JP2003113305A - Polyimide resin composition, polyimide film, polyimide tubular material and electrophotographic tubular material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonblack polyimide resin composition, a polyimide film, a polyimide tubular material and an electrophotographic tubular material having a stable medium resistivity value and excellent insulating properties at normal temperature and humidity to high temperature and humidity with slight fluctuation of resistivity values due to variation between samples and places, a change in amount added and a change in voltage and environment, excellent mechanical characteristics and excellent antistatic properties by transportation, transferability and fixing properties in an electrophotographic machine and easily cleaning a toner though the amount of a filled filler is large. SOLUTION: This polyimide resin composition comprises 100 pts.wt. of a polyimide resin and 5-200 pts.wt. of titanium oxide having >=55% and <=95% purity and/or alumina having >=55% and <=98% purity. The polyimide resin composition has a volume resistivity value within the range of 1×10<6> to 1×10<13> Ωcm.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyimide resin composition, a polyimide film, and a polyimide film-like tubular material having an intermediate resistance value, without impairing properties such as excellent mechanical properties and heat resistance originally possessed by polyimide. Regarding things. Further, the present invention relates to a transfer belt, an intermediate transfer belt, a transfer-fixing belt, a fixing belt, and other electrophotographic tubular articles using these.

[0002]

2. Description of the Related Art Polyimide resin has excellent heat resistance,
Taking advantage of its chemical resistance and electrical insulation properties, the film,
Widely used in the form of tubes, belts, molded products, etc. For example, in the form of a film, a base material such as FPC or TAB, an insulating coating such as an electric wire, a tube,
It is used for various purposes such as parts for office automation equipment such as copiers in the form of belts and separating claws and bearings for copiers as molded bodies. Further, in recent years, it has been used in various applications as an adhesive or the like by taking advantage of its characteristics around semiconductors.

However, due to its high insulating property, the polyimide resin is charged in the FPC or the periphery of the semiconductor during transportation and winding, and in recent high-density circuits, static electricity causes dielectric breakdown between wirings. The problem that it has become apparent. On the other hand, the resistance is high to the extent that conduction does not occur, and excellent insulation must be maintained. In this case, the required resistance value is 10 ¹⁰ to 10 ¹⁵ Ω
・ It is cm. Further, in transfer belts / intermediate transfer belts / fixing belts for electrophotographic applications such as printers, it is well known that having an intermediate resistance value is an important quality issue as a function for transferring and fixing toner. ing. In this case, the required resistance value is 10 ⁶ to 10 ¹³ Ω
・ It is cm. Thus, for the polyimide resin composition, the resistance value is lowered to a certain level in various fields,
And a moderate resistance value (10 ⁶ to 1 that can maintain insulation)
There is a strong demand for control to 0 ¹³ Ω · cm).

In view of these requirements, various attempts have been made to reduce the resistance value by adding various conductive substances to polyimide resin. For example, in Japanese Patent Application Laid-Open No. 2-110138, an aromatic polyimide matrix and a finely divided electrically conductive particle material are contained, and the particle material is uniformly dispersed.
Products present at ˜45% by weight are indicated. In JP-A-63-311263, carbon black is contained in an amount of 5 to 20 wt% and the surface resistance is 10 ⁷ ≦ Rs ≦.
There is shown an intermediate transfer member for an electrophotographic recording device, which is characterized by comprising an aromatic polyamide film or an aromatic polyimide film in the range of 10 ¹⁵ (Ω / □).

However, as mentioned above, polyimide is
Black, graphite, metal particles, indium oxide
Obtained by a method of mixing a conductive filler such as
Molded articles made of the mid resin composition have poor mechanical properties
Is often used in these methods
The filler has a very low resistivity (1.0 × 10 ³
Ω · cm or less), so resistance control in the semi-conductive region is extremely
Difficult, especially resistance with good reproducibility and in-plane variation
Was difficult to reduce. Furthermore, its resistance
Only those with a large dependence on the measured voltage and the number of added parts
I couldn't get it.

Further, Japanese Patent Laid-Open No. 4-133077 discloses
The average particle size of the main conductive filler is 1 to 50 μm.
And the volume resistivity is 10³-10⁹Large particle size of Ω · cm High resistance
The particles have an average particle size of 0.1 μm as an auxiliary conductive filler.
Volume resistance value ratio is less than 10 ²Small particle size resistance of Ω · cm or less
Anti-particles are dispersed and the volume resistivity is 10^Five-10 ⁹
Semi-conductive resin compound characterized by being in the range of Ω · cm
A composite material is shown. However, adding large particle size and high resistance particles
When added, the thickness of the film, tube, etc. is 100 μm
When obtaining thin molded products, dielectric breakdown and voltage dependence of resistance value
Is large, which is not preferable.

Further, in a transfer belt, an intermediate transfer belt, etc. of an electrophotographic apparatus, it is necessary to clean the toner adhered to the belt due to misprinting or conveyance error. However, it is difficult to confirm the completion of cleaning with the conventional belt that requires the addition of carbon because the color becomes black. Further, it is difficult to visually inspect a black belt for foreign matters and defects at the time of production and to confirm the dispersed state of the conductive substance by visual inspection.

[0008] In Japanese Patent No. 2883537, an aromatic group is disclosed.
A set containing a reimide and an inorganic filler having conductivity
A film made of a product having a volume resistance value of 10^-2~
10 ¹²Ω · cm, total light transmittance of 20% or more
Having a transparent conductive film characterized by
, Avoiding deterioration of mechanical strength due to addition of inorganic filler
I can't.

Furthermore, in order to improve the drawbacks of such a method, a method of imparting conductivity with a polymer blend of polyaniline and polyimide is disclosed in JP-A-8-259810.
JP-A-8-259709. However, since polyaniline contains ionic conductivity, its resistance value greatly depends on the environment, and further industrial productivity has not been established, and it is very expensive to use as a polymer blend. ing.

[0010]

In spite of various attempts as described above, it is still possible to stably control the resistance value of polyimide to an intermediate value and maintain high insulation property (dielectric breakdown resistance). Is a very difficult task.

In particular, when carbon black is added to control the resistance of polyimide, there are the following problems peculiar to polyimide molding. Polyimide molding is not simple molding such as extrusion method and calender molding by heat melting, but is very complicated involving heating of a polyamic acid solution as a precursor, solvent drying and imidization reaction. During this drying and reaction, the morphology, polarity, and solubility of the material changes significantly.
Especially with chemical cures, the changes are even more dramatic. Carbon black is originally a material that easily aggregates. The carbon black added for resistance control causes agglomeration during the drying and reaction processes, and a slight change in the molding conditions causes a large change in resistance, so that the molding conditions should be set very carefully. Polyimide resins, especially wholly aromatic polyimide resins, have a very high volume resistance value of 10 ¹⁶ Ω · cm, and a large amount of conductive filler is used as compared with resins having a low volume resistance value such as polyamide and polyvinyl chloride. It was necessary to add to the above, and since it was a large amount, there was a large variation in the volume resistance value due to insufficient kneading and dispersion.

Further, when the resistance is controlled by adding carbon black or conductive particles, these materials have a low resistance value, so that the resistance value greatly changes due to a slight difference in the addition amount or a difference in the dispersion state. There was a problem that the resistance value was different between the samples even if the compositions were exactly the same. Further, when the thickness of the molded body is thin like a belt, partial variation becomes large, which leads to a remarkable decrease in insulation reliability, so that resistance control becomes more difficult.

Further, it is preferable that the belt having a controlled resistance value used as the transfer belt or the intermediate transfer belt has a constant resistance value under any environment. Specifically, the ratio of the resistance value at room temperature and normal humidity to that at high temperature and high humidity is 100 times or less, further 3
It is preferably 0 times or less. However, particularly in a resin material to which a conductive substance such as carbon black or conductive particles is added, water permeates into the interface between the conductive substance and the resin under high temperature and high humidity, and the electric resistance is significantly reduced. Further, when the base resin absorbs moisture and expands, the dispersed state of the additive changes, and the resistance value changes significantly.

When it is used for a transfer belt or an intermediate transfer belt, it is necessary to control the voltage and current according to the type of image and the environment. If the resistance value varies depending on the voltage, control becomes difficult, and the smaller the voltage dependence of the resistance value, the more preferable. The ratio of the resistance values of 100 V and 1000 V is 100 times or less, more preferably 30 times or less.

Further, in the transfer belt, the intermediate transfer belt, etc., it is necessary to clean the toner adhered to the belt due to misprinting or conveyance error. However, with the carbon-containing belt, the color becomes black, and it is difficult to confirm the completion of cleaning. Further, it is difficult to visually inspect a black belt for foreign matters and defects at the time of production and to confirm the dispersed state of the conductive substance by visual inspection.

[0016]

As a result of a comparative study of the effects of various materials in order to solve such problems, the present inventors have found that titanium oxide having a purity of 55% to 95% and / or
Alternatively, by dispersing and mixing a specific amount of alumina having a purity of 55% or more and 98% or less in a polyimide resin, it has a medium resistance value, and the resistance value and the insulation change little at high temperature and high humidity. Polyimide that can be transparent or non-black color if necessary so that the resistance value has little voltage dependency, variation between samples is small, and cleaning status, dispersion state, foreign matter defects, etc. can be visually confirmed. The inventors have found a method for obtaining a resin composition and completed the present invention.

That is, the first aspect of the present invention is the polyimide resin 1
Purity of 20 to 200 parts by weight is 55% with respect to 00 parts by weight
≧ 95% titanium oxide and / or a purity of 55
% To 98% alumina and has a volume resistance value of 1
A polyimide resin composition is characterized in that it is in the range of × 10 ⁶ to 1 × 10 ¹³ Ω · cm.

The polyimide resin composition has a purity of 55%.
When the titanium oxide is contained in an amount of 95% or more and 95% or more, the titanium oxide is preferably titanium oxide in which antimony and chromium are thermally diffused, and the polyimide resin composition has a purity of 55% or more and 98% or less. When containing alumina, the alumina is preferably an alumina complexed with titanium oxide.

The diameter of the titanium oxide and / or alumina is preferably 3 μm or less.

The proportion of titanium oxide having a purity of 55% to 95% and / or alumina having a purity of 55% to 98% with respect to 100 parts by weight of the polyimide resin is more preferably in the range of 50 to 200 parts by weight. Is.

[0021] In one embodiment, the polyimide resin composition has a content of 0.0 to 100 parts by weight of the polyimide resin.
It contains 1 to 20 parts by weight of a conductive material.

In one embodiment, the polyimide resin is a polyimide resin obtained by adding acid anhydride and / or a tertiary amine as an imidization promoter to polyamic acid and then heating and baking the same. And

The second aspect of the present invention is a polyimide film comprising the above polyimide resin composition, and the third aspect is
The polyimide resin composition or a polyimide tubular material composed of the polyimide film as a content, wherein the polyimide tubular material is a transfer belt, an intermediate transfer belt, a transfer fixing belt or an electrophotographic tubular material used in any of the fixing belts. provide.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The polyimide resin in the present invention refers to all resins having an imide bond in its structure,
This includes not only resins called by general names such as polyetherimide, polyesterimide, and polyamideimide, but also copolymerization systems and blends with other resins. In particular, a reaction-curable linear polyimide resin capable of strongly bonding to titanium oxide having a purity of 55% to 95% and / or alumina having a purity of 55% to 98% is preferable. Here, the reaction-curable linear polyimide resin refers to a polyimide resin obtained by subjecting a linear polyamic acid as a precursor to dehydration ring closure of an amic acid site, and pyromellitic acid. A typical example is a polyimide resin obtained by heating, adding a catalyst, or the like to a linear polyamic acid obtained by reacting a dianhydride with 4,4′-diaminodiphenyl ether. The linear polyamic acid has functional groups such as carboxylic acid groups and amino groups, and these functional groups have a purity of 55% to 95% titanium oxide and / or a purity of 55% to 98% alumina. A reaction-curable polyimide resin is preferably used because it strongly interacts with and can form a strong bond with titanium oxide or alumina. If a reaction hardening type polyimide resin is used, titanium oxide having a purity of 55% or more and 95% or less, alumina having a purity of 55% or more and 98% or less, and not brittle and insulating even if highly filled with other inorganic powders are used. It is possible to obtain a polyimide molded body excellent in mechanical strength and electrical characteristics without being deteriorated.

As a general polyimide, it is usual to use a diamine compound and tetracarboxylic dianhydride as monomers. Examples of diamine compounds include

[0026]

[Chemical 1]

(Wherein X is the same or different and
-CH₃, -OCH₃, -O (CH ₂)_nCH₃,-
(CH₂)_nCH₃, -CF₃, -OCF₃From the group consisting of
Represents at least one group selected. Also, A is the same.
Or, differently, O, S, C = O, (CH₂)_n, SO₂,
Represents at least one group selected from the group consisting of N = N
You n is an integer of 1 or more. ) Various monomers shown in
You can Also, as tetracarboxylic dianhydride

[0028]

[Chemical 2]

Various monomers shown in the formula (n is an integer of 1 or more) can be used. Various characteristics can be brought out by combining these, and it can be selected according to the situation such as application and processing method.

For example, by using an aromatic diamine containing a large number of bent chains (preferably two or more) and / or having an amino group in the meta position, and by using a tetracarboxylic dianhydride having two or more rings, thermoplasticity is improved. It is possible to provide a resin composition capable of being melt-molded by heating. For example, a combination of 2,2′-bis (4-aminophenoxyphenyl) propane and oxydiphthalic acid dianhydride, or bis (2- (4-aminophenoxy) ethoxy) ethane and 3,3 ′, 4,4 ′ Examples thereof include a combination of benzophenone tetracarboxylic acid dianhydride.

Polyimide usually has a high water absorption rate due to the presence of imide groups, but a resin composition having a relatively low water absorption rate can be prepared by combining a specific monomer.
As an example, there may be mentioned a polyimide using a tetracarboxylic dianhydride having a structure in which a plurality of benzene nuclei are bound by two or more ester bonds. In particular,

[0032]

[Chemical 3]

(In the formula, n is an integer of 1 or more.)

[0034]

[Chemical 4]

[0035]

[Chemical 5]

Examples include acid dianhydrides as shown in: As the diamine compound used in this case, it is preferable to use a relatively long-chain monomer in order to reduce the imide group content. For example, 1,4-bis (4-aminophenoxy) benzene and its bond position isomer, 2,2 '
Examples thereof include -bis (4-aminophenoxyphenyl) propane. However, for both the acid dianhydride and the diamine, the structure having a long chain and a large number of bent chains is also a condition for exhibiting the above-mentioned thermoplasticity, and is not suitable when sufficient heat resistance is required. In this case, long-chain monomers having a linear structure wholly or partially are suitable. For example, as tetracarboxylic dianhydride,

[0037]

[Chemical 6]

An example is a monomer (TMHQ) having a structure shown by. It has been found that this monomer has a structure in which it contains a bent chain and can take a substantially linear conformation as a whole, and it forms a relatively rigid polyimide in spite of the large number of bonds. If this raw material is used, the coefficient of linear expansion is 15 ppm or less and the water absorption rate is 1.5%.
Hereafter, a polyimide resin having a hygroscopic expansion coefficient of 10 ppm or less and having little dimensional change due to heating or moisture absorption can be easily obtained. Further, as the diamine, for example, a structure in which a biphenyl structure or a naphthalene structure is connected by an ether bond can be selected as a relatively rigid structure although it has a long chain. For example, 4,4′-bisaminophenoxybiphenyl and the like. By combining these acid dianhydrides and diamines, it is possible to obtain a polyimide having a relatively low water absorption and having no remarkable thermal softening property. Moreover, not only these monomers but also general-purpose pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, paraphenylenediamine, 4,4'-diaminodiphenyl ether, etc. are appropriately copolymerized to design a polyimide having arbitrary characteristics. It is possible.

In the present invention, the polyimide resin has a purity of 55%.
Titanium oxide of 95% to 95% and purity of 55% to 98%
The following alumina (hereinafter, these titanium oxide and alumina are sometimes referred to as a conductivity control material), and other inorganic powders are blended as necessary. In particular, higher toughness is required as compared with the case of using polyimide alone. If the toughness of the polyimide itself is not sufficient, the toughness inevitably decreases due to the blending of the inorganic substance, and it may not be practically applicable. In that respect, the most preferable is a polyimide composed of pyromellitic dianhydride and 4,4′-diaminodiphenyl ether. This structure is a well-balanced structure that has both sufficient heat resistance and high toughness and can maintain its characteristics under a wide range of processing conditions.

Titanium oxide having a purity of 55% or more and 95% or less and / or alumina having a purity of 55% or more and 98% or less can be used as the conductivity controlling material to be mixed with the polyimide resin. If a predetermined amount is used, the polyimide resin composition can be controlled in the medium resistance region. These conductivity control materials have a low resistance value because they are lacking in the structure due to impurities and carriers are generated as compared with those having high purity. Therefore, when the purity is higher than these, the resistance value becomes higher, and in order to reduce the resistance of the polyimide resin, the number of blended parts is increased, which causes the deterioration of mechanical properties, and in order to maintain the mechanical properties, the number of blended parts is increased. If it is reduced, the resistance value will not reach the target, which is not preferable. These substances have a higher resistance than materials such as carbon black, graphite, and metals, and since they are close to the target volume resistance value, variations in resistance with respect to the number of added parts can be small. In addition, since the resistance value is closer to that of polyimide than carbon black or metal, it is possible to suppress the occurrence of local bias of voltage in the composite material and to reduce the voltage dependence of the resistance value, which is preferable. In particular, titanium oxide has a refractive index of 2.5 or more and a high hiding rate,
It has the property of making the material white, and when added to polyimide, the material becomes yellow. Further, even if another black additive such as carbon black or an organic pigment is added, it does not become black easily. As a result, the belt made of these materials makes it easy to check the dirt state at the time of toner cleaning, and it is easy to inspect for foreign matters and defects at the time of making, to check the dispersed state, and to easily form markings. In addition, it is possible to immediately identify the location of the dielectric breakdown and the surface scratch.

Examples of the method of introducing impurities into titanium oxide include a method of thermally diffusing antimony and chromium in the crystal lattice of titanium oxide and a method of forming a complex with NiO or Sb ₂ O ₃ . As a method of introducing impurities into alumina, a method of forming a composite with titanium oxide can be mentioned.

In the present invention, the purity of titanium oxide used as the conductivity control material is 95% or less, preferably 90% or less, more preferably 85% or less. The lower limit depends on the type of impurities, but is preferably 55% or more, more preferably 60% or more, and further preferably 65%.
% Or more.

In the present invention, the purity of alumina used as the conductivity control material is 98% or less, preferably 97% or less. The lower limit depends on the type of impurities, but is preferably 55% or more, more preferably 75% or more, and further preferably 95% or more.

The purity of the conductivity controlling material here means the purity expressed in% by weight.

Next, the shape of the conductivity controlling material used in the present invention may be granular, needle-like, plate-like or the like, and any structure can be controlled to a medium resistance region. Among them, needle-like or plate-like ones are preferable because they easily come into contact with each other and the resistance can be controlled in the medium resistance region even if the blending amount is small. In addition, it is highly effective in increasing mechanical strength, reducing linear expansion coefficient, and reducing coefficient of hygroscopic expansion, and prevents rupture due to tearing, etc. and dimensional change due to tension, and provides a belt with excellent durability and high dimensional stability and long-term transport characteristics. it can. Granular, needle-shaped,
Whatever the shape of the plate, the diameter is 3 μm or less, preferably 2 μm or less, more preferably 1 μm or less. The term "diameter" as used herein refers to the average particle diameter in the case of particles, and the minor axis diameter and thickness in the case of needles or plates. In a molded body having a small thickness of 100 μm or less, in the case of a material having a thickness larger than 3 μm, dielectric breakdown may easily occur due to local aggregation due to poor dispersion. On the other hand, if it is 3 μm or less, the insulating property is not deteriorated even if it is a little aggregated, which is preferable. If granular,
The diameter is 3 μm or less, preferably 1 μm or less.
If the diameter is out of this range, it becomes difficult to balance the resistance value and the mechanical strength. In the case of needles, the minor axis diameter is 3 μm or less,
It is preferable to use those having a diameter of 1 μm or less, more preferably 0.5 μm or less, and a major axis diameter of 50 μm or less, preferably 10 μm or less, more preferably 1 μm or less. If the minor axis diameter and the major axis diameter deviate from this range, it becomes difficult to balance the resistance value and the mechanical strength. In the case of a plate, it is preferable to use one having a thickness of 3 μm or less, preferably 1 μm or less, more preferably 0.5 μm or less, and a length of 50 μm or less, preferably 10 μm or less, more preferably 1 μm or less. If the thickness and length deviate from this range, it becomes difficult to balance the insulating property, resistance value, and mechanical strength.

If the particle size is too small in any of the shapes, the viscosity of the polyimide resin solution or the polyimide precursor solution at the time of molding remarkably increases. Therefore, the diameter of 0.03 μm or more is practically used. It is more preferably 0.05 μm or more.

The compounding ratio of these conductivity control materials is as follows. In the case of the granular conductivity control material, the compounding amount is 50 to 200 parts by weight, preferably 70 to 170 parts by weight, and more preferably 90 to 150 parts by weight with respect to 100 parts by weight of the polyimide resin. In the case of the needle-shaped or plate-shaped conductivity controlling material, the compounding amount is 20 to 150 parts by weight, preferably 30 to 120 parts by weight, relative to 100 parts by weight of the polyimide resin.
Parts by weight, more preferably 40 to 100 parts by weight. At least one type of each substance is used, but it is also possible to use two or more types of each. When the content is adjusted within the above range, the change in the resistance value can be suppressed to 3 times or less even if there is a variation in the compounding amount of 10 parts by weight.
It is possible to control in the medium resistance region without causing a large change in resistance. Further, even if a colored conductive substance such as carbon black or graphite is added, the blackening of the film can be suppressed to some extent. Further, the titanium oxide or alumina used in the present invention is excellent in dispersibility because it contains a large amount of active oxygen and hydroxyl groups on the surface and has a strong bond with the polyimide, so that the tensile elongation is 20% and the tear propagation strength is 300 g.
/ Mm or more, it has a retention rate of 50% or more with respect to the filler-free product. If the needle-shaped conductivity control material is used, the tensile elongation is 60% or more and the tear propagation strength is 450 g / m.
m or more, the tensile elongation is 10 with respect to the filler-free product.
It has a retention rate of 0% or more and a tear propagation strength of 100% or more. Even if the conductivity control material is added, the water absorption rate is 5
%, And the amount of increase in water absorption can be suppressed to 3 times or less than the original water absorption of polyimide. When it is combined with another conductive substance, the amount of titanium oxide or alumina added is large, so that the dispersion of the other conductive substance can be assisted and a more uniform dispersed state can be realized. If the amount is less than these blending amounts, the resistance cannot be lowered to the intended medium resistance region. On the other hand, if the amount is larger than these amounts, mechanical properties are deteriorated and the material becomes brittle, which is not preferable.

By appropriately blending them, the volume resistance value can be stably 1 × 10 ⁶ to 1 × 10 ¹³ Ω · cm,
It is possible to realize an intermediate resistance value with a surface resistance value of 10 ⁶ to 10 ¹³ Ω / □. The ratio (Rn / Rh) of the resistance value Rn at room temperature and normal humidity to the volume resistance value Rh at high temperature and high humidity is 0.
It can be controlled within the range of 03 to 30, and a material having excellent environmental stability can be adjusted. Also, the volume resistance value R when _{100 V} is applied and the volume resistance value R when 1000 _V is applied R
_1000V ratio (R _100V / R _1000V) can be controlled within a range of 0.03 to 30, it is possible to adjust the material having less voltage dependence. Further, even if the number of added parts of the conductivity controlling material changes by 10 parts within the range of the number of added parts, the change in volume resistance is 3
It is less than or equal to twice, and it is possible to prepare a material having little dependency on the number of added parts. Further, the variation in the resistance value between the samples can be suppressed to 3 times or less, and the material having the small variation between the samples can be adjusted.

By adding titanium oxide having a purity of 55% or more and 95% or less and / or alumina having a purity of 55% or more and 98% or less, it has a medium resistance value and a high insulation property, and the voltage dependence of the resistance value. Less, fluctuation of resistance value and insulation at high temperature and high humidity is small, excellent in mechanical strength and dimensional stability,
The reason why a belt that does not become black in color is obtained is considered to be as follows. In addition, the blending amount of these is much larger than the amounts added for usual coloring, resistance control, and strength improvement.The reason why the mechanical properties and insulation properties do not deteriorate despite the large addition is as follows. There are many possible reasons.

Titanium oxide having a purity of 55% or more and 95% or less and / or alumina having a purity of 55% or more and 98% or less has a resistance of 1 × 10 ⁹ to 1 × 10 ¹³ Ω · cm, and carbon black. Unlike conductive metals and metal ceramics (1 × 10 ⁻⁵ to 1 × 10 ³ Ω · cm), the resistance value is close to that of polyimide (1 × 10 ¹⁶ Ω · cm). Therefore, these addition systems do not show a sharp decrease in resistance due to percolation as seen in carbon black, and the resistance changes gently with respect to the addition amount. In the case of carbon black, about 10 to 20 parts are added to the resin in order to control the medium resistance region. However, if the number of added parts changes by about 10 parts by weight with respect to such an added part,
The resistance immediately drops 10 to 100 times or more. On the other hand, in the system in which these are added, the resistance value does not change three times even if the addition amount changes by about 10 parts by weight with respect to the number of addition parts whose resistance is controlled in the medium resistance region. Even if the filler is aggregated or biased during the defoaming or dispersing process, the resistance is not significantly changed. From these facts, it can be said that titanium oxide having a purity controlled to medium resistance of 55% or more and 95% or less and / or alumina having a purity of 55% or more and 98% or less is a material in which resistance changes little due to variations in the added amount.

Titanium oxide having a purity of 55% or more and 95% or less and / or alumina having a purity of 55% or more and 98% or less has a medium resistance, which also improves the insulation and reduces the voltage dependency of the resistance value. It is thought to play a major role. When a voltage is applied to the film in order to measure the resistance of a film made of a polyimide in which a conductive material is dispersed, the voltage is divided between the polyimide and the conductive material. The voltage is believed to be on the part of the polyimide that has a higher resistance than the conductive material. In particular, as a conductive substance, a low resistance material such as carbon black or a metal-based material and a purity of 55% or more 95
% Titanium oxide and / or purity 55% or more 9
It is considered that the voltage applied to the polyimide is smaller when the medium resistance material is added than when the medium resistance material such as 8% or less of alumina is added. As a result, it is considered that the voltage applied to the polyimide is reduced and thus the dielectric breakdown in the polyimide is reduced.

Generally, a high voltage (for example, 100 μm1) is applied to the resin.
(approx. kV or more), the resin approaches dielectric breakdown,
The voltage dependence of the resistance value deteriorates rapidly. That is, a large current flows just before the destruction. From this, it can be considered that the voltage dependency of the resistance value is a phenomenon that occurs when the resin approaches destruction due to the high voltage applied to the resin. However, the purity is 55%
≧ 95% titanium oxide and / or a purity of 55
% To 98%, in a system to which a medium resistance material such as alumina is added, a high voltage is locally applied to the polyimide portion which is a resin, as compared with the case where a low resistance material such as carbon black is added. It is considered that this can be prevented, and the voltage dependence of the resistance value can be improved.

Titanium oxide having a purity of 55% or more and 95% or less and / or alumina having a purity of 55% or more and 98% or less has a hydroxyl group or active oxygen on the surface thereof, and therefore can be imidized without surface treatment. At that time, it strongly interacts with the resin and becomes a strong composite material. For this reason, it becomes a material with strong tear propagation strength and elongation, and even if it is added in a larger amount than the amount usually added for coloring, resistance control and mechanical property improvement (usually up to about 20 parts by weight), it has sufficient mechanical properties. , Insulation resistance can be maintained. Further, these strong composite materials can prevent a decrease in resistance value and deterioration of insulation property at high temperature and high humidity for the following reasons. It is considered that the cause of the deterioration of electric characteristics during moisture absorption is that a skin layer made of water is formed at the interface between the resin and the filler due to moisture absorption, and a flow path where electricity easily flows is formed. Is surface-treated with filler or carbon. However, since a material composed of titanium oxide or alumina and polyimide, particularly a reaction-curable linear polyimide, is a strong composite material, such a skin layer is not formed, and a large change in resistance and insulation occurs. Absent.

In order to form a strong bond between titanium oxide having a purity of 55% or more and 95% or less and / or alumina having a purity of 55% or more and 98% or less and polyimide, surface treatment may be performed. As the surface treatment agent, a coupling agent can be used, and a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, an amino acid coupling agent, etc. can be used. When the resin is a reaction-curable linear polyimide resin, the bond becomes stronger by the surface treatment, but sufficient strength can be obtained without the treatment.

Polyamic acid and titanium oxide having a purity of 55% to 95% and / or a purity of 55% to 98%
When mixing the following alumina, there are mainly the following two methods. The first is to add these conductivity control materials to the polyamic acid polymerization solvent in advance to adjust the conductivity control material dispersion solution, and then add the diamine and dianhydride, which are the raw materials for the polyamic acid, to prepare the polyamic acid. There is a method of polymerizing. As another method, there is a method of mixing a polyamic acid obtained by polymerization in advance and a conductive control material dispersion solution. Whichever such method is used, it is necessary to prepare a conductive control material dispersion solution. The conductivity control material has a larger specific gravity than the resin and is very heavy, and when the conductivity control material is added to the solvent, the conductivity control material is immediately precipitated. As a result, when mixed with amic acid, agglomerates of the conductivity control material are formed, and irregularities are formed on the surface or a portion where the resistance is locally different is formed.

Therefore, it is preferable to add a dispersant when preparing a titanium oxide having a purity of 55% to 95% and / or an alumina dispersion having a purity of 55% to 98%. Examples of the dispersant include metal salts and surfactants. Metal salts are particularly preferred, and Li
Salt, Na salt, K salt, Rb salt, Cs salt, Be salt, Mg salt,
More preferably, one kind or a combination of two or more kinds selected from the group consisting of Ca salt, Sr salt and Ba salt, L
The i salt, Na salt, and K salt are particularly preferable. The Li salt is preferably a Li salt having a lattice energy of 1100 or less, specifically, LiF, LiCl, LiBr, LiI, LiSC.
Examples thereof include N and LiCF ₃ SO ₃ . As the Na salt, a Na salt having a lattice energy of 800 or less is preferable,
Specifically, NaF, NaCl, NaBr, NaI,
Examples include NaSCN and NaCF ₃ SO ₃ . The K salt is preferably a K salt having a lattice energy of 800 or less, and specifically, KF, KCl, KBr, KI, K.
Examples include SCN and KCF ₃ SO ₃ . These metal salts are preferable because the ions are easily dissociated at room temperature and the interaction with titanium oxide or alumina becomes strong.
However, if the lattice energy is too small, the effect of the addition amount becomes too large, so that one having a large lattice energy is preferable. Since these metal salts do not contain organic substances, the resin will not be burnt even during high temperature drying during molding.
The dispersant may be added in a predetermined amount of 1 part by weight or less based on 100 parts by weight of the polyimide resin.
Even if the amount is 0.1 parts by weight or less, the effect is sufficient. A practical lower limit is 0.000001 parts by weight or more. Generally, in the application of electric wire coating, when a metal salt is added, the insulating property deteriorates, and when it is added to a material having a dielectric constant of 4 or more, ionic conductivity increases, which is not particularly preferable, but polyimide and semiconductive inorganic materials are used. In the combination, since the polyimide is excellent in the insulating property and the dielectric constant is 4 or less, the insulating property and the voltage dependency of the resistance are not particularly deteriorated in the range of the above-mentioned composition.

10 ⁹ Ω when titanium oxide or alumina is added
・ It is difficult to achieve a resistance value lower than cm, but 1 or less
In order to obtain a stable volume resistance value even in the range of 0 ⁶ to 10 ¹³ , it is effective to add a conductive substance other than titanium oxide and alumina.

Other conductive substances may be added to the polyimide resin to the extent that the color is not blackened. Examples of other conductive substances include carbon black, graphite, metal powder, metal oxide powder, metal oxide subjected to conductive treatment, antistatic agent, conductive ceramics and the like.

As the carbon black to be blended with the above polyimide resin, various existing carbon blacks can be used as long as they have conductivity, and furnace black, acetylene black, thermal black, channel black and the like can be used. is there. Among them, carbon black called Ketjen black, which is one type of furnace black, has a particularly large specific surface area, but when this is used, it is highly effective even if the amount of carbon black blended is small, and yet other carbons are used. Compared to the case of using black, the voltage dependence (the property changes when the voltage changes, and the property does not show the behavior according to Ohm's law)
However, it is particularly preferable to use Ketjen Black.

Examples of the metal powder blended with the above polyimide resin include powders of copper, iron, aluminum, SUS and the like, examples of the metal oxide powders include conductive semiconductor ceramics, and metals subjected to conductive treatment. As the oxide, titanium oxide, potassium titanate, barium sulfate,
An example of the conductive material is mica. Such an inorganic additive has a lower cohesive force than carbon black and is not black, and therefore has little adverse effect on cleaning.

As a mixing ratio of these, a predetermined amount of 20 parts by weight or less is preferably added to 100 parts by weight of the polyimide resin, preferably 5 parts by weight or less, more preferably 4 parts by weight or less. It is good to add. If the blending amount is too small, the purpose of blending the conductive substance may not be achieved. Therefore, the practical lower limit value is 0.
01 parts by weight or more. At least 1 for each substance
Each species is used, but it is also possible to use two or more species for each species. If the blending amount is increased, the voltage dependence of the resistance and the insulating property are deteriorated, which is not preferable.

It is also possible to add other non-conductive inorganic powder to these compounding systems. Examples of non-conductive inorganic powders include small-diameter granular materials such as alumina and silica, plate-like and scale-like materials such as mica and clay minerals, short fiber-like or whisker-like substances such as barium titanate and potassium titanate. Something is used. The non-conductive filler may be added to control other properties such as elastic modulus, and the non-conductive powder may appropriately assist the dispersion of the conductive powder and may cause aggregation of the conductor, etc. In some cases, a stable resistance value can be realized by preventing this.

By appropriately blending these materials, it is possible to stably realize an intermediate volume resistance value of 1 × 10 ⁶ to 1 × 10 ¹³ Ω · cm. Further, the ratio (R _n / R _h ) of the resistance value R _n at room temperature and normal humidity to the volume resistance value R _h at high temperature and high humidity can be controlled within a range of 0.03 to 30, and the material has excellent environmental stability. Can be adjusted. Also, the volume resistance value R when _{100 V} is applied and the volume resistance value R when 1000 _V is applied R
_1000V ratio (R _100V / R _1000V) can be controlled within a range of 0.03 to 30, it is possible to adjust the material having less voltage dependence. Further, within the range of the number of parts added, the purity is 55
% And 95% or less of titanium oxide and / or a purity of 5
Even if the number of added parts of alumina of 5% or more and 98% or less changes by 10 parts, the change in volume resistance is 3 times or less, and a material having little dependence on the number of added parts can be prepared. Further, it is possible to suppress the variation in the resistance value between the samples to 3 times or less, and it is possible to adjust the material having the small variation between the samples.

The polyimide having the above composition can be used in various shapes, but it is particularly difficult for the thin one to have a constant resistance value while maintaining the insulating property. Thus, the above-mentioned composition is particularly effective in a film form in a broad sense such as a film form, a sheet form, a belt form and a tube form, particularly in a form having a thickness of 150 μm or less.

Various methods can be used to disperse the added conductivity control material or other conductive material in the polyimide resin.

When the polyimide resin is soluble in a solvent, the powder or a powder obtained by pre-dispersing the powder in a solvent is added to the polyimide resin dissolved in the solvent, and the mixture is mixed with a stirring blade or kneaded with a three-roll mill. A machine can be used to promote dispersion. On the contrary, it is also possible to add a solvent-soluble polyimide powder or pellets to a material in which powders are preliminarily dispersed in a solvent and mix them well. As a method of preliminary dispersion, it is effective to add powders to a solvent and sufficiently disperse the mixture with an ultrasonic disperser. In particular, the needle-like powder may be destroyed in shape when it is subjected to an excessive shearing force, so that the method not using three rolls is preferable.

When the polyimide resin is insoluble in a solvent, it is also possible to add the above-mentioned preliminary dispersion to a solution of a polyamic acid which is a precursor of polyimide, and carry out mixing and kneading in the same manner.

At this time, it is also possible to use a dispersant for assisting the dispersibility of the solid powder in a range in which the characteristic deterioration of the polyimide is not significantly caused. When a metal salt is added as a dispersant to the pre-dispersion solution, the dispersed state is extremely uniform, and thus a sufficiently uniform dispersed state can be achieved even by stirring by hand. In addition, it is better to add the polyamic acid solution to the pre-dispersion liquid while stirring little by little.
The dispersibility is improved more than the above reverse procedure.

As another method of obtaining particularly good dispersibility, the powders are first added to the solvent and sufficiently dispersed by an ultrasonic disperser or the like, and then polyimide (polyamic acid) There is a method in which a diamine compound and an acid dianhydride compound, which are the raw materials of, are added to carry out a polymerization reaction. According to this method, dispersion at a micro level can be maintained well by ultrasonic dispersion, and at the same time, stirring is always performed from the initial solid powder dispersion to the polymerization, so that dispersion at a macro level is achieved. The sex is also very good.

When the solution is a polyimide solution, it can be processed into an arbitrary shape, and then the solvent can be volatilized by heating or by using a reduced pressure in some cases to obtain a polyimide molded body. Even when the solution is a polyamic acid solution, a polyimide molded body can be obtained by the same steps as in the case of the polyimide solution. In this case, prior to heating, an acid anhydride such as acetic anhydride as a dehydrating agent or a tertiary amine as a catalyst can be used alone or in combination in order to accelerate imidization. However, acid anhydride can not only accelerate the imidization reaction but also cause the main chain of the polyamic acid chain to be cleaved. Therefore, due to the mechanical properties of polyimide, a combination of an acid anhydride and a tertiary amine or a tertiary amine is used. Addition of amine alone is more preferable, and a product having a higher tear propagation strength can be obtained as compared with imidization by heat only. Specifically, the tear propagation strength is 300 g / mm or more, more preferably 5
A product of 00 g / mm or more can be obtained. However, if these are not added, the tear propagation strength is often 100 g / mm or less. Also, the addition of a catalyst is very preferable because it can reduce the heating time and suppress the thermal deterioration of the conductivity control material. Further, since the heating time is short, it is possible to suppress the thermal deterioration of the resin and the deterioration due to the reaction between the resin and the conductivity control material, which is preferable. In addition, in the manufacturing method by adding a catalyst, the in-plane orientation of the resin proceeds,
The conductivity control material also tends to be oriented in a plane. As a result, in the case of a thin molded product with a thickness of 150 μm or less,
This is preferable because the conductive control material oriented in the thickness direction can be reduced, the electrical insulation can be improved, the portion where the electrical characteristics deteriorate in the thickness direction due to moisture absorption of the filler can be reduced, and the humidity dependency of resistance can be reduced.

The following method can be mentioned as an example of a concrete method for forming a tubular article.

The resin solution in which the above inorganic components are dispersed is applied onto the endless belt after controlling the thickness by using a T die, a comma coater, a doctor blade or the like. The resin solution is heated and dried by hot air or the like until it has self-supporting property, and then peeled off from the endless belt. A film-like molded article can be obtained by fixing both ends of the peeled semi-dried film with a pin or a clip, and sequentially passing them through a high-temperature heating furnace while defining the length in the width direction. Alternatively, it is applied in the same manner on a continuous sheet-shaped support such as metal, and a film or sheet-shaped polyimide molded body fixed in a sheet is obtained by passing this through a heating furnace, and then supporting. A method of peeling off from the body sheet or removing the support sheet by means such as etching may be adopted.
The easiest method is to obtain a belt or tube by cutting the thus obtained film or sheet-shaped molded product into a predetermined length and width and connecting them to each other in a belt or tube shape. An adhesive, an adhesive tape, or the like can be used for the joining, but this method inevitably causes a step or a break at the joint, which may cause inconvenience depending on the application.

As a method for obtaining an endless tubular product, a resin solution is applied to the inner surface or outer surface of a cylindrical mold, and the solvent is volatilized by heating or drying under reduced pressure, and this is heated to the final firing temperature as it is. Alternatively, it may be peeled off once, fitted into the outer periphery of another mold for finally defining the inner diameter, and heated to the final firing temperature. When applying the resin solution to the cylindrical mold,
It is also effective to rotate the mold in order to reduce the variation in thickness due to the dripping of the resin solution. The final firing temperature needs to be appropriately selected depending on the structure of the polyimide and the heat resistance of the added carbon, but when heating and firing from a polyamic acid state with a non-thermoplastic polyimide, it is generally 350 ° C to 4 ° C.
A suitable range is between 50 ° C and -20 ° C to + 100 ° C with respect to the glass transition temperature of the polyimide in the case of thermoplastic polyimide.

In order to improve the releasability and transferability of the toner and the cleaning property of the toner, it is advisable to form a fluororesin outermost layer whose conductivity is controlled on the surface of the polyimide tubular material. Examples of the fluororesin include PTFE and PFA, and examples of the additive for controlling conductivity include those listed as the additive for controlling conductivity of polyimide. As a method for forming the outermost layer, coating, laminating films, etc. can be considered, but a method in which these materials are spray-coated as a dispersion is general.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments.

[0076]

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

Next, the method for evaluating the physical properties of the resin composition will be described. The physical properties were measured by molding a tubular product made of a resin composition and cutting out a film sample.

(Physical property evaluation method) The surface resistance value and the volume resistance value in the thickness direction of the film were measured as follows.
Four pieces of 10 cm x 10 cm are cut from a human sample and left in an environment (NN) of temperature 23 ° C and humidity 55% Rh and in an environment (HH) of temperature 30 ° C and humidity 80% Rh for 48 hours, and under each environment. The volume resistance value and surface resistance value at 500 V were measured using a digital ultra-high resistance / micro ammeter R8340 and a resiliency chamber R12702A manufactured by Advantest.

The insulation measurement in the film thickness direction was carried out as follows. This film has a temperature of 23 ° C and a humidity of 55
% Rh environment (NN), temperature 30 ° C, humidity 80%
Leave in Rh environment (HH) for 48 hours and take out immediately N
Under N environment, the insulation property was measured with a YSS type electric breakdown tester manufactured by Yasuda Seiki Seisakusho. The time from removal to measurement is within 3 minutes.

The tensile modulus and tensile elongation of the film were measured according to ASTM D882. The tear propagation strength measurement of the film was performed according to ASTM D1938.

The water absorption of the film is measured according to JISK72.
It carried out based on 09.

Next, examples and comparative examples will be described.

(Example 1) 4,4 as an aromatic diamine
DMF solution of polyamic acid obtained by using pyromellitic dianhydride as ???-diaminodiphenyl ether as aromatic tetracarboxylic acid dianhydride (solid content concentration 18.
75 g of 5% and a solution viscosity of 3,000 poise) was prepared. On the other hand, 21 g of DMF is mixed with brown titanium oxide (TY-30
0: Ishihara Sangyo Co., Ltd .: Purity 76%, impurities Cr, Sb
A liquid in which 18.0 g of an average particle size of 0.35 μm) was dispersed was prepared. The linear expansion coefficient of the polyimide film thus polymerized is 21 ppm and the hygroscopic expansion coefficient is 16
ppm, the elastic modulus was 2.9 GPa, and the water absorption rate was 2.5%.

A dispersion of these polyamic acid solutions and brown titanium oxide was added and kneaded. Before casting the obtained dope into a tubular film, acetic anhydride / isoquinoline /
A solution of 9.03 g / 11.4 g / 15.6 g of DMF was added and mixed, and then cast into a cylindrical SUS,
40 ° C / 240 seconds, 275 ° C / 40 seconds, 400 ° C / 93
Second heat treatment was carried out to obtain a brown polyimide tubular product of about 50 μm. The amount of filler in the present polyimide tubular material is 130 parts with respect to 100 parts by weight of polyimide solid content. The characteristic values of the obtained film are shown in Table 1.

Table 1 shows the measurement results of the volume resistance values and insulating properties of NN and HH. Volume resistance of NN and HH is 10 ¹¹ Ω ・
It has been adjusted to a medium resistance region below cm and has an insulating property of 40
It was very excellent at kV / mm or more. Further, the ratio of the volume resistance values due to the difference in the number of added parts of the filler (10 parts) was 3 times or less, and the dependency of the volume resistance value on the number of added parts was small. Moreover, the ratio of the volume resistance values of NN and HH was 30 times or less, and the environment dependency of the volume resistance value was small. Further, the ratio of the volume resistance values measured at 100 V and 1000 V was 30 times or less, and the voltage dependency of the volume resistance value was small. In addition, for 5 samples prepared by the same operation as above, 500
As a result of measuring the volume resistance value at V, the difference between the maximum value and the minimum value was 3 times or less, and the variation between samples was also very small. The variation within the same sample was three times or less, which was very small.

The tensile modulus of the film was 3 GPa or more, the elongation was 35% or more, the tear propagation strength was 300 g / mm or more, and the mechanical properties were excellent. Tensile elastic modulus of mere 2.9 GPa of a polyimide simple substance containing no titanium oxide,
Since the elongation was 70% and the tear propagation strength was 450 g / mm, it means that the elongation was kept at 50% or more and the propagation strength was kept at 75% or more.

Example 2 21 g of DMF was added to brown alumina (A: Saint-Gobain Ceramic Materials Co., Ltd.):
A brown polyimide tubular product was obtained in the same manner as in Example 1 except that a liquid in which 18.0 g of a purity of 96.2%, impurity TiO _2, etc., having an average particle size of 1 μm or less) was dispersed was prepared. The amount of filler in the polyimide tubular product is 10% of polyimide solid content.
130 parts to 0 parts by weight. The characteristic values of the obtained film are shown in Table 1.

Table 1 shows the measurement results of the volume resistance values and insulating properties of NN and HH. Volume resistance of NN and HH is 10 ¹² Ω ・
It has been adjusted to a medium resistance region below cm and has an insulating property of 40
It was very excellent at kV / mm or more. Further, the ratio of the volume resistance values due to the difference in the number of added parts of the filler (10 parts) was 3 times or less, and the dependency of the volume resistance value on the number of added parts was small. Moreover, the ratio of the volume resistance values of NN and HH was 30 times or less, and the environment dependency of the volume resistance value was small. Further, the ratio of the volume resistance values measured at 100 V and 1000 V was 30 times or less, and the voltage dependency of the volume resistance value was small. In addition, for 5 samples prepared by the same operation as above, 500
As a result of measuring the volume resistance value at V, the difference between the maximum value and the minimum value was 3 times or less, and the variation between samples was also very small. The variation within the same sample was three times or less, which was very small.

The tensile modulus of the film was 3 GPa or more, the elongation was 35% or more, the tear propagation strength was 300 g / mm or more, and the mechanical properties were excellent. The tensile modulus of elasticity of the polyimide alone, which does not contain alumina, is 2.9 GPa, the elongation is 70%, and the tear propagation strength is 450 g / mm. Therefore, the elongation was kept at 50% or more and the propagation strength was kept at 75% or more. Become.

(Example 3) In the same manner as in Example 1 except that a solution in which 18.0 g of brown titanium oxide and 0.55 g of carbon black (# 3030B: Mitsubishi Chemical Corporation) were dispersed in 21 g of DMF was prepared. A brown polyimide tubular product was obtained. The amount of filler in the present polyimide tubular material is 130 parts and 4 parts based on 100 parts by weight of polyimide solid content. The characteristic values of the obtained film are shown in Table 1.

Table 1 shows the measurement results of the volume resistance values and insulating properties of NN and HH. Volume resistance of NN and HH is 10 ¹⁰ Ω ・
It has been adjusted to a medium resistance region below cm and has an insulating property of 40
It was very excellent at kV / mm or more. Further, the ratio of the volume resistance values due to the difference in the number of added parts of the filler (10 parts) was 3 times or less, and the dependency of the volume resistance value on the number of added parts was small. Moreover, the ratio of the volume resistance values of NN and HH was 30 times or less, and the environment dependency of the volume resistance value was small. Further, the ratio of the volume resistance values measured at 100 V and 1000 V was 30 times or less, and the voltage dependency of the volume resistance value was small. In addition, for 5 samples prepared by the same operation as above, 500
As a result of measuring the volume resistance value at V, the difference between the maximum value and the minimum value was 3 times or less, and the variation between samples was also very small. The variation within the same sample was three times or less, which was very small.

The tensile modulus of the film was 3 GPa or more, the elongation was 35% or more, the tear propagation strength was 300 g / mm or more, and the mechanical properties were excellent. Tensile elastic modulus of mere 2.9 GPa of a polyimide simple substance containing no titanium oxide,
Since the elongation was 70% and the tear propagation strength was 450 g / mm, it means that the elongation was kept at 50% or more and the propagation strength was kept at 75% or more.

(Example 4) Brown was obtained in the same manner as in Example 1 except that a liquid in which 18.0 g of brown alumina and 0.55 g of carbon black (# 3030B: Mitsubishi Chemical Corporation) were dispersed in 21 g of DMF was prepared. A polyimide tubular article of was obtained. The amount of filler in the present polyimide tubular material is 130 parts and 4 parts based on 100 parts by weight of polyimide solid content. The characteristic values of the obtained film are shown in Table 1.

Table 1 shows the measurement results of the volume resistance values and insulating properties of NN and HH. Volume resistance of NN and HH is 10 ¹² Ω ・
It has been adjusted to a medium resistance region below cm and has an insulating property of 40
It was very excellent at kV / mm or more. Further, the ratio of the volume resistance values due to the difference in the number of added parts of the filler (10 parts) was 3 times or less, and the dependency of the volume resistance value on the number of added parts was small. Moreover, the ratio of the volume resistance values of NN and HH was 30 times or less, and the environment dependency of the volume resistance value was small. Further, the ratio of the volume resistance values measured at 100 V and 1000 V was 30 times or less, and the voltage dependency of the volume resistance value was small. In addition, for 5 samples prepared by the same operation as above, 500
As a result of measuring the volume resistance value at V, the difference between the maximum value and the minimum value was 3 times or less, and the variation between samples was also very small. The variation within the same sample was three times or less, which was very small.

The tensile modulus of the film was 3 GPa or more, the elongation was 35% or more, the tear propagation strength was 300 g / mm or more, and the mechanical properties were excellent. The tensile modulus of elasticity of the polyimide alone, which does not contain alumina, is 2.9 GPa, the elongation is 70%, and the tear propagation strength is 450 g / mm. Therefore, the elongation was kept at 50% or more and the propagation strength was kept at 75% or more. Become.

Example 5 A DMF solution of polyamic acid was used as an aromatic diamine, and 5 equivalents of 4,4'-diaminodiphenyl ether and 5 equivalents of paraphenylenediamine were added to DMF.
In the same manner as in Example 1 except that 5 equivalents of TMHQ and 5 equivalents of PMDA were further added to polymerize a polyamic acid DMF solution (solid content concentration 18.5%, solution viscosity 3,000 poise). A polyimide tubular article of was obtained. The linear expansion coefficient of the polyimide film thus polymerized is 9 ppm, and the hygroscopic expansion coefficient is 5 pp.
m, the elastic modulus was 5.5 GPa, and the water absorption rate was 1.2%.

Table 1 shows the measurement results of the volume resistance values and insulating properties of NN and HH. Volume resistance of NN and HH is 10 ¹¹ Ω ・
It has been adjusted to a medium resistance region below cm and has an insulating property of 40
It was very excellent at kV / mm or more. Further, the ratio of the volume resistance values due to the difference in the number of added parts of the filler (10 parts) was 3 times or less, and the dependency of the volume resistance value on the number of added parts was small. Moreover, the ratio of the volume resistance values of NN and HH was 30 times or less, and the environment dependency of the volume resistance value was small. Further, the ratio of the volume resistance values measured at 100 V and 1000 V was 30 times or less, and the voltage dependency of the volume resistance value was small. In addition, for 5 samples prepared by the same operation as above, 500
As a result of measuring the volume resistance value at V, the difference between the maximum value and the minimum value was 3 times or less, and the variation between samples was also very small. The variation within the same sample was three times or less, which was very small.

The tensile modulus of the film is 5.5 GPa or more, the elongation is 20% or more, and the tear propagation strength is 250 g /
mm or more, and the mechanical properties were excellent. Tensile modulus of elasticity of polyimide alone without titanium oxide 5.5G
Since Pa, elongation is 40%, and tear propagation strength is 450 g / mm, it means that elongation is maintained at 50% or more and propagation strength is maintained at 75% or more.

Example 6 A solution of polyamic acid in DMF was used as an aromatic diamine, and 5 equivalents of 4,4′-diaminodiphenyl ether and 5 equivalents of paraphenylenediamine were added to DMF.
In the same manner as in Example 2 except that 5 equivalents of TMHQ and 5 equivalents of PMDA were further added to polymerize a polyamic acid DMF solution (solid content concentration 18.5%, solution viscosity 3,000 poise). A polyimide tubular article of was obtained.

Table 1 shows the measurement results of the volume resistance values and insulating properties of NN and HH. Volume resistance of NN and HH is 10 ¹³ Ω ・
It has been adjusted to a medium resistance region below cm and has an insulating property of 40
It was very excellent at kV / mm or more. Further, the ratio of the volume resistance values due to the difference in the number of added parts of the filler (10 parts) was 3 times or less, and the dependency of the volume resistance value on the number of added parts was small. Moreover, the ratio of the volume resistance values of NN and HH was 30 times or less, and the environment dependency of the volume resistance value was small. Further, the ratio of the volume resistance values measured at 100 V and 1000 V was 30 times or less, and the voltage dependency of the volume resistance value was small. In addition, for 5 samples prepared by the same operation as above, 500
As a result of measuring the volume resistance value at V, the difference between the maximum value and the minimum value was 3 times or less, and the variation between samples was also very small. The variation within the same sample was three times or less, which was very small.

The tensile modulus of the film is 5.5 GPa or more, the elongation is 20% or more, and the tear propagation strength is 250 g /
mm or more, and the mechanical properties were excellent. Tensile modulus of elasticity of polyimide alone without alumina etc. 5.5GP
Since a has an elongation of 40% and a tear propagation strength of 450 g / mm, the elongation has been maintained at 50% or more and the propagation strength at 75% or more.

Comparative Example 1 21 g of DMF was mixed with 18.0 of white titanium oxide (CR-EL: Ishihara Sangyo: purity> 99%).
A yellow polyimide tubular product was obtained in the same manner as in Example 1 except that the dispersed liquid was adjusted. The amount of filler in the present polyimide tubular material is 130 parts with respect to 100 parts by weight of polyimide solid content. The characteristic values of the obtained film are shown in Table 1.

Table 1 shows the measurement results of the volume resistance values of NN and HH.
Shown in. The volume resistance values of NN and HH were 10 ¹³ Ω · cm or more, which were high resistance values.

Comparative Example 2 DMF 21 g was mixed with white alumina (WA: Saint-Gobain Ceramic Materials Co., Ltd .: purity> 99%, average particle size 1 μm or less) 18.
A yellow polyimide tubular product was obtained in the same manner as in Example 1 except that the 0-dispersed liquid was prepared. The amount of filler in the present polyimide tubular material is 130 parts with respect to 100 parts by weight of polyimide solid content. The characteristic values of the obtained film are shown in Table 1.

Table 1 shows the measurement results of the volume resistance values of NN and HH.
Shown in. The volume resistance values of NN and HH were 10 ¹³ Ω · cm or more, which were high resistance values.

Comparative Example 3 A black polyimide tubular product was obtained in the same manner as in Example 1 except that a liquid prepared by dispersing 2.78 g of carbon black (# 3030B: Mitsubishi Chemical Corporation) in 21 g of DMF was prepared. It was The amount of filler in this polyimide tubular material is 2 with respect to 100 parts by weight of polyimide solid content.
It is 0. The characteristic values of the obtained film are shown in Table 1.

Table 1 shows the measurement results of the volume resistance values and the insulating properties of NN and HH. The volume resistance value of NN was adjusted to a medium resistance region, but HH had a very low resistance value and was inferior in environmental dependence. Also, the insulating property was very poor at 10 kV / mm or less. Also, the difference in the number of added fillers (10
The ratio of the volume resistance value by part) was 3 times or more, and the dependency of the volume resistance value on the number of added parts was large. Further, the ratio of the volume resistance values of NN and HH was 1000 times or more, and the environment dependency of the volume resistance value was very large. Also, 100V and 1000
The ratio of the volume resistance values measured by V was 100 times or more, and the voltage dependency of the volume resistance value was large. In addition, as a result of measuring the volume resistance value at 500 V with respect to 5 samples prepared by the same operation as described above, the difference between the maximum value and the minimum value was 3 times or more, and the variation among the samples was very large. The variation within the same sample was three times or more, which was very large.

(Comparative Example 4) A DMF solution (solid content concentration 18.5%, solution viscosity 300 poise) of PVDF (polyvinylidene fluoride) (Kynar 741: Elfina Japan Co., Ltd.) was prepared. On the other hand, DMF21
Brown titanium oxide for g (TY-300: Ishihara Sangyo Co., Ltd.):
Purity 76%, impurities Cr, Sb, etc., average particle size 0.35μ
A liquid in which 18.0 g of m) was dispersed was prepared.

A dispersion of these PVDF solutions and brown titanium oxide was added and kneaded. The obtained dope has a diameter of 80 mm.
Cast on the outer circumference of a tubular SUS made of 200 ℃ / 2
After heat treatment for 40 seconds, a white PVDF tubular product having a thickness of about 50 μm was obtained. Table 1 shows the characteristic values of the obtained PVDF tubular product. The amount of filler in the present PVDF tubular material is 130 parts with respect to 100 parts by weight of PVDF solid content. The characteristic values of the obtained film are shown in Table 1.

Table 1 shows the measurement results of the volume resistance values and insulating properties of NN and HH. The volume resistance value of NN was 10 ¹¹ Ω · cm or less and was adjusted to a medium resistance region, but the volume resistance value of HH was significantly reduced and the insulating property was also poor.

The tensile modulus of the film was 2 GPa or more, the elongation was 15% or less, the tear propagation strength was 100 g / mm or less, and the mechanical properties were very inferior to those of the examples. Although the elongation of PVDF alone was 70% or more, it was found that the original elongation of the resin was significantly reduced by adding titanium oxide.

[0112]

[Table 1]

[0113]

[Effects of the Invention] Despite a large amount of filler, it has a stable medium resistance value at normal temperature and normal humidity to high temperature and high humidity, and resistance value changes between samples, addition amount change, voltage change, environmental change. Of the transparent or non-transparent toner that is easy to clean due to misprint on the transfer belt or fixing belt. A black polyimide resin can be obtained.

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Claims (10)

[Claims] 1. 20 parts by weight per 100 parts by weight of polyimide resin
To 200 parts by weight of titanium oxide having a purity of 55% or more and 95% or less and / or alumina having a purity of 55% or more and 98% or less, and a volume resistance value of 1 × 10 ⁶ to 1 × 10 ¹³ Ω · c.
A polyimide resin composition characterized by being in the range of m. 2. The polyimide resin composition according to claim 1, which contains at least titanium oxide having a purity of 55% or more and 95% or less, wherein the titanium oxide is titanium oxide in which antimony and chromium are thermally diffused. The polyimide resin composition according to claim 1, which is characterized in that. 3. The polyimide resin composition according to claim 1 or 2, containing at least 55% to 98% of purity, wherein the alumina is an alumina complexed with titanium oxide. Claim 1 or 2
The polyimide resin composition described in 1. 4. The polyimide resin composition according to claim 1, wherein the titanium oxide and / or alumina has a diameter of 3 μm or less. 5. A blending ratio of titanium oxide having a purity of 55% or more and 95% or less and / or alumina having a purity of 55% or more and 98% or less with respect to 100 parts by weight of a polyimide resin is 50 to 50%.
2. It is in the range of 200 parts by weight.
The polyimide resin composition according to any one of to 4. 6. A resin composition containing 100 parts by weight of a polyimide resin is used.
The polyimide resin composition according to any one of claims 1 to 5, comprising 01 to 20 parts by weight of a conductive substance. 7. The polyimide resin is a polyimide resin obtained by adding an acid anhydride and / or a tertiary amine as an imidization promoter to a polyamic acid and then heating and baking it. 6. The polyimide resin composition according to any one of 6 above. 8. A polyimide film comprising the polyimide resin composition according to claim 1. 9. A polyimide tubular product comprising the polyimide resin composition according to claim 1 or the polyimide film according to claim 8. 10. The polyimide tubular article according to claim 9, which is used for a transfer belt, an intermediate transfer belt, a transfer fixing belt or a fixing belt.