JP2614323B2 - Manufacturing method of annular film - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a seamless annular film applicable not only to a general conveyor belt but also to a conveyor film, a transfer film and a fixing film of an image forming apparatus. It is.

[Prior Art] A general transport belt or a transport film of an image forming apparatus, a transfer film or a fixing film usually has no seams, and its upper outer peripheral surface is smooth, or in some cases, is determined on the outer peripheral surface. An annular film having an uneven shape is required. When manufacturing a seamless annular film having such an outer peripheral surface shape, usually, a method of forming a film on the inner peripheral surface of a cylindrical mold by performing a necessary shape treatment, that is, a cylindrical mold Forming a film on the inner surface of
A method of transferring the shape applied to the inner surface of the cylindrical mold to the outer peripheral surface of the film has been adopted.

Conventionally, a centrifugal molding method is known as a method for forming a film using the inner surface of a cylindrical mold.

That is, a required amount of the organic polymer or its precursor solution is injected into the inner surface of the cylindrical mold rotating at high speed, and is developed on the inner surface of the cylindrical mold using centrifugal force and dried and solidified. This is a method of obtaining an annular film by peeling from a mold. As another method, the cylindrical mold is immersed in a solution of an organic polymer or a precursor thereof, and is gradually pulled up to apply the solution using the surface tension of the cylindrical mold and the organic polymer or a precursor solution thereof. A dip coating method is known.

[Problems to be solved by the invention]

The centrifugal molding method and the dip coating method can relatively easily form a coating film having a uniform film thickness, but the centrifugal molding method has the following problems.

(1) It is necessary to lower the viscosity of a solution used for development by centrifugal force, and therefore a large amount of solvent is required, which is disadvantageous in terms of formulation.

(2) It is difficult to produce a small-diameter annular film because of utilizing centrifugal force.

(3) The apparatus is expensive because high-speed rotation is required.

The dip coating method has the following problems.

(1) A large amount of solution to be used is required.

(2) It is necessary to sufficiently control the concentration of the solution.

(3) Since the immersion part is applied, a coating film is also formed on a part that does not need to be applied, so that the loss of the solution is increased and it is economically disadvantageous.

(4) In the case of a solution using a solvent having a low volatilization rate, it takes a long time to dry and solidify, and during that time, dripping occurs and the coating film becomes uneven. It should be noted that this problem can be solved by mounting the device on a rotating device, but the number of steps of mounting the device on the rotating device increases, and the work efficiency is reduced.

[Object of the invention]

The present invention has been made to solve the above-mentioned drawbacks of the conventional example.

[Summary of the Invention]

The present invention relates to a method for producing a cyclic film by applying a solution of an organic polymer or a precursor thereof onto the inner surface of a rotating cylindrical mold, drying and solidifying or completing the reaction, and peeling off the cylindrical mold. And spraying the solution continuously from a discharge port movable from one end to the other end on the inner surface of the cylindrical mold in a streak shape without substantially atomizing (hereinafter, abbreviated as beam coating). And a method for producing an annular film.

[Specific description of the invention]

According to the present invention, a method for producing a cyclic film after applying a solution of an organic polymer or a precursor thereof to the inner surface of a rotating cylindrical mold and drying and solidifying or after completion of the reaction,
Beam coating of the solution from one end on the inner surface of the cylindrical mold to the other end is possible by using a relatively inexpensive apparatus and using a minimum amount of solvent or solution from a large diameter to a small diameter. In particular, it has become possible to produce a cyclic film having a uniform thickness from an organic polymer or a precursor thereof, in which a solvent having a low volatilization rate must be used.

In the present invention, a solution of an organic polymer or a precursor thereof soluble in a solvent is used.

The organic polymer is not particularly limited but polystyrene, polymethyl methacrylate, polycarbonate,
Amorphous thermoplastic resins that are relatively soluble in solvents, such as polyphenylene ether, polysulfone, polyarylate, polyetherimide, and polyethersulfone, are preferred.

The precursor is not particularly limited, but is a polyimide precursor polyamic acid or polyamide imide resin, polybenzimidazole resin, further epoxy resin,
Thermosetting resins such as unsaturated polyester, diallyl phthalate and silicone resin are preferred.

The solvent used is not particularly limited as long as the organic polymer or its precursor is soluble.

 Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing an outline of an apparatus for performing beam coating used in manufacturing an annular film of the present invention. Here, reference numeral 1 denotes a cylindrical mold for forming an annular film, which is set in a cylindrical mold holder 6;
It is rotated about a rotation axis l by a drive source (not shown).

Reference numeral 3 denotes a discharge port for applying a solution of an organic polymer or a precursor thereof, and the discharge port is substantially more movable than the solution moving in the axial direction of the cylindrical mold via the solution supply pipe 4 and the gun 2. It is discharged in a streak form without being atomized and is applied on the inner surface of the cylindrical mold 1 to form a coating film 5.

Here, as a method of supplying the solution, for example, a method of pressurizing the liquid surface of the solution stored in the closed tank with air or the like and sending the solution to the solution supply pipe 4 or a method of sending the solution by a gear pump is used.

In the present invention, the rotational speed of the cylindrical mold is 100 P
Although a rotation speed of RM or more is effective, a rotation speed of 100 RPM or more and 1000 RPM or less is preferably used.

The material of the cylindrical mold is not particularly limited, such as glass, aluminum, iron, brass, stainless steel, and a resin that is not immersed in the solvent used. Furthermore, a fluorine-based or silicon-based release agent can be applied to the inner surface in consideration of the later peeling.

Next, the inner diameter of the cylindrical mold is appropriately selected within a range that does not hinder the movement of the gun 2, and preferably one having a diameter of 20 mm or more can be used. The length is not particularly limited and can be used.

The viscosity of the organic polymer or its precursor solution used in the present invention is preferably 0.01 to 500 poise (at room temperature), and preferably 10 poise or less in consideration of the smoothness of the coating film surface.

Next, the distance between the discharge port and the inner surface of the cylindrical mold is 2 to
It is preferably in the range of 100 mm, especially 5 to 50 mm.
The shape of the discharge port is usually one hole as shown in FIG. 3a, but a three-hole type shown in FIG. 3b may be used in order to increase the film forming speed.

It is effective to heat the entire cylindrical mold with the heater 9 in order to increase the drying speed of the formed coating film 5.

It is desirable that the temperature setting of the heater be appropriately selected depending on the evaporation rate of the solvent. Further, in order to increase the drying speed of the solvent, it is also effective to send air or the like from the opening of the cylindrical mold to lower the vapor concentration inside the cylindrical mold.

The thickness of the annular film produced as described above is determined by the rotational speed of the cylindrical mold, the moving speed of the discharge port, the discharge port speed of the solution, the concentration of the solution, and the like.

 Hereinafter, the present invention will be further described with reference to examples.

Example 1 Polyamic acid, which is a precursor of a polyimide resin, was N,
The solution was adjusted to a solid content of 10% with N'-dimethylacetamide. At this time, the viscosity of the solution was 2 at 30 ° C.
Poise. Stainless steel inner diameter for cylindrical type
After using a 50 mm, 55 mm outside diameter and 300 mm length set in a cylindrical mold holder, it was rotated at a rotation speed of 400 RPM and maintained at a temperature of 100 ° C. by a heater. Next, using a one-hole type discharge port with a diameter of 100 μm, adjust the air pressure so that the discharge port is 2 kg / cm ^2, and adjust the air pressure from the longitudinal direction 10 mm of the inner surface of the cylindrical mold
The solution was discharged to a width of 290 mm to form a coating film. The application conditions at this time were as follows: the moving speed of the discharge port was 200 mm / min, the distance between the discharge port and the inner surface of the cylindrical mold was 5 mm, and after coating, the rotation speed of 400 PRM was maintained at a temperature of 100 ° C., and the coating was dried for 30 minutes. After that, the cylindrical mold was removed from the cylindrical mold holder, and calcined in a high-temperature furnace set at 350 ° C. for 15 minutes to perform imidization. Next, the cylindrical mold taken out of the high-temperature furnace was immersed in water, cooled to room temperature, and then an annular polyimide film was peeled from the cylindrical mold. The thickness of the obtained annular polyimide film is determined in the longitudinal direction of the formed annular film.
The average thickness in the range of 5 mm to 275 mm was 25 μm, and the unevenness of the entire thickness was ± 2 μm or less.

Comparative Example-1 Using a polyamic acid solution prepared in the same manner as in Example 1, and a cylindrical mold of the same shape and the same material as in Example 1, the cylindrical mold was immersed in the polyamic acid solution, and the inner surface of the cylindrical mold was A coating of a polyamic acid solution was formed. Next, the film was dried in a dryer set at 100 ° C. for 30 minutes in a state where the cylindrical mold on which the coating film was formed was erected, and then imidized and stripped in the same manner as in Example 1 to obtain a cyclic polyimide film. Was.
The thickness of this annular film is 5 mm in the longitudinal direction of the film.
From 295mm to 25mm on average, but the overall thickness unevenness is ± 1
The thickness became 0 μm, and the thickness increased as it went from the top to the bottom of the cylindrical mold during drying.
Also, the polyimide film was formed on the outer surface of the cylindrical mold, which is an unnecessary part.

Comparative Example-2 Using a polyamic acid solution prepared in the same manner as in Example 1 and a cylindrical mold having the same shape and the same material as in Example 1, set in an apparatus capable of high-speed rotation, and set 5.9 g of the solution into a cylindrical mold. Inject 30
After heating and drying at 100 ° C. while maintaining the rotation speed of 00 RPM, a cyclic polyimide film was obtained in the same manner as in Example 1. As a result, a film having an average thickness of 25 μm was obtained. It has become a good film.

[Other embodiments]

Example 2 Each of the three-hole type discharge ports having a diameter of 100 μm was used, and the moving speed of the discharge ports was 600 mm / min, and the air pressure was 6 kg / min.
As a result of producing a cyclic polyimide film in the same manner as in Example 1 except that the thickness was set to cm ² , a cyclic polyimide film having an average thickness of 25 μm and a total thickness unevenness of ± 2 μm was obtained.

Example 3 Polyetherimide was used as an organic polymer, and methylene chloride was used as a solvent, and a solution was adjusted so as to have a solid content of 10%. As a cylindrical mold, glass inner diameter 100 mm, outer diameter 1
Using a 10 mm long and 300 mm long one, it was set in a cylindrical mold holder and then rotated at a rotation speed of 400 RPM and maintained without any particular heating. Then, using a 1-hole type discharge port having a diameter of 100 μm, the solution was set to a discharge port of 3 kg / cm ² by a gear pump, and the solution was discharged to a width of 10 to 290 mm from the longitudinal direction of the inner surface of the cylindrical mold to form a coating film. The application conditions at this time were that the moving speed of the discharge port was 200 mm / min, and the distance between the discharge port and the inner surface of the cylindrical mold was 10 mm. After the coating was dried at a rotation speed of 400 RPM for 10 minutes, the cylindrical mold was removed from the cylindrical mold holder, immersed in water, and the cyclic polyetherimide film formed from the inner surface of the cylindrical mold was peeled off. The thickness of the obtained cyclic polyetherimide film was 30 μm on average within the range of 5 mm to 275 mm in the longitudinal direction of the formed film, and the unevenness of the entire thickness was ± 3 μm or less.

〔The invention's effect〕

As described above, according to the method for producing an annular film of the present invention, the organic polymer or its precursor is applied to the inner surface of the cylindrical mold by the beam coating method, so that the organic polymer or its precursor can be rotated at a relatively low speed as compared with the conventional centrifugal molding method. Therefore, an inexpensive device can be used, and a small-diameter annular film can be formed. Furthermore, it is possible to easily form a uniform thickness cyclic film from an organic polymer or a precursor thereof, which requires the use of a solvent having a minimum necessary amount of solution and a slow volatilization rate compared to the dip coating method. became.

[Brief description of the drawings]

FIG. 1 shows a sectional view of a coating apparatus used in the present invention,
FIG. 2 shows an enlarged view of the coating portion in FIG. 1, and FIGS. 3a and 3b show specific examples of the discharge ports. 1 is a cylindrical type, 2 is a gun, 3 is a discharge port, 4 is a solution supply tube, 5 is a coated organic polymer or its solution, 6 is a cylindrical type holder, 7 is a cylindrical type fixing tool, 8 is Heater holder, 9 is a heater.

Claims (1)

(57) [Claims] 1. A method for producing an annular film by applying a solution of an organic polymer or a precursor thereof to the inner surface of a rotating cylindrical mold, and peeling off the cylindrical mold after drying and solidification or completion of the reaction. In the annular film, the solution is continuously sprayed in a streak form without substantially atomizing from a discharge port movable from one end to the other end on the inner surface of the cylindrical mold, and the coating is performed. Production method.