JP2006047587A - Endless belt for electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt for an electrophotographic apparatus with low friction coefficient and excellent durability. <P>SOLUTION: The endless belt for an electrophotographic apparatus is circumferentially driven in a state that a surface of the belt is in contact with or is adjacent to a photoreceptor. At least a base layer 1 of the belt comprises a modified polyamide imide resin formed by copolymerizing the following components (A) to (C). They are: (A) an aromatic isocyanate compound; (B) an aromatic polycarboxylic acid anhydride; and (C) a silicone polymer having a polydimethylsiloxane structure in its molecule and having a group reactive with an isocyanate group of the component (A) at a terminal or both terminals thereof. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless belt for an electrophotographic apparatus, and more particularly, to an electrophotographic apparatus employing an electrophotographic technique such as a full color LBP (laser beam printer) or a full color PPC (plain paper copier). The present invention relates to an endless belt for electrophotographic equipment used for a transfer conveyance belt or the like.

  In general, endless belts (seamless belts) are widely used for electrophotographic equipment employing electrophotographic technology such as full color LBP and full color PPC for applications such as toner image transfer, paper transfer conveyance, and photoreceptor substrate. Yes. As such an endless belt, for example, a material in which a conductive carbon black is blended with a fluorine-based resin such as PVDF (polyvinylidene fluoride) and formed into a cylindrical film by a molding method such as a dipping method is used. It has been.

  However, although the fluororesin belt is excellent in electrical characteristics, it has the disadvantages that the physical properties of the belt such as the elastic modulus are lowered and the cost is increased.

On the other hand, it has been proposed to use a semiconductive tubular polyamideimide in which carbon black is contained in a polyamideimide resin for a transfer belt for an image forming apparatus (see Patent Document 1).
JP 2003-261768 A

  However, since the polyamide-imide resin described in Patent Document 1 has a rigid molecular structure, it has high rigidity. Therefore, the transfer belt for an image forming apparatus using such a polyamide-imide resin has poor bending resistance, so it is inferior in durability and has a high friction coefficient, so that it is inferior in turning up of the blade and toner releasability. There are difficulties such as.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an endless belt for an electrophotographic apparatus having a small friction coefficient and excellent durability.

In order to achieve the above object, the endless belt for electrophotographic equipment of the present invention is an endless belt for electrophotographic equipment that is driven in the circumferential direction with the surface in contact with or close to the photoreceptor, and at least the endless belt thereof. The base layer is configured to be formed using a modified polyamideimide resin obtained by copolymerizing the following (A) to (C).
(A) An aromatic isocyanate compound.
(B) An aromatic polycarboxylic acid anhydride.
(C) A silicone polymer having a polydimethylsiloxane structure in the molecule and having a reactive group for the isocyanate group of (A) at one or both ends.

  In order to obtain an endless belt for an electrophotographic apparatus having a small friction coefficient and excellent durability, the present inventors have made extensive studies focusing on a material for a base layer (base layer). In the course of that research, we made a modified polyamideimide resin by copolymerizing an aromatic isocyanate compound, an aromatic polycarboxylic acid anhydride, and a specific silicone polymer, and using this modified polyamideimide resin As a result, it was found that good results were obtained when the base layer (base layer) was formed. That is, the reactive group of the specific silicone polymer can directly react with the isocyanate group of the aromatic isocyanate compound to incorporate a polydimethylsiloxane structure into the polyamideimide resin in the form of a block copolymer or a graft copolymer. Therefore, the bending resistance of the polyamideimide resin is improved. Therefore, in an endless belt for an electrophotographic apparatus having a single layer consisting of only a base layer or a multi-layer including two or more layers including a base layer, at least the base layer is formed using the modified polyamideimide resin. It has been found that the durability of the endless belt for use can be improved, the friction coefficient can be lowered, the problem of turning up of the blade, the releasability of the toner and the like can be improved, and the present invention has been achieved.

  As described above, the endless belt for electrophotographic equipment of the present invention is a single layer consisting of only a base layer or a multi-layer endless belt for electrophotographic equipment consisting of two or more layers including a base layer. It is formed using a modified polyamideimide resin incorporating a polydimethylsiloxane structure. Therefore, the durability of the endless belt for electrophotographic equipment can be improved, the friction coefficient can be lowered, and the problem of turning up of the blade, the releasability of toner, and the like can be improved.

  And when the said specific silicone polymer has a hydroxyl group or a carboxyl group in both ends, the reactive group (hydroxyl group or carboxyl group) in both ends of a silicone polymer is an aromatic isocyanate compound. Since the polydimethylsiloxane structure can be uniformly incorporated into the polyamide-imide resin in the form of a block copolymer by directly reacting with an isocyanate group, the bending resistance can be particularly improved.

  In addition, when the specific silicone polymer has a total of two reactive groups at least one of a hydroxyl group and a carboxyl group at one end, the reactive group (hydroxyl group or carboxyl at one end of the silicone polymer). Group) can react directly with the isocyanate group of the aromatic isocyanate compound to incorporate a polydimethylsiloxane structure into the polyamideimide resin in the form of a graft copolymer. Therefore, the polydimethylsiloxane structure is unevenly distributed on the surface side of the base layer during heat treatment, and in particular, the friction coefficient can be lowered.

  Moreover, when the modified polyamide imide resin which copolymerized the carboxylic acid both terminal polymer (D) is used with said (A)-(C), the said carboxylic acid both terminal polymer (D) will play the role of a soft segment. Flexibility can be imparted to the polyamideimide resin. Therefore, the endless belt for electrophotographic equipment using this modified polyamideimide resin has a large elongation at break, and the durability is further improved.

  In addition, it is preferable that at least the base layer of the endless belt for an electrophotographic apparatus is formed using a phosphorus-containing polyester resin together with the modified polyamideimide resin because flame retardancy is improved.

  Next, an embodiment of the present invention will be described.

  For example, as shown in FIG. 1, the endless belt for an electrophotographic apparatus of the present invention is configured by directly forming a surface layer 2 on the outer peripheral surface of a base layer 1.

In the present invention, at least the base layer 1 of the endless belt is formed using a modified polyamideimide (PAI) resin obtained by copolymerizing (reacting) the following (A) to (C): This is the biggest feature.
(A) An aromatic isocyanate compound.
(B) An aromatic polycarboxylic acid anhydride.
(C) A silicone polymer having a polydimethylsiloxane structure in the molecule and having a reactive group for the isocyanate group of (A) at one or both ends.

  The aromatic isocyanate compound (A) used for forming the modified polyamideimide (PAI) resin is not particularly limited as long as it is a compound having an aromatic ring in the molecule. For example, diphenylmethane diisocyanate (MDI) , Toluene diisocyanate (TDI), tolidine diisocyanate (TODI), xylylene diisocyanate (XDI), lysine diisocyanate (LDI), naphthalene diisocyanate (NDI), paraphenylene diisocyanate (PPDI), tetramethylxylene diisocyanate (TMXDI) and the like. . These may be used alone or in combination of two or more. Among these, MDI and TODI are preferably used in terms of reactivity, cost, and solubility.

  The anhydride of the aromatic polycarboxylic acid (B) is not particularly limited as long as it has an aromatic ring in the molecule and undergoes a condensation reaction with the aromatic isocyanate compound (A). Examples thereof include aromatic polyvalent carboxylic acid anhydride (B1) and aromatic polyvalent carboxylic acid dianhydride (B2). These may be used alone or in combination of two or more. In the present invention, an aromatic polyvalent carboxylic acid may be used in combination with the anhydride (B) of the aromatic polyvalent carboxylic acid.

  Examples of the aromatic polycarboxylic anhydride (B1) include trimellitic anhydride (trimellitic anhydride), naphthalene-1,2,4-tricarboxylic anhydride, and the like. These may be used alone or in combination of two or more. Among these, trimellitic anhydride (trimellitic anhydride) is preferably used in terms of reactivity, cost, solubility, and the like.

  Examples of the aromatic polycarboxylic dianhydride (B2) include benzene-1,2,4,5-tetracarboxylic dianhydride (pyromellitic dianhydride), benzophenone-3, 3 ', 4,4'-tetracarboxylic dianhydride, diphenyl ether-3,3', 4,4'-tetracarboxylic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride , Biphenyl-3,3 ', 4,4'-tetracarboxylic dianhydride, biphenyl-2,2', 3,3'-tetracarboxylic dianhydride, naphthalene-2,3,6,7-tetra Carboxylic dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, decahydronaphthalene-1,4,5 8-tetracarboxylic dianhydride, , 8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8 -Tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8- Tetracarboxylic dianhydride, phenanthrene-1,3,9,10-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, bis (2,3-dicarboxyphenyl) ) Methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4- Dicarboxyphenyl) ethane dianhydride 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 2,3-bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) sulfone Anhydrides, bis (3,4-dicarboxyphenyl) ether dianhydride, ethylene glycol bis (anhydro trimellitate), propylene glycol bis (anhydro trimellitate) and the like can be mentioned. These may be used alone or in combination of two or more. Among these, ethylene glycol bis (anhydrotrimellitate) is preferably used in terms of reactivity, cost, solubility, and the like.

  As the aromatic polycarboxylic acid anhydride (B) in the present invention, the aromatic polycarboxylic acid anhydride (B1) and the aromatic polycarboxylic acid dianhydride (B2) are used in combination. And preferably used. Thus, when B1 and B2 are used in combination, the ratio of the imide group in the modified PAI resin is increased, so that the water absorption is reduced and the bending of the endless belt can be improved.

  The molar mixing ratio of B1 and B2 is preferably within a range of B1 / B2 = 90/10 to 50/50, and particularly preferably within a range of B1 / B2 = 80/20 to 60/40. It is preferable to use B1 and B2 in such a ratio because the bending wrinkles can be improved without deteriorating the bending resistance.

  Next, the specific silicone polymer (C) used together with the above (A) and (B) is a silicone polymer having a polydimethylsiloxane structure in the molecule, and at one end or both ends, the above-mentioned (A) There is no particular limitation as long as it has a reactive group for the isocyanate group, and examples thereof include one having one reactive group at both ends, or one having two reactive groups at one end.

  The polydimethylsiloxane structure is a structure in which a structural unit represented by the following general formula (1) is a repeating unit.

  The reactive group is not particularly limited as long as it is a functional group that reacts with the isocyanate group of the aromatic isocyanate compound (A), and examples thereof include a hydroxyl group, a carboxyl group, and an amino group.

  Specifically, the silicone polymer having one reactive group at both ends is specifically a carboxylic acid double-end silicone polymer having one carboxyl group at both ends (BY16-750, manufactured by Toray Dow Corning Silicone Co., Ltd.). ) Etc.

  The silicone polymer having two reactive groups at one end is specifically a one-end bifunctional silicone polymer having two hydroxyl groups at one end (Shin-Etsu Chemical Co., Ltd., X-22-176DX). Etc.

  The acid value of the specific silicone polymer (C) is preferably in the range of 1 to 1000 mgKOH / g, particularly preferably in the range of 4 to 150 mgKOH / g.

  The number average molecular weight (Mn) of the specific silicone polymer (C) is preferably in the range of 200 to 40,000, particularly preferably in the range of 1,000 to 20,000.

  The blending ratio of the specific silicone polymer (C) is the total amount of the above (A) to (C) [In addition, as described later, when the carboxylic acid both-end polymer (D) is used, (A) to The total amount of (D) is preferably in the range of 1 to 20% by weight, particularly preferably in the range of 2 to 15% by weight. That is, if the blending ratio of the specific silicone polymer (C) is less than 1% by weight, the durability of the belt tends to be inferior, whereas if it exceeds 20% by weight, the elongation resistance of the belt may be deteriorated. Because there is.

  In addition, the modified polyamideimide resin used in the present invention may be a copolymer obtained by copolymerizing the carboxylic acid terminal polymer (D) together with the above (A) to (C). The carboxylic acid both-end polymer (D) is not particularly limited as long as it has one carboxylic acid at each end of the polymer. Examples thereof include carboxylic acid both-end polybutadiene, carboxylic acid both-end hydrogenated polybutadiene, and carboxylic acid. Examples thereof include polyesters at both ends, polyamides at both ends of carboxylic acid, and polyacrylonitrile-butadiene copolymers at both ends of carboxylic acid. These may be used alone or in combination of two or more.

  The carboxylic acid used for introducing the carboxylic acid into both ends of the polymer is not particularly limited, and examples thereof include aliphatic carboxylic acids and aromatic carboxylic acids. These may be used alone or in combination of two or more.

  Examples of the aliphatic carboxylic acid include adipic acid, sebacic acid, suberic acid, oxalic acid, succinic acid, corkic acid, azelaic acid, dodecanedicarboxylic acid, undecanedicarboxylic acid, maleic acid, fumaric acid, itaconic acid and the like. It is done. Examples of the aromatic carboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, chlorophthalic acid, and nitrophthalic acid.

  The said carboxylic acid both terminal polymer (D) can be obtained by introduce | transducing the above carboxylic acid into the both terminal of polymers, such as polybutadiene, hydrogenated polybutadiene, polyester, and polyamide which were synthesize | combined according to the normal manufacturing method. The method for synthesizing the polymer such as polybutadiene, hydrogenated polybutadiene, polyester, and polyamide is not particularly limited. For example, polyesters and polyamides are described in pages 208 to 231 and pages 252 to 287 of 4th edition Experimental Chemistry Course 28 Polymer Synthesis (edited by the Chemical Society of Japan, 1992, published by Maruzen Co., Ltd.). It can be produced according to the method.

  Of the carboxylic acid both-end polymer (D), the carboxylic acid both-end polyester can be prepared, for example, as follows. That is, in a reaction vessel equipped with a heating device, a stirring device, a reflux device, a water separator, a distillation column and a thermometer, a dicarboxylic acid such as adipic acid or sebacic acid, methylpentanediol, nonanediol, methyloctanediol, etc. A diol is charged, and the temperature is raised to a predetermined temperature (for example, 220 ° C.) over a predetermined time (for example, 1 hour). Furthermore, after continuing the polycondensation reaction at a predetermined temperature (for example, 220 ° C.), the desired carboxylic acid-terminated polyester can be obtained by cooling to a predetermined temperature (for example, room temperature).

  In addition, carboxylic acid both terminal polymer (D), such as carboxylic acid both terminal polybutadiene, can also be produced according to the said manufacturing method.

  The acid value of the carboxylic acid both-end polymer (D) is preferably in the range of 15 to 150 mgKOH / g, particularly preferably in the range of 45 to 110 mgKOH / g.

  Moreover, the number average molecular weight (Mn) of the said carboxylic acid both terminal polymer (D) has the preferable inside of the range of 750-7500, Most preferably, it exists in the range of 1000-2500.

  The blending ratio of the carboxylic acid both terminal polymer (D) is preferably in the range of 5 to 50% by weight, particularly preferably in the range of 10 to 30% by weight of the total amount of the above (A) to (D). is there. That is, when the blending ratio of the carboxylic acid both terminal polymers (D) is less than 5% by weight, the durability tends to be deteriorated, whereas when it exceeds 50% by weight, the creep rate tends to be deteriorated. Because.

  Here, the total number of moles of the isocyanate group of the aromatic isocyanate compound (A) (a) and the total number of moles of the acid anhydride group and the carboxyl group of the anhydride of the aromatic polyvalent carboxylic acid (B) ( The molar mixing ratio of b) and the total number of moles (d) of the carboxyl groups of the carboxylic acid both-end polymer (D) with the total number of moles [(b) + (d)] is (a) / [(b ) + (D)] = 90/100 to 130/100 is preferable, and (a) / [(b) + (d)] = 100/100 to 120/100 is particularly preferable. That is, when the value of (a) / [(b) + (d)] is out of the upper limit or lower limit, it is difficult to increase the molecular weight of the PAI resin, and the durability tends to deteriorate. Because.

  Next, the modified PAI resin can be prepared, for example, as follows. That is, a reaction vessel equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a cooling tube was prepared, and the aromatic isocyanate compound (A) and an anhydride of an aromatic polycarboxylic acid such as trimellitic anhydride ( B), a specific silicone polymer (C), and, if necessary, a carboxylic acid both terminal polymer (D) are blended in a predetermined amount, and N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide ( DMF), N, N-dimethylacetamide (DMAC), γ-butyrolactone, and other polar solvents are charged and stirred for a predetermined time (preferably 1 to 3 hours) under a nitrogen stream with a predetermined temperature (preferably 130). To 150 ° C). Next, after reacting at a predetermined temperature (preferably 130 to 150 ° C.) for a predetermined time (preferably about 3 to 5 hours), the reaction is stopped, whereby a modified PAI resin can be prepared.

  The modified PAI resin thus obtained preferably has a number average molecular weight (Mn) in the range of 5,000 to 100,000, particularly preferably Mn in the range of 10,000 to 50,000. That is, if the Mn of the PAI resin is less than 5,000, the tear strength is lowered and the durability is deteriorated. Conversely, if the Mn of the PAI resin exceeds 100,000, the solution viscosity is increased and the workability is deteriorated. This is because the tendency to do is seen. The number average molecular weight (Mn) can be measured by a gel permeation chromatograph (GPC) method.

  In addition, as a material (material for base layers) used for formation of the said base layer 1, a conductive filler, a phosphorus containing polyester resin, etc. may be used with the said modified PAI resin. The base layer material may contain an organic solvent such as DMF, DMAC, toluene, acetone, and NMP, and a normal filler such as calcium carbonate, if necessary. .

The conductive filler is not particularly limited. For example, conductive powder such as carbon black and graphite, metal powder such as aluminum powder and stainless powder, conductive zinc oxide (c-ZnO), and conductive titanium oxide. (C-TiO ₂ ), conductive iron oxide (c-Fe ₃ O ₄ ), conductive metal oxides such as conductive tin oxide (c-SnO ₂ ), quaternary ammonium salts, phosphate esters, sulfonic acids Examples thereof include ionic conductive agents such as salts, aliphatic polyhydric alcohols, and aliphatic alcohol sulfate salts. These may be used alone or in combination of two or more.

  The phosphorus-containing polyester resin preferably has a phosphorus content in the range of 3 to 15% by weight of the entire phosphorus-containing polyester resin, and particularly preferably has a phosphorus content in the range of 5 to 10% by weight. It is what is inside. It is preferable for the phosphorus content to be in such a range because flame retardancy is improved.

  The base layer material may be, for example, the modified PAI resin, a conductive filler, an organic solvent, and a filler appropriately blended as necessary, mixed with a stirring blade, and then a ring mill, ball mill, sand mill, etc. It can be prepared by dispersing using.

  Next, the material (surface layer material) used for forming the surface layer 2 is not particularly limited, and examples thereof include silicone resins, fluorine resins, urethane resins, acrylic resins, polyamide resins, and the like. These may be used alone or in combination of two or more. Among these, in consideration of workability, a liquid or solvent-soluble type is preferably used. In addition, for the purpose of preventing dirt, improving the strength of the coating film, or improving adhesion, a modified resin material may be used, and examples thereof include a modified acrylic resin. The modified acrylic resin is not particularly limited as long as it is based on the molecular structure of the acrylic resin and modified with other resins or resin components, but a silicone-modified acrylic resin is preferably used.

  Examples of the silicone-modified acrylic resin include silicone graft acrylic resins. The silicone graft acrylic resin is not particularly limited as long as the silicone resin is graft polymerized with the acrylic resin (main chain). Specific examples of this silicone graft acrylic resin include Saimak US-350 manufactured by Toagosei Co., Ltd.

  In addition, as the material for the surface layer, the resin material is subjected to resin crosslinking using a resin crosslinking agent such as isocyanate resin, amino resin, phenol resin, xylene resin, or a photosensitive monomer or polymer. An ultraviolet curable material mixed with a photopolymerization initiator may be used.

  The surface layer material can be prepared, for example, by appropriately blending a modified acrylic resin and an organic solvent such as DMF, toluene, and acetone and mixing with a stirring blade. In order to form each layer with high accuracy, it is preferable to use different types of organic solvents as materials for forming adjacent layers. That is, it is preferable to use different types of organic solvents used for the surface layer material and organic solvents used for the base layer material.

  Here, the endless belt for an electrophotographic apparatus of the present invention shown in FIG. 1 can be produced, for example, as follows. That is, a base layer material is prepared in the same manner as described above, and this is spray-coated on the surface of a mold (cylindrical substrate). Next, this is dried at 150 to 300 ° C. for 3 to 6 hours to form the base layer 1 on the surface of the mold. Next, the surface layer material prepared in the same manner as described above is coated on the surface of the base layer 1 by a dipping method and dried, and then air is blown between the base layer 1 and the cylindrical substrate to form a cylindrical shape. An endless belt (see FIG. 1) having a two-layer structure in which the surface layer 2 is formed on the surface of the base layer 1 can be produced by extracting the substrate. In addition, the formation method of the surface layer 2 is not limited to the said dipping method, You may form by spray coating similarly to the formation method of the base layer 1.

  In addition, the base layer 1 of the endless belt for electrophotographic equipment of the present invention can be produced by an extrusion molding method, an inflation method, a blow molding method, a dipping method, a centrifugal molding method, or the like, in addition to the above production method. Then, by omitting the formation of the surface layer 2, an endless belt having a single layer structure composed of only the base layer 1 can be produced.

  The thickness of each layer of the endless belt for electrophotographic equipment of the present invention is appropriately set according to the use of the belt, but the thickness of the base layer 1 is usually in the range of 30 to 300 μm, preferably 50 to 200 μm. Is within the range. The thickness of the surface layer 2 is preferably in the range of 0.1 to 10 μm, particularly preferably in the range of 0.5 to 5 μm. The endless belt for electrophotographic equipment of the present invention preferably has an inner peripheral length of 90 to 1500 mm and a width of about 100 to 500 mm. That is, if the size is set within the above range, the size is suitable for use in an electrophotographic copying machine or the like.

  The endless belt for electrophotographic equipment of the present invention only needs to have a structure including at least the base layer 1, and has a two-layer structure in which the surface layer 2 is directly formed on the outer peripheral surface of the base layer 1 as shown in FIG. It is not limited. The endless belt for electrophotographic equipment of the present invention has, for example, a single-layer structure composed of only the base layer 1, a three-layer structure in which a thermoplastic resin layer or a rubber elastic layer is interposed between the base layer 1 and the surface layer 2, and the base layer 1 A four-layer structure in which both a thermoplastic resin layer and a rubber elastic layer are interposed between the surface layer 2 and the surface layer 2 may be used. However, in these cases, the base layer 1 needs to be formed using the above-mentioned modified PAI resin.

  In this case, the material for the thermoplastic resin layer interposed between the base layer 1 and the surface layer 2 is not particularly limited, but may be a solvent such as methyl ethyl ketone (MEK), toluene, etc., if necessary, together with the thermoplastic resin. Is used. In addition, the conductive filler as described above may be blended in the thermoplastic resin layer material.

  The thermoplastic resin is not particularly limited, and examples thereof include polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and ethylene-tetrafluoroethylene copolymer (ETFE). Fluorine resin, polyethylene resin, polystyrene resin, acrylic resin, polycarbonate (PC) resin, polyamide resin, EVA (ethylene-vinyl acetate copolymer) resin, EEA (ethylene-ethyl acrylate copolymer) Coalesced resin. These may be used alone or in combination of two or more. Among these, it is preferable to use a fluorine-based resin such as PVDF from the viewpoint of excellent flame retardancy.

  The rubber elastic layer material interposed between the base layer 1 and the surface layer 2 may be a vulcanization accelerator, a solvent, a processing aid, an anti-aging agent, etc. Is used. Note that the conductive elastic filler as described above may be blended in the rubber elastic layer material.

  The rubber material is not particularly limited, and chlorinated polyethylene rubber (CPE), chloroprene rubber (CR) and the like are used from the viewpoint of flame retardancy. Among these, the optimum material is selected according to the electrical characteristics, elasticity, and durability required for the endless belt for electrophotographic equipment.

  The endless belt for electrophotographic equipment of the present invention is suitable for use in electrophotographic equipment employing electrophotographic technology such as full-color LBP and full-color PPC, such as toner image transfer, paper transfer conveyance, and photoreceptor substrate. However, the present invention is not limited to this. For example, it can be used for a transfer belt of a monochrome electrophotographic copying machine which is not full color.

  Next, examples will be described together with comparative examples.

[Example 1]
(Preparation of base layer material)
In a reaction vessel equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a cooling tube, 22 parts by weight of MDI (manufactured by Nippon Polyurethane, Millionate MT, Mn: 250.26) (hereinafter abbreviated as “part”) and TODI ( Nippon Soda Co., Ltd., TODI / R203, Mn: 264.29) 29 parts, aromatic polycarboxylic acid anhydride (B1) trimellitic anhydride (Mn: 192.12) 38 parts, As silicone polymer (C), 10 parts of one-end bifunctional silicone polymer having two hydroxyl groups at one end (Shin-Etsu Chemical Co., Ltd., X-22-176DX, acid value: 30 mgKOH / g, Mn: 3740), 280 parts of NMP solvent was added, and the temperature was raised to 130 ° C. over 1 hour with stirring under a nitrogen stream. The reaction was stopped at 130 ° C. for about 5 hours, and then the reaction was stopped. P solution (solid concentration: 29 wt%) was prepared. Next, 4 parts of carbon black (Show Black Ca220, Show Black N220) was added to the PAI-NMP solution, mixed with a stirring blade, and then dispersed in a ball mill to prepare a base layer material.

(Preparation of surface layer material)
100 parts of a silicone graft acrylic resin (Saimak US-350, manufactured by Toagosei Co., Ltd.) and 500 parts of a toluene solvent were blended and mixed with a stirring blade to prepare a surface layer material.

(Production of endless belt)
A mold (cylindrical substrate) was prepared, and the base layer material was spray-coated on the surface to form a base layer on the mold surface, followed by heat treatment at 250 ° C. for 2 hours. Next, the surface layer material is coated on the surface of the base layer by a dipping method and dried, and then the air is blown between the base layer and the cylindrical base body, whereby the cylindrical base body is extracted and the base layer (thickness: An endless belt having a two-layer structure in which a surface layer (thickness: 1 μm) was formed on the surface of 80 μm was produced.

[Example 2]
Carboxylic acid having one carboxyl group at both ends in place of the one-terminal bifunctional silicone polymer (X-22-176DX, manufactured by Shin-Etsu Chemical Co., Ltd.) A base layer material was prepared in the same manner as in Example 1 except that both-end silicone polymer (manufactured by Dow Corning Toray, BY16-750, acid value: 75 mgKOH / g, Mn: 1496) was used. Then, an endless belt was produced in the same manner as in Example 1 except that this base layer material was used.

Example 3
(Preparation of base layer material)
In a reaction vessel equipped with a stirrer, nitrogen introducing tube, thermometer, and cooling tube, 22 parts of MDI (manufactured by Nippon Polyurethane, Millionate MT), 29 parts of TODI (manufactured by Nippon Soda Co., Ltd., TODI / R203), 36 parts of merit acid, 10 parts of one-end bifunctional silicone polymer (Shin-Etsu Chemical Co., Ltd., X-22-176DX) which is a specific silicone polymer (C), and polybutadiene (Nippon Soda Co., Ltd., C) -1000, acid value: 52 mg KOH / g, Mn: 2158) and 330 parts of NMP solvent were charged, and the temperature was raised to 130 ° C. over 1 hour with stirring in a nitrogen stream, and about 5 at 130 ° C. as it was. After reacting for a period of time, the reaction was stopped, and a PAI-NMP solution (solid content concentration: 30% by weight) was prepared. Next, 4 parts of carbon black (Show Black Ca220, Show Black N220) was added to the PAI-NMP solution, mixed with a stirring blade, and then dispersed in a ball mill to prepare a base layer material.

(Production of endless belt)
A two-layer endless belt having a surface layer (thickness: 1 μm) formed on the surface of the base layer (thickness: 80 μm) was prepared in the same manner as in Example 1 except that the base layer material was used.

Example 4
(Preparation of base layer material)
In a reaction vessel equipped with a stirrer, nitrogen introducing tube, thermometer, and cooling tube, 22 parts of MDI (manufactured by Nippon Polyurethane, Millionate MT), 29 parts of TODI (manufactured by Nippon Soda Co., Ltd., TODI / R203), 35 parts of merit acid, 10 parts of carboxylic acid both-end silicone polymer (manufactured by Toray Dow Corning Silicone, BY16-750) which is a specific silicone polymer (C), and carboxylic acid both-end polybutadiene (manufactured by Nippon Soda Co., Ltd., C-1000, acid value: 52 mg KOH / g, Mn: 2158) and 330 parts of NMP solvent were charged, and the temperature was raised to 130 ° C. over 1 hour with stirring under a nitrogen stream. After reacting for 5 hours, the reaction was stopped, and a PAI-NMP solution (solid content concentration: 30% by weight) was prepared. Next, 4 parts of carbon black (Show Black Ca220, Show Black N220) was added to the PAI-NMP solution, mixed with a stirring blade, and then dispersed in a ball mill to prepare a base layer material.

(Production of endless belt)
A two-layer endless belt having a surface layer (thickness: 1 μm) formed on the surface of the base layer (thickness: 80 μm) was prepared in the same manner as in Example 1 except that the base layer material was used.

Example 5
It replaces with carboxylic acid both terminal polybutadiene (Nippon Soda Co., Ltd. make, C-1000), except using carboxylic acid both terminal hydrogenated polybutadiene (Nippon Soda Co., Ltd. make, CI-1000, acid value: 59 mgKOH / g, Mn: 1902). Prepared a base layer material in the same manner as in Example 4. Then, an endless belt was produced in the same manner as in Example 1 except that this base layer material was used.

Example 6
The blending ratio of trimellitic anhydride was changed to 36 parts, and in place of carboxylic acid both-end polybutadiene (Nippon Soda Co., Ltd., C-1000), carboxylic acid both-end polyacrylonitrile-butadiene copolymer (Ube Industries, Ltd.) , CTBN1300X13, acid value: 32 mg KOH / g, Mn: 3506), a base layer material was prepared in the same manner as in Example 4. Then, an endless belt was produced in the same manner as in Example 1 except that this base layer material was used.

Example 7
While changing the blending ratio of trimellitic anhydride to 34 parts, instead of carboxylic acid both-end polybutadiene (Nippon Soda Co., Ltd., C-1000), carboxylic acid both-end polyester (Nippon Kasei Co., Ltd., Crobax 300-8S) , Acid value: 103 mg KOH / g, Mn: 1089) was used in the same manner as in Example 4 to prepare a base layer material. Then, an endless belt was produced in the same manner as in Example 1 except that this base layer material was used.

Example 8
The blending ratio of trimellitic anhydride was changed to 36 parts, and C ₃₆ dimer acid (a dimer of C ₁₈ unsaturated fatty acid was used instead of carboxylic acid both-end polybutadiene (Nippon Soda Co., Ltd., C-1000)). A base layer material was prepared in the same manner as in Example 4 except that a carboxylic acid-terminated polyamide (acid value: 38.0 mgKOH / g, Mn: 2953) composed of hexamethylenediamine and hexamethylenediamine was used. did. Then, an endless belt was produced in the same manner as in Example 1 except that this base layer material was used.

Example 9
(Preparation of base layer material)
In a reaction vessel equipped with a stirrer, nitrogen introducing tube, thermometer, and cooling tube, 22 parts of MDI (manufactured by Nippon Polyurethane, Millionate MT), 29 parts of TODI (manufactured by Nippon Soda Co., Ltd., TODI / R203), 35 parts of merit acid, 10 parts of carboxylic acid both-end silicone polymer (manufactured by Toray Dow Corning Silicone, BY16-750) which is a specific silicone polymer (C), and carboxylic acid both-end polybutadiene (manufactured by Nippon Soda Co., Ltd., C-1000, acid value: 52 mg KOH / g, Mn: 2158) and 330 parts of NMP solvent were charged, and the temperature was raised to 130 ° C. over 1 hour with stirring under a nitrogen stream. After reacting for 5 hours, the reaction was stopped, and a PAI-NMP solution (solid content concentration: 30% by weight) was prepared. Next, to this PAI-NMP solution, 4 parts of carbon black (Showa Cabot, Show Black N220) and 8 parts of phosphorus-containing polyester (phosphorus content 5.5% by weight) prepared as described below were added. After mixing and mixing with a stirring blade, a base layer material was prepared by dispersing in a ball mill.

  The phosphorus-containing polyester was prepared as follows. That is, 65 parts of dimethyl phthalate, 290 parts of ethylene glycol and 125 parts of a phosphinic acid derivative represented by the following structural formula (1), 0.1 wt% manganese acetate based on dimethyl terephthalate and phosphinic acid derivative as a catalyst, 5% by weight of lithium acetate and 0.03% by weight of antimony trioxide were mixed and heated at 160-220 ° C. for 3 hours at normal pressure to conduct a transesterification reaction. The temperature of the system was adjusted to 250 ° C., the pressure was gradually reduced to 1 Torr or less, and the reaction was performed for 6 hours to obtain a phosphorus-containing polyester having a weight average molecular weight of 9000 and a phosphorus content of 5.5% by weight.

(Production of endless belt)
A two-layer endless belt having a surface layer (thickness: 1 μm) formed on the surface of the base layer (thickness: 80 μm) was prepared in the same manner as in Example 1 except that the base layer material was used.

Example 10
The blending ratio of trimellitic anhydride is 37 parts, the blending ratio of carboxylic acid double-terminal silicone polymer (BY16-750, manufactured by Toray Dow Corning Silicone Co., Ltd.) is 1 part, and the blending ratio of NMP solvent is 310 parts. A base layer material was prepared in the same manner as in Example 4 except for changing to Then, an endless belt was produced in the same manner as in Example 1 except that this base layer material was used.

Example 11
The blending ratio of trimellitic anhydride is 34 parts, the blending ratio of carboxylic acid double-terminal silicone polymer (BY16-750, manufactured by Toray Dow Corning Silicone Co., Ltd.) is 26 parts, and the blending ratio of NMP solvent is 370 parts. A base layer material was prepared in the same manner as in Example 4 except for changing to Then, an endless belt was produced in the same manner as in Example 1 except that this base layer material was used.

Example 12
The blending ratio of trimellitic anhydride to 37 parts, the blending ratio of carboxylic acid bi-terminal silicone polymer (BY16-750, manufactured by Toray Dow Corning Silicone Co., Ltd.) to 0.7 parts, and the blending ratio of NMP solvent A base layer material was prepared in the same manner as in Example 4 except for changing to 300 parts. Then, an endless belt was produced in the same manner as in Example 1 except that this base layer material was used.

Example 13
The blending ratio of trimellitic anhydride is 33 parts, the blending ratio of carboxylic acid both-end silicone polymer (manufactured by Toray Dow Corning Silicone, BY16-750) is 30 parts, and the blending ratio of NMP solvent is 380 parts. A base layer material was prepared in the same manner as in Example 4 except for changing to Then, an endless belt was produced in the same manner as in Example 1 except that this base layer material was used.

Example 14
(Preparation of base layer material)
In a reaction vessel equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a cooling tube, 22 parts of MDI (manufactured by Nippon Polyurethane, Millionate MT), 29 parts of TODI (manufactured by Nippon Soda Co., Ltd., TODI / R203), and aromatic -Based polycarboxylic acid anhydride (B1), 27 parts trimellitic anhydride, and aromatic-based polycarboxylic acid dianhydride (B2), ethylene glycol bis (anhydrotrimellitate) (Shin Nippon Rika Co., Ltd.) 19 parts manufactured by Ricacid TMEG-100, Mn: 410.3), and 10 parts carboxylic acid bi-terminal silicone polymer (BY16-750 manufactured by Toray Dow Corning Silicone Co., Ltd.), which is a specific silicone polymer (C), 20 parts of carboxylic acid both-end polyester (Nippon Kasei Co., Ltd., Crovacs 300-8S, acid value: 103 mgKOH / g, Mn: 1089), 360 parts of MP solvent was added, and the temperature was raised to 130 ° C. over 1 hour with stirring in a nitrogen stream. The reaction was stopped at 130 ° C. for about 5 hours, and then the reaction was stopped, and the PAI-NMP solution (solid concentration) : 30% by weight). Next, 4 parts of carbon black (Show Black Ca220, Show Black N220) was added to the PAI-NMP solution, mixed with a stirring blade, and then dispersed in a ball mill to prepare a base layer material.

(Production of endless belt)
A two-layer endless belt having a surface layer (thickness: 1 μm) formed on the surface of the base layer (thickness: 80 μm) was prepared in the same manner as in Example 1 except that the base layer material was used.

[Comparative Example]
(Preparation of base layer material)
A base layer material was prepared in the same manner as in the Examples except that the specific silicone polymer and carboxylic acid both terminal polymer were not blended. That is, in a reaction vessel equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a cooling tube, 22 parts of MDI (manufactured by Nippon Polyurethane, Millionate MT), 29 parts of TODI (manufactured by Nippon Soda Co., Ltd., TODI / R203), 38 parts of trimellitic anhydride and 250 parts of NMP solvent were added, the temperature was raised to 130 ° C. over 1 hour with stirring under a nitrogen stream, and the reaction was stopped at 130 ° C. for about 5 hours. A PAI-NMP solution (solid content concentration: 26% by weight) was prepared. Next, 4 parts of carbon black (Show Black Ca220, Show Black N220) was added to the PAI-NMP solution, mixed with a stirring blade, and then dispersed in a ball mill to prepare a base layer material.

(Production of endless belt)
A two-layer endless belt having a surface layer (thickness: 1 μm) formed on the surface of the base layer (thickness: 80 μm) was prepared in the same manner as in Example 1 except that the base layer material was used.

  Using the endless belts of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. These results are shown in Tables 1 to 3 below. In addition, the compounding ratio [ratio of (C) in the total amount of said (A)-(D)] of specific silicone polymer was described in the table | surface.

[PAI (Mn)]
A THF diluted solution of the PAI resin obtained in each example and comparative example was prepared, and the molecular weight by GPC (polystyrene conversion) was measured.

[Tensile modulus, elongation at break]
The tensile modulus and elongation at break were measured according to JIS K7127. The tensile speed was 10 ± 2.0 mm per minute.

[Creep rate]
The endless belt was cut into a size of 20 mm × 180 mm to produce a strip-shaped test piece. The test piece was hung on one end of the test piece under a load of 250 ± 5 g, and the elongation after being left in an environment of 50 ° C. × 95% RH for 24 hours was calculated.

[Flexibility]
According to JIS P8115, the number of MITs of each endless belt was measured under a load of 9.8 N using a Folding Endurancetester MIT-D (manufactured by Toyo Seiki Co., Ltd.). The number of MITs serves as an index for evaluating flex resistance, and the greater the number of MITs, the better the flex resistance.

[Bench durability test]
Two metal rollers having a diameter of 13 mm were prepared, and one metal roller was fixed on the table in a state where an endless belt (width 150 mm) was stretched between the two metal rollers. Next, the other metal roller not fixed to the table is placed at the end of the table, and 2 kg of weight is suspended from each end of the metal roller (total load 4 kg), and the laboratory environment (25 ° C x 40% RH), the endless belt was driven to rotate. Then, the cumulative number of revolutions until a crack was confirmed on the endless belt was measured.

[Static friction coefficient]
The static friction coefficient of each endless belt was measured using STATIC FRICTIONTESTER μs (Type 94i, manufactured by Haydon).

〔Flame retardance〕
Using the material for the base layer of each endless belt, a flame retardancy evaluation test was performed in accordance with UL-94. In addition, evaluation of a flame retardance shows that the direction of "VTM-0" is more excellent in a flame retardance than "VTM-1."

[Water absorption rate]
The endless belt was cut into a size of 10 mm × 150 mm to produce a strip-shaped test piece. The test piece was allowed to stand for 24 hours in an environment of 80 ° C. × 95% RH, and the water absorption was calculated from the change in weight before and after being left.

[Opening angle]
As shown in FIG. 2, the endless belt was cut into a size of 25 mm × 150 mm to produce a strip-shaped test piece 20. After winding the test piece 20 around a metal pipe 21 having a diameter of 13 mm, the ends of the test piece 20 are overlapped with each other, and 0.5 kg of weight (not shown) is hung on the test piece 20, and 50 ° C. × 95 It was left for 24 hours in an environment of% RH. Next, the weight is removed, and as shown in FIG. 3, both ends of the overlapped test piece 20 are opened, and the surfaces of the left and right test pieces 20 sandwiching the arc-shaped portion of the test piece 20 are directed upward. The angle θ created by the left and right virtual extensions 23 was measured as an opening angle θ. When the opening angle θ is close to 180 °, it indicates that there are few bends (curl wrinkles). If the opening angle θ is 50 ° or more, the image is not affected.

  From the above results, all of the examples had high tensile elastic modulus and elongation at break, low creep rate, and excellent durability. Further, since the static friction coefficient is low, it is possible to improve the turning of the blade and the releasability of the toner. In particular, the product of Example 14 uses an aromatic polyvalent carboxylic acid anhydride (B1) and an aromatic polyvalent carboxylic acid dianhydride (B2) in combination. The angle was large and the curl habit characteristics were excellent.

  In contrast, the comparative product has a base layer made of PAI that is not copolymerized with a specific silicone polymer and a carboxylic acid terminal polymer, so the elongation at break is small, the durability is inferior, and the static friction coefficient Therefore, the turning of the blade and the toner releasability could not be improved. Further, the comparative product had a large water absorption rate, a small opening angle, and was inferior in curl wrinkle characteristics.

  The endless belt for an electrophotographic apparatus of the present invention is suitable for an intermediate transfer belt, a paper transfer conveyance belt, etc. in an electrophotographic apparatus employing an electrophotographic technology such as a full color LBP (laser beam printer) or a full color PPC (plain paper copier). Used for.

It is a fragmentary sectional view which shows an example of the endless belt for electrophotographic apparatuses of this invention.

It is explanatory drawing which shows the measuring method of the opening angle of the endless belt for electrophotographic apparatuses.

It is explanatory drawing which shows the opening angle to measure.

Explanation of symbols

1 base layer 2 surface layer

Claims (7)

An endless belt for an electrophotographic apparatus, the surface of which is in contact with or close to the photoreceptor and driven in the circumferential direction, at least the base layer of which is obtained by copolymerizing the following (A) to (C) An endless belt for an electrophotographic apparatus, characterized by being formed using a polyamideimide resin.
(A) An aromatic isocyanate compound.
(B) An aromatic polycarboxylic acid anhydride.
(C) A silicone polymer having a polydimethylsiloxane structure in the molecule and having a reactive group for the isocyanate group of (A) at one or both ends.   The endless belt for an electrophotographic apparatus according to claim 1, wherein the silicone polymer (C) has a hydroxyl group or a carboxyl group at both ends.   The endless belt for electrophotographic equipment according to claim 1, wherein the silicone polymer (C) has a total of two reactive groups of at least one of a hydroxyl group and a carboxyl group at one end.   The blend ratio of the silicone polymer (C) is in the range of 1 to 20% by weight of the total amount of the (A) to (C). The electrophotography according to any one of claims 1 to 3. Endless belt for equipment. The endless belt for an electrophotographic apparatus according to any one of claims 1 to 3, wherein the modified polyamideimide resin is obtained by copolymerizing the following (D) together with the (A) to (C).
(D) Carboxylic acid both terminal polymer.   The endless belt for an electrophotographic apparatus according to claim 5, wherein the blending ratio of the silicone polymer (C) is in the range of 1 to 20% by weight of the total amount of the (A) to (D).   The endless belt for electrophotographic equipment according to any one of claims 1 to 6, wherein at least a base layer of the endless belt for electrophotographic equipment is formed using a phosphorus-containing polyester resin together with the modified polyamideimide resin. .