JPH09328610A - Tubular material made of heat-resistant resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tubular material made of a heat-resistant resin excellent in thermal conductivity and mechanical strength, by disturbing the orientation of thermally conductive inorganic powder such as scaly or fibrous powder in the circumferential direction during the curing and molding of the heat- resistant resin and increasing the mutual contact of the inorganic powder in the tubular material made of the heat-resistant resin obtained by dispersing the thermally conductive inorganic powder to the heat-resistant resin. SOLUTION: First thermally conductive inorganic powder such as scaly or fibrous powder or laminar powder having a high aspect ratio and second thermally conductive inorganic powder such as spherical or laminar powder having a low aspect ratio or amorphous powder are dispersed into a heat- resistant resin such as a polyimide resin. Boron nitride of hexagonal system is used as the first thermally conductive inorganic powder. Aluminum nitride, boron nitride, alumina, silicon carbide, silica, etc., are used as the second thermally conductive inorganic powder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless belt which constitutes a fixing belt of a belt fixing system in a fixing portion of an image forming apparatus such as an electrophotographic copying machine, a printer (laser beam printer, etc.), a facsimile machine ( The present invention relates to a heat-resistant resin tubular article that is preferably used as an endless belt or the like.

[0002]

2. Description of the Related Art A heat roller fixing method is an example of a method for fixing an image on a transfer sheet in an electrophotographic fixing device. In this heat roller system, as shown in FIG. 1, a heat roller 1 and a pressure roller 2 are vertically opposed to each other, a transfer paper 3 is fed between the rollers 1 and 2, and is built in the heat roller 1. This is a method in which the toner 5 temporarily attached to the transfer paper 3 is melted and fixed by the heat generated by the heater 4 and is pressed by the pressure roller 2 to strengthen the fixing. By this method,
A toner image 6 is formed by the toner 5 on the transfer paper 3. In order to prevent toner from adhering to the surface of the heat roller,
The roller surface is generally coated with a fluororesin or silicone rubber, or the coating layer is impregnated with oil.

[0003] In dissolving and fixing toner on transfer paper by the above-mentioned heat roller fixing method, the surface temperature of the heat roller needs to be higher than the melting temperature of the toner. Therefore, in electrophotographic copying machines, printers, facsimiles, etc. using the heat roller fixing method, it is necessary to wait until the surface temperature of the heat roller reaches the melting temperature of the toner after each fixing operation (usually 20 seconds to 10 seconds). Min) Inefficient. For this reason, when a large number of persons use the apparatus in an office or the like, the power is turned on during a period of use, so that the fixing operation can be performed immediately. But,
In this method, since it is necessary to always supply power to the heat roller, the power consumption becomes extremely large, which is not economically preferable.

Therefore, a belt fixing system has been developed in order to shorten the waiting time until the fixing becomes possible and to save power.
In this belt fixing method, as shown in FIG. 2, an endless belt 10 is stretched over two rollers 7 and 8 and a heater 9 which are separated from each other, and a pressure roller 2 is arranged so as to face the heater 9 and In this method, the transfer paper 3 to which 5 is temporarily attached is sent between the endless belt 10 and the pressure roller 2, and the toner 5 is fused and fixed to form the image 6. According to this method, since the endless belt 10 can be formed extremely thin to reduce the heat capacity, heat generated by the heater is immediately transmitted to the fixing belt. 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.
As an endless belt used in such a belt fixing method, a tubular article made of a polyimide resin having excellent heat resistance and mechanical strength, or a composite tubular article made of a polyimide resin inner layer and a fluororesin outer layer (Japanese Patent Laid-Open No. 3-130149).
Publication). In these tubular materials, a pair of rollers are inserted into the tubular material and separated from each other to form the endless belt 10 of FIG. 2, and the outer peripheral surface thereof is used as a fixing surface. .

The above endless belt used in the belt fixing system is required to have excellent heat resistance and mechanical strength, but in order to further increase the fixing speed of the belt fixing system, improvement in heat conduction performance is strongly required. To be done. However, like other plastics, the polyimide resin has extremely poor heat conduction performance as compared with metal, and therefore there is a strong demand for improvement of the heat conduction performance of the fixing belt made of the polyimide resin.

There are mainly the following two methods for solving this problem. The first method is a method of reducing the thickness of the endless belt, and the second method is a method of adding an insulating heat conductive inorganic powder. When the first method is used, it is necessary that the endless belt has a thickness of substantially 10 μm or less, but at such a thickness, the belt loses rigidity and wrinkles occur when incorporated in a fixing device. It is not preferable because it will meander and meander.
The second method is a generally used method, and examples of this method include JP-A-6-222695, JP-A-7-110632 and JP-A-7-186162.
It is described in the official gazette.

In order to manufacture the endless belt by the second method, for example, a polyamic acid solution to which an insulating thermally conductive inorganic powder is added is supplied to the inner peripheral surface of a heat resistant cylinder made of metal or glass. Then, a traveling body such as a bullet having an outer diameter smaller than the inner diameter is run in the cylinder to apply the polyamic acid solution in a layer having a uniform thickness, and then heated. Then, by heating the solvent to evaporate and remove the solvent of the polyamic acid solution and converting the imide, a polyimide resin tubular product containing a thermally conductive inorganic powder dispersed therein is formed, and then the tubular product is peeled from the heat-resistant cylinder. Can be obtained by

[0008]

The endless belt used in the above belt fixing system is required to have heat resistance, mechanical strength and thermal conductivity. In order to add the inorganic powder for improving the thermal conductivity, the mechanical strength of the belt will be reduced unless it is uniformly dispersed.

Among the thermally conductive inorganic powders to be added, when the flaky inorganic powder such as hexagonal boron nitride is used, the contact between the inorganic powders increases because the inorganic powders have a long shape. It is considered to have excellent thermal conductivity. Therefore,
The use of long-shaped inorganic powder composed of scaly, fibrous, or plate-shaped material with a large aspect ratio does not require much use, and therefore has the advantage of reducing the mechanical strength of the entire belt less. .

However, according to the findings of the present inventors, when the above-mentioned long-shaped inorganic powder is used, when the bullet-shaped running body runs in the cylinder, when the solvent is removed by evaporation, and when the polyamic acid is converted into imide. It is unavoidable that the elongated inorganic powder is oriented in the circumferential direction of the tubular article (that is, in the direction parallel to the belt surface when used as a fixing belt). Therefore, in such a state that the inorganic powder is oriented, the proportion of the inorganic powder in the radial direction of the tubular body (the thickness direction of the belt) becomes small, and if this is uniformly dispersed, the contact between the inorganic powders decreases. It is difficult to transfer heat effectively. Further, if the inorganic powder is added in such a large amount that the inorganic powders come into contact with each other, there is a problem that the mechanical strength of the belt decreases.

The present invention has been made in view of the above circumstances, and the first heat conductive inorganic powder having a long shape is used in the heat-resistant resin, while the first heat conductive inorganic powder has a non-long shape. A tube made of a heat-resistant resin excellent in thermal conductivity and mechanical strength by disturbing the orientation of the first thermally conductive inorganic powder by adding the second thermally conductive inorganic powder and further increasing the contact between the inorganic powders. Provide things.

[0012]

A heat-resistant resin tubular article according to the present invention comprises a heat-resistant resin having a first heat-conductive inorganic powder in an elongated shape and a second heat-conductive material in a non-elongated shape. Inorganic powder is dispersedly contained.
The heat-resistant resin constituting the tubular material is preferably one mainly composed of a polyimide resin when used as a fixing belt, but the present invention is applied to other heat-resistant resins depending on the application and required characteristics. Of course you can.

The elongated first heat-conductive inorganic powder is preferably in the form of scales, fibers or a plate having a large aspect ratio (preferably greater than 3), which is added to this. The second heat conductive inorganic powder having a non-long shape is preferably spherical or has a plate shape or an amorphous shape having a small aspect ratio (preferably 1 to 3). As the above-mentioned first thermally conductive inorganic powder, hexagonal boron nitride is preferably used as a scale-like inorganic powder. As the second thermally conductive inorganic powder, aluminum nitride having the above-mentioned shape,
Those made of one kind or two or more kinds of boron nitride, alumina, silicon carbide, silicon nitride and silica are preferably used.

The average particle size of the first thermally conductive inorganic powder is preferably less than half the thickness of the heat-resistant resin tubular material. When used as a heat fixing belt, it is usually 1 to 6 μm. Good to have. The average particle size of the second thermally conductive inorganic powder is 1/10 to 1/4 of the average particle size of the first thermally conductive inorganic powder in order to maintain the balance of orientation disturbance and mechanical strength. Is desirable. Therefore, the average particle size is usually 0.1 to 1.5 μm.

For the purpose of disturbing the orientation of the first heat-conductive inorganic powder and increasing the contact between the inorganic powders, the second heat-conductive inorganic powder is more than the amount of the first heat-conductive inorganic powder used. May be small. Usually, it is used in the range of 10 to 200 parts by weight with respect to 100 parts by weight of the first thermally conductive inorganic powder.
The total amount of the first and second thermally conductive inorganic powders used is
From the viewpoint of the balance between improvement of mechanical strength and thermal conductivity of the tubular product, it is preferable to use the tubular product in the heat-resistant resin in an amount of 10 to 75% by weight. The first and second thermally conductive inorganic powders may be surface-treated in advance in order to improve the adhesiveness with the heat-resistant resin used.

The method for producing a heat-resistant resin tubular product according to the present invention comprises: a heat-resistant resin; a first heat-conductive inorganic powder in a long shape and a second heat-conductive inorganic powder in a non-long shape. It can be obtained by applying the raw material of the heat-resistant resin containing dispersed and to the inner peripheral surface of the heat-resistant cylinder, then curing the heat-resistant resin, and peeling the cured tubular heat-resistant resin from the heat-resistant cylinder. it can.

Next, in the case of using a polyimide resin as the heat resistant resin, the method for manufacturing the tubular article according to the present invention will be described in detail. First, a first heat-conductive inorganic powder having a long shape such as a scaly shape, a fibrous shape, or a plate shape having a large aspect ratio, and a second heat-conductive inorganic powder having a spherical shape or a plate shape having a small aspect ratio or an amorphous shape. The polyamic acid solution in which the powder is dispersed is used as a raw material of the polyimide resin composition.

The polyamic acid solution used can be obtained by reacting tetracarboxylic acid dianhydride or its derivative with approximately equimolar amounts of diamine in an organic polar solvent. This tetracarboxylic dianhydride is represented by the following chemical formula 1.

Embedded image

Specific examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ', 4,4'.
-Benzophenone tetracarboxylic dianhydride, 3,
3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,3', 3,4'-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride , 2,2-bis (3,4-
Dicarboxyphenyl) hexafluoropropane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, bis (3,4-di) Examples thereof include carboxyphenyl) ether dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, and ethylenetetracarboxylic dianhydride.

Also, such tetracarboxylic dianhydride
Specific examples of the diamine to be reacted with are 4,4'-diamine
Amino diphenyl ether, 3,3'-diamino diphe
Nyl ether, 4,4'-diaminodiphenylmethane,
3,3'-diaminodiphenylmethane, 3,3'-dime
Cyl-4,4'-diaminodiphenylmethane, 3,3 '
-Diethyl-4,4'-diaminodiphenylmethane,
3,4'-diaminodiphenyl ether, 1,4-bis
(4-aminophenyl) benzene, 1,4-bis (4-
Aminophenoxy) benzene, 1,3-bis (4-ami)
Nophenoxy) benzene, 4,4'-diaminobenzof
Enone, 1,3-bis (3-aminophenoxy) benze
4,4 '-(4-aminophenoxy) biphenyl,
4,4 '-(4-aminophenoxyphenyl) sulfo
4,4 '-(3-aminophenoxyphenyl) sul
Hong, 2,2-bis [4- (4-aminophenoxy) f
Phenyl] propane, 2,2-bis [4- (4-aminophen
Enoxy) phenyl] hexafluoropropane, 4,
4'-diaminodiphenyl sulfide, 3,3'-dia
Minodiphenyl sulfide, 4,4'-diaminodiphe
Nyl sulfone, 3,3'-diaminodiphenyl sulfo
, 1,5-diaminonaphthalene, m-phenylenedia
Min, p-phenylenediamine, p-tolylenediamine
2-chloro-p-phenylenediamine, 2,5-di
Chloro-p-phenylenediamine, benzidine, 3,
3'-dimethylbenzidine, 3,3'-dimethoxyben
Dizine, 3,3'-dicyclobenzidine, 2,2-bis
(4-aminophenyl) propane, 2,4-bis (β-
Amino-t-butyl) toluene, bis (p-β-amino)
-T-butyl) toluene, bis (p-β-amino-t-
Butyl) ether, bis (p-β-methyl-δ-amino
Phenyl) benzene, bis-p- (1,1-dimethyl-
5-aminopentyl) benzene, 1-isopropyl-
2,4-m-phenylenediamine, m-xylylene diamine
Min, p-xylylenediamine, bis (p-aminosic)
Lohexyl) methane, hexamethylenediamine, hepta
Methylenediamine, octamethylenediamine, nonamechi
Diamine, decamethylenediamine, diaminopropy
Rutetramethylenediamine, 3-methylheptamethylene
Diamine, 4,4-dimethylheptamethylenediamine,
2,11-diaminododecane, 1,2-bis (3-amido
Nopropoxy) ethane, 2,2-dimethylpropylenedi
Amine, 3-methoxyhexamethylenediamine, 2,5
-Dimethylhexamethylenediamine, 2,5-dimethyl
Heptamethylenediamine, 3-methylheptamethylenedi
Amine, 5-methylnonamethylenediamine, 2,17-
Diaminoeicosadecan, 1,4-diaminocyclohexe
Sun, 1,10-diamino-1,10-dimethyldeca
1,1,2-diaminooctadecane, piperazine, H
_TwoN (CH_Two)_ThreeO (CH _Two)_TwoO (CH_Two)_ThreeN
H_Two, H_TwoN (CH_Two)_ThreeS (CH_Two)_ThreeNH_Two, H_Two
N (CH_Two)_ThreeN (CH_Three) (CH_Two)_ThreeNH_TwoEtc.
You can

As a preferable example of the organic polar solvent used when the tetracarboxylic dianhydride and the diamine are reacted,
Examples thereof include N, N-dialkylamides such as N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide. These can be easily removed from the polyamic acid solution by evaporation, substitution, diffusion or the like. Further, polar solvents other than the above, for example, dimethyl sulfoxide, hexamethylphosphortriamide, N-methyl-2-pyrrolidone, pyridine, dimethyl sulfone, tetramethylene sulfone, dimethyl tetramethylene sulfone, etc. can be used,
These organic polar solvents may be used alone or in combination of two or more.

In addition, these organic polar solvents include cresol,
It is also possible to mix one or more phenols such as phenol and xylenol, benzonitrile, dioxane, hexane, benzene and toluene. However, addition of water should be avoided in order to prevent lowering of the molecular weight due to hydrolysis of the generated polyamic acid.

In order to obtain a desired heat-resistant resin tubular product using the above-mentioned polyamic acid solution, first, the polyamic acid solution containing the above-mentioned heat-conductive inorganic powder is applied to a heat-resistant cylinder made of, for example, metal or glass. Apply to the inner surface. The application of the polyamic acid solution to the inner peripheral surface of the cylinder is performed by immersing the cylinder in the solution and pulling it up or supplying the solution into one end of the cylinder, and then running a traveling body such as a bullet or a sphere in the cylinder. Although it can be uniformly applied to the inner peripheral surface of the cylinder by a spray method, a method of directly spray-applying the solution into the cylinder may be used.

From the viewpoint of workability, the viscosity of the polyamic acid solution when the polyamic acid solution containing the heat conductive inorganic powder is applied to the inner peripheral surface of the heat-resistant cylinder by these methods is usually 10 to 10000 poise (at the time of coating work). It is preferable that the temperature is measured with a B-type viscometer).

The inner diameter of the cylinder used here is substantially the same as the outer diameter of the desired heat-resistant resin tubular product. The outer diameter of the fixing belt of the image forming apparatus is usually 10
Since it is ~ 500 mm, it is possible to use a cylinder having an inner diameter substantially equal to that of the cylinder. Then, in order to improve the appearance of the composite tubular product, it is preferable that the surface roughness (Rz) of the inner peripheral surface of the cylinder be about 1 to 10 μm.

The running body used in the above coating step may be made of metal, ceramic, solvent-insoluble plastic, or glass. Then, the traveling can be performed by a method of pushing the traveling body by compressed air, gas explosion, etc., a method of towing by a tow wire, a decompression method, or self-weight traveling. No matter which method you use for running, the coating thickness is made uniform.
It is preferable to keep the cylinder vertical or horizontal, and it is also possible to rotate the cylinder and the running body.

In this way, after the above-mentioned polyamic acid solution containing the heat conductive inorganic powder is applied to the inner peripheral surface of the heat-resistant cylinder, it is heated to remove the solvent of the polyamic acid solution and to perform imide conversion to thereby produce a polyimide. A resin tubular product is formed. The heating temperature can be appropriately set, but first, a multi-step heating method is used in which heating is performed at a low temperature of about 80 to 180 ° C to evaporate and remove the solvent, and then the temperature is raised to 250 to 400 ° C to complete the imide conversion. Preferably. The time required for heating is set according to the heating temperature, but normally,
It takes about 20 to 60 minutes for both low temperature heating and subsequent high temperature heating. By adopting such a multi-step heating method, it is possible to effectively prevent the generation of minute voids in the polyimide resin tubular product due to the evaporation of the ring-closing water and the solvent that accompany the imide conversion.

After the tubular body made of polyimide resin is formed on the inner peripheral surface of the heat resistant cylinder in this manner, the tubular body is peeled off from the inner peripheral surface of the cylinder. The peeling work can be easily performed, for example, by providing a small through hole in the wall of the cylinder in advance and feeding air into the hole.

The above-mentioned method uses a polyamic acid solution, but since an organic solvent-soluble polyimide resin is already known, a polyimide resin tubular product can be obtained by using such a polyimide resin solution. . If a solution of a polyimide resin is used, it goes without saying that imide conversion is unnecessary.

The composite tubular article according to the present invention may consist only of a tubular layer made of a polyimide resin containing the above-mentioned thermally conductive inorganic powder, and on the layer, polytetrafluoroethylene ( PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FE
P), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polychlorotrifluoroethylene (PCTFE) or other fluororesin, and a conductive fluororesin layer obtained by mixing a conductive material such as carbon or metal. It is also possible to have a multi-layered structure. Such a multi-layer structure product is preferable because it has a more excellent offset property when used as a fixing belt of an image forming apparatus and is less likely to cause paper jam. The thickness of the inner layer and the outer layer of the multi-layer structure can be set as appropriate, but is usually 10 to 150 μm for the former and 1 to 30 μm for the latter.

The conductive fluororesin layer has 10 layers.
Having a conductivity of ⁴ to 10 ¹³ Ω / □ is preferable for improving the quality of the fixed toner image when used as a heat fixing belt for image formation. In addition, between the heat-resistant resin tubular material and the fluororesin layer having conductivity, 10
It is preferable to provide a conductive adhesive layer of ¹ to 10 ⁹ Ω / □ because the adhesion between the heat-resistant resin tubular material and the fluororesin layer will be strong and the image quality will be stable.

In this multi-layer structure article, for example, a fluororesin tubular layer having conductivity is formed on the inner peripheral surface of a heat-resistant cylinder, and then the above-mentioned similar to the above is formed on the inner peripheral surface of the fluororesin tubular article. A polyamic acid solution containing a thermally conductive inorganic powder is applied, and then heated to remove the solvent of the polyamic acid solution, and imide conversion is performed to integrally form a tubular body made of a polyimide resin, and then peeled from the inner peripheral surface of the cylinder. It can also be obtained by the method.

To form a conductive fluororesin tubular product on the inner peripheral surface of the heat resistant cylinder, 5 to 80 fluororesin powder is used.
A fluororesin liquid containing 1% to 10 parts by weight of a conductive material mixed with 100 parts by weight of a fluororesin is applied to the inner peripheral surface of the cylinder, and then the dispersion medium is evaporated and removed by heating and the fluororesin is added. The method of sintering (sintering) can be adopted. This conductive fluororesin liquid may be added with a surfactant or a thickening agent in order to improve the coatability on the inner peripheral surface of the cylinder. The dispersion medium of the fluororesin liquid is often water, and therefore heating is performed at 80-18.
It is preferable to use a multi-step heating method in which water is evaporated and removed at 0 ° C., and then the temperature is heated to a temperature equal to or higher than the melting point of the fluororesin to perform sintering.

Further, the thermal conductivity can be further improved by previously containing and dispersing the above-mentioned thermally conductive inorganic powder in the electrically conductive fluororesin layer located on the outer peripheral surface of the multi-layer structure product. . From the viewpoints of dispersibility with the fluororesin and surface roughness and mechanical strength of the fluororesin layer after sintering, it is preferable that these inorganic powders have the same average particle size and addition amount as described above.

[0035]

EXAMPLES In the following examples and comparative examples, pyromellitic dianhydride is "PMDA", 3,3 ', 4,4'-
Biphenyltetracarboxylic dianhydride is "BPDA"
And 4,4'-diaminodiphenyl ether is "DD
E ", p-phenylenediamine is" PDA ", N-
Methyl-2-pyrrolidone is abbreviated as "NMP".

Example 1 A hexagonal boron nitride powder (first thermally conductive inorganic powder) having an average particle size of 3.5 μm and a plate-like (or non-existing) having an average particle size of 0.5 μm and an aspect ratio distribution of 1-2. A fixed shape aluminum nitride powder (second thermally conductive inorganic powder) is added to NMP at 60%.
Stir with a stirrer for a minute to disperse, transfer to a flask and then
Dissolve approximately equimolar amounts of MDA and DDE (monomer concentration 20
% By weight) and reacting under a nitrogen gas stream at 20 ° C. for 5 hours with stirring to obtain a polyamic acid solution in which hexagonal boron nitride powder and plate-like aluminum nitride powder are uniformly dispersed and contained. The hexagonal boron nitride and the plate-shaped aluminum nitride are added in amounts of 20 and 20%, respectively, for the final product of the tubular polyimide material.
It was adjusted to be 5% by weight and 5% by weight. The rotational viscosity of this polyamic acid solution was 3 at 20 ° C using a B-type viscometer.
The viscosity was 0000 poise and the logarithmic viscosity [η] was 2.9 at 30 ° C (hexagonal boron nitride was measured by filtration).

The logarithmic viscosity [η] is a value calculated by the following equation 1 by measuring the drop times of the polyamic acid solution and the solvent using a capillary viscometer.

[Equation 1]

Then, the polyamic acid solution was heated to 50 ° C. to adjust the rotational viscosity to 1500 poise (20 ° C.). Then, it is filtered using a # 400 stainless mesh to obtain a polyamic acid solution as a raw material of a polyimide resin in which the hexagonal boron nitride powder and the plate-shaped aluminum nitride powder are dispersed and contained.

Separately from this, a conductive fluororesin solution is prepared. Fluorine resin aqueous dispersion with PFA concentration of 60% by weight (DuPont, product name TE-334J)
And an aqueous dispersion having a carbon black concentration of 16.5% by weight (manufactured by Lion Corporation, product name W-311N) are mixed to obtain a mixed dispersion containing PFA and carbon black. The carbon black content in the solid content of this mixed dispersion was 1.5% by weight.

Further, a conductive adhesive solution is prepared. An adhesive liquid containing carbon black is obtained by mixing the PFA-based adhesive liquid (manufactured by DuPont, product name A-308) and the above-mentioned carbon black-containing aqueous dispersion (manufactured by Lion, product name W-311N). The content of carbon black in the solid content of the conductive adhesive solution is 5
% By weight.

Next, inner diameter 50 mm, wall thickness 5 mm, length 5
A stainless steel cylinder (cylindrical body) having a surface roughness (Rz) of 00 mm and an inner peripheral surface adjusted to 2 μm was immersed in the polyamic acid solution containing the hexagonal boron nitride powder and the plate-shaped aluminum nitride powder, and then pulled up, Next, the cylinder was held vertically, and a bullet-shaped running body having an outer diameter of 49.2 mm was run in the cylinder by its own weight, so that the polyamic acid solution containing hexagonal boron nitride powder and plate-shaped aluminum nitride powder was uniformly distributed on the inner peripheral surface of the cylinder. Apply to.

This is heated at a temperature of 70 ° C. for 60 minutes, the temperature is raised to 300 ° C. and further heated for 60 minutes to remove the solvent and convert the imide (removal of ring-closing water) to obtain a hexagonal boron nitride powder and a plate-like material. A tubular product made of a polyimide resin containing aluminum nitride powder is formed, and then the tubular product is peeled from the inner peripheral surface of the cylinder. The tubular product thus produced had a length of about 500 mm, an outer diameter of 50 mm, and a thickness of 50 μm.

Next, the thus-prepared polyimide resin tubular article is dipped in the above conductive adhesive solution and pulled up, and the conductive adhesive solution adhering to the inner peripheral surface is removed. And 350 ° C
By drying at a temperature of 10 minutes for 10 minutes, a tubular product having a multilayer structure in which a conductive adhesive layer is formed on the outer peripheral surface of a polyimide resin tubular inner layer is obtained. The conductive adhesive layer has a thickness of 3 μm,
The surface resistance was 5 × 10 ⁴ Ω / □.

Further, the tubular product having the multilayer structure with the conductive adhesive layer thus formed is immersed in the conductive fluororesin liquid (mixed dispersion) and pulled up, and the conductive material adhered to the inner peripheral surface thereof The volatile fluororesin liquid is removed. Then, by heating at 100 ° C. for 10 minutes to remove water as a dispersion medium, and further heating at 400 ° C. for 5 minutes, a conductive adhesive layer is formed on the outer peripheral surface of the polyimide resin tubular inner layer, and further this conductive layer is formed. A tubular product having a multi-layer structure in which a sintered tubular outer layer made of a conductive fluororesin was formed on the outer peripheral surface of the conductive adhesive layer was obtained. The fluororesin tubular outer layer had a thickness of 8 μm, a surface roughness Rz of 3.7 μm, and a surface resistance of 1 × 10 ¹⁰ Ω / □.

The thermal conductivity of the thus-prepared multi-layer tubular product measured by the non-steady-state heat ray method (Kemtherm QTM-D3, manufactured by Kyoto Electronics Manufacturing Co., Ltd.) was 2.46 w / mK. Further, when the multi-layer tubular product was cut open and the mechanical strength was measured by a tensile test, it was found to be 18 kgf / mm ² .

Example 2 A hexagonal boron nitride powder and a spherical fused silica powder were uniformly prepared in the same procedure as in Example 1 except that spherical fused silica having an average particle size of 0.7 μm was used in place of the plate-shaped aluminum nitride. A polyamic acid solution dispersed in is obtained. The rotational viscosity (20 ° C.) of this polyamic acid solution was 33,000 poise, and the logarithmic viscosity [η] (30 ° C.) was 2.9. Using this polyamic acid solution, the same operation as in Example 1 is carried out to obtain a polyimide resin tubular product containing hexagonal boron nitride powder and spherical fused silica powder dispersed therein.

In the same manner as in Example 1, a multi-layered tubular product was formed in which a conductive fluororesin tubular outer layer was formed on the outer peripheral surface of this polyimide resin tubular product through a conductive adhesive layer. Thickness of conductive adhesive layer is 3μm, surface resistance is 4 ×
It was 10 ⁴ Ω / □. On the other hand, the thickness of the fluororesin outer layer is 9 μm, the surface roughness Rz is 3.6 μm, and the surface resistance is 2 ×.
It was 10 ¹⁰ Ω / □. The thermal conductivity of the multilayer tubular product thus produced was 2.43 w / m · K. The mechanical strength measured by the tensile test was 20 kgf / mm ² .

Example 3 A polyamic acid solution in which hexagonal boron nitride powder and plate-like aluminum nitride powder were uniformly dispersed and contained was obtained by the same procedure as in Example 1 except that BPDA and PDA were used instead of PMDA and DDE. . The rotational viscosity (2
0 ° C) is 36000 poise, logarithmic viscosity [η] (30 ° C)
Was 2.8. Using this polyamic acid solution, the same operation as in Example 1 is carried out to obtain a polyimide resin tubular product containing hexagonal boron nitride powder and plate-like aluminum nitride powder dispersed therein.

The same conductive adhesive solution as that used in Example 1 was spray-coated on the outer peripheral surface of this polyimide resin tubular article using an air spray gun, and heated at 350 ° C. for 10 minutes to dry it. A conductive adhesive layer is formed. The thickness of this conductive adhesive layer is 3 μm, and the surface resistance is 3 × 10 ^4.
Ω / □.

The same mixed dispersion as used in Example 1 was spray-coated on the outer peripheral surface of the tubular article having the multi-layer structure with the conductive adhesive layer thus formed, by using an air spray gun, and 100 ° C. Heat for 10 minutes at 4 more
The sintered tubular outer layer made of a conductive fluororesin is formed by heating at 00 ° C. for 10 minutes. In the obtained tubular product having a multilayer structure, the thickness of the fluororesin tubular outer layer was 8 μm, the surface roughness Rz was 3.6 μm, and the surface resistance was 2 ×.
It was 10 ¹⁰ Ω / □. The thermal conductivity of the multilayer tubular product thus produced was 2.50 w / m · K. The mechanical strength measured by the tensile test was 20 kgf / mm ² .

Comparative Example 1 A polyamic acid solution similar to that of Example 1 was obtained except that only the same hexagonal boron nitride as that used in Example 1 was added.
The amount of boron nitride added was adjusted so as to be 25% by weight of the final polyimide tubular product. The rotational viscosity (20 ° C.) of this polyamic acid solution is 26000 poise,
Logarithmic viscosity [η] (30 ° C) was 3.1. Using this polyamic acid solution, a polyimide resin tubular product is obtained in the same manner as in Example 1.

A multi-layer structure tubular article comprising an outer layer made of a polyimide resin and an electrically conductive fluororesin tubular outer layer which is sintered through an inner layer made of a polyimide resin and a conductive adhesive layer as in Example 1. To get Thickness of conductive adhesive layer is 3μ
m, and the surface resistance was 3 × 10 ⁴ Ω / □. On the other hand, the fluororesin tubular outer layer has a thickness of 9 μm and a surface roughness Rz of 3.
The surface resistance was 5 μm and the surface resistance was 8 × 10 ⁹ Ω / □. The thermal conductivity of this multi-layer tubular product was 2.38 W / m · K.
The mechanical strength measured by the tensile test was 15 kgf / mm ² .

Comparative Example 2 A polyamic acid solution is obtained in the same manner as in Example 1, except that only the same plate-shaped aluminum nitride as that used in Example 1 is contained. The rotational viscosity of this polyamic acid solution (20
C.) was 28,000 poise and logarithmic viscosity [.eta.] (30.degree. C.) was 2.9. Using this polyamic acid solution, the same operation as in Example 1 is carried out to obtain a polyimide resin tubular product.

On the outer peripheral surface of this polyimide resin tubular article, the same operation as in Example 1 was carried out to form an electrically conductive fluororesin outer layer which was sintered through an electrically conductive adhesive layer. The conductive adhesive layer had a thickness of 3 μm and a surface resistance of 5 × 10 ⁴ Ω / □. On the other hand, the thickness of the fluororesin outer layer was 9 μm, the surface roughness Rz was 2.7 μm, and the surface resistance was 9 × 10 ⁹ Ω / □. The thermal conductivity of this multi-layer tubular product is 1.41 w / m.
It was K. Mechanical strength by tensile test is 23kgf / m
m ² .

Comparative Example 3 A polyamic acid solution similar to that of Example 1 was obtained except that only the same spherical fused silica as used in Example 2 was added. The amount of the fused silica added was adjusted so as to be 25% by weight of the final polyimide tubular product. The rotational viscosity (20 ° C.) of this polyamic acid solution was 31,000 poise, and the logarithmic viscosity [η] (30 ° C.) was 3.0. Using this polyamic acid solution, a polyimide resin tubular product is obtained in the same manner as in Example 1.

In the same manner as in Example 1, the outer peripheral surface of the tubular body made of a polyimide resin has a multilayer structure tubular body composed of an inner layer made of a polyimide resin and a tubular outer layer made of a conductive fluororesin sintered through a conductive adhesive layer. To get Thickness of conductive adhesive layer is 3μ
m, and the surface resistance was 4 × 10 ⁴ Ω / □. On the other hand, the fluororesin tubular outer layer has a thickness of 8 μm and a surface roughness Rz of 3.
The surface resistance was 0 μm and the surface resistance was 1 × 10 ¹⁰ Ω / □. The thermal conductivity of the multilayer tubular product was 1.37 w / m · K.
The mechanical strength measured by the tensile test was 24 kgf / mm ² .

Comparative Example 4 A polyamic acid solution similar to that in Example 3 was obtained except that only the same hexagonal boron nitride as that used in Example 2 was added.
The amount of boron nitride added was adjusted so as to be 25% by weight of the final polyimide tubular product. The rotational viscosity (20 ° C.) of this polyamic acid solution is 27,000 poise,
Logarithmic viscosity [η] (30 ° C) was 2.9. Using this polyamic acid solution, a polyimide resin tubular product is obtained in the same manner as in Example 1.

In the same manner as in Example 1, the outer peripheral surface of the polyimide resin tubular article has a multilayer structure tubular article composed of a polyimide resin inner layer and an electrically conductive fluororesin tubular outer layer sintered through a conductive adhesive layer. To get The thickness of the conductive adhesive layer is 2μ
m, and the surface resistance was 5 × 10 ⁴ Ω / □. On the other hand, the fluororesin tubular outer layer has a thickness of 8 μm and a surface roughness Rz of 3.
The surface resistance was 4 μm and the surface resistance was 2 × 10 ¹⁰ Ω / □. The thermal conductivity of this multi-layer tubular product was 2.40 w / m · K.
The mechanical strength of the tensile test was 16 kgf / mm ² .

Comparative Example 5 A polyamic acid solution similar to that in Example 3 was obtained except that only the same plate-shaped aluminum nitride as that used in Example 1 was added. The amount of the aluminum nitride added was adjusted so as to be 25% by weight of the final polyimide tubular product. The rotational viscosity (20 ° C.) of this polyamic acid solution was 32,000 poise, and the logarithmic viscosity [η] (30 ° C.) was 2.9. Using this polyamic acid solution, a polyimide resin tubular product is obtained in the same manner as in Example 1.

In the same manner as in Example 1, the outer peripheral surface of the tubular body made of polyimide resin has a multi-layered tubular body composed of an inner layer made of polyimide resin and an electrically conductive fluororesin tubular outer layer sintered through a conductive adhesive layer. To get The thickness of the conductive adhesive layer is 2μ
m, and the surface resistance was 5 × 10 ⁴ Ω / □. On the other hand, the fluororesin tubular outer layer has a thickness of 8 μm and a surface roughness Rz of 2.
The surface resistance was 9 μm and the surface resistance was 1 × 10 ¹⁰ Ω / □. The thermal conductivity of this multi-layer tubular product was 1.44 w / m · K.
The mechanical strength measured by the tensile test was 23 kgf / mm ² .

The test results of the above Examples and Comparative Examples are shown in Table 1. As shown in Examples 1 to 3, it is understood that in the present invention, the thermal conductivity is higher and the mechanical strength is higher than the case where the first thermally conductive inorganic powder is used alone.

As described above, according to the present invention, the heat-resistant resin uses the first heat-conductive inorganic powder having a long shape, while the second heat-conductive inorganic powder having a non-long shape is used. Since the inorganic powders are combined and dispersed and contained, the orientation of the first thermally conductive inorganic powder is appropriately disturbed, and the inorganic powder is configured to be sufficiently present also in the thickness direction of the tubular article. Also, it is possible to provide a tubular product made of a heat-resistant resin having good mechanical strength. Therefore, by using this for the fixing belt, the fixing speed of the toner image can be increased.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of an image forming apparatus using a roller fixing method.

FIG. 2 is a schematic view of a main part of an image forming apparatus using a belt fixing method.

[Explanation of symbols]

 1 Heat Roller 2 Pressure Roller 3 Transfer Paper 4 Heater 5 Heat Sensitive Ink 6 Image 7 Roller 8 Roller 9 Heater 10 Fixing Belt

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location C08K 3/38 C08K 3/38 7/18 7/18 9/04 9/04 G03G 15/20 101 G03G 15/20 101

Claims (9)

[Claims] 1. A heat-resistant resin tubular article comprising a heat-resistant resin in which a first heat-conductive inorganic powder having a long shape and a second heat-conductive inorganic powder having a non-long shape are dispersed and contained. . 2. The heat-resistant resin tubular article according to claim 1, wherein the heat-resistant resin is a polyimide resin. 3. The first heat-conductive inorganic powder has a long shape in the form of a scale, a fiber, or a plate having a large aspect ratio.
The heat-resistant resin tubular product according to claim 1 or 2, wherein the heat-conductive inorganic powder has a spherical shape, a plate-like shape with a small aspect ratio, or an amorphous shape. 4. The heat-resistant resin tubular article according to claim 1, wherein the first thermally conductive inorganic powder is hexagonal boron nitride. 5. The second thermally conductive inorganic powder is aluminum nitride, boron nitride, alumina, silicon carbide, silicon nitride,
The heat-resistant resin tubular product according to any one of claims 1 to 4, which comprises one or more types of silica. 6. The average particle size of the second thermally conductive inorganic powder is the first.
The heat-resistant resin tubular product according to any one of claims 1 to 5, wherein the heat-conductive inorganic powder has a mean particle size of 1/10 to 1/4. 7. A heat-resistant resin tubular material having an outer peripheral surface of 10 ⁴ to 10 10
The heat-resistant resin tubular article according to claim 1, further comprising a fluororesin layer having a conductivity of ¹³ Ω / □. 8. A space between the tubular material made of heat-resistant resin and the fluororesin layer
The heat-resistant resin tubular article according to claim 7, wherein a conductive adhesive layer of 0 ¹ to 10 ⁹ Ω / □ is provided. 9. A heat-fixing belt for image formation, comprising the heat-resistant resin tubular article according to claim 1.