JP2002316369A - Tubular aromatic polyimide resin multilayered film and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tubular aromatic polyimide resin multilayered film wherein especially curvature, dielectric breakdown strength and ply adhesion are more improved. SOLUTION: The multilayered film is a tubular multilayered film provided wherein a thermoplastic aromatic polyamideimide resin layer is laminated on a nonthermoplastic aromatic polyimide resin substrate layer, and either of the nonthermoplastic aromatic polyimide resin substrate layer or the thermoplastic aromatic polyamideimide resin layer or both thereof have different semiconductor properties. When about 1 μm of a conductive carbon black- containing or not containing nonthermoplastic aromatic polyimide resin layer is laid between the substrate layer an the resin layer, adhesion of both layers becomes more strong.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular aromatic polyimide resin-based multilayer film formed by laminating different kinds of aromatic polyimide resins, and a method for producing the same. The multilayer film is effective, for example, for an intermediate transfer belt of a color copying machine.

[0002]

2. Description of the Related Art Among many functional resins, in particular, a polyimide resin is superior in many respects.
It is used in various fields mainly in the electronic field. Electrical·
In the field of electronics, applications to printed circuit boards (mainly FPCs), insulating materials, and more recently, members for color copying machines and, in particular, belt members have been actively developed. The application development to the belt member of the color copying machine is, specifically, an intermediate transfer belt required by adopting the intermediate transfer method. Originally, color (toner) copying is a printing method which is performed by the action of electrostatic attraction. Therefore, it is necessary to have the inherent characteristics of polyimide resin, but it is necessary to have the proper chargeability and static elimination property, that is, appropriate capacitance (dielectric constant) ( It is necessary to provide a function that can obtain a charging life.

[0003] Regarding the provision of the above-mentioned proper capacitance,
This is to give the polyimide resin belt appropriate semi-conductivity, that is, electrical resistance (specifically, expressed in terms of surface resistivity or volume resistivity). This is generally done by mixing conductive powder such as conductive carbon black. This is done by dispersing.

[0004] The semiconductive polyimide resin belt has been studied and developed based on a single-layer tubular film. But in this single layer,
Since the electrical resistance is uniquely determined, it is not possible to appropriately control the electrical resistance to obtain a more appropriate capacitance. Particularly in recent years, with the ever-higher image quality and longer life, and also with various models (various manufacturers), the actual situation is that conventional single-layer belts are no longer compatible.

[0005] The present applicant has already found one of the solutions to the above-mentioned problem and has filed a patent application (Japanese Patent Application Laid-Open No. Hei 7-156283). This solution is to form a tubular laminated film composed of at least two layers by using at least two kinds of polyimide resins having different electric resistances. Since then, various patent applications have been filed for this polyimide resin laminating means (unpublished).
However, there are patent applications from other companies. For example, Japanese Patent Application Laid-Open Nos. 11-235765 and 20
No. 001-22189. Both of these publications are proposed as being provided with slightly different conditions (with no substantial difference in the subject) from JP-A-7-156283.

[0006]

The solution by the present applicant has been evaluated as being extremely effective at the time, but with the advance of (color) toner image technology, the problem which must be further solved is also raised. I'm getting up. This is the same for the patented technologies of other companies.

The problem is that a single-layer tubular film made of a polyimide resin, which is generally called thermosetting, tends to shrink (especially at the time of imidization treatment by heating) and is therefore bent inward or outward. Tend. When this has two layers, the curvature tends to be further increased. This can be said to be an unfavorable property particularly observed in the resin. This curvature causes (depending on the degree) image disturbance (when used as the intermediate transfer belt) or rotational meandering. In addition, especially when two layers are formed, one of them contains the conductive carbon black, and the flexibility tends to decrease due to the increase in thickness. When used, it hinders obedient rotation.

In particular, when using a double-layer belt, the applied voltage for charging suddenly increases during use, or when using a charged battery with a higher applied voltage, the dielectric breakdown tends to occur. (Dielectric breakdown resistance). Although the cause is not well understood, either because of the fine dust caught between the two layers at the stage of the lamination process, one of the conductive carbon black bleeds out to the other layer side at the layer boundary, It is conceivable that the electrical resistance originally required in each layer changes, and this may appear as a change in dielectric breakdown resistance (also referred to as withstand voltage).

Furthermore, in the case of two layers, there is a situation where the adhesion between the layers cannot be sufficiently satisfied. This also reduces the belt rotation life.

The present inventors have intensively studied to solve the above-mentioned problems and to produce a further improved polyimide-based belt. As a result, one of the following effective solutions was found.

[0011]

That is, as described above, the present invention has claim 1 as a main invention and claims 9 to 10 as dependent inventions. That is, the main invention is a tubular multilayer film in which a thermoplastic aromatic polyamide-imide resin layer is laminated on a non-thermoplastic aromatic polyimide resin base layer, and the non-thermoplastic aromatic polyimide resin base layer or A tubular aromatic polyimide resin-based multilayer film, wherein one or both of the thermoplastic aromatic polyamide-imide resin layers have different semiconductivity.

According to the second aspect of the present invention, the base layer according to the main invention, which is a main component constituting the resin layer laminated thereon,
The non-thermoplastic aromatic polyimide (hereinafter abbreviated as PI resin) and the thermoplastic aromatic polyamideimide (hereinafter abbreviated as PAI resin) are each specified by a glass transition point. The conductive carbon black is used, and in claim 4, the front-back relationship between the non-thermoplastic aromatic polyimide resin base layer (hereinafter abbreviated as PI base layer) and the thermoplastic aromatic polyamideimide resin layer (hereinafter abbreviated as PAI layer) is described. And claim 5 wherein the PI substrate layer and the PA
The layer thickness relationship of the I layer is specified, and claim 6 specifies and provides that a specific intermediate adhesive layer is interposed between the PI base layer and the PAI layer.

In particular, claims 7 to 10 provide a method for producing a tubular aromatic polyimide resin-based multilayer film according to the main invention. In other words, the seventh aspect of the manufacturing method is characterized in that the following steps (A) to (C) are sequentially performed. (A) An organic solvent solution of a non-thermoplastic aromatic polyimide resin precursor having a glass transition point of 300 ° C. or higher is rotationally molded and heated in a rotating drum to first form an endless tubular precursor film. Is once removed and removed from the inside of the rotary drum, and heated by a separately provided hot air heating means to completely remove the residual solvent and complete imidization, thereby forming an endless tubular non-thermoplastic aromatic polyimide resin back layer ( First step of forming the base layer), (B) 5 to 30% by weight of conductive carbon black is contained on the entire surface of the endless tubular non-thermoplastic aromatic polyimide resin back layer obtained in the step A. A second step in which an organic solvent solution of a non-thermoplastic aromatic polyimide resin precursor is applied and heated to provide the precursor layer as an intermediate adhesive layer; (C) the entire surface of the intermediate adhesive layer provided in the step B; Around A solution of a thermoplastic aromatic polyamideimide resin having a glass transition point of 200 to 310 ° C. dissolved in an organic solvent containing 5 to 30% by weight of conductive carbon black is applied and heated to remove the solvent and remove the precursor layer. In which a semiconductive thermoplastic aromatic polyamideimide resin surface layer is formed by imidation of

Claims 8 to 10 are inventions for achieving claim 7 more preferably. Claim 2 above
Nos. 10 to 10 are inventions in which claim 1 which is the main invention is specified as a preferred embodiment, and it is needless to say that the invention is not limited thereto. Hereinafter, the present invention will be described in more detail with the following embodiments.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION First, the PI resin in claim 1 is specified as non-thermoplastic as a thermal property. Here, the meaning of non-thermoplastic is generally an imide prepolymer terminated with maleimide or nadic acid or acetylene.
Furthermore, it is not a cured polyimide resin in a state of cross-linking (three-dimensionalization) by addition polymerization of the terminal group, but is a prerequisite that it is a wholly aromatic polyimide resin based on one dimension (linear). Among them, the substantially imidized polyimide does not dissolve in an aprotic organic solvent known as a general polyimide organic solvent (eg, N-methylpyrrolidone, dimethylacetamide, dimethylformamide, dimethylsulfoxide, etc.), It means that it is dissolved in the solvent only at the stage of the precursor, that is, the polyamic acid. In other words, a polyimide which is substantially imidized and which dissolves in the solvent, is called a thermoplastic aromatic polyimide resin, and is an aromatic polyimide resin that is distinguished from this. Therefore, the non-thermoplastic aromatic polyimide resin is formed into a film at the stage of the polyamic acid, and finally imidation is performed.

The PI resin is particularly used as the base layer because, unlike the thermoplastic aromatic polyimide, even if the thickness is smaller, the PI is excellent in heat resistance, bending resistance, stretch resistance and the like. . For this reason, the layer can be set as a thinner layer, so that when this is used as a belt, compliant rotation with a roller having a smaller diameter can be performed.

With a PI resin having the above-mentioned properties,
Although it can be used without any particular limitation, some of them are preferable, and when they are shown by a glass transition point (hereinafter referred to as PI · Tg), they are 300 ° C. or higher, preferably 350 ° C. or higher. Although there is an upper limit of about 500 ° C., there is also an unmeasurable one (substantially has no Tg). However, even if the PI resin has no Tg, it does not include a film that cannot be molded or a brittle one that cannot be used. A PI resin having a larger Tg is preferred because a PI resin having a higher Tg generally has a stronger tendency to shrink (that is, a tendency to curve) and a lower adhesiveness. This is because the effect is great.

Generally, Tg depends on the molecular structure of the PI resin. For example, in addition to the imide group directly bonded to the aromatic ring, it depends on what groups are in the main chain and how many are bonded. Such groups include, for example, -O-, -CO
_-, - SO 2 _-, -, and the like - _{(CH 2) n.} The PI
-If there is no such group in the Tg range,
At most one of the structures in which any one is involved in the main chain bond becomes non-thermoplastic.

The PI resin is a homopolymer mainly composed of two components, although there is a copolymer composed of three components. Specifically, for example, a PI resin (having substantially no Tg) from pyromellitic dianhydride and p-phenylenediamine, 3,
PI resin from 3 ', 4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine (Tg about 5
00 ° C.), PI resin from pyromellitic dianhydride and 4,4′-diaminodiphenyl ether (Tg about 420
C), a copolymerized PI resin of pyromellitic dianhydride with 4,4'-diaminodiphenyl ether and 4,4'-diamino3,3'-dimethylbiphenyl (Tg about 35).
0 ° C.), and a PI resin (Tg of about 310 ° C.) from 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether.
Here, the diamine component may be a diisocyanate component.

On the other hand, the PAI resin basically has one or two imide groups bonded to a trivalent or tetravalent aromatic ring and two amide groups bonded to a divalent aromatic ring, and this is called a repeating unit. And a resin which is soluble in the above-mentioned aprotic organic solvent even in a substantially imidized state. And this P
The AI resin can also be used without any particular limitation as long as it has the above-mentioned properties, and among them, preferred are those having a glass transition point (hereinafter referred to as PAI · Tg) of 200 to 200.
The temperature is 310 ° C, preferably 230 to 300 ° C.
This is because, when the temperature is lower than 200 ° C., expansion and contraction are particularly large with respect to changes in dryness and humidity, and delamination is likely to occur in lamination with a PI resin, and a stable semiconductive property is likely to change (with time). It depends. On the other hand, when the temperature exceeds 310 ° C., the effect of improving the curvature, which is a drawback of the PI resin film, is small, and the adhesiveness to the film tends to deteriorate.

The change in the PAI.Tg, together with the number of amide groups, mainly depends on the molecular structure as in the case of the PI resin. Therefore, how much T for PI resin
The choice of g of PAI resin depends on the type and combination of various raw materials (tricarboxylic acid, tetracarboxylic acid, and diamine components), and in the case of three components, also depends on the reaction molar ratio. It is hoped that this will be thoroughly considered in advance.

In selecting the PAI resin, it is necessary to further improve the affinity with the PI resin, that is, since this affects the interlayer adhesion. This is generally the to -O -, - CO -, - SO 2 - also acts against polarity high to groups such as. And PA
A PAI resin having a structure in which two imide groups bonded to the same tetravalent aromatic ring as the PI resin are introduced into a part of the structure of I also has an advantageous effect. good.

Taking the above into consideration, a specific example of the PAI resin is as follows. PA from trimellitic anhydride and diphenyl ether- (4,4 ') diisocyanate or diphenyl ketone-4,4' diisocyanate or diphenyl sulfone- (4,4 ') diisocyanate
I resin (Tg about 280-300 ° C.), copolymer PA from trimellitic anhydride and hexamethylene 1,6-diisocyanate and tolylene-2,4-diisocyanate
I resin (Tg about 240 to 250 ° C), copolymerized PAI resin from trimellitic anhydride with hexamethylene 1,6-diisocyanate and diphenylketone-4,4 'diisocyanate (Tg about 200 to 220 ° C), Copolymer PA from melitic anhydride and benzophenonetetracarboxylic dianhydride with vitriylene diisocyanate
I resin (Tg about 280-300 ° C.), copolymerized PAI resin from diphenyl ether-4,4 ′ diisocyanate or diphenyl sulfone-4,4 ′ diisocyanate instead of the vitriylene diisocyanate (Tg about 220
To 260 ° C.). The polycondensation means of the PAI resin is not particularly limited, since there is a method of using diamine instead of the diisocyanate and using trimellitic acid monochloride monoanhydride instead of trimellitic anhydride.

The PI resin and the PAI resin are as described above, but the two are particularly selected and combined for the following reason. As described above, the PI resin is more excellent in heat resistance, various physical properties, the environment (especially under high temperature and high humidity), etc. than the thermoplastic aromatic polyimide resin and any other functional resin. It is a very effective material for use in However, as described above, there is a drawback that it is easily curved. Curling before or during use does not allow slight curvature deformation, especially for copier belts that form toner images in a plane and transfer that image in a plane. A means for completely eliminating the risk of this bending is to use a combination with the PAI resin which is neither a thermoplastic aromatic polyimide resin nor another resin. Although the mechanism of this action is not clear, the PAI resin adheres firmly to the PI resin,
It is also considered to have a function of canceling the curving action of the I resin. Among the PAI resins, there are some which dissolve in a protonic organic solvent (for example, γ-butyl lactone, cyclohexane, toluene, alcohol, tetrahydrofuran, etc.). It is not preferable in terms of heat resistance.

As described in the above-mentioned prior art, for example, the performance requirement when used as an intermediate transfer belt of a color copying machine has recently been increasing, especially since the electric resistance can be appropriately controlled and a more appropriate capacitance can be freely set. Pointed at the resulting belt. This inevitably results in a solution with two-layer belts having different electrical resistances. At present, as described above, these two layers are formed of a thermosetting polyimide resin. However, in the same two layers made of the same resin, there is a tendency that the dielectric breakdown resistance is deteriorated, in addition to the physical properties that the rotation bending property is further lacked and the curvature is further promoted. This problem is also solved particularly by forming the PI resin as a base layer (one layer) and laminating the PAI resin as an upper layer or a lower layer. The effect of this is not clear, but first, the PAI resin selected for the PI resin has an affinity and is easy to adhere, and as described later, the PI base layer for laminating the PAI layer is substantially Since the imidization has been completed (therefore, the solvent has not been contained), and the PAI resin itself has been substantially imidized, both are laminated. Does not require higher-temperature heating for imidization only by evaporating and removing the organic solvent. . The fact that imidization is not required is because no by-product condensation component (one of CO ₂ , H ₂ O, and HCl) is generated, so that there is no entrapped air bubbles or the like inside the layer as well as inside the layer, and it is contained. It is considered that there is no bleed-out phenomenon at the layer boundary of the conductive carbon to be performed. The absence of the bubbles leads to a function of improving the adhesion.

The substrate layer is made of P
An upper layer or a lower layer is formed by the AI resin. At this time, one or both layers have different semiconductivity. The semiconductivity is imparted by various means. In the present invention, the semiconductivity is preferably achieved by mixing and dispersing conductive carbon black (hereinafter referred to as CB powder) in the resin.

CB powder is compared with other conductive powders.
It is preferable because the dispersibility with the PI resin and the PAI resin (the dispersion is small), the stability after dispersion, and the desired semiconductivity can be imparted by adding a relatively small amount. This is also its raw material (natural gas, acetylene gas, coal tar, etc.)
Some have various physical properties (electrical resistance, volatile matter, specific surface area, particle size, pH value, DBP oil absorption, etc.) depending on the production conditions (combustion conditions), and among them, more preferable are those. In actual selection, it is preferable to select a material that can obtain the desired surface resistivity more stably with as little mixing and dispersion as possible. For example, a material with a high conductivity index with a developed structure (this is common in CB powders obtained by using acetylene gas as a raw material),
Alternatively, the conductivity index is not so high (such as lowering the pH value), but it is better to check with appropriate parameters such as those containing a large amount of volatile matter and select an appropriate one. The mixing and dispersing means and the mixing amount will be described later in the production method.

Regarding the relationship between the front and back surfaces of the PI base layer and the PAI layer, the above-mentioned problems can be achieved in any case, but in particular, when used in belt rotation, contact abrasion with the rotating roller on the back surface, photosensitivity on the front surface, etc. Regarding contact with a drum or copy paper, it is preferable to form the base layer on the back surface and the PAI layer on the front surface (claim 4). This is also preferable from the manufacturing method described later.

The relationship between the different semiconductivity of each layer and the front and back surfaces differs depending on the usage, the user, and the model. For example, when the charging performance is controlled mainly by the capacitance, it is preferable to make the surface layer semiconductive and make the backside layer substantially electric insulating.

When it is desired to freely change the entire volume resistance with respect to the surface resistance of the surface layer, both layers are made semiconductive, but the back layer has a larger resistance than the surface resistance of the surface layer. It is good to set so as to be appropriately changed within a certain range. This is because it is effective for maintaining the property that the charge life is not long or short. In addition, when the semiconductivity referred to here is expressed in terms of surface resistivity, it can be exemplified as 10 ⁵ to 10 ¹⁴ Ω / □, and the substantial electrical insulation can be exemplified as 10 ¹⁵ Ω / □ or more.

The layer thickness relationship between the PI base layer and the PAI layer is as follows:
It may seem effective to make the latter thicker, but it is not necessary. On the contrary, setting the latter thinner is advantageous for solving the problem (claim 5). This layer thickness relationship is about 80 to 150 μm in total thickness, and it is particularly preferable that the substrate layer be thicker than the PAI layer. This is due to the role of strength as the base layer, the compliant belt rotation, and the like.

The tubular aromatic polyimide resin-based multilayer film of the present invention is basically composed of two layers of the PI base layer and the PAI layer, but may be three layers. In this case, it is particularly desirable to interpose an adhesive layer that acts to firmly adhere both layers. Desirable as the layer is an intermediate adhesive layer made of a non-thermoplastic polyimide resin containing or not containing conductive carbon black, as also provided in claim 6. Although the two layers are laminated with a sufficient adhesive force only by the above-mentioned layers, there is a risk of delamination, although partially, particularly in severe use such as belt rotation. This is because, in order to eliminate this danger, it is better to take stronger adhesion means.

In order to improve the adhesion between the PI base layer and the PAI layer, it is generally known as a means for improving the adhesion of a polyimide film. Surface treatment means, for example, a physical treatment method such as polishing, an electrochemical treatment method using plasma or the like,
A chemical treatment method using an oxidizing agent or an alkali may be used.
However, in the present invention, a great improvement effect cannot be obtained. This is also thought to be due to the combination of the two layers with different resins. The interposition of the intermediate adhesive layer has been found as a more preferable means based on such prior art.

That is, the intermediate adhesive layer is composed of the same components as described above, and the conductive cahn black and the non-thermoplastic polyimide resin here are CB powder and P
It is the same as I resin. However, when actually using
It may be the same component or composition as the I base layer, or may be different. This is because there is no difference in the improvement of the adhesion even if they are different, but it is preferable that they are the same in terms of handling. Here, the use of the PI resin may be replaced by the thermoplastic aromatic polyimide resin described above, but the use of the PI resin results in a slight lack of adhesion to the PI base layer and a curving effect is suppressed. Due to the tendency, it is not very favorable.

The presence or absence of CB powder in the intermediate adhesive layer is determined by
It depends on the following three cases. One of the cases is when the PI base layer is electrically insulating (does not contain CB powder) and the PAI layer is semiconductive (containing CB powder). The intermediate adhesive layer contains CB powder to make it semiconductive, but it is preferable to use the semiconductive PAI layer having at least the same digit of resistivity. Here, it is better to make the intermediate adhesive layer particularly semiconductive because if it is different, the CB powder moves at the boundary between the intermediate adhesive layer and the PAI layer, and the initial setting of the PAI layer is performed. This is because there is a risk that the electrical resistance may change.

Two of them are those in which the PI base layer is semiconductive and PA
This is the case when the I layer is electrically insulating. In this case, it is preferable that the intermediate adhesive layer be electrically insulating without CB powder. This is also effective for the barrier effect and the effect of no change in electric resistance.

The three cases are cases where both the PI base layer and the PAI layer have different semiconductivity. In this case, the same intermediate adhesive layer as that in the above one case may be made to have the same semiconductivity as the PAI layer. This is because the PI substrate layer is in a substantially imidized and completely solid state.

Since the intermediate adhesive layer only needs to exhibit an adhesive function, the thickness of the intermediate adhesive layer is preferably as thin as possible.

Next, a method for producing the tubular aromatic polyimide resin-based multilayer film will be described by way of example. This example relates to the tubular aromatic polyimide resin-based multilayer film provided in the third to sixth aspects. This manufacturing method is a manufacturing method that is used as necessary in other examples regardless of the claims.

That is, the manufacturing method is provided in claim 7, and is achieved by sequentially performing the following steps (A) to (C). Note that the tubular molding here is a method of forming an endless tube (endless) at a stroke, unlike a method of connecting both ends of a web film to form a tube. And PA
This is an example in which the I layer is configured as a semiconductive surface layer.

First, the PI base layer is formed in the first step described in (A). Glass transition point 3
It is necessary to prepare an organic solvent solution of a non-thermoplastic aromatic polyimide resin precursor (hereinafter simply referred to as polyamic acid and abbreviated as PA acid) at a temperature of 00 ° C. or higher. The solution is prepared by equiconstituting the raw materials exemplified as the PI resin (the aromatic tetracarboxylic dianhydride component and the aromatic diamine component) in equimolar amounts in the aprotic organic solvent at ordinary temperature or lower at a polycondensation (up to the stage of PA acid). ) It can be produced by reacting. A scavenger for catching water produced as a by-product during this reaction, an accelerator for imidization to be performed later, or the like may be added. At this stage, some imidization (for example, within 20%) is permissible, but it is necessary to avoid imidization reaction.

Next, the obtained PA acid solution is subjected to rotary molding and heating in a rotary drum. Prior to this, the solution is adjusted to an appropriate solution viscosity. When no adjustment is necessary, the stock solution may be used as it is, but in the case of adjustment, it is diluted with the same organic solvent as in the above reaction. The rotational molding is a generally known centrifugal molding method. For example, a metal drum having an internally mirror-finished surface is mounted on four rotating rollers, and the drum rotates at a speed at which centrifugal force acts due to the rotation of the rollers. When a predetermined amount of the solution is supplied into the drum, the solution is uniformly cast on the inner surface by centrifugal force. Therefore, the temperature is gradually increased while rotating, and the organic solvent is first evaporated and removed. As it evaporates, it solidifies to form an endless tubular film of PA acid. The temperature is gradually increased as it is, and the imidization reaction is carried out together with the complete removal of the remaining solvent, and the PI substrate layer may be peeled off and taken out at a stroke in the drum, or at the stage of the endless tubular film of the PA acid, A method may be adopted in which the film is peeled off from the drum, taken out of the drum, externally fitted to a cylindrical mold, separately put into a hot-air dryer, and the imidization reaction is performed together with complete removal of the residual solvent. In the case of the PI resin,
Since a slight shrinkage tendency is observed with the imidization reaction (though it is considered structural), it is better to perform the imidization by the latter separate hot air heating method.

When the PI base layer is semiconductive,
It is better to use a centrifugal force forming method. This is because the PA acid solution containing the CB powder is molded under the action of centrifugal force (rotation of the metal drum is extremely slow) while being supplied in the form of a spray, so that the CB powder is uniformly dispersed without uneven distribution. This is because the dispersion is preferable. Also, unlike centrifugal molding, the rotation of the metal drum is extremely slow (the centrifugal force does not work), so even if the drum with a large diameter is used, it does not shake itself, so a larger diameter endless tubular It also depends on the fact that the film can be molded with high precision. Of course, even when CB powder is not contained, this centrifugal force forming method may be used.

Next, a PA acid organic solvent solution containing 5 to 30% by weight of CB powder is applied over the entire surface of the endless tubular PI base layer and heated to form an intermediate adhesive layer.
The second step described in (B) is performed. First, here the CB
The actual amount of the powder added is the same as the amount of the PAI resin solution to be added in the third step described in the following (C). It is preferable to adopt a method of preliminarily mixing with a bladed mixer, and finally performing full mixing with a ball mill mixer.

The CB powder-containing PA acid solution is uniformly applied to the surface of the endless tubular PI base layer. Here, the applying means may be, for example, a generally known method (together with a sphere and the liquid). Surface running method, gravure roll method,
Spray method) can be applied, and among them, the spray coating method is preferable (claim 8). This coating method is a method in which the solution is supplied in the form of a spray (spray) from a nozzle port while rotating the base layer to coat the solution. However, thinner, quicker and more uniform coating than other methods is possible. .

The conditions for spray coating are basically determined by the setting of the coating thickness. The factors are mainly the state of the solution (viscosity and solids concentration), the injection amount, the rotation speed, the speed when the nozzle is also moved (up and down or left and right with respect to the rotating body mounted on the base layer), There are also round trip times. In setting actual conditions, it is required to consider these factors in advance and determine the optimum conditions. Since the coating thickness here is desirably kept to the minimum thickness necessary for expressing the adhesion, this is about 0.5% in terms of the thickness of the finally formed PI resin intermediate adhesive layer.
The thickness is set to about 5.0 μm (claim 9), preferably 1 to 3 μm (it becomes slightly thicker due to the remaining organic solvent).

After the coating, the CB powder-containing PA
Heat drying (hot air is good) until an acid solid film is formed tightly.
Is done. Here, in particular, the temperature in the heating and drying needs to be at least a temperature at which the organic solvent is removed by evaporation (a little remaining, for example, about 5 to 20% is desirable rather than removing all the solvent). And although some imidization (for example, less than about 50%) may be performed, drying is performed at a temperature (for example, 180 ° C. or lower) that does not excessively proceed. This is because the adhesion to the PAI layer, which is performed in the third step described in (C) below, acts more strongly. It is conceivable that this action and effect may be due to the fact that the PAI resin molecule is entangled with the non-imidated portion (that is, the amide acid portion), and the imidization is finally performed there, thereby contributing to the development of greater adhesion.

It is not bad to take the above-mentioned (0030) surface treatment means on the surface of the base layer before providing the intermediate adhesive layer.

Next, the third step (C), which is performed last, will be described. Here, a CB powder-containing PAI resin (Tg 200 to 310 ° C.) organic solvent (the aprotic) solution (coating material) is coated by the same coating means as that for forming the intermediate adhesive layer. For this purpose, first, the coating material is prepared, which is composed of the above-mentioned raw material components (an aromatic tricarboxylic acid monoanhydride or an acid component obtained by further adding an aromatic tetracarboxylic dianhydride and an aromatic diisocyanate component). Is obtained by polycondensation / imidization of an equivalent mole of the above in an organic solvent. The reaction is performed at a high temperature (for example, 150 to 200 ° C.) because the reaction is performed up to the imidization reaction. It is necessary to consider it. Here, PAI of complete imidization
Resin, but some unring closed part (for example, about 1 to 10%
Degree). And in the obtained PAI solution,
5 to 30% by weight of CB powder is added and mixed. The mixing is the same as described for the intermediate adhesive layer. Such CB
The semiconductivity given by the amount of powder mixed is 1 in surface resistivity.
It is about 0 ⁵ to 10 ¹⁴ Ω / □. The resistivity is, for example, in a range required for use as an intermediate (paper transport / transfer) transfer belt. A non-solvent may be added to the obtained PAI solution, the PAI resin may be once precipitated as a powder, dried, dissolved again in an organic solvent, and CB powder may be added and mixed in the same manner.

The coating material thus obtained is coated on the entire surface of the intermediate adhesive layer by the same coating means as used in the second step. The spray coating conditions here are also basically determined by the setting of the coating thickness.
The main factors are the state of the solution (viscosity and solid content concentration), the injection amount, the rotation speed, and the speed when the nozzle is also moved (up and down or left and right with respect to the rotating body mounted on the base layer), There are also round trips (up and down or left and right). In setting actual conditions, it is required to consider these factors in advance and determine the optimum conditions. The coating thickness here is adjusted so that the PAI layer finally obtained by heating and drying is thinner than the PI base layer and thicker than the intermediate adhesive layer. The thickness of the PAI layer is about 1/3 to 3/4 times that of the PI base layer (Claim 9), preferably 1.
The ratio is preferably 5/3 to 2.5 / 4.

When the coating is completed, the coating is dried by heating (hot air). The heating temperature is such that the organic solvent is removed and the precursor layer of the intermediate adhesive layer is imidized (not necessarily 100%). It is a mess. This temperature is about 200-3
Although it is 00 ° C, instead of heating at a stretch,
It is preferable that the temperature is gradually increased stepwise so that the removal of the organic solvent is performed first and the imidization is completed last.

As exemplified in the above manufacturing method, the back surface layer is an electrically insulating PI layer, and the front surface layer is a semiconductive PAI.
In the case of the structure in which the layers are formed as layers, compared to the structure in which the structure is reversed (the surface layer is formed of an electrically insulating PAI layer), the following points are also advantageous. For example, when the belt is used as an intermediate transfer belt in a color copying machine, the degree of static friction (or kinetic friction) is easily controlled properly when the belt surface is cleaned by rubbing with a urethane rubber spatula. ), So that an excessive load is not applied to the electromotive current, and that the primary transfer from the photosensitive drum is easily and reliably performed.

[0053]

The present invention will be described in more detail with reference to the following examples together with comparative examples. In this example, the degree of curvature and the surface resistivity (Ω /
□) (hereinafter abbreviated as ρs), dielectric breakdown resistance (measured by withstand voltage, referred to as withstand voltage value), interlayer adhesion and Tg are values measured as follows. ● Degree of curvature First, a sample with a width of 380 mm was rolled into a roll 1 with a diameter of 40 mm.
The other end is loaded with a roll 2 of the same diameter and weighing 2 kg, and is suspended from the roll. A value obtained by measuring the inward or outward bending of the sample at a position 100 mm below the horizontal center line of the roll 1 and expressing the result in mm. In each case, the length is 40 mm in the case of a vertical without bending. ● Apply 500V to a total of 24 points, 3 points at equal pitch in the width direction and 8 points in the vertical (circumferential) direction, using a resistance measurement device “Hiresta IP / HR probe” manufactured by Mitsubishi Chemical Corporation with ρs sample. A value measured after 10 seconds and averaged in the width direction and the longitudinal (circumferential) direction. ● The withstand voltage measurement device is “KIKUSUI ELECTRONICS”
CORP voltage tester (WITHSTANDIN)
G VOLTAG TESTER) / model TOS87
50 "was used. The measurement conditions were as follows: a sample cut to 60 × 60 mm was sandwiched between plate electrodes of 60 × 60 mm, and 1 k
A voltage (DC) of 1 to 5 kV was applied at a voltage raising rate of V / 10 seconds, and the voltage at the time when the current value exceeded 10 mA was defined as the withstand voltage value. ● Interlayer adhesion The test described in JIS K6894 (1976) in the section of "6.4 Adhesion" for three samples obtained by cutting the side cut product of the final tubular film obtained in each example into 60 x 100 mm at equal intervals. The state of the peeling was observed by a method (the tester was a paint drawing tester manufactured by Toyo Seiki Co., Ltd.), and the evaluation was made based on the adhesive force criterion classified into 1 to 5 points. A rating of 4 to 5 was no problem, and a rating of 1 to 3 was partial or almost all peeling. The weight was 160 g. ● Tg Differential scanning calorimeter “DSC-50” manufactured by Shimadzu Corporation
Value measured in.

First, the production of each forming raw material will be described by reference examples.

(Reference Example 1) (Synthesis of PI resin precursor) Equimolar amounts of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine were added to N-methylpyrrolidone. , A polycondensation reaction with stirring at room temperature
2 kg of a solution of A acid (precursor) (solution viscosity: 4.9 Pa · s, solid content concentration: 18% by weight) was obtained. Further, N-methylpyrrolidone was further added thereto with stirring to dilute the solution to a solution viscosity of 1.9 Pa · s and a solid content concentration of 14% by weight. Hereinafter, this is referred to as PA acid solution 1. In addition, a part of the PA acid solution 1 was collected, cast on a glass plate, placed in a hot air drier, and gradually heated to 200 ° C. for 30 minutes, and gradually heated.
When the temperature gradually rises to 300 ° C.,
The temperature was further gradually increased for 0 minutes, and when the temperature reached 400 ° C., heating was performed at that temperature for 40 minutes. A PI resin film having a thickness of 50 μm was obtained, and its Tg was measured to be about 502 ° C.

Reference Example 2 (Synthesis of PI Resin Precursor) Polycondensation reaction of equimolar amounts of pyromellitic dianhydride and 4,4'-diaminodiphenyl ether in N-methylpyrrolidone while stirring at room temperature As a result, 2 kg of a PA acid (precursor) solution (solution viscosity: 2.0 Pa · s, solid content concentration: 15% by weight) was obtained. Hereinafter, this is referred to as PA acid solution 2. still,
A part of the PA acid solution 2 was collected, cast on a glass plate, and heated and dried under the same conditions as in Reference Example 1 to perform imidization. The measured Tg was about 415 ° C.

Reference Example 3 (Semiconductivity of PA Acid Solution 2) 1 kg of the above PA acid solution 2 was sampled, and 24 g of CB was added thereto.
Powder (volume resistivity 10 ^-1Ω · cm) (for solid content)
13.8% by weight) while stirring with a stirrer with blades
Transfer to a ball mill and mix thoroughly
did. Hereinafter, this is referred to as PA acid solution 3.

Reference Example 4 (Synthesis of PAI Resin) A total of 1 mol of 0.85 mol of trimellitic anhydride and 0.15 mol of benzophenonetetracarboxylic dianhydride and 1 mol of vitriylene diisocyanate were used as acid components. To N
-Methylpyrrolidone, the temperature was gradually increased with stirring, and when the temperature reached 190 ° C, the temperature was maintained for 7 hours to complete the reaction. A part of this solution was analyzed by IR to confirm that it was completely imidized. The amount of the obtained solution was 2 kg, the solution viscosity was 20 Pa · s, and the solid content concentration was 20.
% By weight. This is hereinafter referred to as PAI solution 4. Note that P
A part of the AI solution 4 was collected, diluted with N-methylpyrrolidone so that the solution viscosity became 2.5 Pa · s, and cast on a glass plate. Next, this was put into a hot-air dryer and gradually heated to 130 ° C. for 15 minutes, and further gradually heated to 290 ° C. for 40 minutes. Thickness 50
A μm PAI resin film was obtained, and its Tg was measured to be about 292 ° C.

(Reference Example 5) (Synthesis of PAI resin) 1 mol of trimellitic anhydride was dissolved in N-methylpyrrolidone together with caustic soda (added at 5 mol% based on the anhydride). 0.25 mole of methylene 1,6-diisocyanate and 0.75 mole of tolylene-2,4-diisocyanate were added. And 200 ° C
, And the reaction was carried out at that temperature for 1 hour. A part of this solution was analyzed by IR to confirm that it was completely imidized. The resulting PAI solution is 2 kg,
The solution viscosity is 10.0 Pa · s, and the solid content concentration is 19.5.
% By weight. This is hereinafter referred to as PAI solution 5. The addition of caustic soda here is based on the fact that it is effective when a generally known polymerization catalyst is used, particularly when an aliphatic diisocyanate is present. In addition, a part of the PAI solution 5 was collected, and N-methylpyrrolidone was added thereto to add 3.0 Pa.
・ It was cast on a glass plate as s. Then, this was put into a hot air drier and gradually heated. When the temperature reached 150 ° C., it was heated for 30 minutes. When the temperature reached 240 ° C., it was heated for 60 minutes. A PAI resin film having a thickness of 50 μm was obtained, and its Tg was measured to be about 245 ° C.

(Reference Example 6) (Semiconductivity of PAI solution 4) 1 kg of the PAI solution 4 was collected, and N-methylpyrrolidone was dissolved and diluted with stirring to obtain a solution viscosity of 2.1 P.
Then, 30 g of CB powder (volume resistivity: 10 ^-1 Ω · cm) (15% by weight based on the solid content) was mixed with the mixture by stirring with a blade, and further transferred to a ball mill. Instead, they were mixed and dispersed sufficiently uniformly. The solution viscosity was 2.2 Pa · s. This is hereinafter referred to as PAI solution 6.

Reference Example 7 (Semiconductivity of PAI solution 5) 1 kg of the PAI solution 5 was collected, and N-methylpyrrolidone was dissolved and diluted with stirring to obtain a solution viscosity of 2.1 P.
a · s, 29 g of CB powder (volume resistivity: 10 ⁻¹ Ω · cm) (14.8% by weight based on solid content)
Was premixed while being stirred by a stirrer with blades, and was further transferred to a ball mill to be stirred and mixed sufficiently to be uniformly dispersed. The solution viscosity was 2.2 Pa · s. This is called PAI
Called Liquid 7.

(Example 1) First, 160 g of the PA acid solution 1 of Reference Example 1 was collected, and this was placed on a rotating metal drum having an inner diameter of 200 mm and a width of 500 mm placed on four rotating rollers (the inner surface was mirror-finished). ) And pour it evenly into the inner surface of
It started spinning slowly. When it was confirmed that the coating was substantially uniformly applied to the entire inner surface, the speed was gradually increased to 400 r.
p. m. When the temperature reached 120 ° C., the drum was rotated for 5 minutes, and then heating of the drum was started. When the temperature reached 120 ° C., the drum was heated at that temperature for 30 minutes. An endless PA acid tubular film was formed on the inner surface. This was cooled to room temperature, peeled from the drum and taken out.

Then, the PA acid tubular film was externally fitted to a cylindrical mold, placed in a separate heating dryer, and heated and dried under the following conditions to remove the residual solvent and imidize.
An endless tubular PI resin film as a back substrate layer was obtained.
First, the temperature was gradually raised to 200 ° C. for 30 minutes, and then gradually raised to 300 ° C., at that temperature for 40 minutes, and gradually further raised to 400 ° C., at that temperature. For 40 minutes each. It was allowed to cool to room temperature and extracted from the mold. The thickness of the obtained PI resin film is 50 μm.
m, the inner diameter was 199.9 mm and the width was 500 mm.

Next, the surface of the endless tubular PI resin film is subjected to plasma treatment, and this is fitted (fitted and fixed) into one vertically fixed rotating metal cylindrical jig (outer diameter: 199.7 mm). A semi-conductive PAI surface layer 2 was spray-coated under the following conditions from a vertically moving spray gun provided 10 mm apart from the film surface (nozzle port). First, set the cylindrical jig to 40 r. p. m. Spin at 13m
Start vertical and vertical movement at a speed of m / sec, and start jetting the semiconductive PAI liquid 6 (Reference Example 6) at a rate of 6.8 g / min just when the nozzle port comes to the uppermost stage. did. When the nozzle port reached the lowermost stage, it rose under the same conditions, and the upper and lower sides were defined as one cycle, and the coating was completed in five cycles. Finally, the rotation was continued as it was, the spray gun was detached, and this time the whole film was heated and dried to form a surface layer while evaporating and removing the organic solvent. Heating was performed using a far-infrared heater as a heat source, and heating was performed at 100 ° C. for 10 minutes, 290 ° C. for 30 minutes, and allowed to cool. The obtained laminated film was separated from the cylindrical jig, and both ends were trimmed to obtain a product having a width of 380 mm. When the total thickness was measured, it was 80 μm. Therefore, the thickness of the semiconductive PAI surface layer 2 was 30 μm.
The curvature, ρs, withstand voltage and interlayer adhesion of this film were measured and are summarized in Table 1.

[0065]

[Table 1]

Example 2 (Example of Intermediate Adhesive Layer Interposition) First, an endless PA acid tubular film was obtained by rotational molding and heating using the same PA acid solution 1 as in Example 1 under the same conditions.
Further, the residual solvent was removed and imidation was performed to obtain an endless tubular PI resin film as a back substrate layer. The film had a thickness of 51 μm, an inner diameter of 199.9 mm, and a width of 500 mm.

Next, the endless tubular PI resin film obtained above was used for the same rotary metal cylindrical jig (outer diameter: 199.7) as in Example 1.
mm) under the same conditions except that the spray gun is arranged in the same manner, the vertical cycle of the gun is 0.5 (one way), and the heating is 100 ° C. for 5 minutes. Liquid 3 (Reference Example 3) was applied by spraying and dried to form a semiconductive intermediate adhesive layer. The total thickness of the obtained film is 52
μm, so that the thickness of the adhesive layer is 1 μm. Although the organic solvent remained in the adhesive layer, the imide was not closed with a ring, and was the PA acid itself of the PA acid solution 3.

Then, on the surface of the intermediate adhesive layer,
While rotating the rotating metal cylindrical jig, the PAI liquid 6 (Reference Example 6) was applied by spraying and dried to form a semiconductive PAI surface layer. The application and drying conditions at this time were the same as in Example 1. The total thickness of the obtained three-layer film was 84 μm, so that the thickness of the semiconductive PAI surface layer was 32 μm.
μm. Both sides were trimmed to obtain a product having a width of 380 mm. The curvature, ρs, withstand voltage and interlayer adhesion of this film were measured and are summarized in Table 1. This example is illustrated in the cross-sectional view of FIG.

(Example 3) First, using the above-mentioned PA acid solution 2 (Reference example 2), it was subjected to rotational molding under the same conditions as in Example 1 and heated to obtain a corresponding endless PA acid tubular film. The remaining solvent was removed and imidation was performed to obtain an endless tubular PI resin film as a back substrate layer. However, the PA
The supply amount of the acid solution 2 was 220 g. The obtained film has a thickness of 68 μm, an inner diameter of 199.9 mm, and a width of 500 m.
m

Next, the surface of the endless tubular PI resin film was surface-treated with plasma in the same manner as in Example 1, and this was similarly fitted and fixed in a rotating metal cylindrical jig, and was sprayed vertically by a vertically moving spray gun. Semiconductive PA acid solution 7 (Reference Example 7) was applied and dried by heating. However, the coating here was performed with 10 nozzle cycles, and the heating and drying was performed by gradually increasing the temperature to 150.
30 ℃ for 30 minutes when temperature reaches 240 ℃
Was reached and heated for 60 minutes. The obtained two-layer film was separated and trimmed on both sides to obtain a product having a width of 380 mm. When the total thickness was measured, it was 97 μm.
Therefore, the thickness of the semiconductive PAI surface layer 2 is 29 μm. The curvature, ρs, withstand voltage and interlayer adhesion of this film were measured and are summarized in Table 1.

(Comparative Example 1) (Single-layer tubular film consisting only of PI resin) Under the same conditions as in Example 1, PA acid solution 1 was subjected to rotary molding and heating to evaporate and remove the organic solvent and imidize the same. Endless tubular PI resin film was obtained. However, the amount of the PA acid solution 1 used here was 256 g. The thickness of the obtained film is 7
The diameter was 8 μm, the inner diameter was 199.9 mm, and the width was 500 mm.
Similarly, both sides were trimmed to a width of 380 mm. Similarly, the degree of curvature was measured and summarized in Table 1.

(Comparative Example 2) (Two-layered tubular film consisting of PI resin only) First, under the same conditions as in Example 1, the PA acid solution 1 was rotationally molded and heated to evaporate and remove the organic solvent and imidize the organic acid solution. An endless tubular PI resin film as a base layer was obtained. Then, the surface thereof was subjected to the surface polishing performed in Example 2 and further to the plasma treatment performed in Example 1, and used for forming the next surface layer. Incidentally, the thickness of the film was 50 μm.

The film subjected to the surface treatment was used in Example 1.
In the same manner as described above, the PA acid solution 3
(Reference Example 3) was applied by spraying and dried by heating. However, the application amount here was 10 cycles (up and down of the nozzle). However, for the heat drying, preliminary drying is performed on the cylindrical jig at 150 ° C. for 30 minutes, and then separated from the cylindrical jig, inserted into a separately provided cylindrical metal mold, and put into a hot air dryer. It takes 30 minutes to reach 200 ° C and the temperature is raised for 30 minutes at that temperature, and then gradually raised to 300 ° C for 40 minutes at that temperature, and further gradually raised to 390 ° C when it reaches 390 ° C. Each was heated at the temperature for 40 minutes. It was allowed to cool to room temperature, extracted from the mold, and trimmed on both sides to obtain a comparative sample (the obtained films have different Tg, but are composed of the same PI resin). Its total thickness is 81 μm,
The inside diameter is 199.9 mm and the width is 380 mm, so that the surface layer is 29 μm. The curvature, ρs, withstand voltage and interlayer adhesion of this film were measured and are summarized in Table 1.

[0074]

The present invention is configured as described above, and has the following effects.

The curving tendency of a conventionally known single-layer or double-layer film using a non-thermoplastic aromatic polyimide resin as a matrix resin has been improved at once.

Further, the weak interlayer adhesion in the case of the two-layer film has been greatly improved.

Further, the weakness of the dielectric breakdown resistance in the case of the two-layer film is greatly improved.

[Detailed description of drawings]

FIG. 1 is a cross-sectional view illustrating a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 back layer (PI base layer / electrical insulation) 2 front layer (PAI / semi-conductive) 3 intermediate adhesive layer (semi-conductive PI layer)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B05D 7/24 303 B05D 7/24 303B B29C 41/04 B29C 41/04 B32B 27/34 B32B 27/34 / / G03G 15/14 G03G 15/14 B29K 77:00 B29K 77:00 F term (reference) 2H200 FA02 FA09 JC04 JC15 JC16 JC17 MA04 MA14 MA20 MB02 MB05 MC20 4D075 AA01 AE03 AE16 BB24 BB33 DA03 DA04 DB31 DC16 EB17 EB17 EB17 EC01 EC54 4F100 AA37G AA37H AK49A AK49G AK50B BA02 BA25 CA21G CB01 DA11 EH462 EH811 EJ421 EJ422 GB41 JA05A JA05B JB13A JB13G JB16B JG01A JG01B JG04 JG04B JK06 JL04 YY02A01

Claims (10)

[Claims] 1. A tubular multilayer film comprising a thermoplastic aromatic polyamide-imide resin layer laminated on a non-thermoplastic aromatic polyimide resin substrate layer, wherein said non-thermoplastic aromatic polyimide resin substrate layer or said thermoplastic aromatic polyimide resin A tubular aromatic polyimide resin-based multilayer film, wherein one or both of the aromatic polyamideimide resin layers have different semiconductivity. 2. The non-thermoplastic aromatic polyimide resin base layer comprises a polyimide resin having a glass transition point of 300 ° C. or higher, and the thermoplastic aromatic polyamideimide resin layer has a glass transition point of 200 to 310 ° C. The tubular aromatic polyimide resin-based multilayer film according to claim 1, further comprising: 3. The conductive carbon black according to claim 1, wherein one or both of the non-thermoplastic aromatic polyimide resin substrate layer and the thermoplastic aromatic polyamideimide resin layer has semiconductivity. Tubular aromatic polyimide resin-based multilayer film described in 4. The tube according to claim 1, wherein said non-thermoplastic aromatic polyimide resin substrate layer is laminated as a back layer, and said thermoplastic aromatic polyamideimide resin layer is laminated as a front layer. Aromatic polyimide resin-based multilayer film. 5. The method according to claim 1, wherein a layer thickness of the non-thermoplastic aromatic polyimide resin base layer is larger than a layer thickness of the thermoplastic aromatic polyamideimide resin layer. The tubular aromatic polyimide resin-based multilayer film according to the above. 6. An intermediate adhesive layer made of a non-thermoplastic aromatic polyimide resin containing or not containing conductive carbon black is interposed between the non-thermoplastic aromatic polyimide resin base layer and the thermoplastic aromatic polyimide resin. The tubular aromatic polyimide resin-based multilayer film according to claim 3, which is formed. 7. A method for producing an endless tubular aromatic polyimide resin-based multilayer film, wherein the steps (A) to (C) are sequentially performed. (A) An organic solvent solution of a non-thermoplastic aromatic polyimide resin precursor having a glass transition point of 300 ° C. or higher is rotationally molded and heated in a rotating drum to first form an endless tubular precursor film. Is once removed from the inside of the rotary drum, and is heated by a hot air heating means provided separately to complete the removal of the residual solvent and complete the imidization, thereby forming an endless tubular non-thermoplastic polyimide resin back layer (substrate layer). A) forming an endless tubular non-thermoplastic aromatic polyimide resin back layer obtained in the step A,
A second step of applying an organic solvent solution of a non-thermoplastic aromatic-aromatic polyimide resin precursor containing 5 to 30% by weight of conductive carbon black and heating to form the precursor layer as an intermediate adhesive layer, C) A thermoplastic aromatic having a glass transition point of 200 to 310 ° C., which is dissolved in an organic solvent containing 5 to 30% by weight of conductive carbon black, over the entire surface of the intermediate adhesive layer provided in the step B. A third step of applying a polyamide-imide resin solution and heating to remove the solvent and imidize the precursor layer to form a semiconductive thermoplastic aromatic polyamide-imide resin surface layer. 8. The method for producing an endless tubular aromatic polyimide resin-based multilayer film according to claim 7, wherein the application in the second and third steps is a spray coating method. 9. The method according to claim 1, wherein the thickness of the intermediate adhesive layer in the second step is 0.5 to 5.0 μm, and the thickness of the thermoplastic aromatic polyamideimide resin back layer in the third step is non-thermal in the first step. 1 / of the plastic aromatic polyimide resin back layer
The method for producing an endless tubular aromatic polyimide resin-based multilayer film according to claim 7 or 8, wherein the film is formed at a ratio of 3 to 3/4. 10. The endless tubular aromatic polyimide resin system according to claim 7, wherein the surface resistivity of the thermoplastic aromatic polyamideimide resin surface layer is 10 ⁵ to 10 ¹⁵ Ω / □. A method for manufacturing a multilayer film.