KR20130141928A

KR20130141928A - Seamless belt

Info

Publication number: KR20130141928A
Application number: KR1020120065052A
Authority: KR
Inventors: 김상균; 송상민; 곽기남
Original assignee: 코오롱인더스트리 주식회사
Priority date: 2012-06-18
Filing date: 2012-06-18
Publication date: 2013-12-27
Also published as: WO2013191440A1; TW201402694A

Abstract

The present invention relates to a seamless belt including carbon nanotubes of which a substrate is dispersed on polyimide resin of a single layer and the polyimide resin. The polyimide resin is obtained by imidizing aromatic dianhydride and aromatic diamine. The aromatic diamine containes 40 to 100 mol% Of 1,4-phenylene diamine (1,4-PDA) with respect to the total amount of the aromatic diamine. The carbon nanotube with the diameter of 5 - 20nm and is included in the seamless belt as 0.1-2.0 the parts by weight of with respect to 100 parts by weight of the polyimide resin.

Description

Seamless belt

The present invention relates to an endless belt which can be used as an intermediate transfer belt of an image forming apparatus.

BACKGROUND OF THE INVENTION Generally, the use of belts is very diverse and has been used as a major replacement for gears in industries that use rotating shafts and motors, such as electronics, automobiles, or conveyors. In particular, it has been used as a fixing belt, an intermediate transfer belt, and a conveyance belt for use in a copying machine, a laser beam printer, a facsimile, and the like in electronic equipment for fixing and transferring a toner image formed on a copying or transferring paper.

The belt generally requires antistatic function since static electricity easily occurs during rotation. Semi-conductive property for antistatic function is also utilized as physical property for toner transfer in electronic equipment.

These belts range from small belts up to a few meters in diameter with a diameter of 20 mm on a tubular basis. However, most belts are seamed belts with flat belts or V-belts, which have irregularities at the joints and have different surface characteristics at the joints. Particularly, the intermediate transfer belt of an electronic apparatus using a flat surface of a belt, in particular, a color laser printer, may cause irregularities of the belt surface to damage the optical drum or deteriorate the quality of a printed image. A slight twist in the seam may also impair the straightness of the tubular belt and cause meandering during rotation. There is a possibility that the belt itself may be damaged when the belt is separated from the driving roll due to the skew of the belt.

Therefore, if there is no joint on the tubular belt, the maximum durability of the belt material can be obtained. Since there is no unevenness, it is possible to prevent the object contacting the belt or the belt from spinning during rotation and to secure the straightness of the belt easily have.

In particular, fixing belts and intermediate transfer belts used for electronic devices such as printers, copying machines, multifunctional apparatuses, facsimile machines and the like must have excellent stain resistance, heat resistance, heat radiation characteristics, elasticity, antistatic properties, durability, water repellency, oil repellency, And a property of having a proper surface resistance value for the function of transferring toner is required. When the surface resistance value is higher or lower than the required surface resistance value, the antistatic property, the transfer property, the image property, The physical properties such as the performance may be deteriorated and fatal defects of the printed image defect may be caused.

Polycarbonate, polyvinylidene fluoride, polyamideimide, polyimide resin and rubber are used for the production of such a fixing belt, an intermediate transfer belt and the like, and a conductive additive such as carbon black is mixed and dispersed . However, in order to increase the printing speed, it is necessary to use a high-strength belt which does not cause color overlapping and deviation due to deformation during running of the transfer belt and which can withstand repetitive use. Further, since flame resistance is also required, do. In addition, a conductive additive such as carbon black is used as the conductive filler. In this case, unless a substantial amount is added, it is difficult to sufficiently secure the electrical conductivity of the semiconductive resin to a desired level. In order to secure uniformity of the surface resistance, Which may result in a decrease in the durability of the belt.

With respect to an endless belt including a polyimide resin and a conductive filler, a conventional technique disclosed in Korean Patent Laid-Open Publication No. 2011-0032917 includes a polyimide or polyamideimide resin, Wherein the 5% weight reduction initiation temperature is greater than or equal to 300 ° C, the surface resistance value is from 10 ⁷ to 10 ¹³ Ω / sq and the maximum and minimum values of the surface resistance measured at any of the 10 locations in a single product And a surface resistance deviation defined by a difference of 10 < ^{1 >} or less. However, the endless belt is not easy to control the dispersion state of the carbon nanotubes, and therefore there is still a problem such as durability when applied as an intermediate transfer belt.

The present invention seeks to provide an endless belt having improved durability and uniformity of excellent surface resistivity.

According to a first preferred embodiment of the present invention, in an endless belt including a single layer of polyimide resin and carbon nanotubes dispersed in the polyimide resin, the polyimide resin may already contain aromatic dianhydride and aromatic diamine. Obtained by dehydration, wherein the aromatic diamine contains 40 to 100 mol% of 1,4-phenylenediamine (1,4-PDA) based on the total amount of aromatic diamine, and the carbon nanotube has a diameter of 5 to 20 nm, It provides an endless belt, characterized in that the content is 0.1 to 2.0 parts by weight based on 100 parts by weight of polyimide resin.

The carbon nanotubes according to the embodiment are dispersed in a solvent and then dispersed in a polyimide resin, and the carbon nanotubes dispersed in the solvent may have a particle diameter of 20 nm to 10 μm.

The aromatic dianhydride according to this embodiment may be biphenyltetracarboxylic dianhydride (BPDA).

The aromatic diamine according to this embodiment can be prepared by reacting 1,3-phenylenediamine (1,3-PDA), 4,4'-methylene dianiline (MDA), 4,4'-oxydianiline (ODA) '-Oxyphenylenediamine (OPDA). The present invention also provides a process for producing the same.

The endless belt according to the embodiment may have a surface resistivity of 10 ⁸ to 10 ¹³ Ω / sq.

The endless belt according to the embodiment may have a common logarithm value of 1.0 or less.

The endless belt according to the embodiment may have a tensile modulus of 4000 MPa or more.

The endless belt according to the embodiment may have a break strength of at least 1000 times.

The endless belt according to the present invention may exhibit proper physical properties as an intermediate transfer belt having uniformity in surface resistivity and improved durability and requiring reliability.

1 is a photograph of a diameter of a carbon nanotube according to the present invention measured using a TEM (Transmission Electron Microscope, transmission electron microscope).
2 is a graph showing particle size measurement results of a carbon nanotube dispersion according to an embodiment (Example 1) of the present invention.
3 is a graph showing particle size measurement results of a carbon nanotube dispersion according to Comparative Example (Comparative Example 6) of the present invention.

Hereinafter, the present invention will be described in more detail.

The present invention relates to an endless belt manufactured by imidizing a semiconductive polyamic acid solution obtained by dispersing carbon nanotubes in a polyamic acid solution made of dianhydride and diamine.

In an endless belt comprising a polyimide resin of a single layer and carbon nanotubes dispersed in the polyimide resin, the polyimide resin is obtained by imidizing an aromatic dianhydride and an aromatic diamine, wherein the aromatic diamine is 1 , 4-phenylenediamine (1,4-PDA) is contained 40 to 100 mol% with respect to the total amount of aromatic diamine, the carbon nanotubes are 5 to 20nm in diameter, the content of 100 parts by weight of polyimide resin It relates to an endless belt, characterized in that 0.1 to 2.0 parts by weight.

A method of using carbon black as a filler for imparting conductivity to an endless belt for a conventional image forming apparatus is known. However, in order to increase the conductivity of the polyimide resin having an insulating property to an area capable of charging toner, at least 10% by weight of carbon black must be added, so the bulk additive of such carbon black has excellent mechanical properties of the polyimide resin. There was a problem of lowering.

As the conductive filler of the present invention, carbon nanotubes are used. Since the carbon nanotubes were first discovered by Iijima [S. Iijima, Nature Vol. 354, p. 56 (1991)]. Carbon nanotubes have high elastic modulus of about 1.0 ~ 1.8TPa, which is not found in conventional materials, as well as heat resistance that can withstand temperatures up to 2800 ℃ in vacuum, thermal conductivity close to twice that of diamond, and copper. Due to the potential physical properties such as 1000 times higher current carrying capacity, it is considered to be highly applicable in all fields such as nanoscale electric devices, electronic devices, nanosensors, optoelectronic devices and high-performance composites.

Carbon nanotubes are graphite sheets that are rounded to the nanoscale diameter and are extremely small in area, with nanometers in diameter.

Carbon nanotubes are broadly classified into single-walled carbon nanotubes, which are single-walled, and multi-walled carbon nanotubes, where multiple carbon nanotubes are concentric. Single-walled carbon nanotubes have a diameter of 1.0 nm, and multi-walled carbon nanotubes have diameters of 2 to 100 nm according to the number of walls. Single-walled carbon nanotubes have excellent electrical conductivity, whereas multi-walled carbon nanotubes have a reduced electrical conductivity as the diameter increases.

The carbon nanotubes of the present invention may have a diameter of 5 to 20 nm. When the diameter is less than 5 nm, the electrical conductivity is very high. Therefore, only a very small amount of carbon nanotubes should be added to satisfy the electrical requirements of the semiconductive endless belt used in the image forming apparatus The operation becomes difficult, and it is also difficult to control the surface resistance variation within the endless belt. In addition, when carbon nanotubes having a diameter exceeding 20 nm are used, the electrical conductivity of the carbon nanotubes is deteriorated. Therefore, a large amount of carbon nanotubes must be added in order to satisfy the electrical characteristics required for the endless belt for an image forming apparatus. It can not be an advantage over using carbon black. The diameter of the carbon nanotubes is measured through a TEM (Transmission Electron Microscope).

In the endless belt according to an embodiment of the present invention, the carbon nanotubes may be prepared by adding the carbon nanotubes to the solvent so that the carbon nanotubes are uniformly dispersed in the polyimide resin , And the particle size of the carbon nanotube particles dispersed in the solvent may be 20 nm to 10 탆. When the carbon nanotubes are put in a solvent and dispersed through a milling and an ultrasonic wave, the particle size becomes small. When the carbon nanotubes are put into a solvent and the initial particle diameter before dispersion is measured, there is a tendency that the carbon nanotubes do not exist one by one and exist as a bundle Therefore, the initial particle diameter is about 1000 mu m, and as the dispersion is repeated, the carbon nanotubes receive an external force to decrease the particle diameter. If the particle diameter of the carbon nanotube particles dispersed in the solvent is more than 10 mu m, the aggregated mass of the carbon nanotube particles dispersed in the solvent is large, so that the binding force of the base resin is weakened. Therefore, from the position where the carbon nanotube particles are dispersed in the solvent A crack is generated, which may lead to a decrease in the strength of the bending strength. In this case, the solvent may be dimethylformamide (DMF).

The content of the carbon nanotubes may be 0.1 to 2.0 parts by weight based on 100 parts by weight of the polyimide resin. When the content of the carbon nanotubes is less than 0.1 parts by weight, the resistance is higher than the required value. When the content of the carbon nanotubes exceeds 2.0 parts by weight, the resistance is lower than the required value. That is, the endless belt used in the image forming apparatus serves to transfer the toner from the drum to the paper, so that the resistance region must be within the semiconductive region. However, since the polyimide resin itself is insulative, that is, it can not flow electricity, a conductive material such as a carbon nanotube is added to make it have a resistance in the semiconductive region. Therefore, it is preferable to use an appropriate amount of the carbon nanotube.

In the endless belt according to the present invention, the polyimide resin is obtained by imidizing biphenyltetracarboxylic dianhydride (BPDA) and aromatic diamine, wherein the aromatic diamine is 1,4'-phenylenediamine (1,4- PDA) may be contained 40 to 100 mol% based on the total amount of aromatic diamine.

When polyimide is polymerized using biphenyltetracarboxylic acid dianhydride and 1,4'-phenylenediamine in diamine in dianhydride used in the production of polyimide resin, a rigid and elastic polyimide resin can be produced, An endless belt excellent in durability can be obtained. The 1,4'-phenylenediamine has the shortest and rigid structure of the diamine. The endless belt produced by using this component in 40 mol% or more of the total diamine has a high tensile elastic modulus. On the other hand, when the aromatic diamine other than 1,4'-phenylenediamine in the diamine is used in an amount of 60 mol% or more, the tensile elastic modulus is lowered, and the belt is stretched when printing for a long time, so that it can not be used for a long time and its durability is shortened.

On the other hand, aromatic diamines include 1,3-phenylenediamine (1,3-PDA), 4,4'-methylene dianiline (MDA), 4,4-phenylenediamine (ODA), 4,4'-oxyphenylenediamine (OPDA), and the dianhydride may include at least one selected from the group consisting of 1,2,4,5- Benzene tetracarboxylic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 4,4'-oxydiphthalic anhydride (ODPA) 4,4'-hexafluoroisopropylidene diphthalic anhydride and the like can be used, but it is preferable to use 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) . Usually diamines and dianhydrides are used at the same molarity level.

Particularly, as the dianhydride, when BPDA is used, the tensile modulus and the fracture resistance may be excellent when compared to other dianhydrides.

Although adjustment of the molecular weight of the polyimide resin of this invention can be performed also according to the kind of dianhydride component, a diamine component, and polymerization conditions, it is preferable to carry out by adjustment of the molar ratio of a dianhydride component and a diamine component. Specifically, the molar ratio of the dianhydride / diamine component is preferably adjusted in the range of 100/100 to 90, or 100 to 90/100. When the molar ratio is excessively decreased, the molecular weight of the resin is lowered, the mechanical strength of the formed belt is lowered, the re-aggregation of the conductive filler dispersed in the semiconductive polyamic acid is caused, The greater the degree.

The solvent used in the polymerization of the polyimide resin of the present invention is preferably a solvent selected from the group consisting of N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, N, N-diethylformamide and N-methylcaprolactam. These solvents may be used alone or in combination of two or more.

On the other hand, the endless belt is preferably manufactured seamlessly, and the manufacturing method thereof is not particularly limited. In the present invention, for example, an endless belt can be manufactured by coating a solution-form polyimide resin on the surface of a cylindrical mold with a dispenser and then performing heat treatment. The heat treatment is performed stepwise at 50 to 400 ° C. First, pre-baking is performed at 50 to 100 ° C for 10 to 120 minutes to remove the solvent and moisture remaining on the surface. After that, the rate of temperature rise of 2 ~ 10 ° C per minute is maintained, and post-curing is finally performed at 350 ~ 400 ° C to completely remove the solvent and water present on the surface to progress the imidization and complete the solidification An endless belt is manufactured.

If the thickness of the belt is made too thin for the purpose of improving its thermal conductivity during the production of the endless belt, a phenomenon that the rigidity of the belt is greatly reduced occurs, so that the belt is cracked or crushed by the repeated rotational stress during the printing process A phenomenon may occur. The thickness of the suitable endless belt is 30 to 300 탆.

The endless belt according to the present invention may have a surface resistivity of 10 ⁸ to 10 ¹³ Ω / sq, has a uniform surface resistivity of less than 1.0 in any region within the endless belt, a tensile modulus of at least 4000 MPa, and abrasion resistance It is possible to provide an endless belt having excellent mechanical properties of more than 1000 times, and the endless belt obtained may be useful as an intermediate transfer belt having durability.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to the following examples. However, the present invention is not limited to these examples.

Example 1

An endless belt was produced in the following manner according to the composition as shown in Table 1.

1460 g of dimethylformamide (DMF) was added to a 2 L double jacketed reactor equipped with a mechanical stirrer, a reflux condenser and a nitrogen inlet. The temperature was adjusted to 30 캜, and 67.7 g of 4,4'-diaminophenylene ether (ODA) and 24.4 g of 1,4'-phenylenediamine (PDA) were added as a diamine under a nitrogen atmosphere. The mixture was stirred for about 30 minutes to confirm that all the components were dissolved. Then, 165.7 g of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added. After the addition, the mixture was stirred for 3 hours while maintaining the temperature. 0.1 part by weight of the carbon nanotubes dispersed in the polyamic acid solution after completion of the reaction was mixed with the polyimide solid component. 5nm diameter was used as the carbon nanotubes, and the minimum particle diameter of the carbon nanotube dispersion was 200 nm (0.2 μm) and the maximum particle diameter was 6 μm. The particle size measurement results of the carbon nanotube dispersion are shown in the graph of FIG. 2.

The prepared semiconductive polyamic acid was a uniform black solution having a viscosity of 200 poise.

A mold release agent (Capia, Korea) was spray-coated on a seamless mold having a diameter of 300 mm, a thickness of 5 mm, and a width of 500 mm made of chrome-plated SUS 304 material and then rotated on a rotary molding machine. The semiconductive polyamic acid solution Was uniformly applied through a dispenser coater. Thereafter, the molding die was placed in a drying oven, and the temperature was raised at a rate of 10 ° C / min at a heating rate of 100 ° C, 200 ° C and 300 ° C for 30 minutes to complete the imidization reaction, After cooling, a polyimide film was obtained from an SUS belt to produce a seamless belt having a thickness of 65 mu m, and both ends of the seamless belt were cut to have a width of 300 mm.

Example 2

1290 g of dimethylformamide (DMF) was added to a 2L double jacket reactor equipped with a mechanical stirrer, reflux condenser and nitrogen inlet. The temperature was 30 degreeC, and 61.0 g of 1,4'- phenylenediamine (PDA) was added to diamine under nitrogen atmosphere. The mixture was stirred for about 30 minutes to confirm that all the components were dissolved. Then, 165.7 g of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added. After the addition, the mixture was stirred for 3 hours while maintaining the temperature. 2.0 parts by weight of the carbon nanotubes dispersed and processed in the polyamic acid solution after completion of the reaction was mixed with the polyimide solid component. 20 nm diameter was used as the carbon nanotubes, and the minimum particle diameter of the carbon nanotube dispersion was 100 nm (0.1 μm) and the maximum particle diameter was 7 μm.

An endless belt was obtained in the same manner as in Example 1 by using the semiconductive polyamic acid thus prepared.

Comparative Example 1

1490 g of dimethylformamide (DMF) was added to a 2L double jacket reactor equipped with a mechanical stirrer, reflux condenser and nitrogen inlet. The temperature was 30 degreeC, and 79.0 g of 4,4'- diamino phenylene ether (ODA) and 18.3 g of 1,4'- phenylenediamine (PDA) were added as diamine under nitrogen atmosphere. The mixture was stirred for about 30 minutes to confirm that all the components were dissolved. Then, 165.7 g of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added. After the addition, the mixture was stirred for 3 hours while maintaining the temperature. 0.5 parts by weight of the carbon nanotubes dispersed in the polyamic acid solution of the reaction was mixed with respect to the polyimide solids. 20 nm diameter was used as the carbon nanotubes, and the minimum particle diameter of the carbon nanotube dispersion was 20 nm (0.02 μm) and the maximum particle diameter was 3 μm.

Comparative Example 2

1460 g of dimethylformamide (DMF) was added to a 2 L double jacketed reactor equipped with a mechanical stirrer, a reflux condenser and a nitrogen inlet. The temperature was adjusted to 30 캜, and 67.7 g of 4,4'-diaminophenylene ether (ODA) and 24.4 g of 1,4'-phenylenediamine (PDA) were added as a diamine under a nitrogen atmosphere. The mixture was stirred for about 30 minutes to confirm that all the components were dissolved. Then, 165.7 g of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added. After the addition, the mixture was stirred for 3 hours while maintaining the temperature. 0.1 part by weight of the carbon nanotubes dispersed in the polyamic acid solution after completion of the reaction was mixed with the polyimide solid component. Carbon nanotubes with a diameter of 2nm were used. The minimum particle diameter of the carbon nanotube dispersion was 20nm (0.02μm) and the maximum particle diameter was 3μm.

Comparative Example 3

1460 g of dimethylformamide (DMF) was added to a 2 L double jacketed reactor equipped with a mechanical stirrer, a reflux condenser and a nitrogen inlet. The temperature was adjusted to 30 캜, and 67.7 g of 4,4'-diaminophenylene ether (ODA) and 24.4 g of 1,4'-phenylenediamine (PDA) were added as a diamine under a nitrogen atmosphere. The mixture was stirred for about 30 minutes to confirm that all the components were dissolved. Then, 165.7 g of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added. After the addition, the mixture was stirred for 3 hours while maintaining the temperature. 2.0 parts by weight of the carbon nanotubes dispersed and processed in the polyamic acid solution after completion of the reaction was mixed with the polyimide solid component. 30 nm diameter was used as the carbon nanotubes, and the minimum particle diameter of the carbon nanotube dispersion was 150 nm (0.15 μm) and the maximum particle diameter was 10 μm.

Comparative Example 4

1460 g of dimethylformamide (DMF) was added to a 2 L double jacketed reactor equipped with a mechanical stirrer, a reflux condenser and a nitrogen inlet. The temperature was adjusted to 30 캜, and 67.7 g of 4,4'-diaminophenylene ether (ODA) and 24.4 g of 1,4'-phenylenediamine (PDA) were added as a diamine under a nitrogen atmosphere. The mixture was stirred for about 30 minutes to confirm that all the components were dissolved. Then, 165.7 g of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added. After the addition, the mixture was stirred for 3 hours while maintaining the temperature. 0.05 parts by weight of the carbon nanotubes dispersed in the polyamic acid solution of the reaction was mixed with respect to the polyimide solids. As the carbon nanotubes, a diameter of 20 nm was used. The minimum particle diameter of the carbon nanotube dispersion was 100 nm (0.1 μm) and the maximum particle diameter was 5 μm.

Comparative Example 5

1460 g of dimethylformamide (DMF) was added to a 2 L double jacketed reactor equipped with a mechanical stirrer, a reflux condenser and a nitrogen inlet. The temperature was adjusted to 30 캜, and 67.7 g of 4,4'-diaminophenylene ether (ODA) and 24.4 g of 1,4'-phenylenediamine (PDA) were added as a diamine under a nitrogen atmosphere. The mixture was stirred for about 30 minutes to confirm that all the components were dissolved. Then, 165.7 g of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added. After the addition, the mixture was stirred for 3 hours while maintaining the temperature. The carbon nanotubes dispersed in the polyamic acid solution of the reaction was mixed with 2.5 parts by weight of the polyimide solids. As the carbon nanotubes, a diameter of 20 nm was used. The minimum particle diameter of the carbon nanotube dispersion was 130 nm (0.13 μm) and the maximum particle diameter was 8 μm.

Comparative Example 6

1460 g of dimethylformamide (DMF) was added to a 2 L double jacketed reactor equipped with a mechanical stirrer, a reflux condenser and a nitrogen inlet. The temperature was adjusted to 30 캜, and 67.7 g of 4,4'-diaminophenylene ether (ODA) and 24.4 g of 1,4'-phenylenediamine (PDA) were added as a diamine under a nitrogen atmosphere. The mixture was stirred for about 30 minutes to confirm that all the components were dissolved. Then, 165.7 g of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added. After the addition, the mixture was stirred for 3 hours while maintaining the temperature. 1.0 parts by weight of the carbon nanotubes dispersed in the polyamic acid solution of the reaction was mixed with respect to the polyimide solids. 20 nm in diameter was used as the carbon nanotubes, and the minimum particle diameter of the carbon nanotube dispersion was 1.7 μm and the maximum particle diameter was 63 μm. The particle size measurement results of the carbon nanotube dispersion are shown in the graph of FIG. 3.

The endurance belt manufactured in the above examples and comparative examples was measured for surface resistivity, common versus numerical value of deviation in surface resistivity, particle diameter of carbon nanotubes, tensile modulus of elasticity, and bending strength in the following manner. .

(1) Surface resistivity

The endless belt produced in the above Examples and Comparative Examples was cut in the width direction and wound in the form of a two-dimensional film. Five arbitrary points are selected on the inner / outer surface of the endless belt. At the selected 10 points, UR-100 Probe was mounted on a Hiresta UP high resistivity meter of Mitsubishi Chemical Co., Ltd. and measured for 10 seconds under an applied voltage of 100V. The average value of the ten measured values was obtained.

(2) The common versus numerical value of surface resistivity variation

The endless belt produced in the above Examples and Comparative Examples was cut in the width direction and wound in the form of a two-dimensional film. Five arbitrary points are selected on the inner / outer surface of the endless belt. At the selected 10 points, UR-100 Probe was mounted on a Hiresta UP high resistivity meter of Mitsubishi Chemical Co., Ltd. and measured for 10 seconds under an applied voltage of 100V. The difference between the maximum value and the minimum value of the ten measured values was obtained by taking a common logarithm.

(3) Particle size of carbon nanotubes dispersed in solvent

The dispersion of the dispersed carbon nanotubes is analyzed in a particle size analyzer Microtrac S3500 model (Microtrac, USA). The volume is based on the average particle size.

(4) Tensile modulus

Five samples of 15 mm x 100 mm in width are collected from one endless belt and transferred to an Instron 3365SER tester. Measure according to ASTM D 882 measurement method.

(5) Strength of bending strength

Ten samples of 15 mm x 100 mm in width are collected from one endless belt and transferred to an MIT tester. R = 2, the angle of refraction is 135 degrees, and the speed is 175 rpm, the test piece is measured by the number of times the test piece breaks back and forth.

menstruum
(g) Water
(g) Diamine
(g) CNT
diameter
(nm) CNT
content
(Parts by weight) The CNTs dispersed in the solvent
at least
Particle size
(탆) The CNTs dispersed in the solvent
maximum
Particle size
(탆) DMF BPDA ROOM 1,4-PDA Example 1 1460 165.7 67.7 24.4 5 0.1 0.2 6 Example 2 1290 165.7 - 61.0 20 2.0 0.1 7 Comparative Example 1 1490 165.7 79.0 18.3 20 0.5 0.02 3 Comparative Example 2 1460 165.7 67.7 24.4 2 0.1 0.02 3 Comparative Example 3 1460 165.7 67.7 24.4 30 2.0 0.15 10 Comparative Example 4 1460 165.7 67.7 24.4 20 0.05 0.1 5 Comparative Example 5 1460 165.7 67.7 24.4 20 2.5 0.13 8 Comparative Example 6 1460 165.7 67.7 24.4 20 1.0 1.7 63

Surface resistivity (/ sq) Deviation of surface resistivity
(log / sq) Tensile modulus
(MPa) Bending strength
(time) Example 1 10 ⁸ 0.6 4,500 20,000 Example 2 10 ¹² 0.7 8,000 1,000 Comparative Example 1 10 ¹⁰ 0.6 3,500 18,000 Comparative Example 2 10 ⁵ 0.5 4,300 45,000 Comparative Example 3 10 ¹⁴ 1.0 4,600 8,000 Comparative Example 4 10 ¹⁴ 1.2 4,500 32,000 Comparative Example 5 10 ⁷ 0.9 4,400 7,000 Comparative Example 6 10 ¹⁰ 1.3 7,200 500

From the results in Table 2, 0.1 to 2.0 parts by weight of carbon nanotubes having a diameter of 5 to 20 nm according to one embodiment of the present invention is contained, the minimum particle diameter of the carbon nanotubes is 20 nm or more, and the maximum particle diameter is 10 μm or more. The endless belt is characterized in that the polyimide resin contains 40 to 100 mol% of the total amount of biphenyl tetracarboxylic dianhydride and aromatic diaminebiphenyl tetracarboxylic dianhydride (BPDA) aromatic diamine. ^{It can be seen that the 8} to 10 ¹³ Ω / sq region, the surface resistivity variation is small to 1.0 or less, the tensile modulus is high to 4000MPa or more, the break strength is high to 1,000 or more times, substantially improving the durability.

Claims

In the endless belt comprising a polyimide resin of a single layer and carbon nanotubes dispersed in the polyimide resin,
The polyimide resin is obtained by imidating an aromatic dianhydride and an aromatic diamine, wherein the aromatic diamine contains 40 to 100 mol% of 1,4-phenylenediamine (1,4-PDA) based on the total amount of aromatic diamine,
The carbon nanotubes are endless belts, characterized in that the diameter is 5 ~ 20nm, the content is 0.1 to 2.0 parts by weight based on 100 parts by weight of polyimide resin.

The method of claim 1,
The carbon nanotubes are dispersed in a solvent and then dispersed in a polyimide resin, and the carbon nanotubes dispersed in the solvent have an endless belt, characterized in that the particle diameter is 20nm ~ 10μm.

The method of claim 1,
Wherein the aromatic dianhydride is biphenyltetracarboxylic dianhydride (BPDA).

The method of claim 1,
The aromatic diamine may be 1,3-phenylenediamine (1,3-PDA), 4,4'-methylene dianiline (MDA), 4,4'-oxydianiline (ODA) And at least one member selected from the group consisting of ruthenium (R) and lenadiamine (OPDA).

The method of claim 1,
An endless belt with a surface resistivity of 10 ⁸ to 10 ¹³ Ω / sq.

The method of claim 1,
An endless belt having a common logarithm value of surface resistivity variation of 1.0 or less.

The method of claim 1,
Endless belts with a tensile modulus of 4000 MPa or more.

The method of claim 1,
Endless belt with 1,000 times or more of strength.