JP3976392B2 - Polyimide coating mold and manufacturing method thereof, and manufacturing method of polyimide endless belt - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a forming die for forming an endless belt used as an intermediate toner carrier in an electrostatic copying apparatus such as a copying machine, a printer, and a facsimile machine, and a method for manufacturing a polyimide endless belt .
[0002]
[Prior art]
An endless belt used as an intermediate toner carrier in an electrostatic copying apparatus is required to have properties such as heat resistance, flame retardancy, tensile strength, bending strength, and electrical stability, and is therefore formed of a material such as polyimide. ing. Such an endless belt is formed by a centrifugal coating method. Centrifugal coating is a method in which a resin solution is poured onto the inner surface of a cylindrical mold made of rotating aluminum, brass, stainless steel, etc. by means of spray coating, etc., and the coating solution is spread in the axial direction by the centrifugal force to be uniform A cylindrical film is formed, and the cylindrical film is dried and solidified and then taken out.
[0003]
Since polyimide is a resin that can be used as an adhesive because of its good adhesiveness, polyimide endless belts cannot be formed by direct centrifugal coating of polyimide. Therefore, conventionally, for example, a solution of polyamic acid, which is a precursor of polyimide, is centrifugally applied to a cylindrical mold such as stainless steel to form a cylindrical film, and this is heated to imidize to endless polyimide. A belt was molded. The polyamic acid solution is obtained, for example, by solution polymerization of two monomers consisting of pyromellitic anhydride and 4,4′-diaminodiphenyl ether in a polar solvent such as dimethylformamide.
[0004]
Such a cylindrical film made of polyamic acid formed by centrifugal coating is soft when the solvent is insufficiently dried and tears when taken out of the mold, and when the solvent is excessively dried or hardened, it becomes a mold. There was a problem that tearing occurred when taking out from the mold due to the close contact. Therefore, in order to solve such problems, conventionally, a cylindrical film made of centrifugally coated and formed polyamic acid (also called polyamic acid) is appropriately dried and then molded with great care. After removing from the mold and then inserting a cylindrical curing mold for curing into the cylindrical film, the cylindrical film was heated and cured to finally produce a polyimide endless belt.
[0005]
In addition, after the cylindrical film is heat-cured using a cylindrical mold in which the inner surface of the cylindrical mold is coated with a release film in advance, the mold release film is held above its melting point and is allowed to flow out of the cylindrical mold. Thus, it has also been proposed to remove the cylindrical membrane from the cylindrical mold (Japanese Patent Laid-Open No. 48-91159).
[Problems to be solved by the invention]
[0006]
However, in the molding of such conventional endless belts made of polyimide, 1) Even if the drying conditions are kept constant, the cylindrical film cannot be peeled off well under environmental conditions, and therefore the cylindrical film cannot be removed. Or if the cylindrical membrane is forcibly removed, the cylindrical membrane may be torn. 2) If the diameter of the cylindrical mold is changed, the drying conditions will change completely. It is necessary to set the conditions from the beginning. 3) When the cylindrical film peeled off from the mold is cured with a cylindrical curing mold and the heating temperature distribution is present, the cylindrical film does not cure and shrink uniformly. 4) It takes a complicated process until an endless belt is formed from a polyimide material, and 5) It is costly due to 1) to 4). It was.
[0007]
Further, when the conventional technique disclosed in Japanese Patent Laid-Open No. 48-91159 is applied to the molding of a polyimide endless belt, it is good to peel off the cylindrical film made of polyimide from the cylindrical mold, In order to allow the released release film to flow out of the cylindrical shape, it is not suitable for repeated use of the cylindrical shape. 7) Since a release membrane having a melting point higher than the curing temperature of the polyimide endless belt must be selected, 8) When the material of the cylindrical film is polyimide, a release film having a melting point of about 300 ° C. is required, and 9) The cost is high because of the above 6) to 8) There was a problem such as.
[0008]
The present invention aims to solve this problem.
That is, the present invention provides a polyimide coating mold that can be easily removed from a polyimide endless belt without changing its shape, a method for manufacturing the same, and a method for manufacturing a polyimide endless belt at a low cost. For the purpose.
[0009]
[Means for Solving the Problems]
The present inventor is a mold release made of polyimide obtained by imidizing polyamic acid at a temperature equal to or higher than imidization temperature in a polyamic acid coating film coated on the inner surface of a cylindrical polyimide coating mold for molding a polyimide endless belt. When a film was provided, it was found that the polyimide endless belt could be easily released and removed without changing its shape, and the present invention was completed.
[0010]
That is, the invention described in claim 1 is a cylindrical polyimide coating mold for molding a polyimide endless belt, wherein the polyimide coating mold is formed on a polyamic acid coating film coated on the inner surface thereof. It is a polyimide coating mold characterized by having a release film composed of polyimide imidized at a temperature equal to or higher than the imidization temperature.
[0011]
The invention described in claim 2 is the polyimide according to the invention described in claim 1, wherein the release film is imidized with polyamic acid at a temperature of 280 to 300 ° C. or higher set as an imidization temperature of polyamic acid. It is a film | membrane comprised by these.
[0012]
According to the third aspect of the present invention, in the manufacture of a cylindrical coating mold for molding a polyimide endless belt, after applying a polyamic acid solution to the inner surface of the polyimide coating mold, this is imidized with polyamic acid. A method for producing a polyimide coating mold, wherein the release film is formed by heating to a temperature equal to or higher than the temperature to imidize the polyamic acid.
[0013]
The invention described in claim 4 is characterized in that, in the invention described in claim 3, the polyamic acid is imidized at a temperature of 280 to 300 ° C. or higher set as an imidization temperature of the polyamic acid. Is.
[0014]
The invention described in claim 5 is applied in the production of a cylindrical polyimide coating mold for molding a polyimide endless belt, or when a tetracarboxylic acid anhydride and a diamine are coated on the inner surface of the polyimide coating mold. Thereafter, the produced polyamic acid is heated to a temperature equal to or higher than the imidization temperature and imidized to form a release film, and a method for producing a polyimide coating mold.
[0015]
The invention described in claim 6 is characterized in that, in the invention described in claim 5, the tetracarboxylic acid anhydride and the diamine are applied by vacuum deposition.
[0016]
The invention described in claim 7 includes (a) a step of applying a polyamic acid coating solution while rotating the polyimide coating mold described in claim 1 or 2 at a low speed, and (b) the polyimide coating mold. A step of forming a polyamic acid coating film having a uniform film thickness by rotating at high speed; (c) a step of drying the polyamic acid coating film to remove the solvent; and (d) a polyamic acid coating from which the solvent has been removed. A process for producing a polyimide endless belt, comprising sequentially heating a film to an imidization temperature or higher to imidize polyamic acid.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a longitudinal sectional view of a cylindrical polyimide coating mold for molding a polyimide endless belt according to an embodiment of the present invention. As shown in FIG. 1, the release film 2 in the present invention is obtained by applying polyamic acid to the inner surface of a cylindrical polyimide coating mold 1 for molding a polyimide endless belt 3, and then imidizing polyamic acid. Heat to a temperature higher than the temperature to imidize, or form a polyimide endless belt 3 from two monomers composed of tetracarboxylic anhydride such as pyromellitic anhydride and diamine such as 4,4'-diaminodiphenyl ether When applying to the inner surface of the cylindrical polyimide coating mold 1 to be applied, or after coating, it is heated to a temperature equal to or higher than the imidization temperature of polyamic acid to be imidized. The application of the tetracarboxylic acid anhydride such as pyromellitic anhydride and the diamine such as 4,4′-diaminodiphenyl ether can also be performed by vacuum deposition.
[0019]
In the present invention, the imidization temperature of the polyimide endless belt 3, that is, the temperature at which the polyimide endless belt 3 is formed by imidizing polyamic acid applied to the inner surface of the cylindrical mold 1 for molding the polyimide endless belt 3, Alternatively, two kinds of tetracarboxylic anhydrides such as pyromellitic anhydride and diamines such as 4,4′-diaminodiphenyl ether coated on the inner surface of the cylindrical polyimide coating mold 1 for molding the polyimide endless belt 3 are used. When the temperature at which the mixed film of monomers is imidized to form the polyimide endless belt 3 is set to, for example, 280 to 300 ° C., the imidization temperature of the release film 2 is higher than 280 to 300 ° C., for example, 310 ° C. Since the imidization temperature of the release film 2 described here is only one embodiment of the present invention, a temperature different from the above temperature is set in consideration of the imidization temperature of the polyimide endless belt 3 to be set. You can also choose.
[0020]
【Example】
Example 1
A polyimide precursor polyamic acid (Toray Industries, Ltd., Torenice # 3000) diluted to 30% with N, N-dimethylacetamide (DMAC) is applied to the inner side of a cylindrical aluminum-made polyimide coating mold. Coating was performed while rotating the mold at a low speed, and then the polyimide coating mold was rotated at a high speed to form a coating film into a uniform film. This film was dried to remove the solvent, and then heated to 310 ° C. to imidize the polyamic acid to form a release film.
[0021]
While rotating the polyimide-coated cylindrical mold having the release film formed in this way at a low speed, a solution obtained by diluting polyamic acid (manufactured by Toray Industries, Inc., Torenice # 3000) to 30% with DMAC was applied. Subsequently, the polyimide coating mold was rotated at high speed to form a coating film into a uniform film. The membrane was dried to remove the solvent, and then heated to 280 ° C. to imidize the polyamic acid to form a polyimide endless belt. After cooling this polyimide endless belt, when its end was slowly peeled off from the release film, the peeled polyimide endless belt slipped slowly, but the release film was a cylindrical polyimide coating mold. It remained attached inside. A polyimide endless belt was formed by repeatedly using this cylindrical polyimide coating mold, but a polyimide endless belt could be formed with good reproducibility.
[0022]
(Example 2)
By applying the same polyamic acid solution as in Example 1 to a cylindrical polyimide coating mold having a release film formed in the same manner as in Example 1, and heating this to 300 ° C. to imidize the polyamic acid. A polyimide endless belt was formed. After cooling this polyimide endless belt, when its end was slowly peeled off from the release film, the peeled polyimide endless belt slipped slowly, but the release film was a cylindrical polyimide coating mold. It remained attached inside. A polyimide endless belt was formed by repeatedly using this cylindrical mold, but a polyimide endless belt could be formed with good reproducibility.
[0023]
(Example 3)
Mixing of these monomers by heating each vapor deposition source of pyromellitic anhydride and 4,4'-diaminodiphenyl ether on the inner surface of a cylindrical aluminum polyimide coating mold inside the vacuum deposition apparatus A film was formed. After returning the inside of the vacuum deposition apparatus to normal pressure, a release film was formed by causing a dehydration polymerization reaction in which the final temperature was maintained at 310 ° C. while gradually heating the formed mixed film. In the same manner as in Example 1, a polyamic acid solution was applied to a cylindrical polyimide coating mold having a release film formed in this way to form a film, this film was dried, the solvent was removed, and then heated to 280 ° C. Then, a polyimide endless belt was formed by imidizing the polyamic acid. After cooling this polyimide endless belt, when its end was slowly peeled off from the release film, the peeled polyimide endless belt slipped slowly, but the release film was a cylindrical polyimide coating mold. It remained attached inside. A polyimide endless belt was formed by repeatedly using this cylindrical polyimide coating mold, but a polyimide endless belt could be formed with good reproducibility.
[0024]
(Comparative Example 1)
The same polyamic acid solution as in Example 1 was applied to a cylindrical polyimide coating mold having a release film formed in the same manner as in Example 1 to form a film. After drying the film and removing the solvent, 320 A polyimide endless belt was formed by heating to 0 ° C. to imidize the polyamic acid. After cooling this polyimide endless belt, its end was slowly peeled off from the release film, but the polyimide endless belt adhered firmly to the release film, and if peeled off forcibly, the release film would also break and peel together have done.
[0025]
(Comparative Example 2)
A polyimide-coated cylindrical mold having a release film formed in the same manner as in Example 1 was coated with the same polyamic acid solution as in Example 1 to form a film. After the film was dried and the solvent was removed, 350 A polyimide endless belt was formed by heating to 0 ° C. to imidize the polyamic acid. After cooling this polyimide endless belt, its end was slowly peeled off from the release film, but the polyimide endless belt adhered firmly to the release film, and if peeled off forcibly, the release film would also break and peel together have done.
[0026]
(Comparative Example 3)
As in Example 3, a mixed film of two monomers composed of pyromellitic anhydride and 4,4′-diaminodiphenyl ether was formed on the inner surface of a cylindrical aluminum polyimide coating mold. After the inside of the vacuum vapor deposition apparatus was returned to normal pressure, a release film was formed by causing the dehydration polymerization reaction while maintaining the final temperature at 250 ° C. while gradually heating the formed mixed film. In the same manner as in Example 1, a polyamic acid solution was applied to a cylindrical polyimide coating mold having a release film formed in this way to form a film, this film was dried, the solvent was removed, and then heated to 280 ° C. Then, a polyimide endless belt was formed by imidizing the polyamic acid. After cooling this polyimide endless belt, its end was slowly peeled off from the release film, but the polyimide endless belt adhered firmly to the release film, and if peeled off forcibly, the release film would also break and peel together have done.
[0027]
The operation of the present invention is described as follows.
[0028]
According to the invention described in claims 1 to 4, the cylindrical polyimide coating mold is an imidization temperature of a polyimide endless belt on its inner surface, for example, polyimide imidized at a temperature of 280 to 300 ° C. or more. Since it has a release film that is configured, the polyimide endless belt can be easily released and removed without changing its shape, i.e., changing its shape due to wrinkles, tears, etc. Moreover, it can be used repeatedly and stably. The reason for this is that the release film composed of polyimide imidized at a temperature of 280 to 300 ° C. or higher has almost no adhesion to the polyimide endless belt.
[0029]
According to the invention described in claims 5 to 6, since two monomers composed of tetracarboxylic anhydride and diamine are used, dry coating is possible, and for that purpose, the inside of the cylindrical polyimide coating mold is made. Application becomes easy. The mixed film of two monomers can be formed by vacuum deposition. In that case, if it heats more than imidation temperature, it can advance at a stretch to the process of superposition | polymerization.
[0030]
【The invention's effect】
It is possible to provide a polyimide coating mold, a manufacturing method thereof, and a manufacturing method of a polyimide endless belt that can be easily released from the polyimide endless belt without changing its shape, and a manufacturing method of the polyimide endless belt. .
[Brief description of the drawings]
FIG. 1 is a longitudinal section of a cylindrical polyimide coating mold for forming a polyimide endless belt according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylindrical polyimide coating mold 2 Release film 3 Polyimide endless belt

Claims (7)

A said cylindrical polyimide coating mold for molding a polyimide endless belt, the polyimide coating mold and imidizing the polyamic acid in the polyamic acid coating film applied to the inner surface at the imidization temperature or higher A polyimide coating mold having a release film made of polyimide.   2. The polyimide coating according to claim 1, wherein the release film is a film composed of polyimide obtained by imidizing polyamic acid at a temperature of 280 to 300 ° C. or more set as an imidization temperature of polyamic acid. Mold.   In the manufacture of the cylindrical coating mold for molding a polyimide endless belt, a polyamide acid solution is applied to the inner surface of the polyimide coating mold and then heated to a temperature equal to or higher than the imidization temperature of the polyamide acid to form a polyamide. A method for producing a polyimide coating mold, wherein a release film is formed by imidizing an acid.   4. The method for producing a polyimide coating mold according to claim 3, wherein the polyamic acid is imidized at a temperature of 280 to 300 ° C. or higher set as an imidization temperature of the polyamic acid.   In the production of the cylindrical polyimide coating mold for molding a polyimide endless belt, the polyamic acid produced is imidized when or after the tetracarboxylic acid anhydride and diamine are coated on the inner surface of the polyimide coating mold. A method for producing a polyimide coating mold, wherein the release film is formed by heating to a temperature equal to or higher than the temperature to imidize.   The method for producing a polyimide coating mold according to claim 5, wherein the tetracarboxylic acid anhydride and the diamine are applied by vacuum deposition.   (B) a step of applying the polyamic acid coating solution while rotating the polyimide coating mold according to claim 1 or 2 at a low speed, and (b) rotating the polyimide coating mold at a high speed to obtain a uniform film thickness. A step of forming a polyamic acid coating film, (c) a step of drying the polyamic acid coating film to remove the solvent, and (d) heating the polyamic acid coating film from which the solvent has been removed to an imidization temperature or higher. A process for producing a polyimide endless belt, comprising sequentially imidizing polyamic acid.

Images