JP2003035996A - Seamless belt - Google Patents

Abstract

[PROBLEMS] To provide a seamless belt for an image forming apparatus having excellent bending resistance and molding dimensional stability. SOLUTION: This is a seamless belt obtained by heating and melting and kneading a thermoplastic resin and a polymerization catalyst which can react with the polymerization catalyst, extruding into a cylindrical shape, and cutting into a predetermined length. MFR (MF
A seamless belt obtained by setting the ratio (MFR ₂₀ / MFR ₅ ) of R ₂₀ ) to the MFR (MFR ₅ ) at 260 ° C. for 5 minutes, 2 or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seamless belt excellent in molding dimensional stability such as thickness unevenness in the circumferential direction of the belt and physical properties such as bending resistance, and an electrophotographic copying machine using the seamless belt. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus belt such as an intermediate transfer belt used in a laser beam printer or a facsimile machine, a transfer transfer belt, and a photoconductor belt, and an image forming apparatus including the image forming apparatus belt.

[0002]

2. Description of the Related Art Conventionally, seamless belts (endless belts) are often used in intermediate transfer devices, transfer separation devices, charging devices and the like of electrophotographic copying machines. FIG. 3 is a side view of a conventional intermediate transfer device. In the figure, 1 is a photosensitive drum, and 6 is a conductive seamless belt. An electrophotographic process unit including a charger 2, an exposure optical system 3 using a semiconductor laser as a light source, a developing device 4 containing toner, and a cleaner 5 for removing residual toner around the photosensitive drum 1. Are arranged. The conductive seamless belt 6 is stretched around the transport rollers 7, 8 and 9 and moved in the arrow direction in synchronization with the photosensitive drum rotating in the arrow direction.

Next, the operation will be described. First arrow A
The surface of the photosensitive drum 1 rotating in the direction is uniformly charged by the charger 2. Next, an electrostatic latent image corresponding to an image obtained by an image reading device (not shown) or the like is formed on the photosensitive drum 1 by the optical system 3. The electrostatic latent image is developed into a toner image by the developing device 4. This toner image is electrostatically transferred to the conductive seamless belt 6 by the electrostatic transfer machine 10, and the transfer roller 9
The image is transferred to the recording paper 11 between the pressure roller 12 and the pressure roller 12. FIG. 4 is a side view of a tandem type intermediate transfer device. In the figure, 1 is a photosensitive drum, and 6 is a conductive seamless belt. An electrophotographic process unit 12 including a charging device 2, an exposure optical system 3 using a semiconductor laser as a light source, and a developing device 4 containing toner is arranged around the photosensitive drum 1. The conductive seamless belt 6 includes a transport roller 7,
It is arranged so that it can be moved in the arrow direction in synchronization with the photosensitive drum rotating in the arrow direction.

Next, the operation will be described. First arrow A
The surface of the photosensitive drum 1 rotating in the direction is uniformly charged by the charger 2. Next, an electrostatic latent image corresponding to an image obtained by an image reading device (not shown) or the like is formed on the photosensitive drum 1 by the optical system 3. The electrostatic latent image is developed into a toner image by the developing device 4. This toner image is electrostatically transferred to the conductive seamless belt 6 by the electrostatic transfer machine 10, and the transfer roller 7
The image is transferred to the recording paper 11 between the pressure roller 12 and the pressure roller 12. A plurality of process units 11 (4
Install about 10 to about 10) and put different color toners in each
A color image is obtained by superimposing each color on the seamless belt (transfer belt) 6.

By the way, in the case of a conductive seamless belt for an electrophotographic copying machine or the like, since it is functionally driven by two or more rolls at a high tension for a long time, sufficient durability is required. Furthermore, when used in an intermediate transfer device,
An image is formed by toner on the belt and transferred to the paper. Therefore, if the belt is slackened or stretched during driving, it causes image misalignment. Further, in the case of the tandem type, the rotational speed fluctuates due to the change in the thickness of the seamless belt in the circumferential direction, which causes color misregistration. Further, since the toner is electrostatically transferred, some conductivity is required.

Such a seamless belt is an important part for determining a toner image, and is considered to be one of the three important parts together with the photoconductor and the toner. Therefore, the following are required for the intermediate transfer belt. The semiconductor region must have a predetermined surface resistivity and volume resistivity. It has toner releasability. It should be thin and uniform. High mechanical strength (hard to break). There is little change in resistance value due to environment (temperature and humidity). Low cost. Be a seamless and round belt.

The following method has been considered as a method for producing a seamless belt.

(I) Rotational molding method (also sometimes referred to as centrifugal molding method) A resin in which a solution is dissolved is put on the inner peripheral surface of a cylindrical mold, and the temperature is added while rotating the mold to remove the solvent. It consists of the step of taking out a seamless tube from the inside of the mold after volatilizing more than half of it, and the step of mounting the seamless tube on the outside of another cylindrical mold and applying a temperature to carry out a thermosetting reaction. (See Japanese Laid-Open Patent Publication No. 60-170862).

(Ii) Extrusion molding method This is a method in which a resin compounded with a conductive filler is melt extruded into a ring shape. (iii) Dipping method This is a method in which the resin solution is applied to the outer surface of a cylindrical or columnar mold by dipping coating or the like to a certain thickness, heated to form a film, and then the formed tubular film is pulled out from the mold.

Conventionally, as such a conductive seamless belt, one formed by blending a thermosetting resin or a thermoplastic resin with a conductive filler such as carbon black has been used. Among them, those containing a thermoplastic resin as a main component are easy to perform continuous molding and have been widely used. Among the thermoplastic resins, the thermoplastic amorphous resin is more excellent in dimensional accuracy than the thermoplastic crystalline resin. As such a thermoplastic amorphous resin seamless belt, for example, a conductive carbon black is blended with a thermoplastic resin such as a polycarbonate resin, and extruded into a tubular film using a cylindrical die. It is known that the above is sliced (see Japanese Patent Laid-Open No. 3-89357).

However, although the thermoplastic amorphous resin is superior in dimensional accuracy to the thermoplastic crystalline resin, it is inferior in bending resistance and, for example, when used as an intermediate transfer belt in electrophotography, cracks are generated during use. Likely to happen.

In order to solve this problem, there has been proposed a seamless belt obtained by blending polycarbonate and polyalkylene terephthalate such as polybutylene terephthalate (JP-A-4-313757 and JP-A-6).
-149083 gazette).

However, polycarbonate (hereinafter,
Sometimes called a PC. ) And a polyalkylene terephthalate (hereinafter, sometimes referred to as PAT) such as polybutylene terephthalate (hereinafter, sometimes referred to as PBT) are blended, and a seamless belt is more durable than the seamless belt made of the above polycarbonate. Although the flexibility is improved, the improvement effect is still insufficient. Further, since the polyalkylene terephthalate resin has high crystallinity, it has a large shrinkage rate, and if the blending amount is increased, the dimensional accuracy of the seamless belt becomes low.

Incidentally, as a general finding, thermoplastic resins can be roughly classified into crystalline thermoplastic resins and amorphous thermoplastic resins, and crystalline thermoplastic resins have excellent bending resistance and chemical resistance, but molding shrinkage. Since the ratio is high, the dimensional stability is poor and it does not have transparency. Conversely, the amorphous thermoplastic resin has excellent molding dimensional stability and transparency, but has problems such as poor bending resistance and poor chemical resistance. It has been said to have.

However, in many cases, it is required to have excellent bending resistance, chemical resistance, and molding dimensional stability.

In order to meet these requirements, various studies have been made so far on the improvement of physical properties by alloying a crystalline thermoplastic resin and an amorphous thermoplastic resin, and certain results have been achieved.

In these studies, for example, in the field of thermoplastic ester resins, it has been reported that crystalline ester resins and amorphous ester resins can be finely dispersed by promoting transesterification (copolymerization). Has been done. However, in the conventional technology, when transesterification (copolymerization) is promoted, the generation of low molecular weight products due to depolymerization accompanies the foaming of the seamless belt, or the molecular chain cutting progresses and the mechanical properties of the seamless belt decrease. In fact, it has not been put to practical use because of a decrease (such as a decrease in tensile elongation at break). Further, since it is unstable in heat stability, a difference in melt viscosity occurs due to a difference in residence time in a die (die) or the like, which adversely affects the thickness distribution in the circumferential direction of the seamless belt.

Practically, a resin product in which physical properties are prevented by suppressing the transesterification reaction has been used as a practical product.

[0019]

In an image forming apparatus such as OA equipment, in addition to mechanical characteristics such as price, flex resistance and Young's modulus, dimensional accuracy such as circumferential thickness distribution of a seamless belt and electrical characteristics are It is very important and the electric resistance value must be uniformly controlled within a certain range. For that purpose, various conductive fillers such as carbon black and metal oxides are being studied, but when conductive fillers are mixed with resin, the lack of affinity with the resin affects the resistance to bending. However, there was a problem that mechanical properties such as In particular, when a seamless belt is to be formed by extrusion molding, it is extruded into a tubular shape with a predetermined thickness and cut into a seamless belt. However, the resin state (heat deterioration, etc.) in the extruder is uneven. Thus, a portion that easily flows into the resin and a portion that does not easily flow are generated, and when extruded from the molding die, the resin that easily flows becomes thick and the resin that does not easily flow becomes thin. The seamless belt has a problem of slight thickness unevenness in its application (precision image forming apparatus such as a copying machine and a printer), and its improvement has been desired.

Thus, the mechanical properties represented by the price, flex resistance, Young's modulus, etc., the dimensional accuracy represented by the thickness distribution in the circumferential direction of the seamless belt, and the electrical properties represented by electric resistance are satisfied. The current situation is that no seamless belt has been found yet.

An object of the present invention is a seamless belt which is excellent in bending resistance, chemical resistance and molding dimensional stability, and which suppresses physical property deterioration due to a reaction during melt mixing and uneven thickness, a belt for an image forming apparatus, and image formation. A device is provided.

[0022]

[Means for Solving the Problems]

The inventors of the present invention have made extensive studies for the above purpose, and as a result, a seamless belt having excellent bending resistance and uniform thickness can be obtained by using a special resin composition and preparing it so as to satisfy specific physical properties. The present invention has been completed by finding out that it can be obtained. That is, the gist of the present invention is (1) a seamless belt obtained by heat-melting and kneading a thermoplastic resin capable of reacting with a polymerization catalyst and a polymerization catalyst, extruding it into a tubular shape, and cutting it into a predetermined length. 260 in the composition
MFR (MFR ₂₀ ) at a temperature of 20 minutes, 260 ° C, 5
Ratio of MFR (MFR ₅ ) at the time of minute retention (MFR ₂₀ / MF
It exists in the seamless belt obtained by setting R ₅ ) to 2 or less.
The seamless belt of the present invention is also characterized by the following aspects. (2) The seamless belt according to (1), wherein the thermoplastic resin capable of reacting with the polymerization catalyst is a combination of crystalline resins, a combination of a crystalline resin and an amorphous resin, or an amorphous resin. (3) The crystalline resin is a crystalline resin having at least one of a hydroxyl group, a carboxylic acid and an ester bond, and the amorphous resin is an amorphous resin having at least one of a hydroxyl group, a carboxylic acid and an ester bond. A seamless belt according to (1) or (2), which is a functional resin. (4) The seamless belt according to any one of (1) to (3), wherein the variation in thickness unevenness in the circumferential direction is ± 10% or less. (5) The thermoplastic resin capable of reacting with the polymerization catalyst is a combination of a crystalline resin and an amorphous resin, and a chemical bond exists between the molecular chain of the crystalline resin and the molecular chain of the amorphous resin. The seamless belt according to (3) or (4), which is characterized. (6) The total mass of the crystalline resin and the amorphous resin per mol of the chemical bond between the molecular chain of the crystalline resin and the molecular chain of the amorphous resin is 300,000 g or less (5 ) Seamless belt described in. (7) The seamless belt according to (5) or (6), wherein the weight ratio of the components satisfies the following conditions. The weight ratio of crystalline resin / amorphous resin is 1/99 to 99 /
1. The metal in the polymerization catalyst is 1 ppm to 10000 ppm with respect to the weight of (crystalline resin + amorphous resin) (8) The compounding ratio of the crystalline resin is X parts by weight, polystyrene (PS) conversion weight average molecular weight is Mw1, The blending ratio of the amorphous resin is Y parts by weight, and the PS-converted weight average molecular weight is Mw.
2. When the resin composition obtained after heating and kneading the crystalline resin, the amorphous resin and the polymerization catalyst has a PS-equivalent weight average molecular weight of Mw3, the following relationships are satisfied (5) to (7) ) Any one of the seamless belts.

[Equation 2] (9) The seamless belt according to any one of (1) to (8), which has a PS-equivalent weight average molecular weight of 130,000 or more. (10) The seamless belt according to any one of (1) to (9), wherein the polymerization catalyst contains Ti. (11) The seamless according to any one of (1) to (10), wherein the polymerization catalyst contains at least one member selected from the group consisting of alkali metals, alkaline earth metals and zinc, and Ti. belt. (12) The seamless belt according to (11), wherein the element of the group is Mg. (13) The crystalline resin is PAT (polyalkylene terephthalate), (1) to (1)
The seamless belt according to any one of 2). (14) The seamless belt according to (13), wherein the PAT is PBT (polybutylene terephthalate). (15) The seamless belt according to any one of (1) to (14), wherein the amorphous resin is PC (polycarbonate). (16) 3 carbon black as a conductive filler
The seamless belt according to any one of (1) to (15), wherein the seamless belt contains 30 to 30% by weight. (17) An image forming apparatus belt which is an intermediate transfer belt for an image forming apparatus, a transfer belt, or a photoconductor belt, which is the seamless belt according to any one of (1) to (16). (18) An image forming apparatus comprising the image forming apparatus belt according to (17).

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below.

(Crystalline resin having at least one of hydroxyl group, carboxylic acid and ester bond) The crystalline resin used in the seamless belt of the present invention has at least one of hydroxyl group, carboxylic acid and ester bond. There is no particular limitation as long as the crystallinity is 10% or more and 100% or less, and a general-purpose resin can be used.

Specifically, among the crystalline ester resins, P
AT (polyalkylene terephthalate) is preferable, and PBT (polybutylene terephthalate) and PET are especially preferable.
(Polyethylene terephthalate) and PEN (polyethylene naphthalate) are more preferable, and since PBT has a high crystal acceleration, the change in crystallinity due to molding conditions is small, and in general, PBT is particularly preferable because the crystallinity is stable at around 30%.

Further, the crystalline resin used in the present invention may be incorporated with a copolymerization component within a range that does not significantly impair the effects of the present invention. Specific examples thereof include those having an ester bond as a main chain and introduced with an ester bond such as polymethylene glycol.

There is no particular limitation on the molecular weight of the crystalline resin used in the seamless belt of the present invention. For example, a resin having a general molecular weight such as a weight average molecular weight of 10,000 to 100,000 can be used. When there is a demand for high mechanical properties, a high molecular weight one is preferable.
Specifically, it is preferably 20,000 or more, and 25,000.
It is more preferable if it is at least 30,000, and particularly preferable if it is at least 30,000.

(Amorphous resin having at least one of hydroxyl group, carboxylic acid and ester bond) The amorphous resin used in the seamless belt of the present invention is at least one of hydroxyl group, carboxylic acid and ester bond. There is no particular limitation as long as the crystallinity is 0% or more and less than 10%, and a general-purpose resin can be used.

Specifically, PC (polycarbonate) and P
Polyester such as Ar (polyarylate) and PMMA
A resin having a side chain having an ester bond, such as (polymethylmethacrylate), may be mentioned as a preferred example.
Among them, polyester is preferable and PC can be used particularly preferably.

The amorphous resin used in the seamless belt of the present invention may contain a copolymerization component within a range that does not significantly impair the effects of the present invention. Specific examples thereof include those having an ester bond as a main chain and introduced with an ester bond such as polymethylene glycol.

The molecular weight of the amorphous resin used in the seamless belt of the present invention is not particularly limited, and for example, a resin having a general molecular weight such as a weight average molecular weight of 10,000 to 100,000 can be used. When there is a demand for high mechanical properties such as elongation, a polymer having a high molecular weight is preferable.
Specifically, it is preferably 20,000 or more, and 25,000.
It is more preferable if it is at least 30,000, and particularly preferable if it is at least 30,000.

(Resin Composition) The present invention intends to obtain an optimum seamless belt by polymerizing (reacting) a thermoplastic resin with a polymerization catalyst using a thermoplastic resin capable of reacting with the polymerization catalyst. It is a thing. Therefore, if the reaction or polymerization can occur by the polymerization catalyst, the raw material resin is a crystalline resin alone, a mixture of different crystalline resins, an amorphous resin alone, a mixture of different amorphous resins, a crystal Various combinations such as a mixture of a crystalline resin and an amorphous resin are possible. However, a mixture (combination) of a crystalline resin and an amorphous resin in the sense of compensating the respective properties of the crystalline resin and the amorphous resin described above.
Is preferably used. (Weight Ratio of Crystalline Resin and Amorphous Resin) The weight ratio of the crystalline resin and the amorphous resin used in the seamless belt of the present invention is not particularly limited. However, in general, crystalline resin has chemical resistance,
Since the amorphous resin is excellent in bending resistance and the molding dimensional stability is excellent, it is possible to set an arbitrary ratio according to the purpose of use. Among them, the crystalline resin / amorphous resin weight ratio is particularly high. 1/99 to 99/1 is preferable and 40/60 to 97/3
Is more preferable, 60/40 to 95/5 is further preferable, and 70/30 to 90/10 is particularly preferable.

The reason why a large ratio of the crystalline resin is selected as a particularly preferable ratio is that the amorphous resin can be expected to sufficiently improve the molding dimensional stability with a small amount of the compound, and the amorphous resin can be slightly improved. The reason for this is that excessive compounding may have a marked effect on the deterioration of chemical resistance such as solvent during coating.

(Viscosity difference between crystalline resin and amorphous resin) If the viscosity difference between both resins is too large, good dispersion cannot be obtained even if the production conditions are adjusted, and uniform dispersion cannot be achieved. Therefore, it is preferable that the difference in viscosity is small.

Specifically, both resins are preferably subjected to MFR measurement under the same conditions, and the value is preferably within the range of about 1/20 to 20/1, and more preferably within the range of 1/10 to 10/1.

The measuring method is based on JIS K-7210, and it is preferable to select the measuring temperature condition close to the processing temperature of the resin.

For example, when PBT and PC are selected, it is preferable to set the processing temperature of 260 ° C. as the measurement temperature and compare the viscosity difference between the two resins. The load can be suitably measured by selecting 2.16 kg, for example.

Also in the case of a combination of a mixture of different crystalline resins and a mixture of different amorphous resins, it is preferable to select the one having the MFR range described above. (Polymerization catalyst) The polymerization catalyst polymerizes a crystalline resin alone, a mixture of different crystalline resins, an amorphous resin alone, a mixture of different amorphous resins or a mixture of a crystalline resin and an amorphous resin. There is no particular limitation as long as it has the ability.

As a specific example, there is no particular limitation as long as it has the ability to condense an organic acid and a hydroxyl group, and a polyester polymerization catalyst can be used.

Among the polymerization catalysts, Ti-based polymerization catalysts are preferable, and alkyl titanate and the like can be preferably used.

Among the alkyl titanates, tetrabutyl titanate and tetrakis (2-ethylhexyl) ortho titanate are preferable, and these are TYZOR TOT.
(Made by DuPont) or TYZOR TBT (DuPont)
commercial product can be easily obtained.

The Ti-based polymerization catalyst is an alkali metal,
A combination with an alkaline earth metal-containing compound or a zinc-containing compound works more effectively, and it is particularly preferable to have a Mg-containing compound as a polymerization catalyst.

The compound containing Mg is not particularly limited, but an organic acid Mg salt is particularly preferable, and Mg acetate is particularly preferable.

If the content of the polymerization catalyst is too small, it may not work effectively. Therefore, the content is preferably high to a certain extent. Specifically, the mass of the metal component in the polymerization catalyst is preferably 1 ppm or more based on the total resin. It is more preferably 10 ppm or more, and particularly preferably 20 ppm or more. On the other hand, it is known that the ester-based resin may cause depolymerization in the presence of a large amount of heavy metals, so it is preferable that the amount is small to some extent, specifically, 10,000 pp.
m or less is preferable, 1000 ppm or less is more preferable, and 500 ppm or less is particularly preferable.

(Chelator) In the present invention, if the activity of the polymerization catalyst is too high, depolymerization of the resin may be promoted to lower the mechanical properties due to the lowering of the molecular weight, and foaming accompanying the generation of the low molecular weight substance may become a problem.

In the present invention, the presence of a chelator capable of chelating a metal in the polymerization catalyst can suppress depolymerization.

The type of chelator is not particularly limited, and a known chelator can be used.

Examples include phosphites, phosphates, phosphates and hydrazines,
These are, for example, Irgaphos 168 (manufactured by Ciba-Geigy Co., Ltd.), PEP36 (manufactured by Asahi Denka Co., Ltd.), PE.
PQ (Clariant Japan KK) phosphite, IRGANOX MD1024 (Nippon Ciba Geigy KK), CDA-6 (Asahi Denka Kogyo KK) hydrazines, etc. easily available from the market. You can

In the present invention, since the depolymerization and the generation of low molecular weight substances can be suppressed by optimizing the molding conditions in the present invention, the amount of the chelator added can be set to 0 part by weight, but the depolymerization is possible. It is preferable to add 0.001 parts by weight or more when it is necessary to suppress the above, and it is preferable to add 0.01 parts by weight or more to obtain more effects.

If the amount of the chelator is too large, the polymerization catalyst loses its activity and a seamless belt having good physical properties may not be obtained. Therefore, it is preferable that the addition amount is not excessive, and 10 parts by weight or less relative to 100 parts by weight of the resin. Is preferred and 5 parts by weight or less is more preferred.

Generally, it is preferable to use the chelator in a small amount of 0.1 part by weight or less. When the chelator is used in the present invention, a particularly preferable example is to use a polymerization agent. Add 50 to 5 catalyst
It is added in an amount as high as 00 ppm, and the chelator is used in an amount of 0.1 to 5 parts by weight, preferably 0.3 to 3 parts by weight, which is higher than common sense, and molding conditions for obtaining a seamless belt (temperature, residence time, etc.). By optimizing the above, it is possible to suppress the depolymerization while promoting the generation of a chemical bond between the crystalline resin and the amorphous resin and increase the molecular weight thereof, and it is possible to obtain a seamless belt having excellent physical properties that has never been obtained. (Conductive Material) In the present invention, a conductive material may be blended when it is necessary to adjust the electric resistance value. Particularly in endless belts, seamless belts and the like used in image forming apparatuses, it is necessary to adjust the surface resistance value and the volume resistance value in accordance with the application in order to electrically adsorb and transfer toner, paper and the like. The conductive substance to be blended is not particularly limited as long as it satisfies the performance required for the application, and various types can be used, specifically,
As the conductive filler, carbon black or carbon fiber, carbon-based filler such as graphite, metal-based conductive filler, metal oxide-based conductive filler, etc. are used. In addition to the conductive filler, an ion-conductive substance, for example, Examples include quaternary ammonium salts. A particularly preferable conductive material is carbon black having excellent dispersibility. As the kind of carbon black, acetylene black, furnace black, channel black and the like can be preferably used, and among these, acetylene black which has few functional groups as impurities and hardly causes appearance defects due to carbon aggregation can be particularly preferably used. Further, the primary particle size is 10 to 100 nm, the specific surface area is 10 to 20.
It is more preferably 0 m ² / g and a PH value of 3 to 11. The carbon black used may be one kind or two or more kinds. Furthermore, there is no problem in using carbon black coated with a resin, graphitized carbon black, or carbon black subjected to a known post-treatment process such as acid-treated carbon black as the carbon black. Further, for the purpose of improving the dispersibility of the conductive filler, a conductive filler such as carbon black treated with a coupling agent such as a silane type, an aluminate type, a titanate type and a zirconate type may be used.
The blending amount of the carbon black used in the present invention varies depending on the required conductivity, but it is usually preferable to contain 3 to 30% by weight, and a particularly preferable range within the above range is 10 to 25%. When the content exceeds the above range, the appearance of the product is deteriorated and the material strength is lowered, which is not preferable. A seamless belt made conductive by adding a conductive substance has different required physical properties depending on the application, but the surface resistance value is 1 to 1 as measured by JIS K6911.
It is about 1 × 10 ¹⁶ Ω. Also, the volume resistance value is J
The value measured by IS K6911 is 1-1 × 10 ¹⁶ Ω
・ It is about cm. A uniform resistance value effect is expected by combining the special resin composition of the present invention with the above conductive material. A surface resistance value is measured at any 20 points on the seamless belt, and a fluctuation rate within 100 times (within 2 digits), preferably within 10 times (within 1 digit), and more preferably within 5 times is realized. It is possible.

(Additional compounding material; optional component) The seamless belt of the present invention may be compounded with optional compounding components according to various purposes.

Specifically, antioxidants such as Irgaphos 168, Irganox 1010, and phosphorus-based antioxidants,
Heat stabilizers, various plasticizers, light stabilizers, ultraviolet absorbers, neutralizers, lubricants, anti-fog agents, anti-blocking agents, slip agents, cross-linking agents, cross-linking aids, colorants, flame retardants, dispersants, etc. Various additives can be added.

Further, as long as the effect of the present invention is not significantly impaired, various thermoplastic resins, various elastomers, thermosetting resins, fillers and other compounding materials can be added as the second and third components.

As the thermoplastic resin, polypropylene, polyethylene (high density, medium density, low density, linear low density), propylene ethylene block or random copolymer, rubber or latex component, for example, ethylene / propylene copolymer rubber , Styrene / butadiene rubber, styrene / butadiene / styrene / styrene block copolymer or hydrogenated derivative thereof, polybutadiene, polyisobutylene, polyamide, polyamideimide, polyacetal, polyarylate, polycarbonate, polyimide,
Liquid crystalline polyester, polysulfone, polyphenylene sulfide, polybisamide triazole, polyetherimide, polyetheretherketone, acrylic,
Polyvinylidene fluoride, polyvinylidene fluoride, chlorotrifluoroethylene, ethylene tetrafluoroethylene copolymer, hexafluoropropylene, perfluoroalkyl vinyl ether copolymer, acrylic acid alkyl ester copolymer, polyester ester copolymer, poly It is possible to use one or a mixture of ether ester copolymer, polyether amide copolymer, polyurethane copolymer and the like. As a thermosetting resin,
For example, epoxy resin, melamine resin, phenol resin,
An unsaturated polyester resin or the like or a mixture thereof may be used. Examples of various fillers include calcium carbonate (heavy and light), talc, mica, silica, alumina, aluminum hydroxide, zeolite, wollastonite, diatomaceous earth, glass fiber, glass beads, bentonite, asbestos, hollow. Glass beads, graphite, molybdenum disulfide, titanium oxide, carbonated fiber,
Aluminum fiber, styrene steel fiber, brass fiber,
In addition to fillers such as aluminum powder, wood powder, chaff, graphite, metal powder, conductive metal oxides, organic metal compounds, and organic metal salts, antioxidants (phenolic, sulfur-based, phosphoric ester-based) as additives Etc.), lubricants, various organic / inorganic pigments, UV inhibitors, antistatic agents, dispersants, neutralizing agents, foaming agents, plasticizers, copper damage inhibitors, flame retardants, crosslinking agents,
Flowability improvers and the like can be mentioned.

(Heat Kneading) In the present invention, a crystalline resin, an amorphous resin or an amorphous resin may be formed by kneading a crystalline resin, an amorphous resin and a polymerization catalyst with heating to form a seamless belt. Alternatively, the polymerization catalyst may be kneaded by heating to obtain a seamless belt as it is.

In this case, the conditions such that the bond between the crystalline resin and the amorphous resin can be formed by either heat kneading at the step of obtaining the resin composition or heat kneading at the step of molding the resin composition into a seamless belt. You can adjust. In any case, the heating temperature cannot be sufficiently dispersed unless it is in a molten state, so it is preferable that the heating temperature is higher to some extent. Specifically, the melting point of the crystalline resin is used as a guide, and the melting point of the crystalline resin is not less than Is preferable, and it is more preferable that the melting point is + 10 ° C. or higher. Further, if the heating temperature is too high, it may cause thermal decomposition to cause deterioration of physical properties, so it is preferable to be low to some extent. Specifically, using the melting point of the crystalline resin as a guide, the melting point of the crystalline resin + 80 ° C. The following is preferable, melting point +
It is more preferably 60 ° C. or lower.

Before heating and kneading, a raw material may be dried to obtain a seamless belt having good physical properties without generation of bubbles, so drying is preferable.

In some cases, after kneading with heat to form a resin composition, heat treatment is performed at a temperature not higher than the melting point to generate an ester bond, and then the seamless belt can be molded.

In the present invention, it is considered that the polymerization catalyst promotes the reaction of the crystalline resin and the amorphous resin to obtain a seamless belt having excellent physical properties. Since the reaction to be promoted is important for the temperature at the time of heat kneading and the time of receiving heat, it is necessary to set the heat kneading conditions while grasping the dispersion form of the obtained seamless belt. It should be noted that a low molecular weight product is generated as a by-product during this reaction, and if it is not removed from the system, this causes a decrease in the molecular weight and foaming of the molded product. On the other hand, it is considered that the best reaction state is immediately before the foaming of these products.
For example, it is preferable to study the residence time variously, determine the residence time at which foaming occurs, and set the residence time to be a little shorter than that time, because the best heat kneading condition can be obtained.

Although it is a means of heating and kneading, it is not particularly limited, and a known technique can be used. For example, if a crystalline resin, an amorphous resin, and a polymerization catalyst are first kneaded by heating to form a resin composition, a single-screw extruder, a twin-screw kneading extruder, a Banbury mixer, a roll, a Brabender, a plastograph, a kneader. Etc. can be used. Further, even when a seamless belt is obtained from the resin composition thus obtained, a known technique can be used. Examples include injection molding machines and extrusion molding machines.

(Heat Treatment) By heat-treating the obtained seamless belt, it becomes possible to obtain a molded member having improved physical properties.

Although the heat treatment conditions depend on the raw material resin used,
Usually a temperature of 60 to 200 ° C, preferably 70 to 120 ° C
The temperature is 5 to 60 minutes, preferably 10 to 30 minutes.

In particular, when the seamless belt described later is used, the number of times of folding and the tensile elastic modulus are improved.

(Chemical bond between molecular chain of crystalline resin and molecular chain of amorphous resin) In the seamless belt of the present invention, a chemical bond between molecular chains of the raw material resin is formed as a specific preferable example. Forms a chemical bond between the molecular chain of the crystalline resin and the molecular chain of the amorphous resin, which promotes the affinity UP between the two resins and the fine dispersion of the morphology, and the high bending resistance of the crystalline resin, It is possible to obtain a seamless belt having both the dimensional stability of the amorphous resin and the transparency (depending on the conditions).

The ratio of the chemical bonds is not particularly limited, but it is basically preferable that the ratio is large, and one specific example is a chemical bond between the molecular chain of the crystalline resin and the molecular chain of the amorphous resin.
In terms of mol, the total mass of the crystalline resin and the amorphous resin is preferably 300,000 g or less, and 10
It is particularly preferable that the amount becomes less than or equal to 10,000 g.

The method of measuring the amount of chemical bonds is not particularly limited, but it can be measured by, for example, NMR.

An example of measurement when PBT is used as the crystalline resin and PC is used as the amorphous resin is shown below.

Measurement model JEOLGSX400 Solvent 1,1,1,2,2,2-hexafluoroisopropanol / d-chloroform = 3/7 (VOL) Cumulative number of times 128 times standard TMS The chart shown in FIGS. Got Note that FIG. 2 is an enlarged view of the II portion of FIG.

The benzene ring hydrogen of terephthalic acid (TPA) has different chemical shifts when carboxylic acid is bonded to butanediol and bisphenol A (BPA).

In general, TPA benzene ring hydrogen (d) in the PBT molecule is equivalent to all four as shown in Chemical formula 1, and shows a singlet peak at a chemical shift of 8.07.

[0073]

[Chemical 1]

On the other hand, the chemical shift of benzene ring hydrogen in TPA of PBT bound to BPA of PC as shown in Chemical formula 2 changes, and hydrogen (b) becomes 8.25 and doublet (c) becomes 8.13. The doublet peak is shown.

[0075]

[Chemical 2]

(D): The area ratio of ((b) + (c)} gives the TPA in the PBT molecule and the TP bound to PC.
The ratio of A can be determined.

In this example, the area ratio is (d): {(b) +
(C)} = 100: {0.4654 + 0.5635} ≈
Since 9: 01: 0.99, the PBT structural unit 10
It can be seen that 0 mol has TPA (derived from PBT) -BPA (derived from PC) bond per 0 mol. In addition, since it is easily estimated that the same amount of butanediol (derived from PBT) -carbon (PC) bond is present in the resin composition, the total amount of PBT constitutional unit is 100 mo.
It can be seen that there is 1.98 mol of PBT-PC bond per liter.

As shown in Chemical formula 3, since the formula weight of the PBT constitutional unit (butanediol + TPA) is 220, PBT2200
1.98 mol per 0 (220 × 100 mol) g
There is PBT-PC binding of.

PBT per mol of PBT-PC binding
Can be calculated to be about 11000 (22000 / 1.98).

In this example, since the weight ratio of PBT and PC was 7/3, the resin component (PB
T mass + PC mass) is 16000 g (11000/0.
7) can be obtained.

[0081]

[Chemical 3]

(Molecular Weight) In the present invention, a crystalline resin, an amorphous resin and a polymerization catalyst are kneaded by heating to form a chemical bond between the molecular chain of the crystalline resin and the molecular chain of the amorphous resin,
Moreover, since it is considered that the physical properties of the obtained seamless belt can be improved by maintaining or increasing the total molecular weight of the resin composition, a higher molecular weight is preferable.

Although this is a method for measuring the molecular weight, it is difficult to determine the true value of the molecular weight when the copolymer is present as in the present invention.

Therefore, in the present invention, all the resins were measured by GPC under the same conditions, and the value obtained as the PS-converted weight average molecular weight was used as a common representative value.

As the measurement conditions, 20 mg of the sample was 0.5
ml 1,1,1,3,3,3-hexafluoro-2-
It was dissolved overnight in propanol and 0.2 ml of chloroform, 25 ml of a mobile phase solvent was further added, and the mixture was filtered through a 0.22 μm filter to obtain a SEC measurement solution. It took less than 12 hours from the addition of the mobile phase to the end of the measurement.

SEC measurement conditions Solvent Chloroform / acetic acid: 99.5: 0.5 (vol / vol) Flow rate 1.0 ml / min Injection amount 0.02 ml Column AD806M / S 2 (manufactured by Showa Denko KK) Column temperature 30 ° C. Detector UV 254 nm Molecular weight 500 (A-500) to 2,890,000
A calibration curve was prepared using 12 samples of monodisperse standard polystyrene (manufactured by Tosoh Corporation) having different molecular weights up to (F-288), and the molecular weight in terms of polystyrene was calculated.

The value of the PS-converted weight average molecular weight (defined as Mw3) of the resin composition obtained by heating and kneading the crystalline resin, the amorphous resin and the polymerization catalyst according to this method is Is the compounding ratio of the crystalline resin is X parts by weight, polystyrene (PS) conversion weight average molecular weight is Mw1, the mixing ratio of the amorphous resin is Y parts by weight, PS conversion weight average molecular weight is Mw2,

[0088]

[Equation 3]

It is preferable that

[0090]

[Equation 4]

More preferably,

[0092]

[Equation 5]

It is particularly preferable that the above-mentioned is because it is possible to obtain sufficiently high physical properties.

In the present invention, it is important that Mw3 is higher than the arithmetic mean value of Mw1 and Mw2 by heating and mixing. Even if a resin having a high Mw1 or Mw2 is used from the beginning, the molecular weight is lowered during heating and mixing. But the final Mw
Since it is considered that good physical properties cannot be expected even if 3 is high, there is no particular limitation on the absolute value of Mw3, but even from a comprehensive point of view, it is preferable that it is high, specifically, a PS-converted weight average molecular weight of 130, 000 or more is preferable, and 14
More preferably, it is 50,000 or more, 150,00
It is particularly preferably 0 or more.

An example of the correlation between the true value of the weight average molecular weight and the PS-converted weight average molecular weight is as follows:
When a PBT of 10,000 is measured by the above method, a value of PS-converted weight average molecular weight of 122,000 is obtained. When a PC of a weight average molecular weight of 28,000 is measured by the above method, a value of PS-converted weight average molecular weight of 64,000 is obtained. I know I can get it.

(Dispersion Form) It is generally known that even if two types of thermoplastic resins are melt-mixed, they are not completely mixed with each other and have a fluid structure. If there is a large difference in volume fraction between the two thermoplastic resins, the one with a larger volume fraction tends to form the sea and the one with a smaller volume fraction tends to form an island structure. If the difference in volume fraction is small, the difference in melt viscosity Influences the sea-island structure, and it is said that the one with smaller melt viscosity tends to become the sea and the one with larger melt viscosity tends to become the island.

In general melt mixing, the dispersed particle size is 100 n.
However, in the present invention, it is possible to make the dispersed particle size finer to several nm or less by optimizing the conditions in the present invention, which makes the seamless belt practically transparent.

Generally, a seamless belt containing a crystalline resin such as PBT is known to have no transparency, but it is surprisingly possible to obtain a transparent seamless belt by using the method of the present invention. .

There is no particular limitation on the method of confirming the dispersed state, and R
After staining with uO4, a known method such as making an ultrathin section and observing with a TEM can be used.

In particular, it can be suitably used in the field of OA equipment, which requires strict physical properties such as dimensional accuracy, resistance to bending, and tensile elongation at break, especially for functional members. For example, the seamless belt shape has few defects such as cracks and elongation. It is suitable. (Flowability of Resin Composition) In the present invention, a crystalline resin, an amorphous resin, and a polymerization catalyst are heated and kneaded to form a chemical bond between the molecular chain of the crystalline resin and the molecular chain of the amorphous resin. According to JIS K-7210, the flowability of the resin composition is 260 ° C. and a load of 2.16 Kg.
M after being left for 20 minutes in the FR measuring device and staying there)
FR (MFR ₂₀ ) and retention for 5 minutes (5 in the MFR measuring device)
The ratio (MFR ₂₀ / MFR ₅ ) of the MFR (MFR ₅ ) of (measured after leaving and standing for minutes) is preferably 2 or less, more preferably 1.5 or less, and particularly preferably 1.2 or less. . If the ratio exceeds 2, there are some differences depending on the structure of the mold, but the resin with low viscosity gathers at the resin confluence part (usually called weld part, spiral mark, spider mark) and only that part. As a result, the seamless belt becomes uneven in thickness in the circumferential direction.
To set (MFR ₂₀ / MFR ₅ ) to 2 or less, select crystalline resin, amorphous resin, type and amount of polymerization catalyst, select type and amount of conductive material, performance of extruder, structure of die It may be carried out by preparing according to the above conditions. Since the conditions are ambiguous and it is difficult to set the conditions, we usually repeat experiments and find the optimum range by trial and error. Whatever conditions are set, in any case (MFR ₂₀ / M
By setting FR ₅ ) to 2 or less, a tubular body (seamless belt) with less thickness unevenness can be obtained.

(Seamless Belt) The seamless belt of the present invention is used as an intermediate transfer belt, a transfer belt, a photosensitive belt, etc. in an image forming apparatus such as an electrophotographic copying machine, a laser beam printer, a facsimile machine and the like.

In order to obtain a seamless belt, a method in which a crystalline resin, an amorphous resin and a polymerization catalyst are mixed by, for example, a twin-screw kneading extruder and pelletized and then molded into a seamless belt is particularly preferably used. .

The molding method is not particularly limited, and a known method such as a continuous melt extrusion molding method, an injection molding method, a blow molding method, or an inflation molding method can be adopted, but it is particularly preferable. Is a continuous melt extrusion process. In particular, a downward extrusion internal cooling mandrel system or a vacuum sizing system capable of controlling the inner diameter of the extruded tube with high accuracy is preferable, and the internal cooling mandrel system is most preferable.

Also, since the seamless belt having better physical properties can be obtained by optimizing the temperature and the residence time at the time of molding, it is preferable to adjust the conditions according to each composition. In molding, it is necessary to set the diameter variation rate to 0.8 to 1.2. The thickness reduction rate is 1.
It is also desirable to mold as 1 to 50. The diameter variation rate is preferably 0.9 to 1.1, and the thickness reduction rate is preferably 3 to 30. By setting the diameter variation rate within this range, that is, by molding so that the diameter of the die slit and the diameter of the seamless belt do not significantly differ, variation in wall thickness is suppressed and circularity is secured. Further, by setting the thickness drop-off rate within this range, it is possible to suppress fluctuations in wall thickness and to balance the strength of the seamless belt in the direction of extrusion and the direction perpendicular to the direction of extrusion. Diameter variation and thickness reduction are due to the fact that the extruded resin is still in a molten state,
That is, it is desirable to be performed while the temperature is higher than the crystalline melting point of the crystalline resin (while the temperature is higher than the glass transition point temperature of the amorphous resin), and if it is performed after the resin is solidified, its effect is small. The diameter variation rate is represented by the ratio of the die diameter to the product diameter, that is, the diameter variation rate = die diameter / product diameter. The thickness reduction rate is represented by the ratio of the die slit width (slit gap, lip width) to the product thickness thickness, that is, the reduction rate = die slit width / product thickness. According to the present invention, a seamless belt having little thickness unevenness, that is, excellent in molding dimensional stability can be obtained by combining the material having the above-mentioned specific composition and the specific molding conditions. That is, since the composition used in the present invention causes the crystalline resin and the amorphous resin to react with each other by the polymerization catalyst during molding, the fluidity of the resin during molding changes. Therefore, delicate adjustment of the balance between the diameter variation rate and the thickness reduction rate during seamless belt molding is necessary to prevent variation in thickness and variation in diameter.

(Physical Properties of Seamless Belt) According to the present invention, a seamless belt having the following physical properties can be obtained.

-Physical properties; folding endurance When the seamless belt used in the present invention is used as an intermediate transfer belt in an image forming apparatus, for example, if the flexing resistance is poor, cracks occur and an image cannot be obtained. A good seamless belt is preferred.

The degree of bending resistance is JIS P-8115.
It can be quantitatively evaluated by following the method for measuring the folding endurance of
It can be judged that the seamless belt having a higher folding endurance is less likely to be cracked and is excellent in bending resistance.

As a specific numerical value, if it is 500 times or more, it can be used by exhibiting a function as a seamless belt, but in practical use, it is preferably 5000 times or more, more preferably 10,000 times or more, 3000
It is particularly preferable that the number of times is 0 or more because cracks are less likely to occur.

Tensile Elastic Modulus If the tensile elastic modulus of the seamless belt is low, for example, when it is used as an intermediate transfer belt in an image forming apparatus, a little elongation occurs due to tension, which may cause problems such as color misregistration. Higher tensile modulus is preferable, specifically 1000 MPa or more is preferable, and 1500 MPa
The above is more preferable, and 2000 MPa or more is further preferable, and 2500 MPa or more is particularly preferable because problems such as color misregistration can be significantly suppressed.

Generally, a soft plastic has a high folding endurance, but tends to have a low tensile elastic modulus, while a hard plastic tends to have a high tensile elastic modulus but tends to be brittle, and only a low folding endurance is often obtained. . In the present invention, it can be said that it is useful in the sense that a high folding endurance can be obtained while maintaining the characteristic of PBT or PC having a high tensile elastic modulus peculiar thereto.

-Physical properties; surface resistivity The seamless belt used in the present invention can obtain conductivity by blending a conductive filler or a substance exhibiting conductivity as required.

The resistance region varies depending on the purpose, but from the range of surface resistivity 1 to 1 × 10 ¹⁶ Ω, volume resistivity 1 to
It is preferable to select from 1 × 10 ¹⁶ Ω · cm.

The more preferable range depends on the use, but
For example, when it is used as a photoconductor belt, it is 1 to 1 × 10 ⁹ so that the charge on the outer surface can be released to the inner surface as necessary.
A surface resistivity as low as Ω is preferable, and when used as an intermediate transfer belt, it can be easily charged and transferred to 1 × 10 ⁶ to
1 × 10 ¹³ Ω is preferable, and when used as a transfer belt, it is easily charged and is not easily damaged even at high voltage.
^A region as high as ¹⁰ to 1 × 10 ¹⁶ Ω is preferable.

The distribution of the surface resistivity in one seamless belt is preferably narrow, and the difference between the maximum value and the minimum value in one is 2 in each preferable surface resistivity region.
It is preferably within one digit (within 100 times), preferably within one digit (within 10 times).

The surface resistivity of the film can be easily measured by, for example, Hiresta (trade name) or Loresta (trade name) manufactured by Dia Instruments Co., Ltd., R8340A (trade name) manufactured by Advantest Corporation.

Thickness of seamless belt The thickness of the seamless belt is preferably 50 to 1000 μm, more preferably 80 to 500 μm, and 100 to 200.
If it is μm, it is particularly preferable. Thickness variation variation in circumferential direction Thickness variation in the circumferential direction of the seamless belt is preferably ± 10% or less (maximum value, minimum value), more preferably ± 7% or less, and ± of the average thickness of the seamless belt. It is particularly preferable if it is 5% or less. If it is out of the above range, color misregistration of four colors is severe and practical application is difficult.

Use of seamless belt The seamless belt may be used as it is as a belt or may be wound around a drum or a roll.

Further, for the purpose of preventing meandering, reinforcing the end surface, etc., a heat-resistant tape is attached near the inner and / or outer ends of a seamless belt of a predetermined size, or a tape such as urethane rubber or silicon rubber is attached to the belt. It may be attached near the inner end.

[0119]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples.

[0120]

(Raw materials) The following raw materials were used, and the mixing ratio was as shown in Table 1 or Table 2. PBT; weight average molecular weight 40,000; PS equivalent weight average molecular weight 122,000 PET; weight average molecular weight 44,000; PS equivalent weight average molecular weight 131,000 PC; weight average molecular weight 28,000; PS equivalent weight average molecular weight 64, 000 PAr; weight average molecular weight 30,000; PS equivalent weight average molecular weight 69,000-Polymerization catalyst; titanium (IV) butoxide-magnesium acetate-heat stabilizer; phosphorylation antioxidant PEPQ (trade name)
Carbon black manufactured by Clariant Japan Co., Ltd .; Denka Black (trade name) manufactured by Denki Kagaku Co., Ltd. (heating kneading). Each raw material is fed into a twin-screw kneading extruder, IKG Co., Ltd.
The material was pelletized using PMT32 (trade name) manufactured by the company.

(Seamless Belt Molding Method) This material pellet was dried to a diameter of 180 mm and a lip width of 1 mm.
With a 40-mm φ extruder with a 6-row spiral type annular die, the molten tube was extruded below the annular die in a molten tube state, and the extruded molten tube was mounted on the same axis as the annular die via a support rod with a 170 mm outer diameter cooling mandrel. While it is in contact with the outer surface of the and cooled and solidified, the core installed in the seamless belt and the roll installed outside of the seamless belt take up the seamless belt in a cylindrical shape while keeping the 340 mm length. The resin seamless belt having a diameter of 169 mm was obtained by cutting the resin into a thickness of 169 mm by adjusting the extrusion amount and the take-up speed so as to obtain the thickness and the residence time described in each table.

Conditions such as molding temperature and residence time are shown in Tables 1 and 2.

(Evaluation) The evaluation was carried out by cutting the seamless belt into a required size if necessary. -Folding endurance JIS P-8115 compliant-Surface resistivity Ω The surface resistivity is different depending on the measuring device, and therefore, it is properly used as follows.

A sample having a surface resistivity of 1 to 1 × 10 ⁶ Ω A Loiresta manufactured by Dia Instruments Co., Ltd. was used, and the belt circumferential direction was measured at a pitch of 20 mm.

Sample of 10 ⁶ to 1 × 10 ¹³ Ω Using a Hiresta (HA terminal) manufactured by Dia Instruments Co., Ltd., 500 V, 10
The belt circumferential direction was measured at a pitch of 20 mm under the condition of seconds.

Sample of 10 ¹³ to 1 × 10 ¹⁶ Ω Advantest Co., Ltd. Microcurrent measuring instrument R8340A (trade name) (JIS electrode) was used, and belt circumference was set at 100 mm pitch under conditions of 500 V and 10 seconds. The direction was measured. Measurement time 10 seconds value

Evaluation of Durability as a Seamless Belt The obtained seamless belt is mounted on an image forming apparatus as a tandem type intermediate transfer belt, and the seamless belt is cracked at the stage of continuous image output and the number of output sheets. I evaluated what to do. -Evaluation of color misregistration The obtained seamless belt is mounted on an image forming apparatus as a tandem type intermediate transfer belt having the structure shown in Fig. 4, a black horizontal line is copied in full color mode, the width of the horizontal line is measured, and the original is printed. Calculate the difference between and. The difference at that time is 150
If it is less than μm, it is considered as good, and if it exceeds 150 μm, it is considered as bad.・ Tensile elastic modulus conforms to ISO R1184-1970, the width of the test piece is 1
Cut to 5 mm and length 150 mm, pulling speed 1 mm /
min, and the distance between grips was 100 mm.・ Tensile rupture elongation rate Based on JISZ1702-62, the width of the test piece is 15m.
m, length 150mm, pulling speed 50mm / m
in, distance between grips is 100 mm, distance between marked lines is 50 m
m. -Thickness measurement method The thickness was measured at a pitch of 20 mm in the circumferential direction of the seamless belt using a micrometer manufactured by Tokyo Seimitsu Co., Ltd. Regarding the thickness unevenness in the circumferential direction of the seamless belt, the maximum value and the minimum value are indicated by ± with respect to the average thickness of the seamless belt.

[Example 1] PBT (polybutylene terephthalate), PC (polycarbonate), polymerization catalyst (tetrabutyl titanate), magnesium acetate and a heat stabilizer were blended as shown in Table 1 and pre-dried at 130 ° C. After that, heat kneading (230 ° C) with an extruder to obtain an average particle size of 3
It was formed into mm pellets. This was used as a material pellet.

The heating and kneading conditions at this time were such that the resin temperature and the residence time in the kneader were adjusted so that the reaction by the polymerization catalyst in the kneader was suppressed.

This material pellet was extruded into a tubular shape and cut into a predetermined length to obtain a transparent tubular film-shaped seamless belt.

Incidentally, the resin temperature and the residence time were adjusted as the extrusion molding conditions so that the reaction was promoted in this extruder to a desired degree and a transparent seamless belt was obtained.
The molding conditions such as the diameter variation rate are shown in Table 1.

Table 1 shows the morphology, characteristics and appearance of the film. A seamless belt having a thickness variation of 140 μm ± 7 μm was stably obtained 3 hours after the start of molding. MFR after 5 minutes
(MFR ₅ ) is 1.95g / 10 minutes, MFR after 20 minutes
(MFR ₂₀ ) was 1.83 g / 10 minutes, and the rate of change was 0.
It was 92 times. Fig. 5 shows the rate of change (MFR ₂₀ / MFR ₅ )
Is shown in the graph.

Furthermore, the obtained seamless belt is heated to 80 ° C.
When heat-treated for 10 minutes, the tensile elastic modulus was improved by 5%.

Comparative Example 1 A seamless belt was obtained under the same conditions as in Example 1 except that the polymerization catalyst was not added.

As PBT, in order to remove the influence of the metal component in the resin as an impurity, the PBT was once dissolved in a solvent, filtered using a column, and then the solvent was removed.

Unlike Example 1, a transparent seamless belt could not be obtained no matter how much the extrusion molding conditions (molding temperature, residence time) were adjusted.

Table 1 shows the morphology, characteristics and appearance of the film. Five hours after the start of molding, a seamless belt having a thickness unevenness of 140 μm ± 16 μm was obtained although it was unstable. The change rate was 2.15 times when the MFR after 5 minutes was 1.81 g / 10 min and the MFR after 20 minutes was 3.89 g / 10 min. The rate of change (MFR ₂₀ / MFR ₅ ) is shown in the graph of FIG.

[0139]

[Table 1]

[Example 2] PBT, P with the composition shown in Table 2
C, tetrabutyl titanate, magnesium acetate, a heat stabilizer, and carbon black were preliminarily pre-dried and then heat-kneaded to obtain material pellets.

Thereafter, the material pellets were extruded into a tubular shape under the molding conditions shown in Table 2 and cut into a predetermined length,
Molded into a seamless belt.

As shown in Table 2, the obtained molded product had a remarkably high folding endurance of 58,000, a high tensile modulus and good physical properties.

The surface resistivity is 1 × 10 ¹⁰ Ω and the volume resistivity is 1 × 10 ¹⁰ Ω · cm. When the image forming apparatus is mounted as an intermediate transfer belt of the apparatus shown in FIG. 3, an excellent image can be obtained. I was able to. Further, even if 100,000 images were output in this state, the intermediate transfer belt was not cracked.

In this example, it is considered that a molded product having good physical properties could be obtained by setting an appropriate residence time and molding temperature during heating and kneading during molding. A seamless belt having a thickness variation of 140 μm ± 8 μm was stably obtained 3 hours after the start of molding. The color misregistration at that time was good at 95 μm. MFR after 5 minutes is 1.70 g / 10 min, 20
After a minute, the MFR is 1.72 g / 10 min, and the rate of change is
It was 1.01 times.

Furthermore, the obtained seamless belt is heated to 80 ° C.
When heat-treated for 20 minutes, the tensile elastic modulus was improved by 8%.

[Example 3] A seamless belt was obtained under the same conditions as in Example 1 except that the weight ratio of PBT and PC was changed and the residence time was increased during molding. Also in this Example 3, as shown in Table 2, the same good physical properties as in Example 1 were obtained.

It is considered that the reason why the residence time was lengthened was that the point of the appropriate reaction condition of the system was changed by changing the PBT / PC ratio. Uneven thickness after 3 hours from the start of molding
A 40 μm ± 7 μm seamless belt was stably obtained. The color shift at that time was 90 μm, which was good. MFR after 5 minutes is 1.32g / 10min, MFR after 20 minutes
Was 1.29 g / 10 min, and the rate of change was 0.98 times.

Furthermore, the obtained seamless belt is heated to 80 ° C.
When heat-treated for 10 minutes, the tensile elastic modulus was improved by 7%.

Example 4 A seamless belt having a high surface resistivity was obtained by reducing the carbon concentration. As shown in Table 2,
In Example 4 also, a uniformly dispersed state was obtained and the physical properties were good. This seamless belt is used as a transfer transfer belt in FIG.
When it was mounted on the image forming apparatus of No. 3, a good image could be obtained. Thickness unevenness 140 μm ± 3 hours after the start of molding
A 9 μm seamless belt was stably obtained. The color misregistration at that time was good at 100 μm. MFR after 5 minutes
Is 1.84 g / 10 min, MFR after 20 minutes is 1.8
The rate of change was 1.02 times at 8 g / 10 min.

Furthermore, the obtained seamless belt is heated to 80 ° C.
When heat-treated for 10 minutes, the tensile elastic modulus was improved by 5%.

Example 5 A seamless belt having a low surface resistivity was obtained by increasing the carbon concentration. As shown in Table 2, in Example 5 also, a uniformly dispersed state was obtained and the physical properties were good.
When this seamless belt is used as a photoconductor belt and a photosensitive layer is provided on the surface of the photoconductor belt and the photoconductor belt is mounted on an image forming apparatus,
A good image could be obtained. A seamless belt having a thickness variation of 140 μm ± 8 μm was stably obtained 3 hours after the start of molding. The color misregistration at that time was good at 95 μm.
The MFR after 5 minutes was 1.54 g / 10 min, the MFR after 20 minutes was 1.49 g / 10 min, and the rate of change was 0.9.
It was 7 times.

Furthermore, the obtained seamless belt is heated to 80 ° C.
When heat-treated for 10 minutes, the tensile elastic modulus was improved by 5%.

[Comparative Example 2] A seamless belt was produced under the same conditions as in Example 2 except that the polymerization catalyst was not added.

As PBT, in order to remove the effect of metal components in the resin as impurities, PBT was once dissolved in a solvent, filtered using a column, and then the solvent was removed.

The tensile modulus was almost the same as in Example 1, but the folding endurance was low. Moreover, when the morphology was observed, P
It was found that C has a two-layer separation structure in which islands are formed. When it was mounted on an image forming apparatus as an intermediate transfer belt, an excellent image could be obtained, but when the image output was continued in this state, a crack occurred when 8000 sheets were output. Thickness unevenness of 140 μm 10 hours after the start of molding
A seamless belt of ± 20 μm was obtained although it was unstable. The color misregistration at that time was 190 μm, which was poor. MFR after 5 minutes is 2.10g / 10min, MF after 20 minutes
When R was 5.00 g / 10 min, the rate of change was 2.38 times. [Example 6] A seamless belt was obtained under the same conditions as in Example 2 except that the combination of PBT and PET was changed. Also in this Example 6, as shown in Table 2, the same good physical properties as in Example 2 were obtained. Thickness unevenness 140 μm ± 3 hours after the start of molding
A 12 μm seamless belt was stably obtained. The color misregistration at that time was 130 μm, which was OK. MFR after 5 minutes
Is 2.12 g / 10 min, and the MFR after 20 minutes is 2.2.
The rate of change was 1.07 times at 6 g / 10 min.
The changed composition and physical properties of the obtained seamless belt are as follows. PBT: 60 parts by weight, PET: 26 parts by weight, folding endurance:
32000 times Tensile elastic modulus: 2600 MPa Tensile rupture elongation: 350% Durability: 100,000 sheets or more [Example 7] A seamless belt was obtained under the same conditions as in Example 2 except that the combination of PC and PAr was changed. Also in this Example 7, good physical properties were obtained as in Example 2 as shown in Table 2. Thickness unevenness 140 μm ± 1 within 3 hours after starting molding
A 1 μm seamless belt was stably obtained. The color shift at that time was OK at 120 μm. MFR after 5 minutes is 1.79 g / 10 min, MFR after 20 minutes is 2.11.
The rate of change was 1.18 times at g / 10 min. The changed composition and physical properties of the obtained seamless belt are as follows. PC: 60 parts by weight, PAr: 26 parts by weight, Folding endurance: 31
000 times Tensile modulus: 2400 MPa Tensile elongation at break: 300% Durability: 100,000 sheets or more [Example 8] A seamless belt was obtained under the same conditions as in Example 2 except that the heat stabilizer was changed to 3 parts by weight. It was Also in this Example 8, as in Table 2, the same good physical properties as in Example 2 were obtained. A seamless belt having a thickness variation of 140 μm ± 14 μm was stably obtained 3 hours after the start of molding. The color shift at that time was OK at 140 μm. MFR after 5 minutes is 1.85
g / 10 min, MFR after 20 minutes is 3.26 g / 10
The change rate was 1.76 times at min. The changed composition and physical properties of the obtained seamless belt are as follows. PC: 26 parts by weight, PBT: 60 parts by weight, Folding endurance: 47
00 times Tensile modulus: 2600 MPa Tensile breaking elongation:
340% Durability: A crack occurred when 30,000 sheets were output.

[0156]

[Table 2]

[0157]

EFFECTS OF THE INVENTION According to the present invention, a seamless belt having excellent bending resistance, chemical resistance and molding dimensional stability and suppressing deterioration of physical properties due to reaction during melt mixing, and an image forming apparatus using this seamless belt A belt and an image forming apparatus using the belt for the image forming apparatus are provided.

[Brief description of drawings]

FIG. 1 is an NMR chart of a mixed reaction product of PBT and PC.

FIG. 2 is an enlarged view of a portion II of FIG.

FIG. 3 is a side view of an example of a conventional intermediate transfer device.

FIG. 4 is a side view of an example of a tandem type intermediate transfer device.

FIG. 5: MFR ₂₀ / MF of Examples 1 to 5 and Comparative Examples 1 and 2
It is a graph of R ₅ .

[Explanation of symbols]

1 photosensitive drum 2 charger 3 Exposure optical system 4 developing device 5 cleaner 6 Conductive seamless belt 7, 8, 9 Transport rollers 10 Electrostatic transfer machine 11 Recording paper 12 Pressing roller

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 21/00 350 G03G 21/00 350 (72) Inventor Katsumi Yamaoka 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Chemical Co., Ltd. (72) Inventor Seiya Mori 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Chemical Co., Ltd. (72) Inventor Kazuya Mizumoto 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Chemical Co. F-term (reference) ) 2H035 CA05 CB06 2H200 GA12 GA23 GA24 GA47 HA02 HA12 HB03 HB12 HB22 JA02 JB07 JB10 JB45 JB46 JB47 JC04 JC15 JC16 JC17 LC03 MA04 MA11 MA12 MA14 MA17 MA20 MB05 MC03 MC04 MC20 4F071 A50 45A05 AF05A05 AF03A05 AF05A05 AB05A05 AB05A05 AB05A05 A05A05 AF03A05 A05A05 AF03A05 AB01 GM01

Claims (18)

[Claims] 1. A seamless belt obtained by heat-melting and kneading a thermoplastic resin capable of reacting with a polymerization catalyst and a polymerization catalyst, extruding it into a tubular shape, and cutting it into a predetermined length, which is 260 ° C. in a resin composition. , MFR at 20 minutes residence (MF
A seamless belt obtained by setting the ratio (MFR ₂₀ / MFR ₅ ) of R ₂₀ ) and MFR (MFR ₅ ) at 260 ° C. for 5 minutes retention to 2 or less. 2. The seamless resin composition according to claim 1, wherein the thermoplastic resin capable of reacting with the polymerization catalyst is a combination of crystalline resins, a combination of a crystalline resin and an amorphous resin, or a combination of amorphous resins. belt. 3. The crystalline resin is a crystalline resin having at least one of a hydroxyl group, a carboxylic acid and an ester bond, and the amorphous resin has at least one of a hydroxyl group, a carboxylic acid and an ester bond. The seamless belt according to claim 1 or 2, which is an amorphous resin. 4. The seamless belt according to claim 1, wherein the variation rate of thickness unevenness in the circumferential direction is ± 10% or less. 5. A thermoplastic resin capable of reacting with a polymerization catalyst is a combination of a crystalline resin and an amorphous resin, and a chemical bond exists between the molecular chain of the crystalline resin and the molecular chain of the amorphous resin. The seamless belt according to claim 3 or 4, characterized in that. 6. The total mass of the crystalline resin and the amorphous resin per mol of the chemical bond between the molecular chains of the crystalline resin and the amorphous resin is 300,000 g or less. The seamless belt according to claim 5. 7. The seamless belt according to claim 5, wherein the weight ratio of the components satisfies the following conditions. The weight ratio of crystalline resin / amorphous resin is 1/99 to 99 /
1 The metal in the polymerization catalyst is 1ppm to 10000ppm with respect to the weight of (crystalline resin + amorphous resin). 8. A crystalline resin blending ratio of X parts by weight, a polystyrene (PS) -converted weight average molecular weight of Mw1, an amorphous resin blending ratio of Y parts by weight, a PS-converted weight average molecular weight of Mw2, and a crystalline resin. The following relationship is satisfied when the PS-equivalent weight average molecular weight of the resin composition obtained after heating and kneading the amorphous resin and the polymerization catalyst is Mw3. Seamless belt. [Equation 1] 9. The PS-converted weight average molecular weight is 130,00.
The seamless belt according to any one of claims 1 to 8, which is 0 or more. 10. The seamless belt according to claim 1, wherein the polymerization catalyst contains Ti. 11. The polymerization catalyst comprises at least one member selected from the group consisting of alkali metals, alkaline earth metals and zinc;
11. The seamless belt according to any one of claims 1 to 10, which contains i. 12. The seamless belt according to claim 11, wherein the element of the group is Mg. 13. The seamless belt according to claim 1, wherein the crystalline resin is PAT (polyalkylene terephthalate). 14. The seamless belt according to claim 13, wherein the PAT is PBT (polybutylene terephthalate). 15. The seamless belt according to claim 1, wherein the amorphous resin is PC (polycarbonate). 16. The conductive filler contains carbon black in an amount of 3 to 30% by weight.
16. The seamless belt according to any one of 1 to 15. 17. A belt for an image forming apparatus, which is an intermediate transfer belt for an image forming apparatus, a transfer belt, or a photoconductor belt, which is the seamless belt according to claim 1. 18. An image forming apparatus comprising the image forming apparatus belt according to claim 17.