylphenyl) ether, bis (p-β-methyl-δ-
Aminophenyl) benzene, bis-p- (1,1-dimension)
Tyl-5-amino-pentyl) benzene, 1-isopro
Pill-2,4-m-phenylenediamine, m-xylylene
Diamine, p-xylylenediamine, di (p-amino
Cyclohexyl) methane, hexamethylenediamine, f
Ptamethylenediamine, octamethylenediamine, nona
Methylenediamine, decamethylenediamine, diaminop
Ropirtetramethylene, 3-methylheptamethylenedia
Min, 4,4-dimethylheptamethylenediamine, 2,
11-diaminododecane, 1,2-bis-3-aminop
Ropoxyethane, 2,2-dimethylpropylene diamine
, 3-methoxyhexamethylenediamine, 2,5-di
Methyl hexamethylene diamine, 2,5-dimethyl hept
Tamethylene diamine, 3-methylheptamethylene diamine
, 5-methylnonamethylenediamine, 2,11-dia
Minododecane, 2,17-diaminoeicosadecane,
1,4-diaminocyclohexane, 1,10-diamino
-1,10-diamino-1,10-dimethyldecane,
1,12-diaminooctadecane, 2,2-bis [4-
(4-Aminophenoxy) phenyl] propane, pipera
Gin, H_TwoN (CH_Two)_ThreeO (CH_Two)_TwoOCH_TwoNH
_Two, H_TwoN (CH_Two)_ThreeS (CH_Two)_ThreeNH_Two, H_TwoN
(CH_Two)_ThreeN (CH_Three) (CH_Two)_ThreeNH _TwoEtc.
Can be

One or more of these tetracarboxylic dianhydrides or derivatives thereof and diamines can be appropriately selected and reacted.

The organic polar solvent used for reacting the tetracarboxylic dianhydride with the diamine has a dipole whose functional group does not react with the tetracarboxylic dianhydride or the diamine. It must be inert to the system and act as a solvent for the product polyamic acid. Moreover, it must act as a solvent for at least one, and preferably both, of the reaction components. As the organic polar solvent, N, N-dialkylamides are particularly useful, and examples thereof include low molecular weight N, N-dimethylformamide, N, N-dimethylacetamide and the like. These can be easily removed from the polyamic acids and polyamic acid moldings by evaporation, displacement or diffusion.
In addition, N, N-diethylformamide, N, N-diethylacetamide, N, N
N-dimethylmethoxyacetamide, dimethylsulfoxide, hexamethylphosphortriamide, N-methyl-
2-pyrrolidone, pyridine, tetramethylene sulfone,
Dimethyltetramethylene sulfone and the like. These may be used alone or in combination. Further, phenols such as cresol, phenol and xylenol, benzonitrile, dioxane, butyrolactone, xylene, cyclohexane, hexane, benzene, toluene and the like can be used alone or in combination with the organic polar solvent. However, it is preferable to avoid using water in order to prevent the generated polyamic acid from being reduced in molecular weight by hydrolysis.

The polyamic acid solution is preferably obtained by reacting the tetracarboxylic dianhydride (x) with the diamine (y) in an organic polar solvent for about 0.5 to 10 hours. That is, if the time is less than 0.5 hour, the reaction becomes insufficient, and if the time exceeds 10 hours, no further effect can be obtained. Further, the monomer concentration (concentration of (x) + (y) in the above-mentioned solvent) at the time of the reaction can be set according to various factors, but is usually 5 to 30% by weight.
It is. The reaction temperature is preferably set to 80 ° C. or lower.

Further, when the tetracarboxylic dianhydride and the diamine are reacted in the organic polar solvent as described above,
Although the viscosity of the solution increases as the reaction proceeds, in the present invention, it is preferable to use a polyamic acid solution having a logarithmic viscosity (η) of 0.5 or more. That is, when formed using a polyamic acid solution having a logarithmic viscosity (η) of 0.5 or more, the reliability (heat resistance) against thermal degradation is particularly excellent as compared with those having a logarithmic viscosity of less than 0.5. There are advantages. In addition, the logarithmic viscosity (η) is determined by measuring the falling time of the polyamic acid solution and the solvent using a capillary viscometer, respectively.
It is a value calculated by the following equation.

[0029]

(Equation 1)

When such a polyamic acid solution is used, if the viscosity is high, the solution is diluted with an appropriate solvent to reduce the viscosity. For example, the viscosity of a polyamic acid solution is
The thickness is set in accordance with the coating thickness, the inner diameter of the cylinder, the solution temperature, the shape of the running body, and the like, but is usually set to 10 to 10,000 poise (measured at the temperature during the coating operation with a B-type viscometer).

When the tubular article of the present invention is used, for example, as a fixing belt, as shown in FIG. 1, a fluororesin coating layer is provided on the outer periphery of a tubular inner layer (tubular article) 11 via a conductive primer layer 12. 13 are provided as a three-layer structure.

Teflon 855-001 (manufactured by DuPont), Teflon 855-
300 (manufactured by DuPont), Polyflon EK-1800
(Manufactured by Daikin Industries, Ltd.) and Polyflon EK-1900
(Daikin Industries Co., Ltd.) and other well-known primers are mixed with a powder having excellent conductivity, such as carbon black powder, aluminum powder, iron, gold powder, and silver powder, in the range of 1 to 40% by weight in the conductive primer layer forming material. Is preferable because the obtained tubular material is less likely to be charged, is easily discharged, prevents offset, and can fix a clear image. further,
A metal deposition layer, a metal sputtering layer, or the like may be interposed. In addition, if the conductive primer layer 12 is exposed at one end side of the tubular object, a conductive brush or the like can be brought into contact with the exposed portion to easily remove charges charged during traveling. it can.

Examples of the material for forming the fluororesin coating layer 13 include a fluororesin as a main component, for example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FE).
P), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and the like, and these can be used alone or in combination of two or more. Among these fluororesins, it is preferable to use PFA from the viewpoint that toner releasability is particularly high.

The fluororesin coating layer 13
In order to impart conductivity, carbon,
A conductive material such as a metal may be added. When the above-mentioned heat conductive inorganic filler powder (component A) is added, when this tubular material is incorporated in an image forming apparatus as a fixing belt,
This is more preferable because the heat from the heater can be efficiently transmitted to the fluororesin coating layer 13 and the toner fixability can be improved. Further, powders of silicon dioxide, glass beads, cross-linked silicone resin, ceramic, polyimide resin, benzoguanamine resin and the like may be added for improving abrasion resistance. These powders usually have a particle size of 5 μm in consideration of dispersibility with fluororesin.
The addition amount is preferably set to the following value.
Usually, it is preferably 0.5 to 50 parts by weight based on parts by weight. When a fluororesin dispersion (dispersion medium: water or the like) is used as the material for forming the fluororesin coating layer 13, the concentration of the fluororesin powder is set in the range of 20 to 40% by weight in consideration of coating workability. And the rotational viscosity (measured with a B-type viscometer at the temperature during the coating operation) is 0.5 to 1.
It is preferable to set 5 poise.

The tubular article of the present invention can be obtained, for example, as follows. That is, first, a cylinder to be a molding die is prepared, and a thermally conductive inorganic filler (A component) and a fluororesin powder (B component) are respectively contained at a specific ratio on the inner or outer peripheral surface of the cylinder, and are uniformly formed. Is applied with the polyamic acid solution dispersed therein. After application,
After heating, the polyamic acid is converted into an imide to form a tubular material, and the tubular material is peeled from the cylinder and taken out. To make this into a three-layer structure as described above, for example, the tubular material obtained above is used as a tubular inner layer 11, and the above-mentioned conductive primer is applied to the outer peripheral surface thereof, etc. The primer layer 12 is formed. And
The above-mentioned fluororesin solution is applied to the outer peripheral surface of the formed conductive primer layer 12 and heated to form the fluororesin coating layer 13, thereby obtaining a desired tubular article.

In the above step, a conductive primer layer 12 is formed and dried by applying a conductive primer to the outer peripheral surface of the semi-cured polyimide product in the middle of the reaction until the imide conversion reaction is completed. Then, by applying a fluororesin solution and performing a heat treatment, when the completion of the imide conversion reaction and the calcination of the fluororesin are simultaneously performed, the completion of the imide conversion reaction and the calcination of the fluororesin are separately performed. As compared with the above, the thermal efficiency can be increased and the processing time can be shortened. Further, it is more preferable because strong integration of polyimide and fluororesin can be achieved.

In the above-mentioned process, any cylinder may be used as a molding die as long as it is conventionally used for manufacturing a tubular article. Among them, a cylindrical one is preferable because a seamless tubular object can be easily obtained. As the material of the cylinder, various materials such as metal, glass, and ceramics can be used from the viewpoint of heat resistance.

[0038] In the tubular article of the present invention, the thickness of the layer is appropriately set according to the apparatus to be incorporated, but usually, when the thickness of the tubular article is in the range of 40 to 100 µm, the mechanical strength is reduced. It is practically preferable because it is high and the thermal conductivity is within a range that does not hinder the heat conductivity. And when the surface roughness Rz of the inner peripheral surface of the tubular article is in the range of 2.5 or less,
This is preferable because the inner peripheral surface of the tubular article is finished smoothly and does not damage members such as the heater. Here, the “surface roughness Rz” is obtained from a contour (which is called a cross-sectional curve) that appears at the cut when cut along a plane perpendicular to the irregularities.
A ten-point average roughness determined from a roughness curve obtained by cutting off a surface undulation component longer than a predetermined wavelength, and the measurement is performed by a method according to JIS B 0601-1982. When the fluororesin coating layer 13 is provided on the outer periphery of the tubular article, the thickness of the fluororesin coating layer 13 is preferably as thin as possible in order to improve the toner fixing property. 13 is reduced in durability.
It is preferable that the distance be set in the range of μm.

Next, examples will be described together with comparative examples.

[0040]

Example 1 Boron nitride powder (MBN-010T, manufactured by Mitsui Chemicals, Inc .: average particle size 1.3 μm) was added to 40% by weight of the following polyimide resin composition, and PTFE fine particles (KTL-
8, manufactured by Kitamura Co., Ltd .: average particle size 4.0 μm) was set to 2% by weight in the following polyimide resin composition, added to an N-methyl-2-pyrrolidone (NMP) solvent, and subjected to ball milling. The mixture was dispersed by stirring for 6 hours, and filtered using a # 400 stainless steel mesh to prepare an NMP solvent. On the other hand, the acid content is 3,
In addition to preparing 3 ', 4,4'-biphenyltetracarboxylic dianhydride, a mixture of p-phenylenediamine and 4,4'-diaminodiphenyl ether (molar ratio 7: 3) was prepared as an amine component. Was dissolved in the above NMP solvent (monomer concentration 20%),
The reaction was carried out at a temperature of 20 ° C. for 6 hours to prepare a polyamic acid solution having a rotational viscosity of 30,000 poise (measured by a B-type viscometer: measuring temperature of 20 ° C.) and an logarithmic viscosity of 2.6. Then 70
After heating to 3,000 ° C. to a viscosity of 3,000 poise,
Filtration was performed using a stainless mesh to prepare a polyamic acid solution (polyimide precursor).

Next, the above-mentioned polyamic acid solution is uniformly applied to a mold according to the above-mentioned method, dried at 70 ° C. for 60 minutes, and further raised from 70 ° C. to 250 ° C. at a rate of 0.8 ° C./min. Then, a heat treatment was performed at 250 ° C. for 60 minutes to obtain a tubular body of a polyimide precursor.

Further, a conductive primer (manufactured by DuPont-Mitsui Co., Ltd.) containing 20% by weight of carbon black powder in the material for forming a conductive primer layer was coated on the outer peripheral surface of the polyimide precursor tube obtained above. Then, it was spray-coated uniformly and air-dried at 150 ° C. for 10 minutes to form a conductive primer layer. The thickness of this conductive primer layer is 1 μm
Met.

Further, an aqueous dispersion (TE-334J, manufactured by DuPont) having a PFA concentration of 60% by weight and carbon black powder (W-311N, lion) were formed on the outer peripheral surface of the tubular material having the conductive primer layer formed thereon. Per 100 parts by weight of PFA (solid content)
The parts contained in parts by weight were uniformly spray-coated and air-dried for 10 minutes. Thereafter, the dispersion medium is heated at 100 ° C. for 10 minutes to evaporate and remove water as a dispersion medium, and further heated at 400 ° C. for 5 minutes to form a tubular inner layer made of a polyimide resin composition and a conductive layer formed on the outer peripheral surface thereof. There was obtained a three-layered tubular body composed of a conductive primer layer and a PFA-made fluororesin coating layer sintered on the outer peripheral surface thereof.
The above-mentioned tubular material has a length of 250 mm, an inner diameter of 25 mm, and a thickness of 60 μm (of which a fluororesin coating layer 10 μ
m).

In the tubular article thus obtained,
Unsteady method hot wire method (Kemtherm QTM, manufactured by Kyoto Electronics Industry Co., Ltd.)
-D3) was 1.40 W / m · K, and the coefficient of kinetic friction of the inner peripheral surface of the tubular article was 200
g, 0.10 at a sliding speed of 150 mm / min. And the mechanical strength by the tensile test is 16 kg / m
m ² .

[0045]

Example 2 The content of the boron nitride powder was set so as to be 10% by weight in the polyimide resin composition. Otherwise, a tubular article was obtained in the same manner as in Example 1.
And the said tubular thing was made into the three-layer structure like Example 1. FIG.

In the tubular article thus obtained,
Unsteady method hot wire method (Kemtherm QTM, manufactured by Kyoto Electronics Industry Co., Ltd.)
-D3) was 1.00 W / m · K, and the coefficient of kinetic friction of the inner peripheral surface of the tubular article was 200
g, 0.13 at a sliding speed of 150 mm / min. And the mechanical strength by the tensile test is 40 kg / m
m ² .

[0047]

Example 3 The content of the boron nitride powder was set so as to be 25% by weight in the polyimide resin composition. Further, the content of the PTFE fine particles was set so as to be 0.1% by weight in the polyimide resin composition. Otherwise, a tubular article was obtained in the same manner as in Example 1.
And the said tubular thing was made into the three-layer structure like Example 1. FIG.

In the tubular article thus obtained,
Unsteady method hot wire method (Kemtherm QTM, manufactured by Kyoto Electronics Industry Co., Ltd.)
-D3) was 1.20 W / m · K, and the coefficient of kinetic friction of the inner peripheral surface of the tubular article was 200
g, 0.12 at a sliding speed of 150 mm / min. And the mechanical strength by the tensile test is 29 kg / m
m ² .

[0049]

Example 4 The content of the boron nitride powder was set so as to be 25% by weight in the polyimide resin composition. Further, the content of the PTFE fine particles was set so as to be 20% by weight in the polyimide resin composition. Otherwise, a tubular article was obtained in the same manner as in Example 1.
And the said tubular thing was made into the three-layer structure like Example 1. FIG.

In the tubular article thus obtained,
Unsteady method hot wire method (Kemtherm QTM, manufactured by Kyoto Electronics Industry Co., Ltd.)
-The thermal conductivity measured in D3) is 0.7 W / m · K.
The coefficient of kinetic friction of the inner peripheral surface of the tubular article is 200 g load,
0.09 at a sliding speed of 150 mm / min.
Was. And the mechanical strength by the tensile test is 21 kg / mm
^TwoMet.

Further, each of the above-mentioned examples was cut into a width of 300 mm and used as a fixing belt (endless belt) of an image fixing apparatus using the belt fixing method (on-demand method) illustrated in FIG. In each of the examples, the system was excellent in thermal conductivity and toner chargeability, and was excellent in offset properties, and the printing state was also good in toner fixability. Also, no scratch on the heater surface was observed. The test was performed without applying silicone grease to the inner peripheral surface of the tubular article.

[0052]

Comparative Example 1 A tubular article was obtained in the same manner as in Example 1 except that the above-mentioned PTFE fine particles were not contained in the above-mentioned polyimide precursor. And the said tubular thing was made into the three-layer structure like Example 1. FIG.

In the tubular article thus obtained,
Unsteady method hot wire method (Kemtherm QTM, manufactured by Kyoto Electronics Industry Co., Ltd.)
-D3) was 1.40 W / m · K, and the coefficient of kinetic friction of the inner peripheral surface of the tubular article was 200
g, 0.20 at a sliding speed of 150 mm / min. And the mechanical strength by the tensile test is 16 kg / m
m ² .

[0054]

Comparative Example 2 The content of the above-mentioned PTFE fine particles was set so as to be 25% by weight in the above-mentioned polyimide resin composition. Otherwise, a tubular article was obtained in the same manner as in Example 1.
And the said tubular thing was made into the three-layer structure like Example 1. FIG.

In the tubular article thus obtained,
Unsteady method hot wire method (Kemtherm QTM, manufactured by Kyoto Electronics Industry Co., Ltd.)
The thermal conductivity measured in -D3) is 1.20 W / m · K
The coefficient of kinetic friction of the inner peripheral surface of the tubular article is 200
g, 0.09 at a sliding speed of 150 mm / min
Was. And the mechanical strength by the tensile test is 9 kg / mm
^TwoMet.

[0056]

Comparative Example 3 The content of the PTFE fine particles was set so as to be 0.05% by weight in the polyimide resin composition. Otherwise, a tubular article was obtained in the same manner as in Example 1. And the said tubular thing was made into the three-layer structure like Example 1. FIG.

In the tubular article thus obtained,
Unsteady method hot wire method (Kemtherm QTM, manufactured by Kyoto Electronics Industry Co., Ltd.)
-D3) was 1.40 W / m · K, and the coefficient of kinetic friction of the inner peripheral surface of the tubular article was 200
g, 0.20 at a sliding speed of 150 mm / min. And the mechanical strength by the tensile test is 16 kg / m
m ² .

[0058]

Comparative Example 4 The content of the boron nitride powder was set so as to be 7% by weight in the polyimide resin composition.
Further, the content of the PTFE fine particles was set so as to be 10% by weight in the polyimide resin composition. Otherwise, a tubular article was obtained in the same manner as in Example 1. And the said tubular thing was made into the three-layer structure like Example 1. FIG.

In the tubular article thus obtained,
Unsteady method hot wire method (Kemtherm QTM, manufactured by Kyoto Electronics Industry Co., Ltd.)
-The thermal conductivity measured in D3) is 0.8 W / m · K.
The coefficient of kinetic friction of the inner peripheral surface of the tubular article is 200 g load,
0.11 at a sliding speed of 150 mm / min
Was. And the mechanical strength by the tensile test is 36 kg / mm
^TwoMet.

[0060]

Comparative Example 5 The content of the boron nitride powder was set to be 50% by weight in the polyimide resin composition. Further, the content of the PTFE fine particles was set so as to be 10% by weight in the polyimide resin composition. Otherwise, a tubular article was obtained in the same manner as in Example 1.
And the said tubular thing was made into the three-layer structure like Example 1. FIG.

In the tubular article thus obtained,
Unsteady method hot wire method (Kemtherm QTM, manufactured by Kyoto Electronics Industry Co., Ltd.)
-D3) was 1.6 W / m · K, and the coefficient of kinetic friction of the inner peripheral surface of the tubular article was 200 g under a load of 200 g.
It was 0.10 at a sliding speed of 150 mm / min. The mechanical strength by the tensile test is 8 kg / mm ²
Met.

Further, each of the comparative examples was cut into a width of 300 mm and used as a fixing belt (endless belt) for an image fixing device using a belt fixing method (on-demand method) illustrated in FIG. For example, in Comparative Example 1, there was no problem in thermal conductivity, toner charging property and toner fixing property, but linear scratches were observed on the heater surface.
Wear powder was also observed. In Comparative Example 2, although no scratch on the heater surface was observed, the end face was torn during the test because the mechanical strength was too low. Also, in the comparative example 3, linear scratches were observed on the heater surface as in the comparative example 1. In Comparative Example 4, no scratch on the heater surface was observed, and there was no problem in mechanical strength. However, since the thermal conductivity was small, the toner fixing property was poor. The end face of the product of Comparative Example 5 was torn during the test because the mechanical strength was too low. The test was performed without applying silicone grease to the inner peripheral surface of the tubular article.

[0063]

As described above, the tubular article of the present invention contains a polyimide resin as a main component, and contains a thermally conductive inorganic filler (component A) and a fluororesin powder (component B) at specific mixing ratios. It is a tubular article made of a polyimide resin composition.

The tubular article of the present invention has a high coefficient of thermal conductivity and other suitable properties as a fixing belt, but the coefficient of friction of the inner peripheral surface of the tubular article becomes 2/3 or less of the conventional one.
Wear on the heater surface and the like can be prevented without applying a lubricant such as silicone grease having poor heat conductivity to the inner peripheral surface of the tubular article.

The tubular article of the present invention may have a three-layer structure in which a fluororesin coating layer is formed on the outer peripheral surface of the tubular article obtained above via a conductive primer layer. Since the conductive primer layer is provided with conductivity, the tubular article and the fluororesin coating layer are hardly charged, easy to remove static electricity, can prevent offset, and can fix a clear image.

By forming the fluororesin coating layer, when the tubular article of the present invention is used as a fixing belt, the fluororesin coating layer reduces the frictional resistance of the outer peripheral surface to make it slippery. In addition, it is possible to enhance the releasability of the toner and prevent offset.

Further, when a heat conductive inorganic filler such as boron nitride powder is contained in the above-mentioned fluororesin coating layer, there is an advantage that high heat conductivity can be realized and good releasability is exhibited. . It is also excellent from the viewpoint of safety.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a tubular article of the present invention.

FIG. 2 is a schematic diagram for explaining a belt fixing method (surf method).

FIG. 3 is a schematic diagram for explaining a belt fixing method (on-demand method).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Tubular inner layer 12 Conductive primer layer 13 Fluororesin coating layer

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hajime Otani 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation F-term (reference) 4F071 AA26 AA60 AB01 AE17 AF22 AF28 AG02 AG12 AG28 AH16 BA02 BB02 BB12 BB13 BC05 4J002 BD122 BD152 CM041 DA026 DA076 DA096 DA116 DE076 DE096 DE136 DE146 DE186 DE236 DF016 DJ006 DJ046 DJ056 DK006 FD016 GP00 GQ00

Claims (2)

[Claims] 1. A tubular article comprising a polyimide resin composition containing a polyimide resin as a main component and the following components (A) and (B), wherein the content of the component (A) is a polyimide resin 10 to 40% by weight in the composition
And the content of the component (B) is set to 0.1 to 20% by weight in the polyimide resin composition. (A) Thermally conductive inorganic filler. (B) Fluororesin powder. 2. The tubular article according to claim 1, wherein a fluororesin coating layer is formed on the outer peripheral surface of the tubular article via a conductive primer layer.