JP6011374B2 - Polyimide precursor composition, method for producing polyimide precursor composition, transfer belt, method for producing transfer belt, transfer belt unit, and image forming apparatus - Google Patents

Description

  The present invention relates to a polyimide precursor composition, a method for producing a polyimide precursor composition, a transfer belt, a method for producing a transfer belt, a transfer belt unit, and an image forming apparatus.

A polyimide resin is a material having high durability and excellent heat resistance, and is widely used for electronic materials.
As a method for producing a molded article of polyimide resin, a polyimide precursor composition obtained by dissolving a precursor polyamic acid in an aprotic polar solvent such as N-methyl-2-pyrrolidone (NMP) is formed on a substrate. A method for producing a polyimide molded body by applying, drying and imidizing by heat treatment is known (for example, see Patent Document 1).

  Also, in the production of polyimide precursor compositions, the polyimide precursor resin is polymerized in an aprotic polar solvent such as NMP, the polyimide precursor resin is taken out by reprecipitation method, and then dissolved in water by the action of an amine salt. It is also known to go through a process (see, for example, Patent Documents 2 to 5).

  Examples of the solvent for dissolving polyamic acid include NMP, dimethylacetamide (DMAc), dimethylformamide (DMF), dimethylsulfoxide (DMSO), and γ-butyrolactone (γ-BL) (for example, non-patent literature). 1).

  On the other hand, as an aprotic polar solvent, a water-soluble alcohol solvent compound and / or a water-soluble ether solvent compound is used. Specifically, in a mixed solvent of tetrahydrofuran (THF) and methanol, or THF and water. It is known that a polyimide precursor composition is obtained without precipitation by adding a tertiary amine to a reaction system in a mixed solvent (see, for example, Patent Document 6).

  It is also known to obtain a water-based polyimide precursor composition by polymerizing a polyimide precursor in water in the presence of imidazole having a specific structure as an amine compound (see, for example, Patent Documents 7 to 8).

U.S. Pat. No. 4,238,528 Japanese Patent Laid-Open No. 08-120077 Japanese Patent Laid-Open No. 08-015519 JP 2003-13351 A JP 08-059832 A JP 08-157599 A JP 2012-036382 A JP 2012-140582 A

Journal of Polymer Science. Macromolecular Reviews, Vol.11, P164 (1976)

  An object of the present invention is to provide a polyimide precursor composition in which conductive particles are uniformly dispersed and blended, and imidization is efficiently promoted during molding of a polyimide molded body.

  In order to achieve the above object, the following invention is provided.

The invention according to claim 1
It is a transfer belt having a polyimide resin layer formed by drying and imidizing a coating film of a polyimide precursor composition,
The polyimide precursor composition, an aqueous solvent, and the resin have a repeating unit 且 one imidization ratio of 0.2 or less represented by the following formula (I), is dissolved and an aliphatic cyclic amine compound And a transfer belt, which is a polyimide precursor composition in which conductive particles are dispersed.

(In general formula (I), A represents a tetravalent organic group, and B represents a divalent organic group.)

The invention according to claim 2
The transfer belt according to claim 1, wherein the aliphatic cyclic amine compound is at least one compound selected from morpholines, piperidines, piperazines, pyrrolidines, and pyrazolidines.

The invention according to claim 3
The transfer belt according to claim 1, wherein the aliphatic cyclic amine compound is at least one compound selected from morpholines.

The invention according to claim 4
The transfer belt according to claim 1, wherein the aliphatic cyclic amine compound is a tertiary amine compound.

The invention according to claim 5
The polyimide precursor composition, the aliphatic cyclic amine compound, the carboxyl groups contained in the resin, in any one of claims 1 to 4, containing at least 50 mole% 500 mole% or less The transfer belt described.

The invention according to claim 6
The transfer belt according to claim 1, wherein the resin is synthesized from an aromatic tetracarboxylic dianhydride and an aromatic diamine compound.

The invention according to claim 7 provides:
The resin is composed of at least one aromatic tetracarboxylic dianhydride selected from pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, and benzophenonetetracarboxylic dianhydride, phenylenediamine, and diaminodiphenyl ether. The transfer belt according to claim 1, which is synthesized from at least one selected aromatic diamine compound.

The invention according to claim 8 provides:
The transfer belt according to claim 1, wherein the resin includes a resin having an amino group at a terminal.

The invention according to claim 9 is:
The transfer belt according to claim 1, wherein the number average molecular weight of the resin is 1000 or more and 100,000 or less.

The invention according to claim 10 is:
Forming a coating film polyimide precursor composition is applied onto a coating object,
A step of heat-treating the coating film to form a polyimide resin layer;
A transfer belt manufacturing method comprising :
The polyimide precursor composition contains a resin having the repeating unit represented by the general formula (I) and an imidization ratio of 0.2 or less and an aliphatic cyclic amine compound in an aqueous solvent. A method for producing a transfer belt, which is a polyimide precursor composition in which conductive particles are dispersed .

The invention according to claim 11 is:
The transfer belt according to any one of claims 1 to 9 ,
A plurality of rolls over which the transfer belt is tensioned;
Transfer belt unit equipped with.

The invention according to claim 12
Image forming apparatus comprising a transfer belt according to any one of claims 1-9.

The invention according to claim 13 is:
An image carrier,
Charging means for charging the surface of the image carrier;
Latent image forming means for forming a latent image on the surface of the image carrier;
Developing means for developing a latent image on the surface of the image carrier with toner to form a toner image;
An intermediate transfer belt to which the toner image formed on the surface of the image carrier is transferred, the intermediate transfer belt comprising the transfer belt according to any one of claims 1 to 9 ,
Primary transfer means for primarily transferring the toner image formed on the surface of the image carrier onto the surface of the intermediate transfer belt;
Secondary transfer means for secondary transfer of the toner image transferred to the surface of the intermediate transfer belt to a recording medium;
Fixing means for fixing the toner image transferred to the recording medium;
An image forming apparatus.

According to the invention which concerns on Claims 1-9 , compared with the case where the polyimide precursor composition in which the aliphatic cyclic amine compound is not melt | dissolved is applied, electroconductive particle is disperse | distributed uniformly and it has high mechanical strength. A transfer belt is provided.
According to the invention of claim 10 , compared to the case where a polyimide precursor composition in which an aliphatic cyclic amine compound is not dissolved is applied, a transfer belt in which conductive particles are uniformly dispersed and blended and has high mechanical strength. A manufacturing method is provided.

According to the invention which concerns on Claim 11 , compared with the case where the transfer belt which has the polyimide resin layer formed with the polyimide precursor composition in which the aliphatic cyclic amine compound is not melt | dissolved, electroconductive particle is uniformly disperse | blended. And a transfer belt unit including a transfer belt having high mechanical strength is provided.
According to the inventions according to claims 12 and 13 , the conductive particles are more uniform than when a transfer belt having a polyimide resin layer formed of a polyimide precursor composition in which an aliphatic cyclic amine compound is not dissolved is provided. There is provided an image forming apparatus including a transfer belt that is dispersed and blended and has high mechanical strength.

It is the schematic plan view (A) and schematic sectional drawing (B) which show an example of a circular electrode. It is a schematic perspective view which shows the transfer belt unit which concerns on this embodiment. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows the image forming apparatus which concerns on other embodiment.

  Hereinafter, embodiments of the present invention will be described in detail.

<Polyimide precursor composition>
The polyimide precursor composition according to the present embodiment has a repeating unit represented by the general formula (I) in an aqueous solvent and has an imidization ratio of 0.2 or less (hereinafter referred to as “specific polyimide precursor”). And an aliphatic cyclic amine compound, and conductive particles are dispersed. That is, the specific polyimide precursor and the aliphatic cyclic amine compound are contained in the composition in a state dissolved in an aqueous solvent, and the conductive particles are contained in the composition in a state dispersed in the solvent. In addition, melt | dissolution shows the state which the residue of melt | dissolution does not confirm visually.

  The polyimide precursor composition according to this embodiment applies an aqueous solvent as a solvent. Here, the aqueous solvent refers to a solvent containing at least 70% by mass of water.

  In this embodiment, since the aqueous solvent is applied, it is excellent in environmental suitability. Moreover, at the time of shaping | molding of the polyimide molded body using a polyimide precursor composition, reduction of the heating temperature for solvent distillation and shortening of heating time are implement | achieved.

Furthermore, in the polyimide precursor composition according to this embodiment, the aliphatic cyclic amine compound is dissolved. Therefore, since the specific polyimide precursor (its carboxyl group) is amine-chlorinated with an aliphatic cyclic amine compound, the solubility in an aqueous solvent is enhanced, and the film-forming property is also excellent.
In addition, when molding a polyimide molded body using a polyimide precursor composition, an aliphatic cyclic amine compound exhibits an excellent imidization promoting action, so that a polyimide resin molded body having excellent mechanical strength can be obtained. A polyimide resin molded article having excellent properties such as properties, electrical characteristics and solvent resistance can be obtained. Furthermore, productivity is also improved by the imidization promoting action.
In addition, since the aliphatic cyclic amine compound is dissolved in the solvent in the state of amine conversion to the specific polyimide precursor (its carboxyl group), the odor peculiar to the amine compound can be suppressed.
Furthermore, the change in viscosity of the polyimide precursor composition is small even over a long period of time, and stable coating processing can be performed.

  In addition, by using the polyimide precursor composition according to this embodiment in which the specific polyimide precursor and the aliphatic cyclic amine compound are dissolved in an aqueous solvent, when forming a polyimide molded body, Corrosion is suppressed. This is considered to be because the acidity of the carboxyl group of the specific polyimide precursor is suppressed by the basicity of the aliphatic cyclic amine compound.

  Furthermore, when conductive particles are dispersed in a system containing the specific polyimide precursor, the dispersibility is improved. This is an acidic functional group such as a carboxyl group present on the surface of carbon black particles or the like widely used as conductive particles, and an aliphatic cyclic amine compound blended in the polyimide precursor composition according to the present embodiment. Is considered to facilitate the dispersion of the conductive particles in the polyimide precursor composition and to suppress the reaggregation of the conductive particles.

  For this reason, in the polyimide precursor composition according to the present embodiment, it is considered that, due to the above composition, the conductive particles are uniformly dispersed and blended, and imidization is efficiently promoted when the polyimide molded body is molded. .

  In particular, in the general formula (I), a specific polyimide precursor (that is, an aromatic polyimide precursor) in which A represents a tetravalent aromatic organic group and B represents a divalent aromatic organic group. When applied, it usually tends to be difficult to dissolve in a solvent, but an aqueous solvent is applied as a solvent, and the specific polyimide precursor is dissolved in an amine-chlorinated state with an aliphatic cyclic amine compound. For this reason, even if it is a case where an aromatic polyimide precursor is applied as a specific polyimide precursor, film forming property is high and it is excellent in environmental suitability.

In addition, as for the polyimide precursor composition which concerns on this embodiment, although an aqueous solvent is applied as a solvent as above-mentioned, it is preferable that this aprotic solvent does not contain an aprotic polar solvent.
The aprotic polar solvent is a solvent having a boiling point of 150 ° C. or higher and 300 ° C. or lower and a dipole moment of 3.0D or higher and 5.0D or lower. Specific examples of the aprotic polar solvent include N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), Hexamethylene phosphoramide (HMPA), N-methylcaprolactam, N-acetyl-2-pyrrolidone and the like can be mentioned.

  The aprotic polar solvent represented by N-methyl-2-pyrrolidone (NMP) has a high boiling point of 150 ° C. or higher, and the solvent in the composition remains in the molded body even after the drying step in the production of the polyimide molded body. Often remains. If this aprotic polar solvent remains in the polyimide molded body, it causes reorientation of the polymer chain of the polyimide precursor and impairs the packing properties of the polymer chain, resulting in a decrease in the mechanical strength of the resulting polyimide molded body. May cause.

On the other hand, in the polyimide precursor composition according to the present embodiment, the aprotic polar solvent is not contained even in the obtained polyimide molded body by not containing the aprotic polar solvent in the aqueous solvent.

As a result, the polyimide molded body by the polyimide precursor composition according to the present embodiment is suppressed from lowering in mechanical strength.
The specific polyimide precursor as a polyimide precursor is not a low-molecular compound. Also, it introduces a bent chain or an aliphatic cyclic structure into the primary structure to lower the interaction force between polymer chains and dissolve in a solvent. The specific polyimide precursor (its carboxyl group) is dissolved by amine-chlorination with an aliphatic cyclic amine compound, and an aqueous solvent is applied as a solvent, not a structure with enhanced properties. For this reason, it does not cause a decrease in the mechanical strength of the polyimide molded body caused by lowering the molecular weight of the polyimide precursor seen in the method for improving solubility in the conventional polyimide precursor resin, and changing the molecular structure of the polyimide precursor The polyimide precursor is water-solubilized.
Moreover, it is easy to obtain a polyimide resin molded article excellent in various characteristics such as heat resistance, electrical characteristics, and solvent resistance in addition to mechanical strength.

  Hereinafter, each component of the polyimide precursor composition according to the present embodiment will be described.

(Specific polyimide precursor)
The specific polyimide precursor is a resin (polyamic acid) having a repeating unit represented by the general formula (I) and having an imidization ratio of 0.2 or less.

(In general formula (I), A represents a tetravalent organic group, and B represents a divalent organic group.)

Here, in the general formula (I), the tetravalent organic group represented by A is a residue obtained by removing four carboxyl groups from a tetracarboxylic dianhydride as a raw material.
On the other hand, the divalent organic group represented by B is a residue obtained by removing two amino groups from a diamine compound as a raw material.

  That is, the specific polyimide precursor having a repeating unit represented by the general formula (I) is a polymer of tetracarboxylic dianhydride and a diamine compound.

  The tetracarboxylic dianhydride includes both aromatic and aliphatic compounds, but is preferably an aromatic compound. That is, in the general formula (I), the tetravalent organic group represented by A is preferably an aromatic organic group.

  Examples of the aromatic tetracarboxylic acid include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic acid. Acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetra Carboxylic dianhydride, 3,3 ′, 4,4′-dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3 ′, 4,4′-tetraphenylsilane tetracarboxylic dianhydride, 1,2, 3,4-furantetracarboxylic dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) Diphenylsulfone dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidenediphthalic dianhydride, 3, 3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,3,3', 4'-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene- Bis (triphenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4′-diphenyl ether dianhydride, bis (triphenylphthalic acid) ) -4,4′-diphenylmethane dianhydride and the like.

  Examples of the aliphatic tetracarboxylic dianhydride include butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4. -Cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarboxynorbonane-2- Acetic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride , Aliphatic or alicyclic tetracarboxylic dianhydrides such as bicyclo [2,2,2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride; 3a, 4,5,9b-Hexahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro -5-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro Aliphatic tetracarboxylic dianhydrides having an aromatic ring such as -8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione Etc.

  Among these, the tetracarboxylic dianhydride is preferably an aromatic tetracarboxylic dianhydride, specifically, for example, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyl. Tetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4 , 4′-benzophenonetetracarboxylic dianhydride is preferable, and pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4 ′ -Benzophenone tetracarboxylic dianhydride is good, especially 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride.

In addition, tetracarboxylic dianhydride may be used individually by 1 type, and may be used together in combination of 2 or more types.
Moreover, when using together and using 2 or more types, you may use together aromatic tetracarboxylic acid or aliphatic tetracarboxylic acid, respectively, or may combine aromatic tetracarboxylic acid and aliphatic tetracarboxylic acid.

  On the other hand, a diamine compound is a diamine compound having two amino groups in the molecular structure. Examples of diamine compounds include aromatic and aliphatic compounds, but aromatic compounds are preferred. That is, in the general formula (I), the divalent organic group represented by B is preferably an aromatic organic group.

Examples of the diamine compound include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfide. 4,4′-diaminodiphenylsulfone, 1,5-diaminonaphthalene, 3,3-dimethyl-4,4′-diaminobiphenyl, 5-amino-1- (4′-aminophenyl) -1,3,3 -Trimethylindane, 6-amino-1- (4'-aminophenyl) -1,3,3-trimethylindane, 4,4'-diaminobenzanilide, 3,5-diamino-3'-trifluoromethylbenzanilide 3,5-diamino-4′-trifluoromethylbenzanilide, 3,4′-diaminodiphenyl ether, , 7-diaminofluorene, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4′-methylene-bis (2-chloroaniline), 2,2 ′, 5,5′-tetrachloro-4 , 4'-diaminobiphenyl, 2,2'-dichloro-4,4'-diamino-5,5'-dimethoxybiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 4,4'-diamino -2,2'-bis (trifluoromethyl) biphenyl, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoro Propane, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) -biphenyl, 1,3′-bis (4-aminophenoxy) benzene, 9,9-bi (4-aminophenyl) fluorene, 4,4 ′-(p-phenyleneisopropylidene) bisaniline, 4,4 ′-(m-phenyleneisopropylidene) bisaniline, 2,2′-bis [4- (4-amino- 2-trifluoromethylphenoxy) phenyl] hexafluoropropane, aromatic diamines such as 4,4′-bis [4- (4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl; and diaminotetraphenylthiophene An aromatic diamine having two amino groups bonded to an aromatic ring such as a hetero atom other than the nitrogen atom of the amino group; 1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine , Pentamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diamy Heptamethylene diamine, 1,4-diaminocyclohexane, isophorone diamine, tetrahydrodicyclopentadiene cyclopentadienylide diamine, hexahydro-4,7-meth Noin mite range diamine, tricyclo [6,2,1,0 ^2.7] Examples thereof include aliphatic diamines such as undecylenedimethyl diamine and 4,4′-methylene bis (cyclohexylamine), and alicyclic diamines.

  Among these, as the diamine compound, an aromatic diamine compound is good, and specifically, for example, p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfide, and 4,4′-diaminodiphenyl sulfone are preferable, and 4,4′-diaminodiphenyl ether and p-phenylenediamine are particularly preferable.

  In addition, a diamine compound may be used individually by 1 type, and may be used together in combination of 2 or more types. Moreover, when using together and using 2 or more types, you may use together an aromatic diamine compound or an aliphatic diamine compound, respectively, or may combine an aromatic diamine compound and an aliphatic diamine compound.

The specific polyimide precursor is a resin having an imidization rate of 0.2 or less. That is, the specific polyimide precursor may be a resin partially imidized.
Specifically, examples of the specific polyimide precursor include a resin having a repeating unit represented by General Formula (I-1), General Formula (I-2), and General Formula (I-3).

In General Formula (I-1), General Formula (I-2), and General Formula (I-3), A represents a tetravalent organic group, and B represents a divalent organic group. In addition, A and B are synonymous with A and B in general formula (I).
l represents an integer of 1 or more, m and n each independently represents 0 or an integer of 1 or more, and satisfies the relationship of (2n + m) / (2l + 2m + 2n) ≦ 0.2.

In general formulas (I-1) to (I-3), l represents an integer of 1 or more, preferably an integer of 1 to 200, more preferably an integer of 1 to 100. m and n each independently represent an integer of 0 or 1 or more, but preferably each independently represents an integer of 0 or 1 to 200, more preferably 0 or an integer of 1 to 100.
L, m, and n satisfy the relationship (2n + m) / (2l + 2m + 2n) ≦ 0.2, but preferably (2n + m) / (2l + 2m + 2n) ≦ 0.15, more preferably (2n + m) / ( 2l + 2m + 2n) ≦ 0.10.

Here, “(2n + m) / (2l + 2m + 2n)” is the total number of bonding parts (2n + m) in which the imide ring is closed in the bonding part of the specific polyimide precursor (reaction part of tetracarboxylic dianhydride and diamine compound). The ratio to the number of coupled parts (2l + 2m + 2n) is shown. That is, “(2n + m) / (2l + 2m + 2n)” represents the imidization ratio of the specific polyimide precursor.
Then, by specifying the imidization ratio of the specific polyimide precursor (the value of “(2n + m) / (2l + 2m + 2n)”) to 0.2 or less (preferably 0.15 or less, more preferably 0.10 or less) Inducing gelation and precipitation separation of the polyimide precursor is suppressed.

  The imidation ratio (value of “(2n + m) / (2l + 2m + 2n)”) of the specific polyimide precursor is measured by the following method.

-Measurement of imidization rate of polyimide precursor-
-Preparation of polyimide precursor sample (i) A polyimide precursor composition to be measured is applied on a silicone wafer in a film thickness range of 1 µm to 10 µm to prepare a coating film sample.
(Ii) The coating film sample is immersed in tetrahydrofuran (THF) for 20 minutes to replace the solvent in the coating film sample with tetrahydrofuran (THF). The solvent to be immersed is not limited to THF, and can be selected from solvents that do not dissolve the polyimide precursor and are miscible with the solvent component contained in the polyimide precursor composition. Specifically, alcohol solvents such as methanol and ethanol, and ether compounds such as dioxane can be used.
The (iii) coating samples, taken out from in THF, blowing _{N 2} gas into THF adhering to the coating surface of the sample, removed. Under a reduced pressure of 10 mmHg or less, the film sample is dried for 12 hours or more in the range of 5 ° C. or more and 25 ° C. or less to prepare a polyimide precursor sample.

-Preparation of 100% imidized standard sample (iv) Similarly to the above (i), a polyimide precursor composition to be measured is applied on a silicone wafer to prepare a coating film sample.
(V) The coating film sample is heated at 380 ° C. for 60 minutes to carry out an imidization reaction to produce a 100% imidized standard sample.

Measurement and analysis (vi) Using a Fourier transform infrared spectrophotometer (FT-730, manufactured by Horiba, Ltd.), the infrared absorption spectrum of a 100% imidized standard sample and a polyimide precursor sample is measured. Aromatic ring-derived absorption peak near 1500 cm ^-1 and 100% imidization standard sample (Ab ratio 'for (1500cm ^-1)), absorption peaks derived from an imide bond in the vicinity of ^{1780cm -1 (Ab' (1780cm -1} )) I '(100) is obtained.
(Vii) In the same manner, was measured on the polyimide precursor sample, relative to the aromatic ring derived absorption peak near ^{1500cm -1 (Ab (1500cm -1)} ), absorption peaks derived from imide bond near 1780 cm ^-1 (Ab ( 1780 cm ⁻¹ )) ratio I (x) is determined.

And the imidation rate of a polyimide precursor is computed based on the following formula using each measured absorption peak I '(100) and I (x).
Formula: Imidation ratio of polyimide precursor = I (x) / I ′ (100)
Formula: I ′ (100) = (Ab ′ (1780 cm ⁻¹ )) / (Ab ′ (1500 cm ⁻¹ ))
Formula: I (x) = (Ab (1780 cm ⁻¹ )) / (Ab (1500 cm ⁻¹ ))

  In addition, the measurement of the imidation rate of this polyimide precursor is applied to the measurement of the imidation rate of an aromatic polyimide precursor. When measuring the imidation ratio of the aliphatic polyimide precursor, a peak derived from a structure having no change before and after the imidation reaction is used as an internal standard peak instead of the absorption peak of the aromatic ring.

-Terminal amino group of polyimide precursor-
The specific polyimide precursor may include a polyimide precursor (resin) having an amino group at a terminal, and preferably a polyimide precursor having an amino group at all terminals.
In order to give an amino group to the molecular terminal of the polyimide precursor, for example, it is realized by adding the molar equivalent of the diamine compound used in the polymerization reaction in excess of the molar equivalent of tetracarboxylic dianhydride. . The molar equivalent ratio between the diamine compound and the tetracarboxylic dianhydride is preferably in the range of 1.0001 or more and 1.2 or less, more preferably 1 in terms of the molar equivalent of the tetracarboxylic acid. The range is from 0.001 to 1.2.
If the molar equivalent ratio of the diamine compound to tetracarboxylic dianhydride is 1.0001 or more, the effect of the amino group at the molecular end is great, and good dispersibility is obtained. If the molar equivalent ratio is 1.2 or less, the molecular weight of the obtained polyimide precursor is large. For example, when a film-like polyimide molded body is obtained, sufficient film strength (tear strength, tensile strength) is obtained. It is easy to obtain.

  The terminal amino group of a specific polyimide precursor is detected by making trifluoroacetic anhydride (react quantitatively with respect to an amino group) act on a polyimide precursor composition. That is, the terminal amino group of the specific polyimide precursor is amidated with trifluoroacetic acid. After the treatment, the specific polyimide precursor is purified by reprecipitation or the like to remove excess trifluoroacetic anhydride and trifluoroacetic acid residue. About the specific polyimide precursor after a process, the amount of terminal amino groups of a specific polyimide precursor is measured by quantifying with a nuclear magnetic resonance (NMR) method.

The number average molecular weight of the specific polyimide precursor is preferably from 1,000 to 100,000, more preferably from 5,000 to 50,000, and even more preferably from 10,000 to 30,000.
When the number average molecular weight of the specific polyimide precursor is within the above range, a decrease in the solubility of the specific polyimide precursor in the solvent is suppressed, and film forming properties are easily secured. In particular, when a specific polyimide precursor containing a resin having an amino group at the terminal is applied, the presence of the terminal amino group increases as the molecular weight decreases, and the influence of the coexisting aliphatic cyclic amine compound in the polyimide precursor composition However, it is possible to suppress the decrease in solubility by setting the range of the number average molecular weight of the specific polyimide precursor within the above range.
In addition, the specific polyimide precursor of the target number average molecular weight is obtained by adjusting the molar equivalent ratio of a tetracarboxylic dianhydride and a diamine compound.

The number average molecular weight of the specific polyimide precursor is measured by gel permeation chromatography (GPC) method under the following measurement conditions.
Column: Tosoh TSKgel α-M (7.8 mm ID × 30 cm)
Eluent: DMF (dimethylformamide) / 30 mM LiBr / 60 mM phosphoric acidFlow rate: 0.6 mL / min
・ Injection volume: 60 μL
・ Detector: RI (differential refractive index detector)

  The content (concentration) of the specific polyimide precursor is preferably 0.1% by mass or more and 40% by mass or less, and preferably 0.5% by mass or more and 25% by mass or less, based on the total polyimide precursor composition. More desirably, it is 1 mass% or more and 20 mass% or less.

(Aliphatic cyclic amine compound)
An aliphatic cyclic amine compound is a compound that amines a specific polyimide precursor (its carboxyl group) to improve solubility in an aqueous solvent and also functions as an imidization accelerator.
The aliphatic cyclic amine compound is preferably a water-soluble compound. Here, water-soluble means that the target substance dissolves 1% by mass or more in water at 25 ° C.

Examples of the aliphatic cyclic amine compound include secondary amine compounds and tertiary amine compounds.
Among these, as the aliphatic cyclic amine compound, a tertiary amine compound is preferable. When a tertiary amine compound is applied as the aliphatic cyclic amine compound, the solubility of the specific polyimide precursor in an aqueous solvent is likely to be increased, and the film forming property is easily improved.

  Moreover, as an aliphatic cyclic amine compound, the polyvalent amine compound more than bivalence is mentioned besides a monovalent amine compound. When a polyvalent amine compound having two or more valences is applied, it becomes easy to form a pseudo-crosslinked structure between the molecules of the specific polyimide precursor, and even if the specific polyimide precursor is a low molecular weight substance, the viscosity of the polyimide composition can be increased and the film forming property can be increased. It becomes easy to improve.

Examples of the aliphatic cyclic amine compound include piperidines, piperazines, morpholines, pyrrolidines, pyrazolidines and the like.
Among these, piperidines represented by the following formula (1), piperazines represented by the following formula (2), morpholines represented by the following formula (3), and pyrrolidines represented by the following formula (4) And pyrazolidines represented by the following formula (5) are preferable.

In the above formulas (1) to (5), R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group.
R ¹ and R ² are preferably a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, or a phenyl group.

  Among the aliphatic cyclic amine compounds, morpholines are more preferable, and morpholine, methylmorpholine, or ethylmorpholine is more preferable.

  Further, the aliphatic cyclic amine compound is preferably a compound having a boiling point of 60 ° C. or higher (desirably 60 ° C. or higher and 200 ° C. or lower, more preferably 70 ° C. or higher and 150 ° C. or lower). When the boiling point of the aliphatic cyclic amine compound is 60 ° C. or higher, the aliphatic cyclic amine compound is prevented from volatilizing from the polyimide precursor composition during storage, and the decrease in the solubility of the specific polyimide precursor in the aqueous solvent is suppressed. It becomes easy to be done.

The aliphatic cyclic amine compound may be contained in an amount of 50 mol% or more and 500 mol% or less, desirably 80 mol% or more and 400 mol% or less, more desirably, based on the carboxyl group contained in the specific polyimide precursor. It is contained in 100 mol% or more and 300 mol% or less.
When the content of the aliphatic cyclic amine compound is within the above range, the solubility of the specific polyimide precursor in an aqueous solvent is likely to be increased, and the film forming property is easily improved. Moreover, the outstanding solution stability is acquired especially by containing more than the equivalent with respect to the said carboxyl group.

(Aqueous solvent)
The aqueous solvent in this embodiment is a solvent containing at least 70% by mass of water. Examples of water include distilled water, ion exchange water, ultrafiltration water, and pure water.

  Water is contained in an aqueous solvent in an amount of 70% by mass to 100% by mass, desirably 80% by mass to 100% by mass, more desirably 90% by mass to 100% by mass, and a solvent other than water. It is particularly preferred not to contain.

In addition, when a solvent other than water is contained as the aqueous solvent, for example, a water-soluble organic solvent is preferably used.
Examples of the water-soluble organic solvent include a water-soluble ether solvent, a water-soluble ketone solvent, a water-soluble alcohol solvent, and the like. Here, water-soluble means that the target substance dissolves 1% by mass or more in water at 25 ° C.

  The water-soluble organic solvent may be used alone, but when two or more are used in combination, for example, a combination of a water-soluble ether solvent and a water-soluble alcohol solvent, a water-soluble ketone solvent and a water-soluble alcohol Examples thereof include a combination with a solvent, and a combination of a water-soluble ether solvent, a water-soluble ketone solvent and a water-soluble alcohol solvent.

  The water-soluble ether solvent is a water-soluble solvent having an ether bond in one molecule. Examples of the water-soluble ether solvent include tetrahydrofuran (THF), dioxane, trioxane, 1,2 dimethoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and the like. Among these, tetrahydrofuran and dioxane are desirable as the water-soluble ether solvent.

  The water-soluble ketone solvent is a water-soluble solvent having a ketone group in one molecule. Examples of the water-soluble ketone solvent include acetone, methyl ethyl ketone, and cyclohexanone. Among these, acetone is desirable as the water-soluble ketone solvent.

  The water-soluble alcohol solvent is a water-soluble solvent having an alcoholic hydroxyl group in one molecule. Examples of the water-soluble alcohol solvent include methanol, ethanol, 1-propanol, 2-propanol, tert-butyl alcohol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, glycerin, 2-ethyl-2- Examples include hydroxymethyl-1,3-propanediol and 1,2,6-hexanetriol. Among these, methanol, ethanol, 2-propipanol, and ethylene glycol are desirable as the water-soluble alcohol solvent.

  When a solvent other than water is contained as the aqueous solvent, the solvent used in combination preferably has a boiling point of 160 ° C. or lower, preferably 40 ° C. or higher and 150 ° C. or lower, more preferably 50 ° C. or higher and 120 ° C. or lower. When the boiling point of the solvent used in combination is within the above range, the solvent hardly remains in the polyimide molded body, and a polyimide molded body with high mechanical strength is easily obtained.

(Conductive particles)
The conductive particles are conductive (for example, a volume resistivity of less than 10 ⁷ Ω · cm, the same applies hereinafter) or semiconductive (eg, a volume resistivity of 10 ⁷ Ω · cm to 10 ¹³ Ω · cm, and the same applies hereinafter). Are selected depending on the purpose of use.
Examples of the conductive particles include carbon black, metal (for example, aluminum and nickel), metal oxide (for example, yttrium oxide and tin oxide), and ion conductive material (for example, potassium titanate, LiCl, and the like). .
These conductive particles may be used alone or in combination of two or more.

Among these, as the conductive particles, carbon black is preferable, and acidic carbon black having a pH of 5.0 or less is particularly preferable.
Examples of the acidic carbon black include carbon black whose surface is oxidized, for example, carbon black obtained by imparting a carboxyl group, a quinone group, a lactone group, a hydroxyl group or the like to the surface.
As the acidic carbon black, when the resulting polyimide molded body is a transfer belt, carbon black having a pH of 4.5 or less is used from the viewpoint of stability over time of electric resistance and electric field dependency that suppresses electric field concentration due to transfer voltage. Desirable, and more desirably acidic carbon black having a pH of 4.0 or less.
In addition, pH of acidic carbon black is a value measured by the pH measuring method of JISZ8802 (2011) regulation.

  Acidic carbon black is commercially available as SPECIAL BLACK4 (Degussa, pH 4.0), Degussa's “Printex 150T” (pH 4.5, volatile content 10.0%), “Special”. Black 350 "(pH 3.5, volatile matter 2.2%)," Special Black 100 "(pH 3.3, volatile matter 2.2%)," Special Black 250 "(pH 3.1, volatile matter 2. 0%), "Special Black 5" (pH 3.0, volatile content 15.0%), "Special Black 4A" (pH 3.0, volatile content 14.0%), "Special Black 550" (pH 2) 0.8, volatile content 2.5%), "Special Black 6" (pH 2.5, volatile content 18.0%), "Color Black FW200" (pH 2.5, volatile) 20.0%), “Color Black FW2” (pH 2.5, volatile content 16.5%), “Color Black FW2V” (pH 2.5, volatile content 16.5%), “MONARCH1000” manufactured by Cabot Corporation. (PH 2.5, volatile content 9.5%), “MONARCH 1300” manufactured by Cabot (pH 2.5, volatile content 9.5%), “MONARCH 1400” manufactured by Cabot (pH 2.5, 9.0% volatile content) “MOGUL-L” (pH 2.5, volatile matter 5.0%), “REGAL400R” (pH 4.0, volatile matter 3.5%), and the like.

The primary particle size of the conductive particles is preferably less than 10 μm, and more preferably 1 μm or less.
In addition, the primary particle diameter of electroconductive particle is a value calculated | required with the following measuring method. First, the obtained polyimide molded body is cut with a microtome, a measurement sample is collected, and the measurement sample is observed with a TEM (transmission electron microscope). Then, the diameter of 50 carbon black particles is measured, and the average value is taken as the primary particle diameter.

  The content of the conductive particles depends on the use of the polyimide molded body molded using the polyimide precursor composition according to the present embodiment, but the moldability and the appearance, mechanical and electrical properties of the resulting polyimide molded body. From the viewpoint of quality, the amount is preferably 1 part by mass or more and 40 parts by mass or less, more preferably 10 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the total resin components.

(Other additives)
The polyimide precursor composition according to the present embodiment may contain various fillers for the purpose of imparting various functions such as mechanical strength to a polyimide molded body produced using the polyimide precursor composition, and may also include an imidization reaction. A catalyst for promotion, a leveling material for improving film forming quality, and the like may be included.
Examples of the filler added for improving the mechanical strength include particulate materials such as silica powder, alumina powder, barium sulfate powder, titanium oxide powder, mica and talc. In addition, in order to improve the water repellency and releasability of the surface of the polyimide molded body, a fluororesin powder such as polytetrafluoroethylene (PTFE) or tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA) is added. Also good.

  In order to accelerate the imidization reaction, a dehydrating agent such as an acid anhydride, an acid catalyst such as a phenol derivative, a sulfonic acid derivative, or a benzoic acid derivative may be used.

  A surfactant may be added to improve the film forming quality of the polyimide molded body. As the surfactant to be used, any of cationic, anionic and nonionic surfactants may be used.

  What is necessary is just to select content of another additive according to the intended purpose of the polyimide molded body to manufacture.

<Method for producing polyimide precursor composition>
The production of the polyimide precursor composition according to this embodiment is not particularly limited, but a tetracarboxylic dianhydride and a diamine compound are polymerized in an aqueous solvent in the presence of an aliphatic cyclic amine compound. A step of generating a resin (hereinafter referred to as “polyimide precursor”) (hereinafter referred to as “polymerization step”), a step of generating conductive resin and dispersing conductive particles in an aqueous solvent (hereinafter referred to as “dispersion step”). It can be easily performed by a production method having the following.

  In the method for producing a polyimide precursor composition according to the present embodiment, the aliphatic cyclic amine compound is contained in an aqueous solvent that does not contain an aprotic polar solvent or at least the content of the aprotic polar solvent is reduced. In the presence, a polyimide precursor is generated.

In the method for producing a polyimide precursor composition according to this embodiment, an aprotic polar solvent that causes a decrease in mechanical strength of a polyimide molded body is not used or reduced as an aqueous solvent. Since the amine compound is added, the production inhibition of the polyimide precursor (inhibition of the polymerization reaction) is suppressed by the aliphatic cyclic amine compound.
For this reason, in the manufacturing method of the polyimide precursor composition which concerns on this embodiment, the polyimide precursor composition from which the polyimide molded body with high mechanical strength is obtained is manufactured.
In addition, in the method for producing a polyimide precursor composition according to this embodiment, a polyimide precursor composition in which a polyimide molded body excellent in various properties such as heat resistance, electrical properties, and solvent resistance in addition to mechanical strength is easily obtained. Things are manufactured.

  Moreover, in the manufacturing method of the polyimide precursor composition which concerns on this embodiment, since the aqueous solvent is applied as a solvent, productivity is also high and a polyimide precursor composition is manufactured.

  Hereinafter, each process of the manufacturing method of the polyimide precursor composition which concerns on this embodiment is demonstrated. In addition, since each material used is the same as that of what was demonstrated with the polyimide precursor composition which concerns on the said this embodiment, description is abbreviate | omitted.

(Polymerization process)
In the polymerization step, a tetracarboxylic dianhydride and a diamine compound are polymerized in an aqueous solvent in the presence of an aliphatic cyclic amine compound to produce a polyimide precursor.

The reaction temperature during the polymerization reaction of the polyimide precursor is, for example, preferably from 0 ° C. to 70 ° C., preferably from 10 ° C. to 60 ° C., more preferably from 20 ° C. to 55 ° C. By setting the reaction temperature to 0 ° C. or higher, the progress of the polymerization reaction is promoted, the time required for the reaction is shortened, and the productivity is easily improved. On the other hand, when the reaction temperature is 70 ° C. or lower, the progress of the imidization reaction occurring in the molecule of the generated polyimide precursor is suppressed, and precipitation or gelation associated with a decrease in solubility of the polyimide precursor is easily suppressed.
The time during the polymerization reaction of the polyimide precursor is preferably in the range of 1 hour to 24 hours depending on the reaction temperature.

(Dispersion process)
In the dispersion step, after the polyimide precursor is generated, the conductive particles are dispersed in an aqueous solvent.
Here, as a method for dispersing the conductive particles, a known method such as a ball mill, a sand mill (bead mill), a jet mill (counter collision type disperser), or the like can be used. When dispersing the conductive particles, a surfactant, a leveling agent or the like may be added as a dispersion aid.

<Usage example of polyimide precursor composition>
The polyimide precursor composition according to this embodiment is used as a coating liquid for forming a polyimide molded body. Examples of the coating liquid for forming a polyimide molded body include a coating liquid for forming a polyimide film, a coating liquid for forming a polyimide film, and the like.
Examples of the polyimide film as the polyimide molded body include a copper-clad laminate film, a laminate film, and a separation film.
Examples of the polyimide coating as the polyimide molded body include a heat resistant coating, an adhesive film, a liquid crystal alignment film, a resist film, a planarization film, a microlens array film, and an optical fiber coating film.
Examples of other polyimide molded bodies include belt members. Examples of the belt member include a transfer belt (for example, an intermediate transfer belt, a transfer conveyance belt, etc.) for an electrophotographic image forming apparatus.

(Polyimide molded product)
The polyimide molded body molded from the polyimide precursor composition according to the present embodiment includes an aqueous solvent contained in the polyimide precursor composition according to the present embodiment and the polyimide precursor composition according to the present embodiment. An aliphatic cyclic amine compound is contained.
The aqueous solvent contained in the polyimide molded body molded from the polyimide precursor composition according to the present embodiment is 1 ppb or more and less than 1% in the polyimide molded body. The amount of the aqueous solvent contained in the polyimide molded body is quantified by gas chromatography with respect to the amount of gas generated by heating the polyimide molded body. Moreover, also about the quantity of an aliphatic cyclic amine compound contained in a polyimide molded object, the gas component generated by heating a polyimide molded object is quantified by the gas chromatography method.

<Transfer belt>
The transfer belt according to the present embodiment has a polyimide resin layer (hereinafter referred to as “specific polyimide resin layer”) formed by heat-treating the coating film of the polyimide precursor composition according to the present embodiment. That is, this specific polyimide resin layer is a layer formed by subjecting the coating film of the polyimide precursor composition to drying treatment and imidization treatment as heat treatment.

Since the transfer belt according to the present embodiment has a specific polyimide resin layer, the transfer belt is a dispersion belt in which conductive particles are uniformly dispersed and blended and has high mechanical strength.
As a result, in the image forming apparatus (or transfer belt unit) including the transfer belt according to the present embodiment, image defects (for example, density unevenness and spot defects) due to reduced dispersibility of the conductive particles are suppressed. Further, breakage and the like are suppressed, and repeated image formation is realized over a long period of time.

Note that the transfer belt according to the present embodiment may be configured by a single layer of a specific polyimide resin layer, or a laminate of a base material layer and a surface layer (surface release layer) on the outer peripheral surface thereof. The structure which applied the specific polyimide resin layer as at least one of the said base material layer and a surface layer may be sufficient. However, when applying a specific polyimide resin layer as a surface layer, it is good to mix | blend a mold release material (For example, a fluorine compound (fluorine resin or its particle | grains etc.) etc.).
Of course, an intermediate layer may be provided between the base material layer and the surface layer, or the base material layer itself may be composed of a laminate of two or more layers.

  The surface resistivity of the outer peripheral surface of the transfer belt according to the present embodiment is desirably 8 (LogΩ / □) or more and 14 (LogΩ / □) or less as a common logarithmic value when applied to an intermediate transfer member. It is more desirable that it is not less than LogΩ / □ and not more than 12 (LogΩ / □). When the common logarithmic value of the surface resistivity exceeds 14 (LogΩ / □), the recording medium and the intermediate transfer member may be electrostatically adsorbed during the secondary transfer, and the recording medium may be difficult to peel off. On the other hand, if the common logarithmic value of the surface resistivity is less than 8 (LogΩ / □), the holding power of the toner image primarily transferred to the intermediate transfer member is insufficient, and image quality graininess and image disturbance may occur. .

This surface resistivity is measured in accordance with JIS K6911 using a circular electrode (“UR probe” of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd.).
A method for measuring the surface resistivity will be described with reference to FIG. FIG. 1A is a schematic plan view and FIG. 1B is a schematic cross-sectional view showing an example of a circular electrode. The circular electrode shown in FIG. 1 includes a first voltage application electrode A and a plate-like insulator B. The first voltage application electrode A has a cylindrical electrode portion C and a cylindrical ring electrode having an inner diameter larger than the outer diameter of the cylindrical electrode portion C and surrounding the cylindrical electrode portion C at a constant interval. Part D is provided.
The belt electrode T is sandwiched between the cylindrical electrode portion C and the ring electrode portion D in the first voltage application electrode A and the plate insulator B, and the cylindrical electrode portion C and the ring electrode portion in the first voltage application electrode A are sandwiched. A current I (A) that flows when a voltage V (V) is applied to D is measured, and a surface resistivity ρs (Ω / □) of the transfer surface of the belt T is calculated by the following equation. Here, in the following formula, d (mm) indicates the outer diameter of the cylindrical electrode portion C, and D (mm) indicates the inner diameter of the ring-shaped electrode portion D.
Formula: ρs = π × (D + d) / (D−d) × (V / I)

  The surface resistivity is a circular electrode (UR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd .: outer diameter Φ16 mm of the cylindrical electrode portion C, inner diameter Φ30 mm, outer diameter Φ40 mm of the ring-shaped electrode portion D), Under a 22 ° C./55% RH environment, a voltage value of 500 V and a current value after application for 10 seconds are obtained and calculated.

When applied to an intermediate transfer member, the entire volume resistivity of the transfer belt according to the present embodiment is desirably 8 (Log Ωcm) or more and 14 (Log Ωcm) or less in common logarithmic values. If the common logarithmic value of the volume resistivity is less than 8 (Log Ωcm), the electrostatic force that holds the charge of the unfixed toner image transferred from the image carrier to the intermediate transfer member is difficult to work. The electrostatic repulsive force between the images and the fringe electric field at the image edge may cause the toner to scatter around the image and form a noisy image. On the other hand, when the common logarithmic value of the volume resistivity exceeds 14 (Log Ωcm), since the charge holding power is large, the surface of the intermediate transfer member is charged by the transfer electric field in the primary transfer, and thus a static elimination mechanism is required. There is a case.
The common logarithmic value of the volume resistivity is controlled by the type of conductive material and the amount of conductive material added.

This volume resistivity is measured in accordance with JIS K6911 using a circular electrode (High Probe IP UR probe manufactured by Mitsubishi Oil Chemical Co., Ltd.). A method for measuring the volume resistivity will be described with reference to FIG. The measurement is performed with the same device as the surface resistivity. However, the circular electrode shown in FIG. 1 includes a second voltage application electrode B ′ instead of the plate-like insulator B at the time of measuring the surface resistivity. Then, the belt T is sandwiched between the cylindrical electrode portion C and the ring-shaped electrode portion D in the first voltage application electrode A and the second voltage application electrode B ′, and the cylindrical electrode portion C in the first voltage application electrode A. The current I (A) flowing when the voltage V (V) is applied between the second voltage application electrode B ′ and the second voltage application electrode B ′ is measured, and the volume resistivity ρv (Ωcm) of the belt T is calculated by the following equation. Here, in the following formula, t represents the thickness of the belt T.
Formula ρv = 19.6 × (V / I) × t

In addition, volume resistivity uses a circular electrode (UR probe of Hiresta IP manufactured by Mitsubishi Oil Chemical Co., Ltd .: outer diameter Φ16 mm of the cylindrical electrode portion C, inner diameter Φ30 mm of the ring-shaped electrode portion D, outer diameter Φ40 mm), Under a 22 ° C./55% RH environment, a voltage value of 500 V and a current value after application for 10 seconds are obtained and calculated.
Moreover, 19.6 shown by the said formula is an electrode coefficient for converting into a resistivity, and it is (pi) d < ² > / 4t from the outer diameter d (mm) of a cylindrical electrode part, and the thickness t (cm) of a sample. Is calculated as The thickness of the belt T is measured using an eddy current film thickness meter CTR-1500E manufactured by Sanko Electronics.

  The thickness of the transfer belt according to the present embodiment is desirably, for example, 0.05 mm or more and 0.5 mm or less, more desirably 0.06 mm or more and 0.30 mm or less, and further desirably 0.06 mm or more and 0.15 mm or less. is there.

<Transfer belt manufacturing method>
The transfer belt manufacturing method according to the present embodiment includes a step of forming a coating film by applying the polyimide precursor composition according to the present embodiment on an object to be coated (hereinafter referred to as a “coating film forming step”). And a step of heat-treating the coating film to form a polyimide resin layer (hereinafter referred to as “heating step”).

  Hereinafter, the manufacturing method of the transfer belt according to the present embodiment will be described in detail.

(Coating film formation process)
First, a core is prepared as an object to be coated. Examples of the core to be prepared include a cylindrical mold. Examples of the core material include metals such as aluminum, stainless steel, and nickel. The length of the core needs to be longer than the target endless belt, but is preferably 10% to 40% longer than the target endless belt.

Next, the polyimide precursor solution is applied to a cylindrical mold as a core to form a coating film of the polyimide precursor solution.
The method of applying the polyimide precursor solution to the cylindrical mold is not particularly limited. For example, a method of dip coating the outer peripheral surface of the cylindrical mold, a method of applying to the inner peripheral surface of the cylindrical mold, a shaft A method of applying a spiral to the outer peripheral surface or inner peripheral surface of the cylindrical mold while rotating the cylindrical mold, a method of applying using a die having a specific distance from the outer periphery of the cylindrical mold, etc. It is done.

(Heating process)
Next, a drying process is performed with respect to the coating film of a polyimide precursor solution. By this drying treatment, a film (dried film before imidization) is formed.
The heating conditions for the drying treatment are, for example, from 80 ° C. to 200 ° C. for 10 minutes to 60 minutes, and the higher the temperature, the shorter the heating time. It is also effective to apply hot air during heating. During heating, the temperature may be increased stepwise or increased without changing the speed. It is preferable to rotate the core body at 5 rpm or more and 60 rpm or less with the axial direction of the core body horizontal. The core may be vertical after drying.

Next, imidation treatment is performed on the film.
The heating conditions for the imidization treatment are, for example, 150 ° C. or more and 400 ° C. or less (preferably 200 ° C. or more and 300 ° C. or less), and the imidization reaction occurs by heating for 20 minutes or more and 60 minutes or less. It is formed. In the heating reaction, before reaching the final temperature of heating, it is preferable to heat by gradually increasing the temperature stepwise or at a constant rate.

  Through the above steps, a belt-shaped polyimide resin layer is formed on the core. Then, the polyimide resin layer is extracted from the core. Thereby, a transfer belt having a belt-like polyimide resin layer is obtained.

<Transfer belt unit>
FIG. 2 is a schematic perspective view showing the transfer belt unit according to this embodiment.
As shown in FIG. 2, the transfer belt unit 130 according to the present embodiment includes the transfer belt 10 according to the present embodiment. For example, the transfer belt 10 includes a driving roll 131 and a driven roll 132 that are arranged to face each other. Is stretched in a tensioned state (hereinafter simply referred to as “stretch”).
When the transfer belt 10 is used as an intermediate transfer member, the transfer belt unit 130 according to the present embodiment can, for example, apply a toner image on the surface of a photoreceptor (image holding member) as each of these rolls or in addition to each of these rolls. A roll for primary transfer onto the transfer belt 10 and a roll for secondary transfer of the toner image transferred onto the transfer belt 10 to a recording medium may be disposed. The number of rolls around which the transfer belt 10 is stretched is not limited, and may be arranged according to the usage mode.
The transfer belt unit 130 according to this embodiment having such a configuration is incorporated in an image forming apparatus as a transfer unit, for example, and the transfer belt 10 is also stretched as the driving roll 131 and the driven roll 132 rotate during image formation. Rotates in a suspended state.

<Image forming apparatus>
The image forming apparatus according to the present embodiment includes the transfer belt according to the present embodiment.
For example, the image forming apparatus according to the present embodiment includes the transfer belt according to the present embodiment as a transfer belt such as an intermediate transfer member (intermediate transfer belt) and a recording medium transport transfer member (recording medium transport transfer belt).

  The image forming apparatus according to the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, a latent image forming unit that forms a latent image on the surface of the image carrier, and an image carrier using toner. Developing means for developing a latent image on the surface of the toner, forming a toner image, transfer means for transferring the toner image formed on the surface of the image carrier to a recording medium, and fixing the toner image transferred to the recording medium And a fixing unit. The transfer unit includes the transfer belt according to the present embodiment.

  Specifically, the image forming apparatus according to this embodiment includes, for example, an intermediate transfer belt to which the toner image formed on the surface of the image carrier is transferred, and the toner image formed on the surface of the image carrier. Primary transfer means for primary transfer to the surface of the intermediate transfer belt, and secondary transfer means for secondary transfer of the toner image transferred to the surface of the intermediate transfer belt to a recording medium, the intermediate transfer belt as the above The structure provided with the transfer belt which concerns on this embodiment is mentioned.

  In addition, the image forming apparatus according to the present embodiment records, for example, a recording medium conveyance transfer belt for the transfer unit to convey the recording medium and a toner image formed on the image carrier by the recording medium conveyance transfer belt. And a transfer means for transferring to a medium, and the transfer belt according to the present embodiment as the recording medium conveyance transfer belt.

  The image forming apparatus according to the present exemplary embodiment may further include other known units as necessary, such as a cleaning unit that cleans the surface of the image carrier, a neutralization unit that neutralizes the image carrier, and the like. .

  The image forming apparatus according to the present embodiment is, for example, a normal monocolor image forming apparatus in which only a single color toner is accommodated in a developing device, and a toner image held on an image holding member is sequentially subjected to primary transfer to an intermediate transfer member. Well-known configurations such as a repetitive color image forming apparatus and a tandem color image forming apparatus in which a plurality of image carriers having developing units for respective colors are arranged in series on an intermediate transfer member are employed.

  Hereinafter, a specific example of the image forming apparatus according to the present exemplary embodiment will be described in detail with reference to the drawings.

  FIG. 3 is a schematic configuration diagram illustrating the image forming apparatus according to the present embodiment. This image forming apparatus uses the transfer belt according to this embodiment as an intermediate transfer member (intermediate transfer belt).

  An image forming apparatus 100 shown in FIG. 3 includes photoconductors (an example of an image carrier) 101Y, 101M, 101C, and 101BK, and a known electrophotographic process (on the surface thereof in accordance with the rotation in the direction of arrow A) ( An electrostatic latent image is formed according to image information (not shown) (in FIG. 3, a charging device, an exposure device, a cleaning device, etc. are not shown).

Around the photoreceptors 101Y, 101M, 101C, and 101BK, developing devices 105 to 108 corresponding to the respective colors of yellow (Y), magenta (M), cyan (C), and black (BK) are arranged. The electrostatic latent images formed on the photoreceptors 101Y, 101M, 101C, and 101BK are developed by the developing devices 105 to 108 to form toner images.
Therefore, for example, the electrostatic latent image written on the photoreceptor 101Y corresponds to yellow image information, and this electrostatic latent image is developed by the developing device 105 containing yellow (Y) toner, and is exposed to light. A yellow toner image is formed on the body 101Y.

  The intermediate transfer belt 102 is a belt-like intermediate transfer belt disposed so as to be in contact with the surfaces of the photoconductors 101Y, 101M, 101C, and 101BK, and an arrow is applied while being tensioned by the back roll 117 and the support rolls 118 to 119. Rotate in the direction of line B.

  The unfixed toner images formed on the photoconductors 101Y, 101M, 101C, and 101BK are sequentially transferred to the photoconductors 101Y, 101M at the respective primary transfer positions where the photoconductors 101Y, 101M, 101C, and 101BK are in contact with the intermediate transfer belt 102. , 101C and 101BK, the toner images of the respective colors are superimposed and transferred onto the surface of the intermediate transfer belt 102.

  In this primary transfer position, the pre-transfer contact area is charged by the shielding members 121 to 124 for suppressing the transfer electric field from acting on unnecessary areas of the intermediate transfer belt 102 on the back side of the intermediate transfer belt 102. Corona discharge devices are disposed as the primary transfer devices 109 to 112 which are prevented, and by applying a voltage having a polarity opposite to the charging polarity of the toner to the primary transfer devices 109 to 112, the photoconductors 101Y, 101M, 101C, The unfixed toner image on 101BK is electrostatically transferred to the outer peripheral surface of the intermediate transfer belt 102. The primary transfer devices 109 to 112 are not limited to the corona discharger as long as they use an electrostatic force, and may be a roll or a brush to which a voltage is applied.

  The unfixed toner image primarily transferred to the intermediate transfer belt 102 in this way is conveyed to a secondary transfer position facing the conveyance path of the recording medium 103 as the intermediate transfer belt 102 rotates. At the secondary transfer position, a secondary transfer roll 120 and a back roll 117 in contact with the back side of the intermediate transfer belt 102 are disposed with the intermediate transfer belt 102 interposed therebetween.

  The recording medium 103 carried out from the paper feed unit 113 by the feed roll 126 is inserted into a contact portion between the secondary transfer roll 120 and the intermediate transfer belt 102. At this time, a voltage is applied to the contact portion between the secondary transfer roll 120 and the back roll 117, and the unfixed toner image held on the intermediate transfer belt 102 is transferred to the recording medium 103 at the secondary transfer position. The

  Then, the recording medium 103 on which the unfixed toner image is transferred is peeled off from the intermediate transfer belt 102, and the heating roll 127 of the fixing device provided with the heating roll 127 and the pressure roll 128 facing each other by the conveying belt 115 is added to the heating roll 127. The unfixed toner image is fixed by being sent to the contact portion with the pressure roll 128. At this time, an apparatus configuration of a transfer fixing process in which the fixing process is performed together with the secondary transfer process may be employed.

  The intermediate transfer belt 102 is provided with a cleaning device 116. The cleaning device 116 is disposed so as to be able to contact and separate from the intermediate transfer belt 102 and is separated from the intermediate transfer belt 102 until the secondary transfer is performed.

  FIG. 4 is a schematic configuration diagram showing another image forming apparatus of the present embodiment. This image forming apparatus is an embodiment in which the transfer belt according to the present embodiment is applied as a recording medium conveyance transfer member (recording medium conveyance transfer belt).

  An image forming apparatus 200 shown in FIG. 4 includes image forming units 200Y, 200M, 200C, and 200Bk each including a photosensitive member, a charging device, a developing device, and a photosensitive member cleaning member, a recording medium conveyance transfer belt 206, a transfer roll 207Y, 207M, 207C, and 207Bk, a recording medium conveyance roll 208, and a fixing device 209 are provided.

  The image forming units 200Y, 200M, 200C, and 200Bk include photoconductors 201Y, 201M, 201C, and 201Bk that are image carriers that rotate in the direction of arrow A (clockwise direction). Around the photosensitive members 201Y, 201M, 201C, and 201Bk, charging devices 202Y, 202M, 202C, and 202Bk, exposure devices 203Y, 203M, 203C, and 203Bk, and color developing devices (yellow developing device 204Y, magenta developing device 204M, Cyan developing device 204C and black developing device 204Bk) and photosensitive member cleaning devices 205Y, 205M, 205C, and 205Bk are disposed, respectively.

  The four image forming units 200Y, 200M, 200C, and 200Bk are arranged in the order of the image forming units 200Bk, 200C, 200M, and 200Y in parallel with the recording medium conveyance transfer belt 206, but the image forming units 200Bk, 200Y are arranged. , 200C, 200M, etc., and the order is set according to the image forming method.

  The recording medium conveyance transfer belt 206 can be rotated by the support rolls 210, 211, 212, and 213 in the arrow B direction (counterclockwise direction) at the same peripheral speed as the photosensitive members 201Bk, 201C, 201M, and 201Y. Further, a part of the support rolls 212 and 213 located in the middle is arranged so as to be in contact with the photosensitive members 201Bk, 201C, 201M, and 201Y, respectively. The recording medium conveyance transfer belt 206 is provided with a cleaning device 214.

  The transfer rolls 207Bk, 207C, 207M, and 207Y are located inside the recording medium conveyance transfer belt 206 and at positions facing the portions where the recording medium conveyance transfer belt 206 is in contact with the photosensitive members 201Bk, 201C, 201M, and 201Y. The transfer areas are respectively arranged to transfer the toner image to the recording medium P via the photoconductors 201Bk, 201C, 201M, and 201Y and the recording medium conveyance transfer belt 206.

  The fixing device 209 is arranged so that it can be conveyed after passing through the transfer areas of the recording medium conveyance transfer belt 206 and the photosensitive members 201Bk, 201C, 201M, and 201Y.

  The recording medium P is conveyed to the recording medium conveyance transfer belt 206 by the recording medium conveyance roll 208.

  In the image forming unit 200Y, the photosensitive member 201Y is rotationally driven. In conjunction with this, the charging device 202Y is driven to charge the surface of the photoreceptor 201Y to a predetermined polarity / potential. Next, the photosensitive member 201Y whose surface is charged is exposed imagewise by the exposure device 203Y, and an electrostatic latent image is formed on the surface.

  Subsequently, the electrostatic latent image is developed by the yellow developing device 204Y. Then, a toner image is formed on the surface of the photoreceptor 201Y. The toner at this time may be either a one-component toner or a two-component toner, but here it is a two-component toner.

  When the toner image passes through the transfer area between the photoconductor 201Y and the recording medium conveyance transfer belt 206, the recording medium P is electrostatically attracted to the recording medium conveyance transfer belt 206 and conveyed to the transfer area. The image is sequentially transferred onto the outer peripheral surface of the recording medium P by an electric field formed by a transfer bias applied from the roll 207Y.

  Thereafter, the toner remaining on the photoconductor 201Y is cleaned and removed by the photoconductor cleaning device 205Y. Then, the photoreceptor 201Y is subjected to the next transfer cycle.

  The above transfer cycle is similarly performed in the image forming units 200M, 200C, and 200Bk.

  The recording medium P onto which the toner image has been transferred by the transfer rolls 207Bk, 207C, 207M, and 207Y is further conveyed to the fixing device 209 and fixed. Thus, the required image is formed on the recording medium.

  Here, the recording medium is usually a sheet-shaped recording medium (so-called paper) or a sheet-like material made of a relatively flexible material such as a recording medium (so-called OHP sheet) made of a plastic film. However, a plate-like member made of a material having a relatively high rigidity (for example, a thick plastic card) may be used as the recording medium.

  Examples will be described below, but the present invention is not limited to these examples. In the following description, “part” and “%” are all based on mass unless otherwise specified.

<Example 1>
[Production of Polyimide Precursor Composition (A-1)]
A flask equipped with a stir bar, thermometer, and dropping funnel was charged with 900 g of water. Here, 27.28 g (252.27 mmol) of p-phenylenediamine (hereinafter referred to as PDA: molecular weight 108.14) and 51.03 g of methylmorpholine (hereinafter referred to as MMO: aliphatic cyclic amine compound) (504) .54 mmol) was added and stirred at 20 ° C. for 10 minutes to disperse. To this solution, 72.72 g (247.16 mmol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (hereinafter referred to as BPDA: molecular weight 294.22) was added, and the reaction temperature was raised to 20 ° C. While being held, the mixture was stirred for 24 hours for dissolution and reaction to obtain a polyimide precursor aqueous solution (A-1).
In addition, the imidation ratio of the produced | generated polyimide precursor was 0.02, and as a result of the measurement of the amount of terminal amino groups as stated above, it contained what has an amino group at least at the terminal.

-Dispersing process-
21.34 g (polyimide precursor) of CB (1) (“SPECIAL BLACK4 (manufactured by Degussa)”, pH 4.0, volatile content: 14.0%) as carbon black was added to the obtained polyimide precursor aqueous solution (A-1). 24 parts) was added to the polyimide equivalent amount of 100 parts of the polyimide precursor contained in the body aqueous solution (A-1), and the resultant was treated with a ball mill for 6 hours to disperse the carbon black.
Thereby, a polyimide precursor composition (A-1) was obtained.

  Each measurement is as follows.

(Viscosity measurement method)
The viscosity was measured using an E-type viscometer under the following conditions.
・ Measuring device: E-type rotational viscometer TV-20H (Toki Sangyo Co., Ltd.)
・ Measurement probe: No. Type 3 rotor 3 ° × R14
・ Measurement temperature: 22 ℃

(Solid content measurement method)
The solid content was measured under the following conditions using a suggested thermothermographic apparatus. In addition, solid content was measured as a solid content rate as a polyimide with the measured value of 380 degreeC.
・ Measuring device: Differential thermothermal gravimetric simultaneous measuring device TG / DTA6200 (Seiko Instruments Inc.)
・ Measurement range: 20 ° C to 400 ° C · Temperature increase rate: 20 ° C / min

[Production of transfer belt]
A silicone-based mold release agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KS-700) was applied to the outer surface of a stainless steel cylindrical mold having an outer diameter of 90 mm and a length of 450 mm, followed by drying treatment (release agent treatment). .
While rotating the cylindrical mold subjected to the release agent treatment in the circumferential direction at a speed of 10 rpm, the polyimide precursor composition (A-1) as the coating liquid is 1.0 mm in diameter from the end of the cylindrical mold. While being discharged from the dispenser, the coating was performed while pressing with a metal blade placed on the mold with a uniform pressure. Specifically, the coating liquid was spirally applied onto the cylindrical mold by moving the dispenser unit in the axial direction of the cylindrical mold at a speed of 100 mm / min. After coating, the blade was released and the cylindrical mold continued to rotate for 2 minutes to perform leveling.

  Thereafter, the mold and the coated material were subjected to a drying treatment for 30 minutes while rotating at 10 rpm in an air atmosphere at 100 ° C. in a drying furnace. In the drying process, the solvent was volatilized from the coated material, so that a polyamic acid resin molded article (endless belt body) having self-supporting property was obtained from the coated material.

Next, a baking treatment was performed at 250 ° C. for 30 minutes in a clean oven to distill off the solvent and complete the imidization reaction.
Thereafter, the cylindrical mold was set to 25 ° C., the resin was removed from the cylindrical mold, and a transfer belt was obtained.

<Evaluation>
The obtained transfer belt was evaluated as follows.

(Film forming property)
The transfer belt was evaluated for (1) void marks and (2) surface unevenness / pattern.

(1) Void traces The presence or absence of void traces on the transfer belt surface was evaluated. The evaluation criteria are as follows.
A: No void mark is observed.
○: One or more and less than 10 void marks can be confirmed on the surface of the transfer belt.
Δ: 10 or more and less than 50 void marks are scattered on the surface of the transfer belt.
×: Innumerable void traces are uniformly generated on the surface of the transfer belt.

(2) Surface Unevenness / Pattern The surface unevenness and pattern presence / absence occurring on the transfer belt surface were evaluated. The evaluation criteria are as follows.
A: No surface unevenness or pattern is observed.
○: Surface unevenness and a slight pattern can be confirmed on a part of the transfer belt surface (less than 10% of the transfer belt surface area).
Δ: Surface unevenness and pattern can be confirmed on a part of the transfer belt surface.
×: Surface unevenness and pattern are uniformly generated on the transfer belt surface (10% or more of the transfer belt surface area).

(Mechanical properties: Measurement of tensile strength and elongation)
A sample piece was punched out from the produced transfer belt using dumbbell No. 3. The sample piece was installed in a tensile tester, and the applied load (tensile strength) and elongation at break (tensile elongation) at which the sample piece was pulled and broken were measured under the following conditions.
・ Test equipment: Tensile tester model 1605 manufactured by Aiko Enijing Co., Ltd. ・ Sample length: 30 mm
・ Sample width: 5mm
・ Tensile speed: 10mm / min

(Electrical properties: surface resistivity / volume resistivity measurement)
The produced transfer belt was measured for surface resistivity / volume resistivity according to the method described above.

(Image quality evaluation)
The obtained transfer belt was mounted as an intermediate transfer belt on a modified Apeos Port-III C4400 manufactured by Fuji Xerox Co., Ltd. (process speed: 250 mm / sec, modified to primary transfer current: 35 μA). At low temperature and low humidity (10 ° C, 15% RH), 50% halftone images of cyan and magenta were output on Fuji Xerox C2 paper, and density unevenness and spot defects were visually observed for the image quality of the 5000th output image. evaluated. Each evaluation standard is as follows.

-Density unevenness-
A: Density unevenness is not confirmed.
○: Density unevenness was slightly confirmed, but at a level with no problem.
X: Density unevenness was clearly confirmed.

-Spot defect-
A: Spot defects are not confirmed.
○: Spot defects were confirmed slightly, but there was no problem.
X: The spot defect was confirmed clearly.

  Table 1 shows the composition of the obtained polyimide precursor composition and the evaluation results of the obtained transfer belt.

<Examples 2 to 20>
[Preparation of polyimide precursor compositions (A-2) to (A-20)]
Except having changed the conditions of the polymerization process and dispersion | distribution process of a polyimide precursor composition into the conditions of following Table 1-2, it is the same as that of Example 1, and polyimide precursor composition (A-2)- (A-20) was produced.
Then, a transfer belt was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 1 and 2.

<Comparative Example 1>
[Preparation of polyimide precursor composition (X-1)]
A flask equipped with a stir bar, thermometer, and dropping funnel was charged with 900 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP). While passing dry nitrogen gas, 27.28 g (252.27 mmol) of PDA (molecular weight 108.14) was added. Stirring was performed while maintaining the solution temperature at 30 ° C., and 72.72 g (247.16 mmol) of BPDA (molecular weight 294.22) was gradually added. After confirming the dissolution of the diamine compound and tetracarboxylic dianhydride, the reaction was further carried out for 24 hours while maintaining the reaction temperature at 30 ° C. It was 50 Pas when the viscosity of the polyimide precursor solution (X-1) (solid content 10 mass%) was measured by the above-mentioned method.

Next, CB (1) ("SPECIAL BLACK4 (manufactured by Degussa)", pH 4.0, volatile content: 14.0%) as a carbon black, 25.48 g (polyimide precursor) was added to the polyimide precursor solution (X-1). 28 parts of the polyimide precursor contained in the body solution (X-1) was added in an amount of 100 parts, and the resultant was treated in a ball mill for 6 hours to disperse the carbon black.
The obtained polyimide precursor solution was designated as a polyimide precursor composition (X-1).

Using the obtained polyimide precursor composition (X-1), a transfer belt was produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 3.
As a result, when the firing temperature was 250 ° C. as in Example 1, NMP remained in the film, so that both the tensile strength and tensile elongation were lower than in Example 1. One of the causes is considered to be that the high boiling point NMP contained in the polyimide precursor composition (X-1) remains in the transfer belt, thereby causing a decrease in mechanical strength.

<Comparative example 2>
[Preparation of polyimide precursor composition (X-2)]
The polyimide precursor solution (X-1) produced in Comparative Example 1 was added to 10 times the volume of acetone to reprecipitate the polyimide precursor. After filtration, it was dried at 40 ° C./reduced pressure (10 mmHg) for 24 hours. After drying, 90 g of water and 4.43 g (9.71 mmol) of dimethylaminoethanol (hereinafter referred to as DMAEt: molecular weight 89.14) are added to 10 g of polyimide precursor (49.71 mmol equivalent of carboxyl group) at 25 ° C. And stirred for 6 hours to obtain a polyimide precursor solution (X-2).

Next, 23.66 g (polyimide precursor) of CB (1) (“SPECIAL BLACK4 (manufactured by Degussa)”, pH 4.0, volatile content: 14.0%) as carbon black was added to the polyimide precursor solution (X-2). 26 parts of the polyimide precursor contained in the body solution (X-2) was added in an amount of 100 parts, and the resultant was treated with a ball mill for 6 hours to disperse the carbon black.
The obtained polyimide precursor solution was defined as a polyimide precursor composition (X-2).

Using the obtained polyimide precursor composition (X-2), a transfer belt was produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
As a result, the film forming property was as good as in Example 1. As a result of the tensile test, it was found that both the tensile strength and the tensile elongation were lower than those of Example 1.
When the content of NMP remaining in the polyimide precursor composition (X-2) was analyzed by a liquid chromatography method, it was 6% by weight in the solvent. The cause of the decrease in the tensile properties of the film-forming sample using the polyimide precursor composition (X-2) is considered to be due to residual NMP in the transfer belt as in Comparative Example 1.

<Comparative Example 3>
[Preparation of polyimide precursor composition (X-3)]
An organic amine compound was added during the polymerization of Comparative Example 1, and polymerization was performed as shown below.
A flask equipped with a stir bar, thermometer, and dropping funnel was charged with 900 g of NMP. While passing dry nitrogen gas, 27.28 g (252.27 mmol) of PDA and 44.97 g (504.54 mmol) of DMAEt were added. Stirring was performed while maintaining the solution temperature at 30 ° C., and 72.72 g (247.16 mmol) of BPDA was gradually added. After confirming dissolution of the diamine compound and tetracarboxylic dianhydride, the reaction was further performed for 24 hours while maintaining the reaction temperature at 30 ° C. to obtain a polyimide precursor solution (X-3). It was 5 Pas when the viscosity of the polyimide precursor solution (X-3) (solid content 20 mass%) was measured by the above-mentioned method.

Next, CB (1) (“SPECIAL BLACK4 (manufactured by Degussa)”, pH 4.0, volatile content: 14.0%) 23.66 g (polyimide precursor) as carbon black in the polyimide precursor solution (X-3). 26 parts of the polyimide precursor contained in the body solution (X-3) was added in an amount of 100 parts, and the resultant was treated with a ball mill for 6 hours to disperse the carbon black.
The obtained polyimide precursor solution was defined as a polyimide precursor composition (X-3).
And using the obtained polyimide precursor composition (X-3), it carried out similarly to Example 1, produced the transfer belt, and evaluated it. The evaluation results are shown in Table 3.

<Comparative Example 4> [Preparation of polyimide precursor composition (X-4)]
A flask equipped with a stir bar, thermometer, and dropping funnel was charged with 450 g of water. Here, 13.44 g (124 mmol) of p-phenylenediamine (PDA) and 29.87 g (310.73 mmol) of 1,2-dimethylimidazole (1,2-DMZ: molecular weight 96.13) were added. And dissolved by stirring at 25 ° C. for 1 hour. To this solution was added 36.56 g (124 mmol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA), and after confirming dissolution of the diamine compound and tetracarboxylic dianhydride, further While maintaining the reaction temperature at 25 ° C., the reaction was conducted by stirring for 12 hours to obtain a polyimide precursor solution (X-4).
In addition, the imidation ratio of the produced | generated polyimide precursor is 0.05, As a result of the measurement of the amount of terminal amino groups as stated above, the amino group derived from an aromatic diamine compound was not substantially detected.

Next, CB (1) (“SPECIAL BLACK4 (manufactured by Degussa)”, pH 4.0, volatile content: 14.0%) as a carbon black, 25.48 g (polyimide precursor) was added to the polyimide precursor solution (X-4). 28 parts of the polyimide precursor contained in the body solution (X-4) was added in an amount of 100 parts, and the resultant was treated with a ball mill for 6 hours to disperse the carbon black.
The obtained polyimide precursor solution was defined as a polyimide precursor composition (X-4).
And using the obtained polyimide precursor composition (X-4), it carried out similarly to Example 1, produced the transfer belt, and evaluated it. The evaluation results are shown in Table 3.

<Comparative Example 5>
[Preparation of polyimide precursor composition (X-5)]
The amine compound added to the polyimide precursor aqueous solution (A-1) in Example 1 was changed to methylmorpholine (MMO / aliphatic cyclic amine, 504.54 mmol), and triethanolamine (hereinafter referred to as TEA: fat) Polymerization was carried out in the same manner as in Example 1 except that the group chain amine was 504.54 mmol), but the monomer did not dissolve and the polymerization could not be performed.

  From the above results, it can be seen that in this example, better results were obtained with respect to evaluation of film forming properties, mechanical properties, electrical properties, and image quality than the comparative example.

  Abbreviations in Tables 1 to 3 are as follows. In Tables 1 to 3, “-” means not added or not implemented, and “→” means the same as the left column.

Tetracarboxylic acid: “BPDA” (3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride), “PMDA” pyromellitic dianhydride, “BTDA” 3,4,3 ′, 4 ′ -Tetracarboxylic dianhydride / diamine compound: "PDA" (p-phenylenediamine), "ODA"(4,4'-diaminodiphenyl ether)
Amine compound: MMO (methylmorpholine), 1-methylpiperidine (molecular weight: 99.17), N-dimethylpiperazine (molecular weight: 114.19), pyrrolidine (molecular weight: 71.12), DMAEt (dimethylaminoethanol), 1,2-DMZ (1,2-dimethylimidazole), TEA (triethanolamine)
Solvent: NMP (N-methyl-2-pyrrolidone)

Carbon black CB (1): “SPECIAL BLACK4 (manufactured by Degussa)”, pH 4.0, volatile content: 14.0%
CB (2): “FW2 (manufactured by Orion Engineered Carbon)”, pH 2.5, volatile content: 20%)

  In this example, “treatment rate” is the amount of amine compound (mol%) relative to the theoretical amount of carboxyl groups contained in the polyimide precursor. Here, the theoretical amount of the carboxyl group indicates a value obtained by doubling the molar amount of tetracarboxylic acid contained in the polyimide precursor.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus, 101Y, 101M, 101C, 101BK Photoconductor, 102 Intermediate transfer belt, 105-108 Developer, 200 Image forming apparatus, 200Y, 200M, 200C, 200Bk Image forming unit, 206 Recording medium conveyance transfer belt

Claims (13)

A coating film of polyimide precursor composition is a transfer belt having a dry and a polyimide resin layer formed by imidization,
In the aqueous solvent, the polyimide precursor composition contains a resin having a repeating unit represented by the following general formula (I) and an imidization ratio of 0.2 or less, and an aliphatic cyclic amine compound. A transfer belt, which is a polyimide precursor composition in which conductive particles are dispersed .

(In general formula (I), A represents a tetravalent organic group, and B represents a divalent organic group.) The transfer belt according to claim 1, wherein the aliphatic cyclic amine compound is at least one compound selected from morpholines, piperidines, piperazines, pyrrolidines, and pyrazolidines. The transfer belt according to claim 1, wherein the aliphatic cyclic amine compound is at least one compound selected from morpholines. The transfer belt according to claim 1, wherein the aliphatic cyclic amine compound is a tertiary amine compound. The polyimide precursor composition, the aliphatic cyclic amine compound, the carboxyl groups contained in the resin, in any one of claims 1 to 4, containing at least 50 mole% 500 mole% or less The transfer belt described. The transfer belt according to claim 1, wherein the resin is synthesized from an aromatic tetracarboxylic dianhydride and an aromatic diamine compound. The resin is composed of at least one aromatic tetracarboxylic dianhydride selected from pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, and benzophenonetetracarboxylic dianhydride, phenylenediamine, and diaminodiphenyl ether. The transfer belt according to claim 1, which is synthesized from at least one selected aromatic diamine compound. The transfer belt according to claim 1, wherein the resin includes a resin having an amino group at a terminal. The transfer belt according to claim 1, wherein the number average molecular weight of the resin is 1000 or more and 100,000 or less. Forming a coating film polyimide precursor composition is applied onto a coating object,
A step of heat-treating the coating film to form a polyimide resin layer;
A transfer belt manufacturing method comprising :
In the aqueous solvent, the polyimide precursor composition contains a resin having a repeating unit represented by the following general formula (I) and an imidization ratio of 0.2 or less, and an aliphatic cyclic amine compound. A method for producing a transfer belt, which is a polyimide precursor composition in which conductive particles are dispersed .

(In general formula (I), A represents a tetravalent organic group, and B represents a divalent organic group.) The transfer belt according to any one of claims 1 to 9 ,
A plurality of rolls over which the transfer belt is tensioned;
Transfer belt unit equipped with. Image forming apparatus comprising a transfer belt according to any one of claims 1-9. An image carrier,
Charging means for charging the surface of the image carrier;
Latent image forming means for forming a latent image on the surface of the image carrier;
Developing means for developing a latent image on the surface of the image carrier with toner to form a toner image;
An intermediate transfer belt to which the toner image formed on the surface of the image carrier is transferred, the intermediate transfer belt comprising the transfer belt according to any one of claims 1 to 9 ,
Primary transfer means for primarily transferring the toner image formed on the surface of the image carrier onto the surface of the intermediate transfer belt;
Secondary transfer means for secondary transfer of the toner image transferred to the surface of the intermediate transfer belt to a recording medium;
Fixing means for fixing the toner image transferred to the recording medium;
An image forming apparatus.