JP4305708B2 - Manufacturing method of high-precision tubular body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a high-precision tubular body in which a polyamic acid solution is applied to the inner surface of a cylindrical mold with a dispenser, and then subjected to rotary centrifugation, solvent removal, and imide conversion.
[0002]
[Prior art]
Conventionally, polyimide resin materials have been put to practical use in a wide range of fields from aerospace to electrical and electronic materials because of their high mechanical strength and heat resistance. Among these, polyimide resin tubular bodies are functional belts such as fixing belts, transfer belts, intermediate transfer belts, transport belts, and photoreceptor belts of electrophotographic image forming apparatuses such as copying machines, laser beam printers, and facsimile machines, and their bases. Used as a material. These belts combine multiple functions as belts, such as conveying the transfer body while pressing and heating an unfixed toner image, or transferring the image developed by the developing unit to the transfer body while holding it as a toner image. It plays a function in the form of For this reason, there is an increasing demand not only for functions such as thermal conductivity, conductivity, and semiconductivity but also for dimensional accuracy such as surface accuracy and film thickness accuracy that affect such functions.
[0003]
As a manufacturing method of such a belt, there is a method in which a polyimide film is formed into a cylindrical shape and is formed into a joining belt by heating and melting, etc. However, since the unevenness of the joining portion affects the image, it is necessary to provide a detection mechanism. There is also a problem that it occurs or the strength of the joint is weak. For this reason, several methods for producing seamless tubular bodies that do not rely on joining have been proposed.
[0004]
As an example, a cylindrical mold (inner mold) is dip-coated in a polyamic acid solution, and then an outer mold having a predetermined inner diameter is dropped onto the cylindrical mold and applied, followed by heat curing. A method for manufacturing a tubular body is known (Japanese Patent Laid-Open No. 7-186162). However, in the case of this dip coating method, it is necessary to thoroughly control the concentration of the immersing solution, and in the case of a tubular body, since the coating is applied even to the portion that does not need to be coated, the loss of the solution increases, which is economically disadvantageous. There were problems such as becoming.
[0005]
On the other hand, when applying liquid heat-resistant resin to the inner surface of the cylindrical mold, the coating layer is formed by moving the dispenser supply section (discharge port) in the mold axial direction while rotating the cylindrical mold. Then, a method for producing a tubular body by curing is known (Japanese Patent Laid-Open Nos. 3-34817 and 9-85756).
[0006]
[Problems to be solved by the invention]
However, as disclosed in Japanese Patent Application Laid-Open No. 3-34817, the length of the solution supply pipe for discharging the polyamic acid solution is reduced in the method in which the application is performed in a streak form from the discharge port movable on the inner surface of the cylindrical mold. It must be at least the width of the tubular body, and the pipe will bend and vibrate due to high-speed movement of the supply pipe during application, resulting in variations in the distance between the discharge port and the mold inner surface. Uneven coating and deterioration of dimensional accuracy due to this are likely to occur. In addition, since the distance between the discharge port and the inner surface of the mold is relatively large, the influence of disturbance of the solution to be applied is likely to occur.
[0007]
On the other hand, in Japanese Patent Application Laid-Open No. 9-85756, the dispenser is in contact with the mold, although the problem caused by the bending is solved because the dispenser supply portion is brought into contact with the inner surface of the mold during application. For this reason, the coated surface of the mold is scratched, or wear debris enters the polyamic acid solution due to wear of the discharge part, which may cause contamination by foreign matter and deterioration of surface accuracy.
[0008]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems, and to obtain a high-precision tubular body that can easily obtain a high-precision tubular body having uniform thickness accuracy and surface accuracy without waviness and streaks. It is in providing the manufacturing method of.
[0009]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present inventors have conducted intensive research on a cylindrical drive system when applying the polyamic acid solution and the arrangement of the discharge port of the dispenser. The discharge port of the dispenser is relatively fixed. The present invention has been completed by finding that uniform application can be performed from the discharge port arranged at a predetermined interval from the inner surface of the mold by a method of driving the cylindrical mold in a spiral shape by arranging in a state.
[0010]
That is, in the method for producing a high-precision tubular body of the present invention, after applying a polyamic acid solution to the inner surface of a cylindrical mold with a dispenser, at least rotational centrifugation, solvent removal, and imide conversion are sequentially or partially performed at the same time. In the method of manufacturing, the discharge port of the dispenser is moved in the direction of the rotation axis while rotating the cylindrical mold in the circumferential direction in a state where the discharge port of the dispenser is disposed in a relatively fixed state at a distance from the inner surface of the cylindrical mold. By doing so, the polyamic acid solution is applied in a spiral shape.
[0011]
In the above, it is preferable that the distance between the discharge port and the inner surface of the cylindrical mold is 0.01 to 5.0 mm.
[0012]
Moreover, it is preferable that the viscosity by the B-type viscometer of the said polyamic acid solution to apply | coat is 10-10000 poise (23 degreeC).
[0013]
Furthermore, it is preferable that the opening shape of the discharge port is rectangular and the length in the rotation axis direction is 5 to 100 mm.
[0014]
Moreover, it is preferable to perform coating by providing two or more discharge ports.
[0015]
[Function and effect]
According to the present invention, since the discharge port of the dispenser is fixed or moved at a low speed, the cylindrical mold is driven, so that there are less restrictions on the components and the like due to the high speed drive on the dispenser side, and the displacement, vibration, etc. of the discharge port It becomes easy to suppress. In particular, when the ejection port is fixed, only one of them is driven, so that the relative driving accuracy is improved as compared with the case where both are driven. Therefore, the positional relationship between the discharge port and the inner surface of the mold can be maintained with high accuracy, and uniform coating can be performed. In other words, in order to avoid problems caused by contact of the discharge port, the method of fixing the discharge port at a distance from the inner surface of the cylindrical mold can maintain the positional relationship between the discharge port and the inner surface of the mold with high accuracy. Importantly, in the present invention, this problem can be solved by the above driving method. As a result, as shown by the results of the examples, it is possible to easily obtain a high-precision tubular body having uniform thickness accuracy and surface accuracy free from waviness and streaks.
[0016]
In addition, when the distance between the discharge port and the inner surface of the cylindrical mold is 0.01 to 5.0 mm, the conventional driving method cannot perform uniform application due to vibration of the dispenser supply unit, etc. In the present invention, since the positional relationship between the discharge port and the inner surface of the mold is maintained with high accuracy, more uniform application can be performed without being substantially affected by the disturbance of the solution during application.
[0017]
When the viscosity of the applied polyamic acid solution measured by a B-type viscometer is 10 to 10,000 poise (23 ° C.), the solution viscosity is particularly preferable for the coating method as described above.
[0018]
When the opening shape of the discharge port is rectangular and the length in the rotation axis direction is 5 to 100 mm, since the opening shape of the discharge port is rectangular, the coating amount tends to be uniform in the rotation axis direction. Since the length in the direction of the rotation axis is 5 to 100 mm, the application width is appropriate for application in a spiral shape.
[0019]
When coating is performed with two or more discharge ports, the time required for coating can be shortened by performing a plurality of coatings simultaneously.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram for explaining a method for producing a tubular body of the present invention, and FIG. 2 is a schematic diagram for explaining an application part.
[0021]
As shown in FIG. 1, the manufacturing method of the high-precision tubular body of the present invention is such that when the polyamic acid solution 1 is applied to the inner surface of a cylindrical mold 2 by a dispenser, the dispenser outlet 3 a is connected to the inner surface of the cylindrical mold 2. The polyamic acid solution 1 is spirally moved by rotating the cylindrical mold 2 in the direction of the rotation axis (arrow A2) while rotating the cylindrical mold 2 in the circumferential direction (arrow A1) in a state of being relatively fixed at a distance from It is characterized in that it is applied in the form.
[0022]
The polyamic acid solution only needs to dissolve the polyamic acid in the solvent, and may contain a partially imidized one, a copolymer component, other components, a filler, and the like.
[0023]
A known polyamic acid solution can be used, and a polyamic acid solution obtained by polymerizing an acid dianhydride and a diamine in a solvent can be suitably used. In particular, when the aromatic polyimide resin is used, it is possible to obtain a tubular body having favorable mechanical strength and heat resistance.
[0024]
Examples of suitable acid dianhydrides include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic acid dianhydride. Anhydride, 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride Products, 1,4,5,8-naphthalenetetracarboxylic dianhydride and the like.
[0025]
On the other hand, examples of the diamine include 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 3,3′-dichlorobenzidine, 4,4′-diaminodiphenyl sulfide, 3 , 3′-diaminodiphenylsulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3′-dimethyl4,4′-biphenyldiamine, benzidine, 3,3′-dimethylbenzidine, 3 , 3′-dimethoxybenzidine, 4,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenylpropane, and the like.
[0026]
A suitable solvent can be used for the polymerization reaction of these acid anhydrides and diamines, but polar solvents are preferably used from the viewpoint of solubility and the like. Specifically, N, N-dimethylformamide, N , N-dimethylacetamide, N, N-diethylformamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, hexamethylphosphortriamide, N-methyl-2-pyrrolidone, pyridine, dimethyl sulfoxide, Examples include tetramethylene sulfone and dimethyltetramethylene sulfone. These may be used alone or in combination. Furthermore, phenols such as cresol, phenol and xylenol, benzonitrile, dioxane, butyrolactone, xylene, cyclohexane, hexane, benzene, toluene and the like can be mixed alone or in combination with the organic polar solvent. Since the polyamic acid is hydrolyzed by the presence of water to lower the molecular weight, the polyamic acid is preferably synthesized and stored in an anhydrous environment.
[0027]
A polyamic acid solution is obtained by reacting the acid anhydride (a) and the diamine (b) in an organic polar solvent. The monomer concentration (concentration of (a) + (b) in the solvent) at that time is set according to various conditions, but is preferably 5 to 30% by weight. The reaction temperature is preferably set to 80 ° C. or less, particularly preferably 5 to 50 ° C., and the reaction time is preferably 0.5 to 10 hours.
[0028]
In the present invention, inorganic particles, inorganic oxides, metal oxides, surfactants are suitably used to give the tubular body desired functions such as thermal conductivity, conductivity, antistatic properties, semiconductivity, and abrasion resistance. It is possible to mix the same filler. The mixing amount of the filler is set according to various conditions, but is 1 to 60% by weight, preferably 5 to 50% by weight. If the amount is less than the above-mentioned filling amount, it is difficult to exhibit the intended characteristics, while if it is more than the above-mentioned amount, mechanical strength tends to be insufficient as a tubular body due to brittleness.
[0029]
Polyamic acid can be obtained as described above, and the solution viscosity increases as the reaction proceeds. Thereby, the viscosity in a B-type viscometer can be adjusted, and the adjustment by the monomer concentration is also possible.
[0030]
The viscosity of the polyamic acid solution to be applied is about 10 to 10000 poise, preferably about 50 to 5000 poise (B-type viscometer, 23 ° C.). If the viscosity is less than 10 poise, so-called sagging or repellency of the coating layer is likely to occur, and the uniformity of the coating thickness tends to be difficult to obtain. Further, such a low-viscosity solution must be dried and solidified while continuously rotating at a high speed after coating, which tends to be disadvantageous in terms of economy and cost. On the other hand, when it exceeds 10,000 poise, it is necessary to apply a high pressure at the time of discharge, and there is a success that it becomes difficult to form at the time of leveling described later.
[0031]
The polyamic acid solution is applied in a spiral manner by driving the cylindrical die 2 in a spiral shape by moving the cylindrical die 2 in the circumferential direction (arrow A1) and moving it in the direction of the rotation axis (arrow A2). Is done.
[0032]
The cylindrical mold 2 may be driven by a driving method in which the rotation in the direction of the arrow A1 and the movement in the direction of the arrow A2 are synchronized. For example, while supporting the cylindrical mold 2 with a cantilevered rotation axis, A method of moving the cylindrical mold 2 together with the support / rotation mechanism at a constant speed while rotating at a constant speed can be adopted. In addition, the shaft that cantilever-supports the cylindrical mold 2 is externally threaded, and the cylindrical mold 2 is supported by a roller from the outer peripheral portion while the shaft is screwed and supported by a support base having a female screw portion. It is also possible to adopt a method of applying a rotational force in the direction or the spiral direction. Regardless of which drive method is used, the discharge port 3a of the dispenser is fixed, so that the relative drive accuracy is improved as compared with the case where both are driven. Can be maintained with high accuracy.
[0033]
As the dispenser and its supply unit, conventionally known ones can be used. However, since there is no need to drive the supply unit, there are few restrictions on its constituent members, and it is possible to adopt materials and structures that are less likely to cause displacement and vibration. The supply amount of the polyamic acid solution from the discharge port 3a is preferably such that the thickness of the coating film is 50 to 1000 μm. The thickness of the coating film can also be controlled by the driving speed of the cylindrical mold 2.
[0034]
It is preferable to apply the spirally applied coating layer so as to have a certain wrapping portion in an adjacent portion because the coating surface tends to be uniform. At this time, the wrap amount is preferably ± 5 mm, more preferably about ± 3 mm. The amount of wrap here refers to the overlap 7 between the coating surface 4 already applied to the cylindrical mold 2 and the polyamic acid solution 1 applied from the discharge port 3a as shown in FIG. In the specification, when the amount of wrap is 0, the dispenser discharge port 3a and the end of the coating film surface 4 coincide with each other, and in the case of a positive value, the degree when there is overlap is indicated by the length, In the case of minus, it indicates the degree when there is no overlap in length. Since the optimum amount of wrapping varies depending on the viscosity of the solution, the rotational speed of the cylindrical mold, the coating width, etc., it must be confirmed experimentally as appropriate. If the amount of wrapping is too small, a thin part of the film thickness is generated and unevenness of the coating film surface is generated. If the amount of wrapping is too large, leveling performed later takes time and tends to cause film thickness unevenness.
[0035]
The opening shape of the discharge port 3a of the dispenser is appropriately determined according to various conditions, but is preferably a rectangle having a long side in the rotation axis direction. The short side and the long side in the opening shape have a short side of 0.5 to 5 mm and a long side of 5 to 100 mm, preferably 10 to 50 mm, and are appropriately determined according to various conditions.
[0036]
In the present invention, it has been experimentally confirmed that the distance (gap amount) between the discharge port 3a and the inner surface of the cylindrical mold 2 greatly affects the uniformity of the coating film surface. The gap amount here indicates a distance 6 between the cylindrical mold 2 and the dispenser discharge port 3a as shown in FIG. A suitable gap amount is 0.01 to 5.0 mm, preferably 0.1 to 3.0 mm. Although there is a balance with the wrap amount, if the gap amount is too small, the coating surface and the discharge port come into contact with each other, streaks remain on the coating surface, and if the gap amount is too large, the solution is disturbed during coating, resulting in thickness There is a tendency to deteriorate the dimensional accuracy such as accuracy.
[0037]
When there are a plurality of dispenser discharge ports 3a, it is possible to quickly apply the entire inner surface of the cylindrical mold, which is preferable because the production can be speeded up. In the case of laminating layers of different materials, conventionally, after applying a low-viscosity polyamic acid solution, smoothing at high speed rotation, drying and solidifying, and then applying the low-viscosity polyamic acid solution again. However, according to the method of the present invention, after applying the polyamic acid solution, it is possible to apply the polyamic acid solution while rotating at a low speed and performing leveling. Can be obtained.
[0038]
In the present invention, after the polyamic acid solution is applied as described above, a tubular body is produced by performing at least rotational centrifugation, solvent removal, and imide conversion sequentially or partially at the same time as in the conventional method. By this rotation centrifugation (leveling), the film thickness of the convex part 5 (or the gap part of an application belt | band | zone) by the wrapping of an application layer can be equalize | homogenized.
[0039]
Accordingly, preferable conditions for the rotary centrifugation vary depending on the viscosity of the solution and the gap amount, but are preferably performed at 100 to 10000 rpm for about 0.1 to 60 minutes, more preferably at 500 to 5000 rpm for about 1 to 30 minutes. Note that the rotary centrifugation can be performed simultaneously with the solvent removal or the like.
[0040]
Solvent removal can be performed by a conventionally known method such as heating or extraction, and is preferably performed while rotating the cylindrical mold at a low speed. Moreover, removal of dehydration ring closure or the like may be performed simultaneously with solvent removal, or imide conversion may be performed by gradually raising the temperature while removing the solvent.
[0041]
The imide conversion can be performed by a conventionally known method such as heating. Generally, the imide conversion starts from around 100 ° C., and the imide conversion reaction is completed by heating at 250 to 450 ° C.
[0042]
In this invention, you may perform the defoaming process for removing the bubble in an application layer, the mold release process of the inner surface of a cylindrical type | mold before application | coating, etc. further. Further, after demolding, a release layer, an elastic body layer and the like may be further laminated on the tubular body.
[0043]
In the present invention, a high-precision tubular body having a uniform thickness accuracy and surface accuracy with a film thickness free from waviness and streaks can be easily obtained by the manufacturing method as described above. In addition, when the film is thickened, it can be accurately formed to a desired thickness without recoating. When such a belt is used as a functional belt such as a fixing belt, a transfer belt, an intermediate transfer belt, a conveyance belt, and a photosensitive belt of an electrophotographic image forming apparatus and a base material thereof, it has excellent dimensional accuracy. Therefore, it is useful as a functional belt that satisfies the required functions such as fixability, transferability, and transportability.
[0044]
【Example】
Examples and the like specifically showing the configuration and effects of the present invention will be described below.
[0045]
[Example]
3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride as an acid component and approximately equimolar amount of p-phenylenediamine as an amine component are dissolved in N-methyl-2-pyrrolidone (NMP) (monomer concentration 20 The mixture was reacted while stirring at room temperature in a nitrogen atmosphere, and then stirred while heating to 70 ° C. to prepare a polyamic acid solution having a viscosity of 2000 poise measured at 23 ° C. using a B-type viscometer. Next, while fixing a rectangular die-type dispenser (opening portion: short side 1.5 mm, long side 15 mm), a cylindrical mold having a length of 500 mm and a diameter of 70 mmφ is moved while rotating, and the polyamic acid solution is moved. Supply from one end of the inner surface of the cylindrical mold to the other end, apply spirally on the inner surface of the cylindrical mold (wrap amount 0.3 mm, gap amount 0.7 mm), and rotate the mold for 10 minutes at 1500 rpm. The unevenness of the wrapping part of the coating film surface was leveled, and a uniform coating film surface was obtained. Next, while rotating the mold at 300 rpm, it was heated stepwise up to 350 ° C. to remove the solvent, dehydrated ring-closing water, and imide conversion. Thereafter, the temperature was returned to room temperature, and it was peeled from the mold to obtain a tubular body having a thickness of about 75 μm. Both the inner peripheral surface and the outer peripheral surface of the tubular body had excellent surface properties, no streaks or patterns were seen, and the thickness variation was ± 1.5 μm.
[0046]
[Comparative example]
The tubular body is the same as in the example except that the cylindrical mold is rotated by the same rotation mechanism as in the example (the axial direction is fixed), and the dispenser is applied while being moved by the same drive mechanism as in the example. Was made. When the surface property of this tubular body was observed, subtle undulations and streaks were observed, and the thickness variation was ± 4.0 μm.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining a method for producing a tubular body according to the present invention. FIG. 2 is a schematic diagram for explaining an application part of the method for producing a tubular body according to the present invention.
DESCRIPTION OF SYMBOLS 1 Polyamic acid solution 2 Cylindrical type | mold 3 Dispenser supply part 3a Discharge port 4 Coating surface 5 Convex part 6 by lapping Gap amount 7 Lapping amount

Claims (5)

In a method for producing a tubular body by applying a polyamic acid solution to the inner surface of a cylindrical mold with a dispenser, and then performing at least rotational centrifugation, solvent removal, and imide conversion sequentially or partly simultaneously,
By moving the cylindrical mold in the direction of the rotation axis while rotating the cylindrical mold in the circumferential direction in a state where the discharge port of the dispenser is disposed relatively fixed at a distance from the inner surface of the cylindrical mold, the polyamide is obtained. A method for producing a high-precision tubular body, which comprises applying an acid solution in a spiral shape. The method for producing a high-precision tubular body according to claim 1, wherein a distance between the discharge port and the inner surface of the cylindrical mold is 0.01 to 5.0 mm. The method for producing a high-precision tubular body according to claim 1 or 2, wherein the polyamic acid solution to be applied has a viscosity measured by a B-type viscometer of 10 to 10,000 poise (23 ° C). The method for producing a high-precision tubular body according to any one of claims 1 to 3, wherein an opening shape of the discharge port is a rectangle, and a length in a rotation axis direction thereof is 5 to 100 mm. The manufacturing method of the high precision tubular body according to any one of claims 1 to 4, wherein the application is performed by providing two or more discharge ports.

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