Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Abstract

The invention discloses an electrophotographic photoreceptor, a process cartridge, and an image forming apparatus, the electrophotographic photoreceptor includes a conductive substrate and a laminated photosensitive layer disposed on the conductive substrate and having a charge generation layer and a charge transport layer. The charge transport layer contains a charge transport material and at least one of a polyester resin and a polycarbonate resin having a structural unit containing a biphenyl represented by formula (1), and the acid value of the charge transport layer is 2 mgKOH / g or less. In formula (1) # imgabs0 #, j is an integer from 0 to 4 (inclusive), j R11 is each independently a methyl group or an ethyl group, k is an integer from 0 to 4 (inclusive), and k R12 is each independently a methyl group or an ethyl group.

Description

Technical Field

[0001] The present invention relates to an electrophotographic photoreceptor, a processing cartridge, and an image forming apparatus. Background Art

[0002] In Japanese Patent Laid-Open No. 2014-209221, an electrophotographic photoreceptor is disclosed which has at least a photosensitive layer on a conductive support, wherein the photosensitive layer contains a polyarylate resin having a carboxylic acid terminal value of 100 μeq / g or more and 500 μeq / g or less and a triphenylamine compound.

[0003] In Japanese Patent Laid-Open No. 2023-121554, an electrophotographic photoreceptor is disclosed which includes a conductive substrate and a laminate photosensitive layer having a charge generation layer and a charge transport layer, the charge transport layer containing a charge transport material, at least one of a polyester resin having a structural unit containing an aromatic ring and a polycarbonate resin having a structural unit containing an aromatic ring, and a compound represented by a specified chemical formula and having a melting point of 40°C or more. Summary of the Invention

[0004] An object of the present invention is to provide an electrophotographic photoreceptor having excellent abrasion resistance and not easily forming a film.

[0005] According to a first aspect of the present invention, there is provided an electrophotographic photoreceptor comprising: a conductive substrate; and a laminate photosensitive layer disposed on the conductive substrate and having a charge generation layer and a charge transport layer, the charge transport layer containing a charge transport material and at least one of a polyester resin and a polycarbonate resin having a structural unit containing biphenyl represented by formula (1), and the acid value of the charge transport layer being 2 mgKOH / g or less.

[0006] Formula (1)

[0007] In formula (1), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl.

[0008] According to a second aspect of the present invention, in the electrophotographic photoreceptor of the first aspect, the mass ratio of the charge transport material in the charge transport layer is 30% by mass or more and 50% by mass or less.

[0009] According to the third aspect of the present invention, in the electrophotographic photoreceptor of the first or second aspect, the polyester resin has at least one of the dicarboxylic acid unit (1-A) represented by the formula (1-A) and the glycol unit (1-B) represented by the formula (1-B), and the polycarbonate resin has the structural unit (1-C) represented by the formula (1-C).

[0010] Formula (1-A)

[0011] Formula (1B)

[0012] Formula (11-C)

[0013] In the formula (1-A), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, and L A is a single bond or a divalent linking group, and Ar A is an aromatic ring which may have a substituent, and n A is 0, 1 or 2.

[0014] In the formula (1-B), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, and L B is a single bond or a divalent linking group, and Ar B is an aromatic ring which may have a substituent, and n B is 0, 1 or 2.

[0015] In the formula (1-C), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, and L C is a single bond or a divalent linking group, and Ar C is an aromatic ring which may have a substituent, and n C is 0, 1 or 2.

[0016] According to the fourth aspect of the present invention, there is provided an electrophotographic photoreceptor including: a conductive substrate; and a single-layer photosensitive layer disposed on the conductive substrate, the single-layer photosensitive layer containing a charge transport material and at least one of a polyester resin and a polycarbonate resin having a structural unit containing biphenyl represented by the following formula (1), and the acid value of the single-layer photosensitive layer is 2 mgKOH / g or less.

[0017] Formula (1)

[0018] In Formula (1), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl.

[0019] According to the fifth aspect of the present invention, in the electrophotographic photoreceptor of the fourth aspect, the mass ratio of the charge transport material in the single-layer photosensitive layer is 40% by mass or more and 60% by mass or less.

[0020] According to the sixth aspect of the present invention, in the electrophotographic photoreceptor of the fourth or fifth aspect, the polyester resin has at least one of the dicarboxylic acid unit (1-A) represented by Formula (1-A) and the glycol unit (1-B) represented by Formula (1-B), and the polycarbonate resin has the structural unit (1-C) represented by Formula (1-C).

[0021] Formula (1-A)

[0022] Formula (1B)

[0023] Formula (1-C)

[0024] In Formula (1-A), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, L A is a single bond or a divalent linking group, Ar A is an aromatic ring which may have a substituent, n A is 0, 1 or 2.

[0025] In Formula (1-B), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, L B is a single bond or a divalent linking group, Ar B is an aromatic ring which may have a substituent, n B is 0, 1 or 2.

[0026] In Formula (1-C), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs12 is independently methyl or ethyl, and L C is a single bond or a divalent linking group, and Ar C is an aromatic ring which may have substituents, and n C is 0, 1 or 2.

[0027] According to the seventh aspect of the present invention, there is provided a process cartridge including the electrophotographic photoreceptor according to any one of the first to sixth aspects, the process cartridge being detachably attached to an image forming apparatus.

[0028] According to the eighth aspect of the present invention, there is provided an image forming apparatus including: the electrophotographic photoreceptor according to any one of the first to sixth aspects; a charging device that charges a surface of the electrophotographic photoreceptor; an electrostatic latent image forming device that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor; a developing device that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing toner to form a toner image; and a transfer device that transfers the toner image onto a surface of a recording medium.

[0029] (Effect)

[0030] According to the first, second or third aspect, there is provided an electrophotographic photoreceptor which is excellent in abrasion resistance and less likely to form a film as compared with an electrophotographic photoreceptor having a laminated photosensitive layer and an acid value of a charge transport layer exceeding 2 mgKOH / g.

[0031] According to the fourth, fifth or sixth aspect, there is provided an electrophotographic photoreceptor which is excellent in abrasion resistance and less likely to form a film as compared with an electrophotographic photoreceptor having a single-layer photosensitive layer and an acid value of the single-layer photosensitive layer exceeding 2 mgKOH / g.

[0032] According to the seventh aspect, there is provided a process cartridge including an electrophotographic photoreceptor which is excellent in abrasion resistance and less likely to form a film as compared with an electrophotographic photoreceptor having a charge transport layer of a laminated photosensitive layer or an acid value of a single-layer photosensitive layer exceeding 2 mgKOH / g.

[0033] According to the eighth aspect, there is provided an image forming apparatus including an electrophotographic photoreceptor which is excellent in abrasion resistance and less likely to form a film as compared with an electrophotographic photoreceptor having a charge transport layer of a laminated photosensitive layer or an acid value of a single-layer photosensitive layer exceeding 2 mgKOH / g. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a partial cross-sectional view showing an example of a layer structure of the electrophotographic photoreceptor according to the first embodiment.

[0035] Figure 2 This is a partial cross-sectional view showing an example of the layer structure of the electrophotographic photoreceptor according to the second embodiment.

[0036] Figure 3 This is a schematic structural diagram showing an example of the image forming apparatus according to the present embodiment.

[0037] Figure 4 This is a schematic structural diagram showing another example of the image forming apparatus according to the present embodiment. Detailed Embodiments

[0038] Hereinafter, embodiments of the present invention will be described. These descriptions and examples are illustrative of the embodiments and do not limit the scope of the embodiments.

[0039] In the present invention, a numerical range shown using "~" represents a range that includes the numerical values described before and after "~" as the minimum value and the maximum value, respectively.

[0040] In the numerical ranges described in stages in the present invention, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of other numerically described ranges. Further, within the numerical ranges described in the present invention, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0041] In the present invention, "A and / or B" has the same meaning as "at least one of A and B". That is, "A and / or B" means that it may be only A, only B, or a combination of A and B.

[0042] In the present invention, the term "step" includes not only an independent step but also, in cases where it cannot be clearly distinguished from other steps, as long as it can achieve the purpose of the step.

[0043] In the present invention, when describing an embodiment with reference to the drawings, the structure of the embodiment is not limited to the structure shown in the drawings. Further, the sizes of the components in each drawing are conceptual, and the relative size relationships between the components are not limited thereto.

[0044] In the present invention, each component may contain a plurality of corresponding substances. In the present invention, when referring to the amount of each component in a composition, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the plurality of substances present in the composition.

[0045] In the present invention, a plurality of particles corresponding to each component may be contained. When there are a plurality of particles corresponding to each component in the composition, unless otherwise specified, the particle size of each component means a value for the mixture of the plurality of particles present in the composition.

[0046] In the present invention, unless otherwise specified, the alkyl group and the alkylene group also include any of linear, branched, and cyclic forms.

[0047] In the present invention, regarding organic groups, aromatic rings, linking groups, alkyl groups, alkylene groups, aryl groups, aralkyl groups, alkoxy groups, aryloxy groups, etc., the hydrogen atoms in the groups may be substituted by halogen atoms.

[0048] In the present invention, when representing a compound by a structural formula, sometimes a structural formula in which the symbols (C and H) representing the carbon atoms and hydrogen atoms in the hydrocarbon group and / or hydrocarbon chain are omitted is used.

[0049] In the present invention, the "structural unit" of a copolymer or a resin has the same meaning as the monomer unit.

[0050] <Electrophotographic photoreceptor>

[0051] The present invention provides a first embodiment and a second embodiment as an electrophotographic photoreceptor (hereinafter, also referred to as "photoreceptor").

[0052] The photoreceptor of the first embodiment includes a conductive substrate and a laminated photosensitive layer disposed on the conductive substrate and having a charge generation layer and a charge transport layer. The photoreceptor of the first embodiment may further include other layers (for example, an undercoat layer and an intermediate layer).

[0053] The photoreceptor of the second embodiment includes a conductive substrate and a single-layer photosensitive layer disposed on the conductive substrate. The photoreceptor of the second embodiment may further include other layers (for example, an undercoat layer and an intermediate layer).

[0054] Figure 1 It is a partial cross-sectional view schematically showing an example of the layer structure of the photoreceptor of the first embodiment. Figure 1 The shown photoreceptor 10A has a laminated photosensitive layer. The photoreceptor 10A has a structure in which an undercoat layer 2, a charge generation layer 3, and a charge transport layer 4 are sequentially laminated on a conductive substrate 1, and the charge generation layer 3 and the charge transport layer 4 constitute a photosensitive layer 5 (so-called function-separated photosensitive layer). The photoreceptor 10A may have an intermediate layer (not shown) between the undercoat layer 2 and the charge generation layer 3. The undercoat layer 2 may or may not be present.

[0055] Figure 2 It is a partial cross-sectional view schematically showing an example of the layer structure of the photoreceptor of the second embodiment. Figure 2 The shown photoreceptor 10B has a single-layer photosensitive layer. The photoreceptor 10B has a structure in which an undercoat layer 2 and a photosensitive layer 5 are sequentially laminated on a conductive substrate 1. The photoreceptor 10B may have an intermediate layer (not shown) between the undercoat layer 2 and the photosensitive layer 5. The undercoat layer 2 may or may not be present.

[0056] Regarding the photoreceptor of the first embodiment, the charge transport layer contains a charge transport material and at least one of a polyester resin and a polycarbonate resin having a structural unit containing biphenyl represented by the following formula (1), and the acid value of the charge transport layer is 2 mgKOH / g or less.

[0057] Regarding the photoreceptor of the second embodiment, the single-layer photoreceptive layer contains a charge transport material and at least one of a polyester resin and a polycarbonate resin having a structural unit containing biphenyl represented by the following formula (1), and the acid value of the single-layer photoreceptive layer is 2 mgKOH / g or less.

[0058] Formula (1)

[0059] In formula (1), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl.

[0060] The biphenyl represented by formula (1) may be the whole or a part of the structure obtained by removing a polyester bond (-C(=O)O-) or a carbonate bond (-OC(=O)O-) from the structural unit containing biphenyl represented by formula (1). In other words, the right end and the left end of the biphenyl represented by formula (1) may be directly bonded to the polyester bond or the carbonate bond respectively independently, or may be bonded to the polyester bond or the carbonate bond via other atoms or atomic groups.

[0061] Hereinafter, when explaining the matters common to the first embodiment and the second embodiment, the two embodiments are collectively referred to as this embodiment.

[0062] The photoreceptor of this embodiment has excellent abrasion resistance and is not prone to film formation. The mechanism is presumed as follows. In the following description, the charge transport layer of the laminate-type photoreceptive layer and the single-layer photoreceptive layer are collectively referred to as the "photoreceptive layer".

[0063] In the photoreceptive layer containing at least one of a polyester resin and a polycarbonate resin as a binder resin and having a structural unit containing biphenyl represented by formula (1), the cohesion between the binder resins is enhanced by the stacking action of the biphenyls represented by formula (1), and the abrasion resistance of the photoreceptive layer is improved.

[0064] However, by making the abrasion resistance of the photoreceptive layer excellent, the renewal of the photoreceptor surface is suppressed, and sometimes the components of the toner adhere to cause film formation.

[0065] By controlling the acid value of the photosensitive layer of the present embodiment to a low value, that is, by reducing the content of acid radicals contained in the photosensitive layer, the adhesion of substances that react with or are attracted by acid radicals is suppressed. As a result, it is presumed that film formation is less likely to occur on the surface of the photoreceptor.

[0066] Regarding the photoreceptor of the first embodiment, from the viewpoint of suppressing the generation of film formation, the lower the acid value of the charge transport layer, the better. The acid value of the charge transport layer is 2 mgKOH / g or less, preferably 1.5 mgKOH / g or less, and more preferably 1 mgKOH / g or less.

[0067] Regarding the photoreceptor of the second embodiment, from the viewpoint of suppressing the generation of film formation, the lower the acid value of the single-layer type photosensitive layer, the better. The acid value of the single-layer type photosensitive layer is 2 mgKOH / g or less, preferably 1.5 mgKOH / g or less, and more preferably 1 mgKOH / g or less.

[0068] As a method for adjusting the acid value of the charge transport layer or the single-layer type photosensitive layer, the following methods can be cited.

[0069] When polymerizing a polyester resin or a polycarbonate resin used as a binder resin for the charge transport layer or the single-layer type photosensitive layer, use a capping agent in an appropriate amount; improve the purity of the monomer as a raw material; dissolve the monomer sufficiently and then start the polymerization reaction; set the concentration of dicarboxylic acid (specifically, dicarboxylic acid chloride) or carbonyl chloride in the polymerization reaction system to a low level, etc.

[0070] The method for measuring the acid value of the charge transport layer or the single-layer type photosensitive layer is as follows. In the following description, the charge transport layer and the single-layer type photosensitive layer of the laminated type photosensitive layer are collectively referred to as the "photosensitive layer".

[0071] Peel the photosensitive layer from the photoreceptor and accurately weigh 500 mg. Mix 500 mg of the photosensitive layer and 20 ml of tetrahydrofuran, stir well, dissolve or disperse the components of the photosensitive layer in tetrahydrofuran, and use it as a titration sample. Using a potentiometric automatic titrator, add a 0.005 mol / L potassium hydroxide·isopropanol solution to the titration sample drop by drop at 0.01 mL each to prepare a titration curve. Take the inflection point of the titration curve as the end point, and obtain the titration volume to the end point. Calculate the acid value (mgKOH / g) of the photosensitive layer based on the titration volume and the mass (500 mg) of the photosensitive layer used for titration.

[0072] Next, the polyester resin and the polycarbonate resin having a structural unit containing biphenyl represented by formula (1) will be described in detail.

[0073] [Polyester Resin (1)]

[0074] In the present invention, the polyester resin having a structural unit containing biphenyl represented by formula (1) is referred to as polyester resin (1).

[0075] Formula (1)

[0076] In formula (1), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl.

[0077] j is an integer of 0 or more and 4 or less, preferably an integer of 0 or more and 3 or less, more preferably an integer of 0 or more and 2 or less, still more preferably 0 or 1, and particularly preferably 0.

[0078] When j is an integer of 1 or more, j Rs 11 are each independently methyl or ethyl, preferably methyl.

[0079] k is an integer of 0 or more and 4 or less, preferably an integer of 0 or more and 3 or less, more preferably an integer of 0 or more and 2 or less, still more preferably 0 or 1, and particularly preferably 0.

[0080] When k is an integer of 1 or more, k Rs 12 are each independently methyl or ethyl, preferably methyl.

[0081] Regarding polyester resin (1), from the viewpoint of having a structural unit containing biphenyl represented by formula (1) in the molecule, it is preferably to have at least one of the dicarboxylic acid unit (1-A) represented by the following formula (1-A) and the diol unit (1-B) represented by formula (1-B), and more preferably to have the dicarboxylic acid unit (1-A) represented by formula (1-A).

[0082] Formula (1-A)

[0083] In formula (1-A), j is an integer of 0 or more and 4 or less, j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, k Rs 12 are each independently methyl or ethyl, L A is a single bond or a divalent linking group, Ar A is an aromatic ring which may have a substituent, and n A is 0, 1 or 2.

[0084] j, k, R in formula (1-A) 11 and R 12 are respectively the same as j, k, R in formula (1) 11 and R12 They have the same meaning, and the specific methods and preferred methods are also the same.

[0085] When L A is a divalent linking group, as the divalent linking group, for example, an oxygen atom, a sulfur atom, -C(Ra 1 )(Ra 2 )- can be cited. Here, Ra 1 and Ra 2 are each independently a hydrogen atom, an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an aralkyl group having 7 or more and 20 or less carbon atoms, and Ra 1 and Ra 2 can bond to form a cyclic alkyl group.

[0086] Ra 1 and Ra 2 The alkyl group having 1 or more and 10 or less carbon atoms may be any of linear, branched, and cyclic. The number of carbon atoms of the alkyl group is preferably 1 or more and 6 or less, more preferably 1 or more and 4 or less, and further preferably 1 or 2.

[0087] Ra 1 and Ra 2 The aryl group having 6 or more and 12 or less carbon atoms may be any of monocyclic and polycyclic. The number of carbon atoms of the aryl group is preferably 6 or more and 10 or less, and more preferably 6.

[0088] Ra 1 and Ra 2 The alkyl group in the aralkyl group having 7 or more and 20 or less carbon atoms may be any of linear, branched, and cyclic. The number of carbon atoms of the alkyl group in the aralkyl group having 7 or more and 20 or less carbon atoms is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less, and further preferably 1 or 2.

[0089] Ra 1 and Ra 2 The aryl group in the aralkyl group having 7 or more and 20 or less carbon atoms may be any of monocyclic and polycyclic. The number of carbon atoms of the aryl group is preferably 6 or more and 10 or less, and more preferably 6.

[0090] Ar A The aromatic ring of Ar may be any of monocyclic and polycyclic. As the aromatic ring, for example, a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring can be cited, and a benzene ring and a naphthalene ring are preferred.

[0091] Ar A The hydrogen atom on the aromatic ring of Ar may be substituted with an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a halogen atom, etc. As Ar AWhen the aromatic ring is substituted, the substituent is preferably an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0092] Formula (1-B)

[0093] In formula (1-B), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, and L B is a single bond or a divalent linking group, and Ar B is an aromatic ring which may have a substituent, and n B is 0, 1, or 2.

[0094] j, k, and R in formula (1-B) 11 and R 12 correspond to j, k, and R in formula (1) respectively, and the specific manners and preferred manners are also the same. 11 and R 12 have the same meanings, and the specific manners and preferred manners are also the same.

[0095] When L B is a divalent linking group, examples of the divalent linking group include an oxygen atom, a sulfur atom, -C(Rb 1 )(Rb 2 ). Here, Rb 1 and Rb 2 are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and Rb 1 and Rb 2 may bond to form a cyclic alkyl group.

[0096] Rb 1 and Rb 2 The alkyl group having 1 to 10 carbon atoms may be linear, branched, or cyclic. The number of carbon atoms of the alkyl group is preferably 1 to 6, more preferably 1 to 4, and further preferably 1 or 2.

[0097] Rb 1 and Rb 2 The aryl group having 6 to 12 carbon atoms may be monocyclic or polycyclic. The number of carbon atoms of the aryl group is preferably 6 to 10, more preferably 6.

[0098] Rb 1 and Rb 2The alkyl group in the aralkyl group having 7 or more and 20 or less carbon atoms may be any of linear, branched and cyclic. The number of carbon atoms of the alkyl group in the aralkyl group having 7 or more and 20 or less carbon atoms is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less, and still more preferably 1 or 2.

[0099] Rb 1 and Rb 2 The aryl group in the aralkyl group having 7 or more and 20 or less carbon atoms may be either monocyclic or polycyclic. The number of carbon atoms of the aryl group is preferably 6 or more and 10 or less, and more preferably 6.

[0100] Ar B The aromatic ring may be either monocyclic or polycyclic. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring, and a benzene ring and a naphthalene ring are preferred.

[0101] Ar B The hydrogen atom on the aromatic ring of Ar may be substituted with an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a halogen atom, etc. As the substituent when the aromatic ring of Ar B is substituted, an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, and an alkoxy group having 1 or more and 6 or less carbon atoms are preferred.

[0102] The dicarboxylic acid unit (1-A) represented by the formula (1-A) is preferably the dicarboxylic acid unit (11-A) represented by the following formula (11-A).

[0103] The diol unit (1-B) represented by the formula (1-B) is preferably the diol unit (11-B) represented by the following formula (11-B).

[0104] Formula (11-A)

[0105] Formula (11-B)

[0106] In the formula (11-A), j is an integer of 0 or more and 4 or less, and j R 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k R 12 are each independently methyl or ethyl.

[0107] In the formula (11-B), j is an integer of 0 or more and 4 or less, and j R 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k R 12 are each independently methyl or ethyl.

[0108] j, k, R in the formula (11-A) 11 and R 12are respectively the same as j, k, and R in Formula (1) 11 and R 12 have the same meaning, and the specific and preferred manners are also the same.

[0109] j, k, and R in Formula (11-B) 11 and R 12 are respectively the same as j, k, and R in Formula (1) 11 and R 12 have the same meaning, and the specific and preferred manners are also the same.

[0110] As specific examples of the dicarboxylic acid unit (1-A), the following dicarboxylic acid units (1-A1) to (1-A10) can be cited. The dicarboxylic acid unit (1-A) is not limited thereto.

[0111]

[0112] As the dicarboxylic acid unit (1-A), it is preferably at least one selected from the group consisting of the dicarboxylic acid units (1-A3) to (1-A7), more preferably at least one selected from the group consisting of the dicarboxylic acid units (1-A3) to (1-A6), and still more preferably the dicarboxylic acid unit (1-A3).

[0113] As specific examples of the diol unit (1-B), the following diol units (1-B1) to (1-B10) can be cited.

[0114] The diol unit (1-B) is not limited thereto.

[0115]

[0116] As the diol unit (1-B), it is preferably at least one selected from the group consisting of the diol units (1-B3) to (1-B7), more preferably at least one selected from the group consisting of the diol units (1-B3) to (1-B6), and still more preferably the diol unit (1-B3).

[0117] The total mass ratio of the structural unit containing the biphenyl shown in Formula (1) in the polyester resin (1) is preferably 15% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 55% by mass or less, and still more preferably 25% by mass or more and 50% by mass or less.

[0118] The polyester resin (1) may also have a structural unit other than the structural unit containing the biphenyl shown in Formula (1). Hereinafter, the structural unit other than the structural unit containing the biphenyl shown in Formula (1) will be described.

[0119] The polyester resin (1) may also have at least one dicarboxylic acid unit (A) selected from the group consisting of the dicarboxylic acid unit (A1) represented by the following formula (A1), the dicarboxylic acid unit (A3) represented by the formula (A3), and the dicarboxylic acid unit (A4) represented by the formula (A4).

[0120] When the polyester resin (1) has the dicarboxylic acid unit (A), the dicarboxylic acid unit (A) may be one kind or two or more kinds. As the dicarboxylic acid unit (A), at least one selected from the group consisting of the dicarboxylic acid unit (A3) and the dicarboxylic acid unit (A4) is preferred.

[0121] Formula (A1)

[0122] In formula (A1), n 101 is an integer of 0 or more and 4 or less, and n 101 Ra groups 101 are each independently an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms.

[0123] n 101 is preferably 0, 1 or 2, more preferably 0 or 1, and still more preferably 0.

[0124] Formula (A3)

[0125] In formula (A3), n 301 and n 302 are each independently an integer of 0 or more and 4 or less, and n 301 Ra groups 301 and n 302 Ra groups 302 are each independently an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an alkoxy group having 1 or more and 6 or less carbon atoms.

[0126] n 301 is preferably 0, 1 or 2, more preferably 0 or 1, and further preferably 0.

[0127] n 302 is preferably 0, 1 or 2, more preferably 0 or 1, and further preferably 0.

[0128] Formula (A4)

[0129] In formula (A4), n 401 is an integer of 0 or more and 6 or less, and n 401 Ra groups 401Each is independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0130] n 401 It is preferably an integer of 0 or more and 4 or less, more preferably 0, 1 or 2, and still more preferably 0.

[0131] Ra of formula (A1) 101 and Ra of formula (A3) 301 and Ra 302 and Ra of formula (A4) 401 have the same specific and preferred forms. Therefore, hereinafter, Ra 101 and Ra 301 and Ra 302 and Ra 401 are collectively referred to as "Ra" for description.

[0132] The alkyl group having 1 to 10 carbon atoms of Ra can be any of linear, branched, and cyclic. The number of carbon atoms of the alkyl group is preferably 1 or more and 6 or less, more preferably 1 or more and 4 or less, and still more preferably 1 or 2.

[0133] Examples of the linear alkyl group having 1 to 10 carbon atoms include: methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl.

[0134] Examples of the branched alkyl group having 3 to 10 carbon atoms include: isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, sec-hexyl, tert-hexyl, isoheptyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodecyl, sec-decyl, tert-decyl, etc.

[0135] Examples of the cyclic alkyl group having 3 to 10 carbon atoms include: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and polycyclic (e.g., bicyclic, tricyclic, spirocyclic) alkyl groups formed by linking these monocyclic alkyl groups.

[0136] The aryl group having 6 to 12 carbon atoms of Ra can be either monocyclic or polycyclic. The number of carbon atoms of the aryl group is preferably 6 or more and 10 or less, and more preferably 6.

[0137] Examples of the aryl group having 6 to 12 carbon atoms include: phenyl, biphenyl, 1-naphthyl, 2-naphthyl, etc.

[0138] The alkyl group in the alkoxy group having 1 to 6 carbon atoms of Ra may be linear, branched or cyclic. The number of carbon atoms of the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and further preferably 1 or 2.

[0139] Examples of the linear alkoxy group having 1 to 6 carbon atoms include: methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, n-hexyloxy.

[0140] Examples of the branched alkoxy group having 3 to 6 carbon atoms include: isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy, tert-hexyloxy, etc.

[0141] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include: cyclopropoxy, cyclobutoxy, cyclopentyloxy, cyclohexyloxy, etc.

[0142] Hereinafter, as specific examples of the dicarboxylic acid unit (A1), dicarboxylic acid units (A1-1) to (A1-9) are shown. The dicarboxylic acid unit (A1) is not limited thereto.

[0143]

[0144] Hereinafter, as specific examples of the dicarboxylic acid unit (A3), dicarboxylic acid units (A3-1) to (A3-2) are shown.

[0145] The dicarboxylic acid unit (A3) is not limited thereto.

[0146]

[0147] Hereinafter, as specific examples of the dicarboxylic acid unit (A4), dicarboxylic acid units (A4-1) to (A4-3) are shown.

[0148] The dicarboxylic acid unit (A4) is not limited thereto.

[0149]

[0150] As the dicarboxylic acid unit (A), it is preferably at least one selected from the group consisting of (A1-1), (A1-7), (A3-2) and (A4-3) of the above specific examples, and more preferably at least one selected from the group consisting of (A3-2) and (A4-3).

[0151] When the polyester resin (1) has a dicarboxylic acid unit (A), the total mass ratio of the dicarboxylic acid unit (A) in the polyester resin (1) is preferably 15% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 55% by mass or less, and still more preferably 25% by mass or more and 50% by mass or less.

[0152] The polyester resin (1) may also have a structural unit containing biphenyl represented by formula (1) and other dicarboxylic acid units other than the dicarboxylic acid unit (A). Examples of other dicarboxylic acid units include: aliphatic dicarboxylic acid (such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, pentenedioic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid) units, alicyclic dicarboxylic acid (such as cyclohexanedicarboxylic acid) units, and their lower (such as 1 to 5 carbon atoms) alkyl ester units. These dicarboxylic acid units contained in the polyester resin (1) may be one kind or two or more kinds.

[0153] The polyester resin (1) may also have at least one glycol unit (B) selected from the group consisting of the glycol unit (B1) represented by the following formula (B1), the glycol unit (B2) represented by formula (B2), the glycol unit (B3) represented by formula (B3), the glycol unit (B4) represented by formula (B4), the glycol unit (B5) represented by formula (B5), the glycol unit (B6) represented by formula (B6), and the glycol unit (B8) represented by formula (B8).

[0154] When the polyester resin (1) has a glycol unit (B), the glycol unit (B) may be one kind or two or more kinds.

[0155] As the glycol unit (B), it is preferably at least one selected from the group consisting of the glycol unit (B1), the glycol unit (B2), the glycol unit (B4), the glycol unit (B5), and the glycol unit (B6),

[0156] More preferably, it is at least one selected from the group consisting of the glycol unit (B1), the glycol unit (B2), the glycol unit (B5), and the glycol unit (B6),

[0157] Still more preferably, it is at least one selected from the group consisting of the glycol unit (B1), the glycol unit (B2), and the glycol unit (B6),

[0158] Most preferably, it is at least one selected from the group consisting of the glycol unit (B1) and the glycol unit (B2).

[0159] Formula (B1)

[0160] In formula (B1), Rb 101is a branched alkyl group having 4 to 20 carbon atoms, Rb 201 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 401 , Rb 501 , Rb 801 and Rb 901 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0161] Rb 101 The branched alkyl group having 4 to 20 carbon atoms of Rb preferably has 4 to 16 carbon atoms, more preferably 4 to 12 carbon atoms, and further preferably 4 to 8 carbon atoms. As Rb 101 Specific examples include: isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, sec-hexyl, tert-hexyl, isoheptyl, sec-heptyl, tert-heptyl, isooctyl, sec-octyl, tert-octyl, isononyl, sec-nonyl, tert-nonyl, isodecyl, sec-decyl, tert-decyl, isododecyl, sec-dodecyl, tert-dodecyl, tert-tetradecyl, tert-pentadecyl, etc.

[0162] Formula (B2)

[0163] In formula (B2), Rb 102 is a straight-chain alkyl group having 4 to 20 carbon atoms, Rb 202 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 402 , Rb 502 , Rb 802 and Rb 902 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0164] Rb 102 The straight-chain alkyl group having 4 to 20 carbon atoms of Rb preferably has 4 to 16 carbon atoms, more preferably 4 to 12 carbon atoms, and further preferably 4 to 8 carbon atoms. As Rb 102 Specific examples include: n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, tridecyl, n-tetradecyl, n-pentadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, etc.

[0165] Formula (B3)

[0166] In formula (B3), Rb 113 and Rb 213Each independently is a hydrogen atom, a linear alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, d is an integer of 7 or more and 15 or less, Rb 403 , Rb 503 , Rb 803 and Rb 903 Each independently is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0167] Rb 113 and Rb 213 The linear alkyl group having 1 to 3 carbon atoms of Rb

[0168] Rb 113 and Rb 213 The alkyl group in the alkoxy group having 1 to 4 carbon atoms can be any of linear, branched, and cyclic. The number of carbon atoms of the alkyl group in the alkoxy group having 1 to 4 carbon atoms is preferably 1 to 3, more preferably 1 or 2, and further preferably 1. Specific examples of this group include: methoxy, ethoxy, n-propoxy, n-butoxy, isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, cyclopropoxy, cyclobutoxy, etc.

[0169] As the halogen atom of Rb 113 and Rb 213 Examples include: fluorine atom, chlorine atom, bromine atom, iodine atom.

[0170] Formula (B4)

[0171] In formula (B4), Rb 104 and Rb 204 Each independently is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 404 , Rb 504 , Rb 804 and Rb 904 Each independently is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0172] Rb 104 The alkyl group having 1 to 3 carbon atoms of Rb 104 can be any of linear, branched, and cyclic. The number of carbon atoms of the alkyl group is preferably 1 or 2, more preferably 1. Specific examples of Rb

[0173] Formula (B5)

[0174] In formula (B5), Ar 105 is an aryl group having 6 to 12 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, and Rb 205 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Rb 405 、Rb 505 、Rb 805 and Rb 905 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0175] Ar 105 The aryl group having 6 to 12 carbon atoms of Ar can be either a monocyclic or polycyclic group. The number of carbon atoms of the aryl group is preferably 6 to 10, more preferably 6.

[0176] Ar 105 The alkyl group in the aralkyl group having 7 to 20 carbon atoms of Ar can be linear, branched, or cyclic. The number of carbon atoms of the alkyl group in the aralkyl group having 7 to 20 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and further preferably 1 or 2. The aryl group in the aralkyl group having 7 to 20 carbon atoms of Ar can be either a monocyclic or polycyclic group. The number of carbon atoms of the aryl group is preferably 6 to 10, more preferably 6. Examples of the aralkyl group having 7 to 20 carbon atoms include: benzyl, phenylethyl, phenylpropyl, 4-phenylbutyl, phenylpentyl, phenylhexyl, phenylheptyl, phenyloctyl, phenylnonyl, naphthylmethyl, naphthylethyl, anthrylmethyl, phenyl-cyclopentylmethyl, etc. 105 The aryl group in the aralkyl group having 7 to 20 carbon atoms of Ar can be either a monocyclic or polycyclic group. The number of carbon atoms of the aryl group is preferably 6 to 10, more preferably 6. Examples of the aralkyl group having 7 to 20 carbon atoms include: benzyl, phenylethyl, phenylpropyl, 4-phenylbutyl, phenylpentyl, phenylhexyl, phenylheptyl, phenyloctyl, phenylnonyl, naphthylmethyl, naphthylethyl, anthrylmethyl, phenyl-cyclopentylmethyl, etc.

[0177] Formula (B6)

[0178] In formula (B6), Rb 116 and Rb 216 are each independently a hydrogen atom, a linear alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, e is an integer of 4 to 6, and Rb 406 、Rb 506 、Rb 806 and Rb 906 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0179] Rb 116 and Rb 216The number of carbon atoms of the straight-chain alkyl group having 1 or more and 3 or less carbon atoms is preferably 1 or 2, more preferably 1. Specific examples of this group include: methyl, ethyl, and n-propyl.

[0180] Rb 116 and Rb 216 The alkyl group in the alkoxy group having 1 or more and 4 or less carbon atoms may be linear, branched, or cyclic. The number of carbon atoms of the alkyl group in the alkoxy group having 1 or more and 4 or less carbon atoms is preferably 1 or more and 3 or less, more preferably 1 or 2, and still more preferably 1. Specific examples of this group include: methoxy, ethoxy, n-propoxy, n-butoxy, isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, cyclopropoxy, cyclobutoxy, and the like.

[0181] As Rb 116 and Rb 216 Examples of the halogen atom include: fluorine atom, chlorine atom, bromine atom, and iodine atom.

[0182] Formula (B8)

[0183] In formula (B8), Rb 408 , Rb 508 , Rb 808 and Rb 908 are each independently a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom.

[0184] Rb of formula (B1) 201 , Rb of formula (B2) 202 , Rb of formula (B4) 204 and Rb of formula (B5) 205 have the same specific and preferred modes. Therefore, hereinafter, Rb 201 , Rb 202 , Rb 204 and Rb 205 are collectively referred to as "Rb 200 " for description.

[0185] Rb 200 The alkyl group having 1 or more and 3 or less carbon atoms may be linear, branched, or cyclic. The number of carbon atoms of the alkyl group is preferably 1 or 2, more preferably 1.

[0186] Examples of the alkyl group having 1 or more and 3 or less carbon atoms include: methyl, ethyl, n-propyl, isopropyl, and cyclopropyl.

[0187] Rb of formula (B1) 401 , Rb of formula (B2) 402 , Rb of formula (B3)403 , Rb of formula (B4) 404 , Rb of formula (B5) 405 , Rb of formula (B6) 406 and Rb of formula (B8) 408 have the same specific and preferred embodiments. Therefore, hereinafter, Rb 401 , Rb 402 , Rb 403 , Rb 404 , Rb 405 , Rb 406 and Rb 408 are collectively referred to as "Rb 400 " for description.

[0188] Rb 400 The alkyl group having 1 to 4 carbon atoms of Rb can be linear, branched or cyclic. The number of carbon atoms of the alkyl group is preferably 1 to 3, more preferably 1 or 2, and further preferably 1.

[0189] Examples of the linear alkyl group having 1 to 4 carbon atoms include: methyl, ethyl, n-propyl, n-butyl.

[0190] Examples of the branched alkyl group having 3 or 4 carbon atoms include: isopropyl, isobutyl, sec-butyl, tert-butyl.

[0191] Examples of the cyclic alkyl group having 3 or 4 carbon atoms include: cyclopropyl, cyclobutyl.

[0192] Rb 400 The alkyl group in the alkoxy group having 1 to 6 carbon atoms of Rb can be linear, branched or cyclic. The number of carbon atoms of the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and further preferably 1 or 2.

[0193] Examples of the linear alkoxy group having 1 to 6 carbon atoms include: methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, n-hexyloxy.

[0194] Examples of the branched alkoxy group having 3 or more and 6 or less carbon atoms include: isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy, tert-hexyloxy, etc.

[0195] Examples of the cyclic alkoxy group having 3 or more and 6 or less carbon atoms include: cyclopropoxy, cyclobutoxy, cyclopentyloxy, cyclohexyloxy, etc.

[0196] Examples of the halogen atom of Rb 400 include: fluorine atom, chlorine atom, bromine atom, iodine atom.

[0197] Rb of formula (B1) 501 、Rb of formula (B2) 502 、Rb of formula (B3) 503 、Rb of formula (B4) 504 、Rb of formula (B5) 505 、Rb of formula (B6) 506 and Rb of formula (B8) 508 have the same specific and preferred manners, so hereinafter, Rb 501 、Rb 502 、Rb 503 、Rb 504 、Rb 505 、Rb 506 and Rb 508 are collectively referred to as "Rb 500 " for description.

[0198] Rb 500 The alkyl group having 1 to 4 carbon atoms of Rb can be any of linear, branched and cyclic. The number of carbon atoms of the alkyl group is preferably 1 to 3, more preferably 1 or 2, and further preferably 1.

[0199] Examples of the linear alkyl group having 1 to 4 carbon atoms include: methyl, ethyl, n-propyl, n-butyl.

[0200] Examples of the branched alkyl group having 3 or 4 carbon atoms include: isopropyl, isobutyl, sec-butyl, tert-butyl.

[0201] Examples of the cyclic alkyl group having 3 or 4 carbon atoms include: cyclopropyl, cyclobutyl.

[0202] Rb 500 The alkyl group in the alkoxy group having 1 to 6 carbon atoms of Rb can be any of linear, branched and cyclic. The number of carbon atoms of the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and further preferably 1 or 2.

[0203] Examples of the linear alkoxy group having 1 to 6 carbon atoms include: methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, n-hexyloxy.

[0204] Examples of the branched alkoxy group having 3 or more and 6 or less carbon atoms include: isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy, tert-hexyloxy, etc.

[0205] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include cyclopropoxy, cyclobutoxy, cyclopentyloxy, cyclohexyloxy and the like.

[0206] As Rb 500 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0207] Rb of formula (B1) 801 , Rb of formula (B2) 802 , Rb of formula (B3) 803 , Rb of formula (B4) 804 , Rb of formula (B5) 805 , Rb of formula (B6) 806 and Rb of formula (B8) 808 have the same specific and preferred modes. Therefore, hereinafter, Rb 801 , Rb 802 , Rb 803 , Rb 804 , Rb 805 , Rb8 06 and Rb 808 are collectively referred to as "Rb 800 " for description.

[0208] The alkyl group having 1 to 4 carbon atoms of Rb 800 may be linear, branched or cyclic. The number of carbon atoms of the alkyl group is preferably 1 to 3, more preferably 1 or 2, and further preferably 1.

[0209] Examples of the linear alkyl group having 1 to 4 carbon atoms include methyl, ethyl, n-propyl and n-butyl.

[0210] Examples of the branched alkyl group having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl and tert-butyl.

[0211] Examples of the cyclic alkyl group having 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0212] Rb 800 The alkyl group in the alkoxy group having 1 to 6 carbon atoms of may be linear, branched or cyclic. The number of carbon atoms of the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and further preferably 1 or 2.

[0213] Examples of the linear alkoxy group having 1 to 6 carbon atoms include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy and n-hexyloxy.

[0214] Examples of the branched alkoxy group having 3 to 6 carbon atoms include isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy, tert-hexyloxy, and the like.

[0215] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include cyclopropoxy, cyclobutoxy, cyclopentyloxy, cyclohexyloxy, and the like.

[0216] As for the halogen atom of Rb 800 , examples thereof include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0217] Rb in formula (B1) 901 , Rb in formula (B2) 902 , Rb in formula (B3) 903 , Rb in formula (B4) 904 , Rb in formula (B5) 905 , Rb in formula (B6) 906 and Rb in formula (B8) 908 have the same specific and preferred modes. Therefore, hereinafter, Rb 901 , Rb 902 , Rb 903 , Rb 904 , Rb 905 , Rb 906 and Rb 908 are collectively referred to as "Rb 900 " for description.

[0218] The alkyl group having 1 to 4 carbon atoms of Rb 900 can be any of linear, branched, and cyclic. The number of carbon atoms of the alkyl group is preferably 1 to 3, more preferably 1 or 2, and further preferably 1.

[0219] Examples of the linear alkyl group having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, and n-butyl.

[0220] Examples of the branched alkyl group having 3 or 4 carbon atoms include isopropyl, isobutyl, sec-butyl, and tert-butyl.

[0221] Examples of the cyclic alkyl group having 3 or 4 carbon atoms include cyclopropyl and cyclobutyl.

[0222] Rb 900 The alkyl group in the alkoxy group having 1 to 6 carbon atoms of can be any of linear, branched, and cyclic. The number of carbon atoms of the alkyl group in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and further preferably 1 or 2.

[0223] Examples of the straight-chain alkoxy group having 1 to 6 carbon atoms include: methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, and n-hexyloxy.

[0224] Examples of the branched-chain alkoxy group having 3 to 6 carbon atoms include: isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, neopentyloxy, tert-pentyloxy, isohexyloxy, sec-hexyloxy, tert-hexyloxy, and the like.

[0225] Examples of the cyclic alkoxy group having 3 to 6 carbon atoms include: cyclopropoxy, cyclobutoxy, cyclopentyloxy, cyclohexyloxy, and the like.

[0226] As for Rb 900 Examples of the halogen atom include: fluorine atom, chlorine atom, bromine atom, and iodine atom.

[0227] Hereinafter, as specific examples of the diol unit (B1), diol units (B1-1) to (B1-6) are shown. The diol unit (B1) is not limited thereto.

[0228]

[0229] Hereinafter, as specific examples of the diol unit (B2), diol units (B2-1) to (B2-11) are shown. The diol unit (B2) is not limited thereto.

[0230]

[0231] Hereinafter, as specific examples of the diol unit (B3), diol units (B3-1) to (B3-4) are shown. The diol unit (B3) is not limited thereto.

[0232]

[0233] Hereinafter, as specific examples of the diol unit (B4), diol units (B4-1) to (B4-7) are shown. The diol unit (B4) is not limited thereto.

[0234]

[0235] Hereinafter, as specific examples of the diol unit (B5), diol units (B5-1) to (B5-6) are shown. The diol unit (B5) is not limited thereto.

[0236]

[0237] Hereinafter, as specific examples of the diol unit (B6), diol units (B6-1) to (B6-4) are shown. The diol unit (B6) is not limited thereto.

[0238]

[0239] Hereinafter, as specific examples of the diol unit (B8), diol units (B8-1) to (B8-3) are shown. The diol unit (B8) is not limited thereto.

[0240]

[0241] When the polyester resin (1) has a diol unit (B), the mass ratio of the diol unit (B) in the polyester resin (1) is preferably 25% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 75% by mass or less, and still more preferably 35% by mass or more and 70% by mass or less.

[0242] The polyester resin (1) may also have a structural unit containing a biphenyl represented by the formula (1) and other diol units other than the diol unit (B). Examples of the other diol units include: aliphatic diol (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol) units, alicyclic diol (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A) units. These diol units contained in the polyester resin (1) may be one kind or two or more kinds.

[0243] The terminals of the polyester resin (1) can be sealed or modified by a capping agent or a molecular weight regulator used in the production. Examples of the capping agent or the molecular weight regulator include: monohydric phenols, monohydric acid chlorides, monohydric alcohols, and monohydric carboxylic acids.

[0244] Examples of the monohydric phenol include: phenol, o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-propylphenol, m-propylphenol, p-propylphenol, o-tert-butylphenol, m-tert-butylphenol, p-tert-butylphenol, amylphenol, hexylphenol, octylphenol, nonylphenol, 2,6-dimethylphenol derivatives, 2-methylphenol derivatives, o-phenylphenol, m-phenylphenol, p-phenylphenol, o-methoxyphenol, m-methoxyphenol, p-methoxyphenol, 2,3,5-trimethylphenol, 2,3,6-trimethylphenol, 2,3-dimethylphenol, 2,4-dimethylphenol, 2,5-dimethylphenol, 2,6-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2-phenyl-2-(4-hydroxyphenyl)propane, 2-phenyl-2-(2-hydroxyphenyl)propane, 2-phenyl-2-(3-hydroxyphenyl)propane.

[0245] Examples of the monohydric acid chloride include: benzoyl chloride, benzochloride, methanesulfonyl chloride, phenyl chloroformate, acetyl chloride, butyryl chloride, octanoyl chloride, benzenesulfonyl chloride, benzenesulfinyl chloride, sulfinyl chloride, phenylphosphonyl chloride, and monofunctional acyl halides such as their substituents.

[0246] As the monohydric alcohol, examples thereof include: methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, pentanol, hexanol, dodecanol, stearyl alcohol, benzyl alcohol, phenethyl alcohol.

[0247] As the monobasic carboxylic acid, examples thereof include: acetic acid, propionic acid, octanoic acid, cyclohexanecarboxylic acid, benzoic acid, methylbenzoic acid, phenylacetic acid, p-tert-butylbenzoic acid, p-methoxyphenylacetic acid.

[0248] The weight-average molecular weight of the polyester resin (1) is preferably 30,000 or more and 300,000 or less, more preferably 40,000 or more and 250,000 or less, and still more preferably 50,000 or more and 200,000 or less.

[0249] The molecular weight of the polyester resin (1) is the molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography). Tetrahydrofuran is used as the eluent for GPC.

[0250] Regarding the polyester resin (1), it can be obtained by polycondensing a monomer having a structural unit containing the biphenyl shown in the formula (1), a monomer optionally having a dicarboxylic acid unit (A) and a monomer having a diol unit (B), and other monomers as needed by a conventional method. Examples of the polycondensation method of the monomers include an interfacial polymerization method, a solution polymerization method, a melt polymerization method, etc. The interfacial polymerization method is a polymerization method for obtaining a polyester by mixing a dicarboxylic acid halide dissolved in an organic solvent immiscible with water and a diol dissolved in an aqueous alkali solution. As the literature related to the interfacial polymerization method, examples include W.M. EARECKSON, J. Poly. Sci., XL 399, 1959, Japanese Patent Publication No. 40-1959, etc. The interfacial polymerization method has a faster reaction compared to the solution polymerization method. Therefore, hydrolysis of the dicarboxylic acid halide can be suppressed, and as a result, a high molecular weight polyester resin can be obtained.

[0251] [Polycarbonate resin (1)]

[0252] In the present invention, the polycarbonate resin having a structural unit containing the biphenyl shown in the formula (1) is referred to as polycarbonate resin (1).

[0253] Formula (1)

[0254] In the formula (1), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl.

[0255] j is an integer of 0 or more and 4 or less, preferably an integer of 0 or more and 3 or less, more preferably an integer of 0 or more and 2 or less, still more preferably 0 or 1, and particularly preferably 0.

[0256] When j is an integer of 1 or more, j Rs 11 are each independently methyl or ethyl, preferably methyl.

[0257] k is an integer of 0 or more and 4 or less, preferably an integer of 0 or more and 3 or less, more preferably an integer of 0 or more and 2 or less, still more preferably 0 or 1, and particularly preferably 0.

[0258] When k is an integer of 1 or more, k Rs 12 are each independently methyl or ethyl, preferably methyl.

[0259] Regarding the polycarbonate resin (1), from the viewpoint of having a structural unit containing a biphenyl represented by the formula (1) in the molecule, it is preferably a structural unit (1-C) represented by the following formula (1-C).

[0260] Formula (1-C)

[0261] In the formula (1-C), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, L C is a single bond or a divalent linking group, Ar C is an aromatic ring which may have a substituent, and n C is 0, 1 or 2.

[0262] j, k, R in the formula (1-C) 11 and R 12 are respectively the same as j, k, R in the formula (1) 11 and R 12 in meaning, and the specific manners and preferred manners are also the same.

[0263] When L C is a divalent linking group, examples of the divalent linking group include: an oxygen atom, a sulfur atom, -C(Rc 1 )(Rc 2 ). Here, Rc 1 and Rc 2 are each independently a hydrogen atom, an alkyl group having 1 or more and 10 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an aralkyl group having 7 or more and 20 or less carbon atoms, and Rc 1 and Rc 2 may bond to form a cyclic alkyl group.

[0264] Rc 1 and Rc 2The alkyl group having 1 to 10 carbon atoms may be linear, branched or cyclic. The number of carbon atoms of the alkyl group is preferably 1 to 6, more preferably 1 to 4, and further preferably 1 or 2.

[0265] Rc 1 and Rc 2 The aryl group having 6 to 12 carbon atoms may be monocyclic or polycyclic. The number of carbon atoms of the aryl group is preferably 6 to 10, and more preferably 6.

[0266] Rc 1 and Rc 2 The alkyl group in the aralkyl group having 7 to 20 carbon atoms may be linear, branched or cyclic. The number of carbon atoms of the alkyl group in the aralkyl group having 7 to 20 carbon atoms is preferably 1 to 4, more preferably 1 to 3, and further preferably 1 or 2.

[0267] Rc 1 and Rc 2 The aryl group in the aralkyl group having 7 to 20 carbon atoms may be monocyclic or polycyclic. The number of carbon atoms of the aryl group is preferably 6 to 10, and more preferably 6.

[0268] Ar C The aromatic ring may be monocyclic or polycyclic. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring, and a benzene ring and a naphthalene ring are preferred.

[0269] Ar C The hydrogen atom on the aromatic ring of Ar may be substituted with an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a halogen atom, etc. As the substituent when the aromatic ring of Ar C is substituted, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms are preferred.

[0270] The structural unit (1-C) represented by the formula (1-C) is preferably the structural unit (11-C) represented by the following formula (11-C).

[0271] Formula (11-C)

[0272] In the formula (11-C), j is an integer of 0 or more and 4 or less, and j R's 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k R's 12 are each independently methyl or ethyl.

[0273] j, k, R in the formula (11-C) 11 and R12 are respectively the same as j, k, and R in formula (1) 11 and R 12 have the same meaning, and the specific and preferred manners are also the same.

[0274] As specific examples of the structural unit (1-C), the following structural units (1-C1) to (1-C10) can be cited.

[0275] The structural unit (1-C) is not limited thereto.

[0276]

[0277] As the structural unit (1-C), it is preferably at least one selected from the group consisting of the structural units (1-C3) to (1-C7), more preferably at least one selected from the group consisting of the structural units (1-C3) to (1-C6), and further preferably the structural unit (1-C3).

[0278] The polycarbonate resin (1) may also have structural units other than the structural unit containing the biphenyl shown in formula (1). Hereinafter, the structural units other than the structural unit containing the biphenyl shown in formula (1) will be described.

[0279] The polycarbonate resin (1) may also have at least one structural unit (C) selected from the group consisting of the structural unit (Ca1) shown by the following formula (Ca1), the structural unit (Ca3) shown by the formula (Ca3), the structural unit (Ca4) shown by the formula (Ca4), the structural unit (Cb1) shown by the formula (Cb1), the structural unit (Cb2) shown by the formula (Cb2), the structural unit (Cb3) shown by the formula (Cb3), the structural unit (Cb4) shown by the formula (Cb4), the structural unit (Cb5) shown by the formula (Cb5), the structural unit (Cb6) shown by the formula (Cb6), and the structural unit (Cb8) shown by the formula (Cb8).

[0280] When the polycarbonate resin (1) has the structural unit (C), the structural unit (C) may be one kind or two or more kinds.

[0281] As the structural unit (C), it is preferably at least one selected from the group consisting of the structural unit (Cb1), the structural unit (Cb2), the structural unit (Cb3), the structural unit (Cb4), the structural unit (Cb5), the structural unit (Cb6), and the structural unit (Cb8).

[0282] Formula (Ca1)

[0283] In formula (Ca1), n 101 is an integer of 0 or more and 4 or less, n101 each Ra 101 is independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0284] Ra in formula (Ca1) 101 and n 101 respectively have the same meanings as Ra in formula (A1) 101 and n 101 and are in the same specific manner.

[0285] Formula (Ca3)

[0286] In formula (Ca3), n 301 and n 302 are each independently an integer of 0 to 4, and n 301 number of Ra 301 and n 302 number of Ra 302 are each independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0287] Ra in formula (Ca3) 301 , Ra 302 , n 301 and n 302 respectively have the same meanings as Ra in formula (A3) 301 , Ra 302 , n 301 and n 302 and are in the same specific manner.

[0288] Formula (Ca4)

[0289] In formula (Ca4), n 401 is an integer of 0 to 6, and n 401 number of Ra 401 are each independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0290] Ra in formula (Ca4) 401 and n 401 respectively have the same meanings as Ra in formula (A4) 401 and n 401 and are in the same specific manner.

[0291] Formula (Cb1)

[0292] In formula (Cb1), Rb 101 is a branched alkyl group having 4 to 20 carbon atoms, Rb 201 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 401 、Rb 501 、Rb 801 and Rb 901 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0293] Rb in formula (Cb1) 101 、Rb 201 、Rb 401 、Rb 501 、Rb 801 and Rb 901 correspond to Rb in formula (B1) 101 、Rb 201 、Rb 401 、Rb 501 、Rb 801 and Rb 901 in meaning and in the specific manner.

[0294] Formula (Cb2)

[0295] In formula (Cb2), Rb 102 is a straight-chain alkyl group having 4 to 20 carbon atoms, Rb 202 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Rb 402 、Rb 502 、Rb 802 and Rb 902 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0296] Rb in formula (Cb2) 102 、Rb 202 、Rb 402 、Rb 502 、Rb 802 and Rb 902 correspond to Rb in formula (B2) 102 、Rb 202 、Rb 402 、Rb 502 、Rb 802 and Rb 902 in meaning and in the specific manner.

[0297] Formula (Cb3)

[0298] In formula (Cb3), Rb 113 and Rb 213 are each independently a hydrogen atom, a straight-chain alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, d is an integer of 7 to 15, and Rb 403 , Rb 503 , Rb 803 and Rb 903 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0299] Rb in formula (Cb3) 113 , Rb 213 , d, Rb 403 , Rb 503 , Rb 803 and Rb 903 correspond to Rb in formula (B3) 113 , Rb 213 , d, Rb 403 , Rb 503 , Rb 803 and Rb 903 in meaning and in the specific manner.

[0300] Formula (Cb4)

[0301] In formula (Cb4), Rb 104 and Rb 204 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Rb 404 , Rb 504 , Rb 804 and Rb 904 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a halogen atom.

[0302] Rb in formula (Cb4) 104 , Rb 204 , Rb 404 , Rb 504 , Rb 804 and Rb 904 correspond to Rb in formula (B4) 104 , Rb 204 , Rb 404 , Rb 504 , Rb 804 and Rb 904 in meaning and in the specific manner.

[0303] Formula (Cb5)

[0304] In formula (Cb5), Ar 105 is an aryl group having 6 or more and 12 or less carbon atoms or an aralkyl group having 7 or more and 20 or less carbon atoms, and Rb 205 is a hydrogen atom or an alkyl group having 1 or more and 3 or less carbon atoms, and Rb 405 、Rb 505 、Rb 805 and Rb 905 are each independently a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom.

[0305] Ar in formula (Cb5) 105 、Rb 205 、Rb 405 、Rb 505 、Rb 805 and Rb 905 correspond to Ar in formula (B5) 105 、Rb 205 、Rb 405 、Rb 505 、Rb 805 and Rb 905 in meaning and in the same specific manner.

[0306] Formula (Cb6)

[0307] In formula (Cb6), Rb 116 and Rb 216 are each independently a hydrogen atom, a straight-chain alkyl group having 1 or more and 3 or less carbon atoms, an alkoxy group having 1 or more and 4 or less carbon atoms, or a halogen atom, e is an integer of 4 or more and 6 or less, and Rb 406 、Rb 506 、Rb 806 and Rb 906 are each independently a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom.

[0308] Rb in formula (Cb6) 116 、Rb 216 、e、Rb 406 、Rb 506 、Rb 806 and Rb 906 correspond to Rb in formula (B6) 116 、Rb 216 、e、Rb 406 、Rb 506 、Rb 806 and Rb 906They have the same meaning and the same specific manner.

[0309] Formula (Cb8)

[0310] In formula (Cb8), Rb 408 , Rb 508 , Rb 808 and Rb 908 are each independently a hydrogen atom, an alkyl group having 1 or more and 4 or less carbon atoms, an alkoxy group having 1 or more and 6 or less carbon atoms, or a halogen atom.

[0311] Rb in formula (Cb8) 408 , Rb 508 , Rb 808 and Rb 908 respectively have the same meaning and the same specific manner as Rb in formula (B8) 408 , Rb 508 , Rb 808 and Rb 908 They have the same meaning and the same specific manner.

[0312] Hereinafter, as specific examples of the structural unit (Ca1), structural units (Ca1-1) to (Ca1-9) are shown.

[0313] The structural unit (Ca1) is not limited thereto.

[0314]

[0315] Hereinafter, as specific examples of the structural unit (Ca3), structural units (Ca3-1) to (Ca3-2) are shown.

[0316] The structural unit (Ca3) is not limited thereto.

[0317]

[0318] Hereinafter, as specific examples of the structural unit (Ca4), structural units (Ca4-1) to (Ca4-3) are shown.

[0319] The structural unit (Ca4) is not limited thereto.

[0320]

[0321] Hereinafter, as specific examples of the structural unit (Cb1), structural units (Cb1-1) to (Cb1-6) are shown.

[0322] The structural unit (Cb1) is not limited thereto.

[0323]

[0324] Hereinafter, as specific examples of the structural unit (Cb2), structural units (Cb2-1) to (Cb2-11) are shown.

[0325] The structural unit (Cb2) is not limited thereto.

[0326]

[0327] Hereinafter, as specific examples of the structural unit (Cb3), structural units (Cb3-1) to (Cb3-4) are shown.

[0328] The structural unit (Cb3) is not limited thereto.

[0329]

[0330] Hereinafter, as specific examples of the structural unit (Cb4), structural units (Cb4-1) to (Cb4-7) are shown.

[0331] The structural unit (Cb4) is not limited thereto.

[0332]

[0333] Hereinafter, as specific examples of the structural unit (Cb5), structural units (Cb5-1) to (Cb5-6) are shown.

[0334] The structural unit (Cb5) is not limited thereto.

[0335]

[0336] Hereinafter, as specific examples of the structural unit (Cb6), structural units (Cb6-1) to (Cb6-4) are shown.

[0337] The structural unit (Cb6) is not limited thereto.

[0338]

[0339] Hereinafter, as specific examples of the structural unit (Cb8), structural units (Cb8-1) to (Cb8-3) are shown.

[0340] The structural unit (Cb8) is not limited thereto.

[0341]

[0342] When the polycarbonate resin (1) has the structural unit (C), the mass ratio of the structural unit (C) in the polycarbonate resin (1) is preferably 20% by mass or more and 70% by mass or less, more preferably 30% by mass or more and 60% by mass or less, and still more preferably 40% by mass or more and 50% by mass or less.

[0343] The polycarbonate resin (1) may also have a structural unit containing a biphenyl represented by the formula (1) and other structural units other than the structural unit (C). Examples of the other structural units include: structural units derived from aliphatic diols (such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol) and carbonyl chloride, and structural units derived from alicyclic diols (such as cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A) and carbonyl chloride. These structural units contained in the polycarbonate resin (1) may be one kind or two or more kinds.

[0344] The terminals of the polycarbonate resin (1) are preferably sealed or modified by a capping agent or a molecular weight regulator used in the production of the resin. As the capping agent or the molecular weight regulator, the capping agent or the molecular weight regulator previously described for the polyester resin (1) is preferred.

[0345] The weight average molecular weight of the polycarbonate resin (1) is preferably 35,000 or more and 300,000 or less, more preferably 40,000 or more and 250,000 or less, and further preferably 50,000 or more and 200,000 or less.

[0346] The molecular weight of the polycarbonate resin (1) is the molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography). GPC is measured using a conventional method, and as an example, tetrahydrofuran or chloroform is used as the eluent.

[0347] As a method for producing the polycarbonate resin (1), known polymerization methods (interfacial polymerization method, solution polymerization method, melt polymerization method) can be cited. As a specific example of the polymerization reaction, a polymerization reaction in which a diol reacts with a carbonate precursor such as carbonyl chloride or a carbonic acid diester can be cited. For example, the structural unit of the polycarbonate resin (1) can be introduced into the polycarbonate resin by using the diol that gives the structural unit for polymerization.

[0348] Hereinafter, each layer of the photoreceptor will be described in detail.

[0349] [Conductive substrate]

[0350] As the conductive substrate, for example, a metal plate, a metal drum, and a metal strip containing a metal (such as aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or an alloy (such as stainless steel) can be cited. In addition, as the conductive substrate, for example, paper, a resin film, a tape, etc. coated, vapor-deposited, or laminated with a conductive compound (such as a conductive polymer, indium oxide, etc.), a metal (such as aluminum, palladium, gold, etc.), or an alloy can also be cited. Here, "conductive" means that the volume resistivity is lower than 1×10 13 Ωcm.

[0351] When an electrophotographic photoreceptor is used in a laser printer, for the purpose of suppressing interference fringes generated when irradiating a laser, the surface of the conductive substrate is preferably roughened to 0.04 μm or more and 0.5 μm or less in terms of the center line average roughness Ra. When non-interference light is used as the light source, roughening to prevent interference fringes is not particularly required, but since the generation of defects caused by the unevenness of the surface of the conductive substrate is suppressed, it is more suitable for long life.

[0352] As a roughening method, for example, wet honing in which an abrasive is suspended in water and blown onto the conductive substrate, centerless grinding in which the conductive substrate is pressed against a rotating grinding wheel and continuously ground, anodizing treatment, etc. can be cited.

[0353] As a roughening method, the following method can also be cited: Instead of roughening the surface of the conductive substrate, a conductive or semi-conductive powder is dispersed in a resin, a layer is formed on the surface of the conductive substrate, and roughening is performed by the particles dispersed in the layer.

[0354] The roughening treatment based on anodizing is a treatment in which a metal (for example, aluminum) conductive substrate is used as an anode and anodized in an electrolyte solution, thereby forming an oxide film on the surface of the conductive substrate. As the electrolyte solution, for example, a sulfuric acid solution, an oxalic acid solution, etc. can be cited. However, the porous anodic oxide film formed by anodizing has chemical activity in its original state, is easily contaminated, and the resistance variation caused by the environment is also large. Therefore, it is preferable to perform a sealing treatment on the porous anodic oxide film to block the micropores of the oxide film by volume expansion caused by a hydration reaction in pressurized steam or boiling water (metal salts such as nickel can be added) to change it into a more stable hydrated oxide.

[0355] The film thickness of the anodic oxide film is preferably 0.3 μm or more and 15 μm or less, for example. When the film thickness is within the above range, there is a tendency for the barrier property against injection to function, and there is also a tendency for the increase in the residual potential caused by repeated use to be suppressed.

[0356] The conductive substrate can be subjected to treatment with an acidic treatment solution or boehmite treatment.

[0357] The treatment based on the acidic treatment liquid is carried out, for example, in the following manner. First, an acidic treatment liquid containing phosphoric acid, chromic acid, and hydrofluoric acid is prepared. As the mixing ratio of phosphoric acid, chromic acid, and hydrofluoric acid in the acidic treatment liquid, for example, the range of phosphoric acid is 10% by mass or more and 11% by mass or less, the range of chromic acid is 3% by mass or more and 5% by mass or less, the range of hydrofluoric acid is 0.5% by mass or more and 2% by mass or less, and the concentration of these acids as a whole is in the range of 13.5% by mass or more and 18% by mass or less. The treatment temperature is preferably 42°C or more and 48°C or less, for example. The film thickness of the coating film is preferably 0.3 μm or more and 15 μm or less.

[0358] The boehmite treatment is carried out, for example, by immersing in pure water at 90°C or more and 100°C or less for 5 minutes to 60 minutes or contacting in heated steam at 90°C or more and 120°C or less for 5 minutes to 60 minutes. The film thickness of the coating film is preferably 0.1 μm or more and 5 μm or less. Anodic oxidation treatment can be further carried out using an electrolyte solution with low solubility of the coating film such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate, etc.

[0359] [Undercoat layer]

[0360] The undercoat layer is, for example, a layer containing inorganic particles and a binder resin.

[0361] As the inorganic particles, for example, inorganic particles with a powder resistance (volume resistivity) of 1×10 2 Ω·cm or more and 1×10 11 Ω·cm or less can be cited.

[0362] Among them, as the inorganic particles having the above resistance value, for example, metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, zirconium oxide particles, etc. can be used, and zinc oxide particles are particularly preferred.

[0363] The specific surface area of the inorganic particles obtained by the BET method is, for example, 10 m 2 / g or more.

[0364] The volume average particle diameter of the inorganic particles is, for example, 50 nm or more and 2000 nm or less (preferably 60 nm or more and 1000 nm or less).

[0365] The content of the inorganic particles is, for example, preferably 10% by mass or more and 80% by mass or less, more preferably 40% by mass or more and 80% by mass or less, relative to the binder resin.

[0366] The inorganic particles can be surface-treated. Two or more kinds of particles with different surface treatments or different particle diameters can be mixed and used for the inorganic particles.

[0367] As the surface treatment agent, for example, the following can be cited: silane coupling agents, titanate coupling agents, aluminum coupling agents, surfactants, etc. In particular, a silane coupling agent is preferably used, and a silane coupling agent having an amino group is more preferably used.

[0368] As the silane coupling agent having an amino group, for example, the following can be cited: 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, etc., but it is not limited thereto.

[0369] Two or more silane coupling agents can be used in combination. For example, a silane coupling agent having an amino group and other silane coupling agents can be used in combination. As other silane coupling agents, for example, the following can be cited: vinyltrimethoxysilane, 3-methacryloxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, etc., but it is not limited thereto.

[0370] As long as the surface treatment method using the surface treatment agent is a known method, it can be any method and can be either a dry method or a wet method.

[0371] The treatment amount of the surface treatment agent is preferably 0.5% by mass or more and 10% by mass or less with respect to the inorganic particles, for example.

[0372] Here, from the viewpoints of improving the long-term stability of electrical properties and carrier blocking properties, the undercoat preferably contains both inorganic particles and an electron-accepting compound (acceptor compound).

[0373] Examples of the electron-accepting compound include: quinone compounds such as tetrachlorobenzoquinone and tetrabromobenzoquinone (Bromanil); tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone; oxadiazole compounds such as 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, 2,5-bis(4-naphthyl)-1,3,4-oxadiazole, and 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole; xanthone compounds; thiophene compounds; biphenylquinone compounds such as 3,3’,5,5’-tetra-tert-butylbiphenylquinone; benzophenone compounds such as 4-hydroxybenzophenone and 2,3,4-trihydroxybenzophenone; and electron-transporting substances, etc.

[0374] Particularly as the electron-accepting compound, a compound having an anthraquinone structure is preferred. Examples of the compound having an anthraquinone structure include, for example, hydroxyanthraquinone compounds, aminoanthraquinone compounds, amino-hydroxyanthraquinone compounds, etc. Specifically, for example, anthraquinone, alizarin, quinizarin, anthrarufin, purpurin, etc. are preferred.

[0375] The electron-accepting compound can be dispersed and contained in the undercoat together with inorganic particles, or can be contained in the undercoat in a state of being attached to the surface of the inorganic particles.

[0376] Examples of the method for attaching the electron-accepting compound to the surface of the inorganic particles include a dry method or a wet method.

[0377] The dry method is, for example, a method in which while stirring the inorganic particles with a mixer having a large shearing force, etc., the electron-accepting compound is directly dropped or the electron-accepting compound dissolved in an organic solvent is dropped, and is sprayed together with dry air or nitrogen to attach the electron-accepting compound to the surface of the inorganic particles. When dropping or spraying the electron-accepting compound, it can be carried out at a temperature below the boiling point of the solvent. After dropping or spraying the electron-accepting compound, sintering can also be carried out at 100°C or higher. The sintering is not particularly limited as long as it is a temperature and time that can obtain electrophotographic characteristics.

[0378] The wet method is, for example, a method in which inorganic particles are dispersed in a solvent by means of a stirrer, an ultrasonic disperser, a sand mill, a grinder, a ball mill, etc., and an electron-accepting compound is added and stirred or dispersed, and then the solvent is removed to attach the electron-accepting compound to the surface of the inorganic particles. The solvent removal method is, for example, distilling off by filtration or distillation. After removing the solvent, sintering can also be carried out at 100 °C or higher. The sintering is not particularly limited as long as it is at a temperature and for a time that can obtain electrophotographic characteristics. In the wet method, the moisture contained in the inorganic particles can be removed before adding the electron-accepting compound. As an example, a method of removing while stirring and heating in a solvent or a method of removing by azeotroping with the solvent can be cited.

[0379] The attachment of the electron-accepting compound can be carried out before or after the surface treatment of the inorganic particles with a surface treatment agent, or the attachment of the electron-accepting compound and the surface treatment with the surface treatment agent can be carried out simultaneously.

[0380] The content of the electron-accepting compound is, for example, 0.01% by mass or more and 20% by mass or less with respect to the inorganic particles, and preferably 0.01% by mass or more and 10% by mass or less.

[0381] Examples of the binder resin for the undercoat include known polymer compounds such as acetal resins (e.g., polyvinyl butyral, etc.), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, unsaturated polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, urea resins, phenolic resins, phenol-formaldehyde resins, melamine resins, urethane resins, alkyd resins, epoxy resins, etc.; zirconium chelate compounds; titanium chelate compounds; aluminum chelate compounds; titanium alkoxide compounds; organotitanium compounds; silane coupling agents and other known materials.

[0382] Examples of the binder resin for the undercoat also include charge-transporting resins having charge-transporting groups, conductive resins (e.g., polyaniline, etc.).

[0383] Among them, as the binder resin for the undercoat, a resin insoluble in the coating solvent of the upper layer is preferred, and a resin obtained by the reaction of at least one resin selected from the group consisting of thermosetting resins such as urea resins, phenolic resins, phenol-formaldehyde resins, melamine resins, polyurethane resins, unsaturated polyester resins, alkyd resins, and epoxy resins; polyamide resins, polyester resins, polyether resins, methacrylic resins, acrylic resins, polyvinyl alcohol resins, and polyvinyl acetal resins and a curing agent is particularly preferred.

[0384] When using two or more of these adhesive resins in combination, set their mixing ratio as needed.

[0385] To improve electrical properties, environmental stability, and image quality, various additives may be included in the undercoat.

[0386] Examples of additives include: known materials such as polycyclic condensed compounds, azo compounds, and other electron-transporting pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, and silane coupling agents. As described above, silane coupling agents are used for the surface treatment of inorganic particles, but can also be added to the undercoat as additives.

[0387] Examples of silane coupling agents as additives include: vinyltrimethoxysilane, 3-methacryloxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, etc.

[0388] Examples of zirconium chelate compounds include: zirconium butoxide, zirconium ethyl acetoacetate, zirconium triethanolamine, zirconium acetylacetonate butoxide, zirconium ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, zirconium butoxide methacrylate, zirconium butoxide stearate, zirconium butoxide isostearate, etc.

[0389] Examples of titanium chelate compounds include: tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, titanium acetylacetonate, poly(titanium acetylacetonate), titanium octanediol, ammonium lactate titanate, titanium lactate, titanium lactate ethyl ester, titanium triethanolamine complex, titanium polyhydroxystearate, etc.

[0390] Examples of aluminum chelate compounds include: aluminum isopropoxide, diisopropanol monobutoxy aluminum, aluminum butoxide, diethylacetoacetate diisopropanol aluminum, tris(ethylacetoacetate) aluminum, etc.

[0391] These additives can be used alone, or as a mixture or condensate of multiple compounds.

[0392] The Vickers hardness of the undercoat should be 35 or higher.

[0393] In order to suppress moiré images, the surface roughness (ten-point average roughness) of the undercoat layer is adjusted to be from 1 / (4n) (where n is the refractive index of the upper layer) to 1 / 2 of the laser wavelength λ used for exposure.

[0394] In order to adjust the surface roughness, resin particles or the like can be added to the undercoat layer. Examples of the resin particles include silicone resin particles and crosslinked polymethyl methacrylate resin particles. In addition, in order to adjust the surface roughness, the surface of the undercoat layer can be polished. Examples of the polishing method include buffing, sandblasting, wet honing, and grinding.

[0395] The formation of the undercoat layer is not particularly limited, and a known formation method can be used. For example, it is carried out by forming a coating film of a coating liquid for forming an undercoat layer in which the above components are added to a solvent, drying the coating film, and heating it as needed.

[0396] Examples of the solvent used for preparing the coating liquid for forming the undercoat layer include known organic solvents, such as alcohol solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone solvents, keto-alcohol solvents, ether solvents, and ester solvents.

[0397] Specifically, examples of these solvents include common organic solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, dichloromethane, chloroform, chlorobenzene, and toluene.

[0398] Examples of the dispersion method of inorganic particles when preparing the coating liquid for forming the undercoat layer include known methods such as a roll mill, a ball mill, a vibration ball mill, a grinder, a sand mill, a colloid mill, and a paint stirrer.

[0399] Examples of the method of coating the coating liquid for forming the undercoat layer on the conductive substrate include conventional methods such as a doctor blade coating method, a wire bar coating method, a spraying method, a dipping coating method, a bead coating method, an air knife coating method, and a curtain coating method.

[0400] The average thickness of the undercoat layer is, for example, set in the range of preferably 15 μm or more, more preferably 20 μm or more and 50 μm or less.

[0401] [Intermediate layer]

[0402] An intermediate layer can be further provided between the undercoat layer and the photosensitive layer.

[0403] The intermediate layer is, for example, a resin-containing layer. Examples of the resin used in the intermediate layer include: acetal resins (such as polyvinyl butyral, etc.), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenol-formaldehyde resins, melamine resins and other high molecular compounds.

[0404] The intermediate layer may be a layer containing an organometallic compound. Examples of the organometallic compound used in the intermediate layer include: organometallic compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, silicon, etc.

[0405] The compounds used in these intermediate layers may be used alone, or may also be used as a mixture or condensate of multiple compounds.

[0406] Among them, the intermediate layer is preferably a layer containing an organometallic compound containing a zirconium atom or a silicon atom.

[0407] The formation of the intermediate layer is not particularly limited, and known formation methods can be used. For example, it can be carried out by forming a coating film of a coating liquid for forming an intermediate layer in which the above components are added to a solvent, drying the coating film, and heating as needed.

[0408] As the coating method for forming the intermediate layer, conventional methods such as dip coating method, push coating method, wire bar coating method, spraying method, doctor blade coating method, air knife coating method, curtain coating method, etc. can be used.

[0409] The thickness of the intermediate layer is, for example, set in the range preferably of 0.1 μm or more and 3 μm or less. The intermediate layer can be used as an undercoat.

[0410] [Charge generation layer]

[0411] The charge generation layer is, for example, a layer containing a charge generation material and a binder resin. In addition, the charge generation layer may be a vapor deposition layer of a charge generation material. The vapor deposition layer of the charge generation material is suitable for the case of using incoherent light sources such as LEDs (Light Emitting Diodes), organic EL (Electro-Luminescence) image arrays, etc.

[0412] Examples of the charge generation material include: azo pigments such as bisazo and trisazo; polycyclic aromatic pigments such as dibromoanthraquinone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; trigonal selenium, etc.

[0413] Among them, in order to cope with laser exposure in the near-infrared region, as the charge generation material, it is preferable to use metal phthalocyanine pigments or metal-free phthalocyanine pigments. Specifically, for example, it is more preferably: gallium phthalocyanine hydroxide; gallium phthalocyanine chloride; tin phthalocyanine dichloride; titanium oxyphthalocyanine, etc.

[0414] On the other hand, in order to cope with laser exposure in the near-ultraviolet region, as the charge generation material, it is preferably polycyclic aromatic pigments such as dibromoanthraquinone; thioindigo pigments; perylene compounds; zinc oxide; trigonal selenium; bisazo pigments, etc.

[0415] Even when using incoherent light sources such as LEDs and organic EL image arrays with the central wavelength of emission being above 450 nm and below 780 nm, the above-mentioned charge generation materials can also be used.

[0416] In contrast, when using n-type semiconductors such as polycyclic aromatic pigments, perylene pigments, and azo pigments as the charge generation material, dark current is not easily generated, and even when made into a thin film, image defects called black dots can be suppressed. Regarding the determination of n-type, it is determined by the commonly used time-of-flight method based on the polarity of the flowing photocurrent, and a substance in which electrons are more easily mobile than holes as carriers is defined as n-type.

[0417] As the binder resin for the charge generation layer, it is selected from a wide range of insulating resins. In addition, as the binder resin, it can be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyethylene anthracene, polyethylene pyrene, polysilane, etc.

[0418] As the binder resin, for example, there can be mentioned: polyvinyl butyral resin, polyarylate resin (condensates of bisphenols and aromatic dicarboxylic acids, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin, polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, polyurethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, etc. Here, "insulating" means that the volume resistivity is 1×10 13 Ω·cm or more.

[0419] These binder resins can be used alone or in combination of two or more.

[0420] The mixing ratio of the charge generation material and the binder resin is preferably in the range of 10:1 to 1:10 by mass ratio.

[0421] Other known additives can be contained in the charge generation layer.

[0422] The formation of the charge generation layer is not particularly limited, and known formation methods can be used. For example, it can be carried out by forming a coating film of a coating liquid for forming a charge generation layer in which the above components are added to a solvent, drying the coating film, and heating it as needed. The formation of the charge generation layer can be carried out by vapor deposition of a charge generation material. The formation of the charge generation layer based on vapor deposition is particularly suitable when using condensed ring aromatic pigments or perylene pigments as the charge generation material.

[0423] Examples of the solvent for preparing the coating liquid for forming the charge generation layer include: methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, dichloromethane, chloroform, chlorobenzene, toluene, etc. These solvents can be used alone or in combination of two or more.

[0424] As a method for dispersing particles (such as a charge generation material) in the coating liquid for forming the charge generation layer, for example, media dispersers such as ball mills, vibration ball mills, grinders, sand mills, horizontal sand mills or stirrers, ultrasonic dispersers, roll mills, high-pressure homogenizers and other media-free dispersers can be used. Examples of the high-pressure homogenizer include a collision method in which a dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision under a high-pressure state, and a penetration method in which it is dispersed by passing through a fine flow path under a high-pressure state.

[0425] When carrying out this dispersion, it is effective to set the average particle diameter of the charge generation material in the coating liquid for forming the charge generation layer to 0.5 μm or less, preferably 0.3 μm or less, and more preferably 0.15 μm or less.

[0426] As a method for coating the coating liquid for forming the charge generation layer on the undercoat (or intermediate layer), for example, conventional methods such as blade coating method, wire bar coating method, spraying method, dip coating method, bead coating method, air knife coating method, curtain coating method, etc. can be cited.

[0427] The thickness of the charge generation layer is, for example, set in the range of preferably 0.1 μm or more and 5.0 μm or less, more preferably 0.2 μm or more and 2.0 μm or less.

[0428] [Charge transport layer]

[0429] The charge transport layer is a layer containing at least a charge transport material and a binder resin. The charge transport material can also be a polymer charge transport material.

[0430] Examples of the charge transport material include quinone compounds such as p-benzoquinone, tetrachlorobenzoquinone, tetrabromobenzoquinone, and anthraquinone; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; xanthone compounds; benzophenone compounds; cyano vinyl compounds; and electron-transporting compounds such as ethylene compounds. Examples of the charge transport material also include hole-transporting compounds such as triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, and hydrazone compounds. These charge transport materials may be used alone or in combination of two or more, but are not limited thereto.

[0431] Examples of the polymer charge transport material include known chemical substances having charge transport properties such as poly-N-vinylcarbazole and polysilane. For example, a polyester-based polymer charge transport material is preferably used. The polymer charge transport material may be used alone or in combination with a binder resin.

[0432] Examples of the charge transport material or the polymer charge transport material also include polycyclic aromatic compounds, aromatic nitro compounds, aromatic amine compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds (especially triphenylamine compounds), diamine compounds, oxadiazole compounds, carbazole compounds, organopolysilane compounds, pyrazoline compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds, cyano compounds, benzofuran compounds, aniline compounds, butadiene compounds, and resins having groups derived from these substances. Specifically, examples include the compounds described in paragraphs 0078 to 0080 of JP-A-2021-117377, paragraphs 0046 to 0048 of JP-A-2019-035900, paragraphs 0052 to 0053 of JP-A-2019-012141, paragraphs 0122 to 0134 of JP-A-2021-071565, paragraphs 0101 to 0110 of JP-A-2021-015223, paragraph 0116 of JP-A-2013-097300, paragraphs 0309 to 0316 of WO2019 / 070003, paragraphs 0103 to 0107 of JP-A-2018-159087, and paragraphs 0102 to 0113 of JP-A-2021-148818.

[0433] From the viewpoint of charge mobility, the charge transport material preferably contains at least one selected from the group consisting of a compound (D1) represented by the following formula (D1), a compound (D2) represented by the formula (D2), a compound (D3) represented by the formula (D3), and a compound (D4) represented by the formula (D4).

[0434] Formula (D1)

[0435] In formula (D1), Ar T1 、Ar T2 and Ar T3 are each independently an aryl group, -C6H 4- C(R T4 )=C(R T5 )(R T6 ) or -C6H 4- CH=CH-CH=C(R T7 )(R T8 ). R T4 、R T5 、R T6 、R T7 and R T8 are each independently a hydrogen atom, an alkyl group or an aryl group. When R T5 and R T6 are aryl groups, the aryl groups may be linked to each other by a divalent group of -C(R 51 )(R 52 )- and / or -C(R 61 )=C(R 62 ). R 51 、R 52 、R 61 and R 62 are each independently a hydrogen atom or an alkyl group having 1 or more and 3 or less carbon atoms.

[0436] The groups in formula (D1) may be substituted with a halogen atom, an alkyl group having 1 or more and 5 or less carbon atoms, an alkoxy group having 1 or more and 5 or less carbon atoms, or a substituted amino group substituted by an alkyl group having 1 or more and 3 or less carbon atoms.

[0437] As the compound (D1), from the viewpoint of charge mobility, a compound having at least one aryl group or -C6H 4- CH=CH-CH=C(R T7 )(R T8 ) is preferred, and a compound (D'1) represented by the following formula (D'1) is more preferred.

[0438]

[0439] In formula (D'1), R T111 、R T112 、R T121 、R T122 、R T131 and R T132Each is independently a hydrogen atom, a halogen atom, an alkyl group (preferably an alkyl group having 1 or more and 3 or less carbon atoms), an alkoxy group (preferably an alkoxy group having 1 or more and 3 or less carbon atoms), a phenyl group, or a phenoxy group. Tj1, Tj2, Tj3, Tk1, Tk2, and Tk3 are each independently 0, 1, or 2.

[0440] Formula (D2)

[0441] In formula (D2), R T201 , R T202 , R T211 , and R T212 are each independently a halogen atom, an alkyl group having 1 or more and 5 or less carbon atoms, an alkoxy group having 1 or more and 5 or less carbon atoms, an amino group substituted with an alkyl group having 1 or 2 carbon atoms, an aryl group, -C(R T21 )=C(R T22 )(R T23 ), or -CH=CH-CH=C(R T24 )(R T25 ). R T21 , R T22 , R T23 , R T24 , and R T25 are each independently a hydrogen atom, an alkyl group, or an aryl group. R T221 and R T222 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 or more and 5 or less carbon atoms, or an alkoxy group having 1 or more and 5 or less carbon atoms. Tm1, Tm2, Tn1, and Tn2 are each independently 0, 1, or 2.

[0442] The group in formula (D2) may be substituted with a halogen atom, an alkyl group having 1 or more and 5 or less carbon atoms, an alkoxy group having 1 or more and 5 or less carbon atoms, or a substituted amino group substituted with an alkyl group having 1 or more and 3 or less carbon atoms.

[0443] As the compound (D2), from the viewpoint of charge mobility, a compound having at least one alkyl group, aryl group, or -CH=CH-CH=C(R T24 )(R T25 ) is preferred, and a compound having two alkyl groups, aryl groups, or -CH=CH-CH=C(R T24 )(R T25 ) is more preferred.

[0444] Formula (D3)

[0445] In formula (D3), R T301 , R T302 , R T311 , and R T312Each independently is a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted by an alkyl group having 1 or 2 carbon atoms, an aryl group, -C(R T31 )=C(R T32 )(R T33 ) or -CH=CH-CH=C(R T34 )(R T35 ). R T31 , R T32 , R T33 , R T34 and R T35 are each independently a hydrogen atom, an alkyl group or an aryl group. R T321 , R T322 and R T331 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms. To1, To2, Tp1, Tp2, Tq1, Tq2 and Tr1 are each independently 0, 1 or 2.

[0446] The group in formula (D3) can be substituted by a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or a substituted amino group substituted by an alkyl group having 1 to 3 carbon atoms.

[0447] Formula (D4)

[0448] In formula (D4), R T401 , R T402 , R T411 and R T412 are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted by an alkyl group having 1 or 2 carbon atoms, an aryl group, -C(R T41 )=C(R T42 )(R T43 ) or -CH=CH-CH=C(R T44 )(R T45 ). R T41 , R T42 , R T43 , R T44 and R T45 are each independently a hydrogen atom, an alkyl group or an aryl group. R T421 , R T422 and R T431 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms. Ts1, Ts2, Tt1, Tt2, Tu1, Tu2 and Tv1 are each independently 0, 1 or 2.

[0449] The group in formula (D4) may be substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a substituted amino group substituted with an alkyl group having 1 to 3 carbon atoms.

[0450] The mass ratio of the charge transport material in the charge transport layer is preferably 20% by mass or more and 70% by mass or less, more preferably 25% by mass or more and 60% by mass or less, and still more preferably 30% by mass or more and 50% by mass or less.

[0451] The charge transport layer contains at least polyester resin (1) and / or polycarbonate resin (1) as a binder resin.

[0452] When the charge transport layer contains polyester resin (1) as a binder resin, the proportion of polyester resin (1) in the total amount of the binder resin contained in the charge transport layer is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more. When polyester resin (1) and other resins are used in combination, as the other resin used in combination, polycarbonate resin (1) is preferred.

[0453] When the charge transport layer contains polyester resin (1) and polycarbonate resin (1) as binder resins, the mass ratio of the two resins is preferably polyester resin (1): polycarbonate resin (1) = 95:5 to 50:50, more preferably 90:10 to 55:45, and still more preferably 85:15 to 60:40.

[0454] The charge transport layer may also contain other binder resins other than polyester resin (1) and polycarbonate resin (1). Examples of other binder resins include: polyester resins other than polyester resin (1), polycarbonate resins other than polycarbonate resin (1), methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl acetate resins, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, silicone resins, silicone alkyd resins, phenol-formaldehyde resins, styrene-alkyd resins, poly-N-vinylcarbazole, polysilanes, etc. These binder resins may be used alone or in combination of two or more.

[0455] Other known additives may be contained in the charge transport layer. Examples of additives include: antioxidants, leveling agents, defoaming agents, fillers, viscosity regulators, etc.

[0456] The formation of the charge transport layer is not particularly limited, and known formation methods can be used. For example, a coating film of a coating liquid for forming a charge transport layer obtained by adding the above components to a solvent is formed, the coating film is dried, and heating is performed as needed.

[0457] Examples of the solvent for preparing the coating liquid for forming the charge transport layer include: aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene; ketones such as acetone and 2-butanone; halogenated aliphatic hydrocarbons such as dichloromethane, chloroform, and dichloroethane; and common organic solvents such as cyclic or linear ethers such as tetrahydrofuran and ether. These solvents can be used alone or in combination of two or more.

[0458] Examples of the coating method when the coating liquid for forming the charge transport layer is coated on the charge generation layer include: conventional methods such as a doctor blade coating method, a wire bar coating method, a spraying method, a dipping coating method, a bead coating method, an air knife coating method, and a curtain coating method.

[0459] The average thickness of the charge transport layer is preferably 20 μm or more and 50 μm or less, more preferably 25 μm or more and 45 μm or less, and further preferably 30 μm or more and 40 μm or less.

[0460] [Single-layer photosensitive layer]

[0461] The single-layer photosensitive layer (charge generation / charge transport layer) is a layer containing a charge generation material, a charge transport material, a binder resin, and other additives as needed. These materials are the same as those described in the charge generation layer and the charge transport layer.

[0462] The single-layer photosensitive layer contains at least a polyester resin (1) and / or a polycarbonate resin (1) as the binder resin.

[0463] When the single-layer photosensitive layer contains a polyester resin (1) as the binder resin, the proportion of the polyester resin (1) in the total amount of the binder resin contained in the single-layer photosensitive layer is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and particularly preferably 90% by mass or more. When a polyester resin (1) and other resins are used in combination, the other resin used in combination is preferably a polycarbonate resin (1).

[0464] When the single-layer photosensitive layer contains a polyester resin (1) and a polycarbonate resin (1) as the binder resin, the mass ratio of the two resins is preferably polyester resin (1): polycarbonate resin (1) = 95:5 to 40:60.

[0465] The mass proportion of the charge generation material in the single-layer photosensitive layer is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.8% by mass or more and 5% by mass or less.

[0466] The mass ratio of the charge transport material in the single-layer photosensitive layer is preferably 30% by mass or more and 70% by mass or less, more preferably 35% by mass or more and 65% by mass or less, and still more preferably 40% by mass or more and 60% by mass or less.

[0467] The method for forming the single-layer photosensitive layer is the same as the method for forming the charge generation layer or the charge transport layer.

[0468] The average thickness of the single-layer photosensitive layer is preferably 25 μm or more and 50 μm or less, more preferably 28 μm or more and 45 μm or less, and still more preferably 30 μm or more and 40 μm or less.

[0469] [Protective layer]

[0470] The protective layer is provided on the photosensitive layer as needed. The protective layer is provided, for example, for the purpose of preventing chemical changes in the photosensitive layer during charging or further improving the mechanical strength of the photosensitive layer.

[0471] Therefore, the protective layer may be a layer composed of a cured film (crosslinked film). As such layers, for example, the layers shown in the following 1) or 2) can be cited.

[0472] 1) A layer composed of a cured film of a composition containing a charge transport material having a reactive group and a charge transport skeleton in the same molecule (that is, a layer containing a polymer or crosslinked body of the charge transport material having a reactive group)

[0473] 2) A layer composed of a cured film of a composition containing a non-reactive charge transport material and a reactive group-containing non-charge transport material having no charge transport skeleton and having a reactive group (that is, a layer containing a non-reactive charge transport material and a polymer or crosslinked body of the reactive group-containing non-charge transport material)

[0474] Examples of the reactive group of the charge transport material having a reactive group include: chain polymerizable groups, epoxy groups, -OH, -OR [wherein, R represents an alkyl group], -NH2, -SH, -COOH, -SiR Q1 3-Qn (OR Q2 ) Qn [wherein, R Q1 represents a hydrogen atom, an alkyl group, or a substituted or unsubstituted aryl group, R Q2 represents a hydrogen atom, an alkyl group, or a trialkylsilyl group. Qn represents an integer of 1 to 3] and other known reactive groups.

[0475] As the chain polymerizable group, as long as it is a functional group capable of radical polymerization, there is no particular limitation. For example, it is a functional group having a group containing at least a carbon double bond. Specifically, groups containing at least one selected from vinyl, vinyl ether group, vinyl thioether group, styryl, styrylphenyl, acryloyl, methacryloyl and their derivatives can be cited. Among them, since its reactivity is excellent, as the chain polymerizable group, a group containing at least one selected from vinyl, styryl, styrylphenyl, acryloyl, methacryloyl and their derivatives is preferably used.

[0476] As the charge transport skeleton of the charge transport material containing a reactive group, as long as it is a known structure in the electrophotographic photoreceptor, there is no particular limitation. For example, structures derived from nitrogen-containing hole transport compounds such as triarylamine compounds, benzidine compounds, and hydrazone compounds and conjugated with nitrogen atoms can be cited. Among them, a triarylamine skeleton is preferably used.

[0477] The charge transport material containing a reactive group, non-reactive charge transport material, and non-charge transport material containing a reactive group having these reactive groups and charge transport skeletons can be selected from known materials.

[0478] Other known additives can be contained in the protective layer.

[0479] There is no particular limitation on the formation of the protective layer. A known formation method can be used. For example, a protective layer-forming coating liquid obtained by adding the above components to a solvent is formed into a coating film, the coating film is dried, and a curing treatment such as heating is performed as needed.

[0480] As the solvent for preparing the protective layer-forming coating liquid, the following can be cited: aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; ether solvents such as tetrahydrofuran and dioxane; cellosolve solvents such as ethylene glycol monomethyl ether; alcohol solvents such as isopropyl alcohol and butanol. These solvents can be used alone or in combination of two or more.

[0481] The protective layer-forming coating liquid can be a solvent-free coating liquid.

[0482] As a method of coating the protective layer-forming coating liquid on the photosensitive layer (for example, the charge transport layer), the following can be cited: conventional methods such as dip coating method, push coating method, wire bar coating method, spraying method, doctor blade coating method, air knife coating method, and curtain coating method.

[0483] The thickness of the protective layer is, for example, set in a range of preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 10 μm or less.

[0484] <Image forming apparatus, processing cartridge>

[0485] The image forming apparatus according to the present embodiment includes: an electrophotographic photoreceptor, a charging device that charges the surface of the electrophotographic photoreceptor, an electrostatic latent image forming device that forms an electrostatic latent image on the surface of the charged electrophotographic photoreceptor, a developing device that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing toner to form a toner image, and a transfer device that transfers the toner image onto the surface of a recording medium. Moreover, as the electrophotographic photoreceptor, the electrophotographic photoreceptor according to the present embodiment is applied.

[0486] The image forming apparatus according to the present embodiment is applicable to the following well-known image forming apparatuses: an apparatus having a fixing device that fixes the toner image transferred onto the surface of a recording medium; a direct transfer type apparatus that directly transfers the toner image formed on the surface of the electrophotographic photoreceptor onto a recording medium; an intermediate transfer type apparatus that transfers the toner image formed on the surface of the electrophotographic photoreceptor once onto the surface of an intermediate transfer body and then transfers the toner image transferred onto the surface of the intermediate transfer body twice onto the surface of a recording medium; an apparatus having a cleaning device that cleans the surface of the electrophotographic photoreceptor before charging after transferring the toner image; an apparatus having a static eliminator that irradiates static elimination light onto the surface of the electrophotographic photoreceptor to eliminate static electricity before charging after transferring the toner image; and an apparatus having an electrophotographic photoreceptor heating member for raising the temperature of the electrophotographic photoreceptor and lowering the relative humidity, etc.

[0487] In the case of an intermediate transfer type apparatus, for example, the transfer device is applicable to a structure having the following devices: an intermediate transfer body on which the toner image is transferred on its surface, a primary transfer device that transfers the toner image formed on the surface of the electrophotographic photoreceptor once onto the surface of the intermediate transfer body, and a secondary transfer device that transfers the toner image transferred onto the surface of the intermediate transfer body twice onto the surface of a recording medium.

[0488] The image forming apparatus according to the present embodiment can be either a dry developing type image forming apparatus or a wet developing type (developing method using a liquid developer) image forming apparatus.

[0489] In the image forming apparatus according to the present embodiment, for example, the part having the electrophotographic photoreceptor may be a cartridge structure (processing cartridge) that is detachable from the image forming apparatus. As the processing cartridge, for example, a processing cartridge having the electrophotographic photoreceptor according to the present embodiment is preferably used. In the processing cartridge, in addition to the electrophotographic photoreceptor, for example, at least one selected from the group consisting of a charging device, an electrostatic latent image forming device, a developing device, and a transfer device may be provided.

[0490] An example of the image forming apparatus according to the present embodiment will be shown below, but the present invention is not limited thereto. The main parts shown in the drawings will be described, and the description of the other parts will be omitted.

[0491] Figure 3 It is a schematic configuration diagram showing an example of the image forming apparatus according to the present embodiment.

[0492] As Figure 3 shown, the image forming apparatus 100 according to the present embodiment includes a processing cartridge 300 having an electrophotographic photosensitive member 7, an exposure device 9 (an example of an electrostatic latent image forming device), a transfer device 40 (a primary transfer device), and an intermediate transfer member 50. In the image forming apparatus 100, the exposure device 9 is disposed at a position where the electrophotographic photosensitive member 7 can be exposed from the opening of the processing cartridge 300, the transfer device 40 is disposed at a position facing the electrophotographic photosensitive member 7 with the intermediate transfer member 50 interposed therebetween, and a part of the intermediate transfer member 50 is disposed in contact with the electrophotographic photosensitive member 7. Although not shown, there is also a secondary transfer device that transfers the toner image transferred to the intermediate transfer member 50 to a recording medium (e.g., paper). The intermediate transfer member 50, the transfer device 40 (primary transfer device), and the secondary transfer device (not shown) are examples of a transfer device.

[0493] Figure 3 In the processing cartridge 300, an electrophotographic photosensitive member 7, a charging device 8 (an example of a charging device), a developing device 11 (an example of a developing device), and a cleaning device 13 (an example of a cleaning device) are integrally supported in a housing. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is disposed in contact with the surface of the electrophotographic photosensitive member 7. The cleaning member may be a conductive or insulating fibrous member instead of the cleaning blade 131, and it may be used alone or in combination with the cleaning blade 131.

[0494] Figure 3 In, as an image forming apparatus, an example is shown in which a fibrous member 132 (roller shape) for supplying a lubricating material 14 to the surface of the electrophotographic photosensitive member 7 and a fibrous member 133 (flat brush shape) for assisting cleaning are provided, and they are disposed as needed.

[0495] Hereinafter, each structure of the image forming apparatus according to the present embodiment will be described.

[0496] - Charging Device -

[0497] As the charging device 8, for example, a contact type charger using a conductive or semiconductive charging roller, charging brush, charging film, charging rubber blade, charging hose, etc. can be used. In addition, a non-contact type roller charger, a grid electrode charger using corona discharge, a corona tube charger, or other chargers known per se can also be used.

[0498] -Exposure device-

[0499] As the exposure device 9, for example, an optical system device that exposes light such as a semiconductor laser beam, LED light, or liquid crystal shutter light onto the surface of the electrophotographic photoreceptor 7 in a specified image form can be cited. The wavelength of the light source is set within the spectral sensitivity region of the electrophotographic photoreceptor. As the wavelength of the semiconductor laser, near-infrared light having an oscillation wavelength near 780 nm is the mainstream. However, it is not limited to this wavelength, and lasers having an oscillation wavelength in the 600 nm band or blue lasers, as well as lasers having an oscillation wavelength in the range of 400 nm or more and 450 nm or less, can also be used. In addition, a surface-emitting type laser source capable of outputting multiple light beams for forming a color image is also effective.

[0500] -Developing device-

[0501] As the developing device 11, for example, a conventional developing device that develops by contacting or non-contacting with a developer can be cited. As the developing device 11, as long as it has the above functions, there is no particular limitation, and it is selected according to the purpose. For example, a known developer having a function of attaching a single-component developer or a two-component developer to the electrophotographic photoreceptor 7 using a brush, a roller, etc. can be cited. Among them, a developer using a developing roller that holds the developer on its surface is preferably used.

[0502] The developer used in the developing device 11 can be a single-component developer of a single toner or a two-component developer containing a toner and a carrier. In addition, the developer can be magnetic or non-magnetic. These developers are applicable to known developers.

[0503] -Cleaning device-

[0504] The cleaning device 13 can use a cleaning blade method device equipped with a cleaning blade 131. In addition to the cleaning blade method, a brush cleaning method or a developing and cleaning parallel method can be adopted.

[0505] -Transfer device-

[0506] As the transfer device 40, for example, a contact type transfer charger using a belt, a roller, a film, a rubber blade, etc., a grid electrode type transfer charger using corona discharge, or a corona tube transfer charger, etc., which are known transfer chargers themselves, can be cited.

[0507] -Intermediate transfer body-

[0508] As the intermediate transfer body 50, a belt-shaped intermediate transfer body (intermediate transfer belt) containing polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber, etc. to which semiconduction has been imparted can be used. In addition, as a form of the intermediate transfer body, a drum-shaped intermediate transfer body can be used in addition to the belt shape.

[0509] Figure 4 It is a schematic structural diagram showing another example of the image forming apparatus of the present embodiment.

[0510] Figure 4 The image forming apparatus 120 shown is a tandem type full-color image forming apparatus equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged side by side on the intermediate transfer body 50, and a structure is adopted in which one electrophotographic photoreceptor is used for one color. The image forming apparatus 120 has the same structure as the image forming apparatus 100 except for the tandem type.

[0511] [Examples]

[0512] Hereinafter, the disclosed embodiments will be described in detail using examples, but the disclosed embodiments are not limited by these examples at all.

[0513] In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0514] In the following description, unless otherwise specified, synthesis, processing, manufacturing, etc. are carried out at room temperature (25 ° C ± 3 ° C).

[0515] <Synthesis of polyester resin>

[0516] [Synthesis of polyester resin (PE-1-1)]

[0517] In a reaction vessel equipped with a stirring device, 12.64 g of 4,4'-(2-ethylhexylidene)biphenol, 0.123 g of 4-tert-butylphenol, 0.063 g of sodium dithionite, and 250 ml of water were placed to prepare a suspension. While stirring this suspension at a temperature of 20 ° C, 4.84 g of sodium hydroxide, 0.200 g of benzyltributylammonium chloride, and 150 ml of water were added, and it was stirred for 30 minutes under a nitrogen atmosphere to prepare an aqueous solution. 200 ml of dichloromethane was added to this aqueous solution, and after stirring for 30 minutes under a nitrogen atmosphere, 12.0 g of 4,4'-biphenyldicarbonyl chloride was added in a powder state. After the addition was completed, it was stirred for 2 hours at a temperature of 20 ° C under a nitrogen atmosphere to carry out a polymerization reaction. The following purification treatment was performed on the polymerized solution.

[0518] The aggregated solution was diluted with 300 ml of dichloromethane, and the aqueous layer was removed. After washing with a dilute acetic acid solution and ion-exchanged water, it was poured into methanol to precipitate the polyester resin. The precipitated polyester resin was filtered out and dried at 50 °C. The dried polyester resin was dissolved again in 900 ml of tetrahydrofuran, and then poured into methanol to precipitate the polyester resin. The precipitated polyester resin was filtered out, washed with methanol, and dried at 50 °C to obtain 17.4 g of a white polyester resin. The weight-average molecular weight of this polyester resin was 110,000.

[0519] [Synthesis of Polyester Resin (PE-1-2)]

[0520] In a reaction vessel equipped with a stirring device, 13.1 g of 4,4'-(2-ethylhexylidene)biphenol and 8.26 g of triethylamine were placed, and 60 ml of dichloromethane was added to prepare a solution. While stirring this solution at a temperature of 5 °C, 11.33 g of 4,4'-biphenyldicarbonyl chloride was added in a powder state. After the addition was completed, the temperature of the solution was raised to 30 °C, and it was stirred for 2 hours under a nitrogen atmosphere to carry out a polymerization reaction. The following purification treatment was performed on the polymerized solution.

[0521] It was allowed to stand to separate into an aqueous layer and an organic layer, and the aqueous layer was removed. The organic layer was washed with ion-exchanged water until the pH became neutral. The inside of the reaction vessel was depressurized, and dichloromethane was distilled off to obtain 18.0 g of a polyester resin. The weight-average molecular weight of this polyester resin was 110,000.

[0522] [Synthesis of Polyester Resin (PE-x-y)]

[0523] The same operations as in the synthesis of polyester resin (PE-1-1) or (PE-1-2) were carried out, but the types of monomers used in the polymerization reaction were changed, and the charging amounts were changed so that the molar numbers of the monomers were equal, to synthesize the polyester resin (PE-x-y) shown in Table 1. Here, x is an integer from 2 to 7, and y is an integer from 1 to 2.

[0524] Polyester resin (PE-x-1) is a polyester resin obtained by the same polymerization method as polyester resin (PE-1-1).

[0525] Polyester resin (PE-x-2) is a polyester resin obtained by the same polymerization method as polyester resin (PE-1-2).

[0526] [Synthesis of Comparative Polyester Resin]

[0527] The same operations as in the synthesis of polyester resin (PE-1-1) were carried out, but the types of monomers used in the polymerization reaction were changed to synthesize the polyester resin (PE-X1) shown in Table 1.

[0528] The same operation as the synthesis of polyester resin (PE-1-2) was carried out, but the types of monomers used in the polymerization reaction were changed, and the charging amounts were changed in such a way that the molar numbers of the monomers were equal, to synthesize the polyester resins (PE-X2) shown in Table 1.

[0529] [Determination of acid value of polyester resin]

[0530] The acid value of the polyester resin was determined by the following method.

[0531] Precisely weigh 50 mg of the polyester resin and dissolve it in 20 ml of tetrahydrofuran, which is used as the titration sample. Using the potentiometric automatic titrator GT-310 (Nitto Seiko Analytical Technology Co., Ltd.), a 0.005 mol / L potassium hydroxide·isopropanol solution was added dropwise to the titration sample in 0.01 mL portions to prepare a titration curve. Taking the inflection point of the titration curve as the end point, the titration volume to the end point was determined. The acid value (mgKOH / g) of the polyester resin was calculated based on the titration volume and the mass (50 mg) of the polyester resin used for titration. The results are shown in Table 1.

[0532] 1-A3, etc. recorded in Table 1 are specific examples of the dicarboxylic acid unit (1-A) already described.

[0533] A3-2, etc. recorded in Table 1 are specific examples of the dicarboxylic acid unit (A) already described.

[0534] B1-4, etc. recorded in Table 1 are specific examples of the diol unit (B) already described.

[0535] In the case where there are two types of dicarboxylic acid units, the composition ratio (mol%) is also recorded in Table 1.

[0536] [Table 1]

[0537]

[0538] [Synthesis of polycarbonate resin]

[0539] [Synthesis of polycarbonate resin for this embodiment]

[0540] Biphenol and phosgene were reacted to synthesize the polycarbonate resins (PC-1) to (PC-4) shown in Table 2, respectively.

[0541] [Synthesis of comparative polycarbonate resin]

[0542] Biphenol and phosgene were reacted to synthesize the polycarbonate resin (PC-X1) shown in Table 2.

[0543] 1-C3, etc. recorded in Table 2 are specific examples of the structural unit (1-C) already described.

[0544] Cb6-3 and the like described in Table 2 are specific examples of the structural unit (C) already described.

[0545] In the case where there are two types of structural units, the composition ratio (mol%) is also described in Table 2.

[0546] [Table 2]

[0547]

[0548] <Manufacture of a Photoconductor Having a Laminated Photoconductive Layer>

[0549] [Example S1]

[0550] -Formation of the Undercoat Layer-

[0551] As the conductive substrate, an aluminum cylindrical tube with an outer diameter of 30 mm, a length of 365 mm, and a wall thickness of 1.6 mm was prepared.

[0552] 100 parts of zinc oxide (average particle diameter 70 nm, specific surface area 15 m 2 / g, manufactured by TAYCA Corporation) and 500 parts of toluene were stirred and mixed, 1.3 parts of a silane coupling agent (trade name: KBM603, manufactured by Shin-Etsu Chemical Co., Ltd., N-2-(aminoethyl)-3-aminopropyltrimethoxysilane) was added, and the mixture was stirred for 2 hours. Then, toluene was distilled off under reduced pressure, and sintering was carried out at 120 °C for 3 hours to obtain zinc oxide surface-treated with a silane coupling agent.

[0553] 110 parts of the surface-treated zinc oxide and 500 parts of tetrahydrofuran were stirred and mixed, and a solution obtained by dissolving 0.6 part of alizarin in 50 parts of tetrahydrofuran was added, and the mixture was stirred at 50 °C for 5 hours. Then, the solid component was filtered out by vacuum filtration and dried under reduced pressure at 60 °C to obtain alizarin-imparted zinc oxide.

[0554] 100 parts of a solution obtained by dissolving 60 parts of alizarin-imparted zinc oxide, 13.5 parts of a curing agent (blocked isocyanate, trade name: SUMIDUR 3175, manufactured by Sumitomo Bayer Urethane Co., Ltd.), and 15 parts of a butyral resin (trade name: S-LEC BM-1, manufactured by Sekisui Chemical Co., Ltd.) in 68 parts of methyl ethyl ketone were mixed with 5 parts of methyl ethyl ketone, and using glass beads with a diameter of 1 mm, dispersion was carried out with a sand mill for 2 hours to obtain a dispersion. 0.005 part of dioctyltin dilaurate and 4 parts of organosilicon resin particles (trade name: Tospearl 145, manufactured by Momentive Performance Materials Inc.) were added to the dispersion as catalysts to obtain a coating liquid for forming the undercoat layer. The coating liquid for forming the undercoat layer was applied to the outer peripheral surface of the conductive substrate by dip coating, and drying and curing were carried out at 185 °C for 35 minutes to form the undercoat layer. The average thickness of the undercoat layer was 25 μm.

[0555] - Formation of charge generation layer -

[0556] A mixture consisting of 15 parts of hydroxygallium phthalocyanine as a charge generation material (which has diffraction peaks at positions where the Bragg angles (2θ ± 0.2°) of the X-ray diffraction spectrum using CuKα characteristic X-rays are at least 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1°, and 28.3°), 10 parts of vinyl chloride - vinyl acetate copolymer resin as a binder resin (trade name: VMCH, manufactured by Nippon Unicar Company Limited), and 200 parts of n-butyl acetate was dispersed for 4 hours using glass beads with a diameter of 1 mm through a sand mill. 175 parts of n-butyl acetate and 180 parts of methyl ethyl ketone were added to the dispersion and stirred to obtain a coating liquid for forming the charge generation layer. The coating liquid for forming the charge generation layer was impregnated and coated on the undercoat layer and dried at room temperature (25°C ± 3°C) to form a charge generation layer with an average thickness of 0.25 μm.

[0557] - Formation of charge transport layer -

[0558] · Binder resin: 60 parts of polyester resin (PE - 1 - 1)

[0559] · Charge transport material: 40 parts of CTM - 1

[0560] The above materials were dissolved or dispersed in a mixed solvent of 550 parts of tetrahydrofuran and 50 parts of toluene to obtain a coating liquid for forming the charge transport layer. The coating liquid for forming the charge transport layer was impregnated and coated on the charge generation layer and dried at a temperature of 150°C for 40 minutes to form a charge transport layer with an average thickness of 32 μm.

[0561]

[0562] [Examples S2 - S19, Comparative Examples S1 - S13]

[0563] The same operations as in Example S1 were carried out, but the type and amount of the binder resin in the formation of the charge transport layer were changed to the specifications described in Table 3, and respective photoreceptors were produced.

[0564] [Manufacture of Photoreceptor with Single - Layer Photoreceptive Layer]

[0565] [Example T1]

[0566] - Formation of photoreceptive layer -

[0567] · Binder resin: 50 parts of polyester resin (PE - 1 - 1)

[0568] · Charge generation material: V-type hydroxygallium phthalocyanine (having diffraction peaks at positions where the Bragg angles (2θ ± 0.2°) of the X-ray diffraction spectrum using CuKα characteristic X-rays are at least 7.3°, 16.0°, 24.9°, and 28.0°.) 1 part

[0569] · Charge transport material: CTM-1 40 parts

[0570] · Charge transport material: CTM-2 9 parts

[0571] Dissolve or disperse the above materials in a mixed solvent of 175 parts of tetrahydrofuran and 75 parts of toluene, use glass beads with a diameter of 1 mm, and perform dispersion treatment for 4 hours with a sand mill to obtain a coating liquid for forming a photosensitive layer. Coat the coating liquid for forming a photosensitive layer on the outer peripheral surface of a conductive substrate (an aluminum cylindrical tube with an outer diameter of 30 mm, a length of 365 mm, and a wall thickness of 1.6 mm) by dip coating, and dry at a temperature of 150°C for 60 minutes to form a single-layer photosensitive layer with an average thickness of 36 μm.

[0572]

[0573] [Examples T2 - T8, Comparative Examples T1 - T5]

[0574] Operate in the same manner as in Example T1, but change the type and amount of the binder resin to the specifications described in Table 4 to fabricate respective photoreceptors.

[0575] [Performance Evaluation of Photoreceptor]

[0576] [Abrasion Resistance]

[0577] Load the photoreceptor into an electrophotographic image forming apparatus (Apeos C5570, Fujifilm Business Innovation Corporation). In a low-temperature and low-humidity environment with a temperature of 10°C and a relative humidity of 15%, output 5000 sheets each of 20% halftone images of yellow, magenta, cyan, and black monochromes on A3-sized paper, for a total of 20,000 sheets. Before and after image formation, measure the layer thickness of the charge transport layer or the single-layer photosensitive layer at 4 positions along the circumference at intervals of 90° at the center of the axial direction of the photoreceptor. During the measurement, use an electromagnetic film thickness gauge (FISCHER·INSTRUMENTS Co., Ltd., PERMASCOPE). Average the layer thicknesses at the 4 positions, subtract the average value after image formation from the average value before image formation, calculate the wear amount. Divide the wear amount by the number of photoreceptor operating cycles to calculate the wear rate (nm / kcy), and classify as follows. The results are shown in Table 3 and Table 4.

[0578] A: The wear rate (nm / kcy) is 16 or less.

[0579] B: The wear rate (nm / kcy) exceeds 16 and is below 24.

[0580] C: The wear rate (nm / kcy) exceeds 24.

[0581] [Film formation]

[0582] Load the photoreceptor into an electrophotographic image forming apparatus (Apeos C6570, Fujifilm Business Innovation Co., Ltd.). Output 1000 black grid images with an image density of 5% on A3-sized plain paper in a high-temperature and high-humidity environment of 28°C and 85% relative humidity. After forming the images, visually observe the surface of the photoreceptor and classify it as follows. The results are shown in Tables 3 and 4.

[0583] A: No film formation was confirmed.

[0584] B: Film formation was slightly confirmed locally. There is no problem in practical use.

[0585] C: Film formation was confirmed. There is a problem in practical use.

[0586] [Table 3]

[0587]

[0588] [Table 4]

[0589]

[0590] [Remarks]

[0591] ((1)) An electrophotographic photoreceptor, comprising a conductive substrate and a laminated photoreceptor layer disposed on the conductive substrate and having a charge generation layer and a charge transport layer.

[0592] The charge transport layer contains a charge transport material and at least one of a polyester resin and a polycarbonate resin containing a structural unit of biphenyl represented by formula (1).

[0593] The acid value of the charge transport layer is 2 mgKOH / g or less.

[0594] Formula (1)

[0595] In formula (1), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl.

[0596] ((2))The electrophotographic photoreceptor according to ((1)), wherein a mass ratio of the charge transport material in the charge transport layer is 30% by mass or more and 50% by mass or less.

[0597] ((3))The electrophotographic photoreceptor according to ((1)) or ((2)), wherein the polyester resin has at least one of a dicarboxylic acid unit (1-A) represented by formula (1-A) and a diol unit (1-B) represented by formula (1-B),

[0598] The polycarbonate resin has a structural unit (1-C) represented by formula (1-C).

[0599] Formula (1-A)

[0600] Formula (1B)

[0601] Formula (1-C)

[0602] In formula (1-A), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, L A is a single bond or a divalent linking group, Ar A is an aromatic ring which may have a substituent, n A is 0, 1 or 2.

[0603] In formula (1-B), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, L B is a single bond or a divalent linking group, Ar B is an aromatic ring which may have a substituent, n B is 0, 1 or 2.

[0604] In formula (1-C), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, L C is a single bond or a divalent linking group, Ar C is an aromatic ring which may have a substituent, n C is 0, 1 or 2.

[0605] (((4)))An electrophotographic photoreceptor, comprising a conductive substrate and a single-layer photosensitive layer disposed on the conductive substrate.

[0606] The single-layer photosensitive layer contains a charge transport material and at least one of a polyester resin and a polycarbonate resin having a structural unit containing biphenyl represented by the following formula (1).

[0607] The acid value of the single-layer photosensitive layer is 2 mgKOH / g or less.

[0608] Formula (1)

[0609] In formula (1), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl.

[0610] (((5)))The electrophotographic photoreceptor according to ((4)), wherein the mass ratio of the charge transport material in the single-layer photosensitive layer is 40% by mass or more and 60% by mass or less.

[0611] (((6)))The electrophotographic photoreceptor according to ((4)) or ((5)), wherein the polyester resin has at least one of the dicarboxylic acid unit (1-A) represented by formula (1-A) and the glycol unit (1-B) represented by formula (1-B),

[0612] The polycarbonate resin has a structural unit (1-C) represented by formula (1-C).

[0613] Formula (1-A)

[0614] Formula (1B)

[0615] Formula (1-C)

[0616] In formula (1-A), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, L A is a single bond or a divalent linking group, Ar A is an aromatic ring which may have a substituent, n A is 0, 1 or 2.

[0617] In formula (1-B), j is an integer of 0 or more and 4 or less, and j Rs 11Each independently is methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 Each independently is methyl or ethyl, L B is a single bond or a divalent linking group, Ar B is an aromatic ring which may have substituents, n B is 0, 1 or 2.

[0618] In formula (1-C), j is an integer of 0 or more and 4 or less, and j Rs 11 Each independently is methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 Each independently is methyl or ethyl, L C is a single bond or a divalent linking group, Ar C is an aromatic ring which may have substituents, n C is 0, 1 or 2.

[0619] ((7)) A process cartridge, which includes the electrophotographic photoreceptor according to any one of ((1)) to ((6)),

[0620] and the process cartridge is detachably attached to an image forming apparatus.

[0621] ((8)) An image forming apparatus, which includes:

[0622] the electrophotographic photoreceptor according to any one of ((1)) to ((6));

[0623] a charging device that charges the surface of the electrophotographic photoreceptor;

[0624] an electrostatic latent image forming device that forms an electrostatic latent image on the surface of the charged electrophotographic photoreceptor;

[0625] a developing device that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing toner to form a toner image; and

[0626] a transfer device that transfers the toner image to the surface of a recording medium.

[0627] According to ((1)), ((2)) or ((3)), there is provided an electrophotographic photoreceptor which is excellent in abrasion resistance and less likely to form a film as compared with an electrophotographic photoreceptor having a laminated photosensitive layer and an acid value of the charge transport layer exceeding 2 mgKOH / g.

[0628] According to (((4))), (((5))), or (((6))), there is provided an electrophotographic photoreceptor which is excellent in abrasion resistance and less likely to form a film as compared with an electrophotographic photoreceptor having a single-layer photosensitive layer and an acid value of the single-layer photosensitive layer exceeding 2 mgKOH / g.

[0629] According to (((7))), there is provided a process cartridge including an electrophotographic photoreceptor which is excellent in abrasion resistance and less likely to form a film as compared with an electrophotographic photoreceptor having a charge transport layer of a laminated photosensitive layer or an acid value of a single-layer photosensitive layer exceeding 2 mgKOH / g.

[0630] According to (((8))), there is provided an image forming apparatus including an electrophotographic photoreceptor which is excellent in abrasion resistance and less likely to form a film as compared with an electrophotographic photoreceptor having a charge transport layer of a laminated photosensitive layer or an acid value of a single-layer photosensitive layer exceeding 2 mgKOH / g.

Claims

1. An electrophotographic photoreceptor, characterized in that, Comprising: A conductive substrate; and A laminated photosensitive layer disposed on the conductive substrate, having a charge generation layer and a charge transport layer, The charge transport layer contains a charge transport material and at least one of a polyester resin and a polycarbonate resin having a structural unit containing biphenyl represented by the following formula (1), The acid value of the charge transport layer is 2 mgKOH / g or less, Equation (1) In formula (1), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl.

2. The electrophotographic photoreceptor according to claim 1, wherein, The mass ratio of the charge transport material in the charge transport layer is 30% by mass or more and 50% by mass or less.

3. The electrophotographic photoreceptor according to claim 1 or 2, wherein, The polyester resin has at least one of a dicarboxylic acid unit (1-A) represented by the formula (1-A) and a diol unit (1-B) represented by the formula (1-B), The polycarbonate resin has a structural unit (1-C) represented by the formula (1-C), In formula (1-A), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, and L A is a single bond or a divalent linking group, and Ar A is an aromatic ring which may have substituents, and n A is 0, 1 or 2. In formula (1-B), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, and L B is a single bond or a divalent linking group, Ar B is an aromatic ring which may have a substituent, and n B is 0, 1 or 2. In formula (1-C), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, L C is a single bond or a divalent linking group, Ar C is an aromatic ring which may have a substituent, and n C is 0, 1 or 2.

4. An electrophotographic photoreceptor, characterized in that, Comprising: A conductive substrate; and A single-layer photosensitive layer disposed on the conductive substrate, The single-layer photosensitive layer contains a charge transport material and at least one of a polyester resin and a polycarbonate resin having a structural unit containing biphenyl represented by the following formula (1), The acid value of the single-layer photosensitive layer is 2 mgKOH / g or less, Equation (1) In formula (1), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl.

5. The electrophotographic photoreceptor according to claim 4, wherein, The mass ratio of the charge transport material in the single-layer photosensitive layer is 40% by mass or more and 60% by mass or less.

6. The electrophotographic photoreceptor according to claim 4 or 5, wherein The polyester resin has at least one of a dicarboxylic acid unit (1-A) represented by the formula (1-A) and a diol unit (1-B) represented by the formula (1-B), The polycarbonate resin has a structural unit (1-C) represented by the formula (1-C), In formula (1-A), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, L A is a single bond or a divalent linking group, Ar A is an aromatic ring which may have substituents, n A is 0, 1 or 2, In formula (1-B), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, L B is a single bond or a divalent linking group, Ar B is an aromatic ring which may have substituents, n B is 0, 1 or 2, In formula (1-C), j is an integer of 0 or more and 4 or less, and j Rs 11 are each independently methyl or ethyl, k is an integer of 0 or more and 4 or less, and k Rs 12 are each independently methyl or ethyl, L C is a single bond or a divalent linking group, Ar C is an aromatic ring which may have substituents, n C is 0, 1 or 2.

7. A processing cartridge, characterized in that, An electrophotographic photoreceptor according to any one of claims 1 to 6, The processing cartridge is detachably attached to the image forming apparatus.

8. An image forming apparatus, characterized in that, Comprising: An electrophotographic photoreceptor according to any one of claims 1 to 6; A charging device for charging the surface of the electrophotographic photoreceptor; An electrostatic latent image forming device for forming an electrostatic latent image on the surface of the charged electrophotographic photoreceptor; A developing device for developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing toner to form a toner image; And A transfer device for transferring the toner image to the surface of a recording medium.

Images