WO1999059033A1

WO1999059033A1 - Melt extruded material suitable for forming transfer layer of photosensitive unit of image forming device

Info

Publication number: WO1999059033A1
Application number: PCT/JP1999/002194
Authority: WO
Inventors: Tatsuya Higuchi; Masami Kato
Original assignee: Daikin Industries, Ltd.
Priority date: 1998-05-13
Filing date: 1999-04-26
Publication date: 1999-11-18
Also published as: EP1079282A4; KR20010034795A; JP3743288B2; EP1079282A1

Abstract

A melt extruded material suitable for forming the transfer layer of the photosensitive unit of an image forming device; specifically, a melt extruded material consisting of fluorine-containing resin easy in controlling volume resistivity and excellent in non-adhesiveness, smoothness and strength, and a transfer belt using the material. The melt extruded material suitable for forming the transfer layer of the photosensitive unit of an image forming device which comprises a composition consisting of (A) a filler at least part of which is fluorinated and (B) a fluorine containing thermoplastic resin, characterized by comprising the composition used to form a coating surface having a volume resistivity of 10?8 to 1013¿ Φ.cm, a contact angle to water of 96° or larger and surface roughness Ra of 0.5 νm or smaller, a tensile strength of the coating being 400 kgf/cm2 or higher at 25 °C.

Description

Akira Itoda For forming the transfer layer of the light-sensing part of the image forming device

Suitable melt extrusion material technology field

The present invention relates to a melt-extrusion material suitable for forming a transfer layer of a photosensitive section of an image forming apparatus and a transfer belt of a photosensitive section formed by using the same. About. Background technology

Fluororesin is excellent in chemical lubrication, thermal stability, surface lubrication, electrical properties, mechanical properties, and abrasion resistance. Widely used in material carriers and image forming units.

The fluororesin composition is an insulator with a volume-specific resistivity exceeding ^{10 16} Ω-cm, and the pressurized roller in the electronic copying machine ゃIn the mouth, etc., static electricity may cause paper sheets to be adsorbed, and toner powder to be absorbed or scattered may cause trouble. It was.

For this reason, it has been attempted to mix a conductive material into a fluororesin composition. Examples of the conductive material include carbon black, graphite powder, carbon material such as carbon fiber, and metal powder.

However, if a sufficient amount of carbon black is used to provide conductivity, the structure of the power black can be reduced. For this reason, there is a problem that the resin viscosity becomes high and the moldability is remarkably deteriorated. Anisotropic materials such as graphite powder and carbon fiber There is a problem in that when powders with different shapes are mixed, the roughness of the resin surface increases, and when the surface roughness increases, drums and paper The contact with the leaves produces turbulence, which causes image distortion. There is a problem in that the addition of metal powder impairs the excellent chemical resistance of fluororesin.

Intermediate transfer devices such as electronic photocopiers, printers, facsimiles, transfer / separation devices, transport devices, charging devices, and current image devices. In all cases, conductive belts are frequently used. As the conductive belt, for example, a thermoplastic resin in which a conductive carbon black is combined is generally used. This is formed into a film and processed to form a belt. In addition, what is extruded and formed into a cylindrical film, and this cylindrical file is cut in a direction of a water square, is known as a simple belt. (Japanese Patent Publication No. Hei 2—2 3 3 7 65, Japanese Patent Publication No. Hei 3—893 577, and Japanese Patent Publication No. Hei 64-264339, etc.) ).

For the conductive belt, various thermoplastic resins are used as required. In particular, fluorine-based polymers are superior to other thermoplastic resins in terms of flame retardancy, durability, and filming resistance (toner releasability). Therefore, it is frequently used. However, the resistance value of the conductive belt in a multi-function printer, a printer, a facsimile machine, etc. using a fluorine-based polymer conductive belt increases over time. There was a problem that the image was degraded due to a drastic drop. For example, when the belt is used for an intermediate transfer belt such as a duplicator, the toner is electrically pulled to the belt surface. It must be charged in order to generate a high voltage repeatedly, for example by corona discharge. The high voltage causes the fluorine-based polymer belt to have a gradual decrease in the resistance value, and as a result, The amount of transfer of the toner to the camera is reduced, which has an adverse effect on the image. This phenomenon occurs on the fluorine-containing polymer belt because of the separation of the conductive filler from the fluorine-containing polymer and the interface between the conductive filler and the fluorine-containing polymer. It is thought that a trap in the conductive carrier due to a crystal defect inside the polymer causes the resistance to decrease due to the space charge limiting current. It is.

In addition, so-called semi-conductive rollers and belts, such as charged rollers and belts, transfer rollers, and image openings in electronic duplicators. In this technology, a specific range of conductivity is required. Specifically, mouth - volume is have you in La Ya bell door-specific resistivity of force ^{^{"0 8 ~: 1 0 1}} 3 Ω · cm need to range Ru is co-emissions collected by filtration Lumpur is is there .

In such a use, in order to use a fluororesin composition in which a normal conductive material is mixed, precise control of the amount to be mixed is required. Thorough kneading is required. Its Re is rather have Blend conductive Substance normal to full fluororesin If, because sudden the resistance boundary Oh Ru amount was bovine or by One is lower, 1 0 ⁸ - This is because it is difficult to control within the range of 10 ¹³ Q * cm. As a result, the resistance does not change rapidly with the amount of compounding, and it does not readily take advantage of the inherent properties of fluororesin, such as chemical resistance. In addition, a conductive or non-conductive material capable of minimizing changes in mechanical properties such as increase in viscosity, surface roughness, and non-adhesiveness. There is a need for an adhesive fluororesin composition.

The present invention relates to a melt-extrusion material suitable for forming a transfer layer of a photosensitive portion of an image forming apparatus, and in particular, a volume-specific resistivity control that is easy and non-viscous Melt extrusion material made of fluorine-containing resin with excellent adhesion, smoothness and strength, and transfer using it Disclosure of the invention aimed at providing beryrets

The present invention relates to a composition comprising (A) at least a part of a fluorinated filler and (B) a fluorine-containing thermoplastic resin. and Oh one, e la Re that the front surface of the body volume-specific resistance ratio of the film is ^{^{10 8 ~ 10 1 3 Ω ·}} cm, vs. water contact touch corner 96 degrees or more on your good beauty the film tensile Suitable for forming a transfer layer of the light-sensitive part of an image forming apparatus characterized by being a composition having a strength of 400 kgf / cm ² or more at 25 ° C. The present invention relates to a melt-extruded material and a transfer belt formed by using the material. Best form for carrying out the invention The melt-extruded material of the present invention contains at least a partly fluorinated filler (A) and a filler. The (A) component consisting of a fluorine-containing thermoplastic resin (B) and at least a part of which is a fluorinated filler, is a force pump. Preferably, carbon materials such as rack, carbon fiber, petroleum coke, and graphite powder are fluorinated.

Of these, the fluorination power obtained by fluorinating a carbon book is a carbon black, especially a fluorine against a carbon atom. Fluorinated carbon black with an atomic ratio FZC of 0.1 or more and less than 1.0, particularly 0.1 or more and less than 0.5 is preferable. I

Fluorination force of component (A)-If the FZC force of the bomb black is less than 0.1, the effect of fluorination is insufficient and the fluorination effect is not sufficient. One of the problems with the carbon materials is that the rate of change of resistance with respect to the amount of connection is extremely large, and the control of the conductive material is very large. Difficulty and uneven distribution of the fluorinated carbon black due to the structure that has been developed. The problem that the resulting composition becomes hard remains. If the F / C force is greater than 1.0, it is not possible to impart the desired conductivity to the composition.

In the present invention, FZC is measured as follows. Wrap the fluorinated carbon black in filter paper together with the flame retardant Na ₂ O ₂ and polyethylene film, and fill with oxygen. Combustion in a hermetically closed flask, the generated hydrogen fluoride is converted into a fluoride ion meter (Olyon Corporation: Ion Analyzer 901). Measure according to the standard method. This value is used to calculate the fluorine content. The FZC is calculated based on the obtained fluorine content.

The carbon black (A) is composed mainly of poly (carbon monofluoride), and the average of the carbon black (A) is the average. Particle size 0.01 to 50 μπι, preferably 0.01 to ：: A ポ μπα force block is a fluorine gas that has been fluorine-fluorinated. I like it. Fluorination obtained from carbon materials with an average particle size of more than 50 μm, for example, petroleum coke, graphite powder, carbon fiber, etc. The carbon black must have a large amount to impart conductivity and non-adhesion to the resin, and the resulting composition must have a rough surface. The tendency is to cause problems such as an increase in temperature, deterioration in mechanical strength, and unevenness in resistivity.

Suitable as a carbon material for the fluorinated carbon black (A) is a carbon black having the above-mentioned average particle size. . The carbon black is, for example, a rubber fan black (for example, Asahi # 55 manufactured by Asahi Rikiichi Bonn Co., Ltd.). ), Color channel black (for example, Carbon Carbon Revenue 7000), Thermal Black (Colonia Carbon Seno, 'Carbon MT-C1), etc. Commercially available products can be used.

Preference is given to carbon blacks, especially those commonly referred to as conductive carbon blacks. Conductive mosquitoes over Bonn Bed rack is had average particle size of small flat (average particle diameter 0. 1 mu m or less under flat), have come front surface product is large (N ₂ surface area 50 m ² / g or more), the structure is developed (P and oil amount lOOccZg or more), the amount of impurities is small (ash content is less than 0.1%), and the grapha It is defined by the fact that it is advancing, and it is possible to impart conductivity to the material with a relatively small amount of compounding. Therefore, it is widely used. Specific examples include, but are not limited to, ketchbox EC, ketchbox EC-600 JD (hereinafter, ketchbox black). International Co., Ltd.), Black Pearls 200, Vulcan XC-72, CSX-99 (hereafter referred to as Black Denka Black Co., Ltd. (Electrical Chemistry Engineering Co., Ltd.), Conductex 950 (Columbia Carbon Co., Ltd.), etc. Is on the market.

The fluorine black carbon black (A) used in the present invention is prepared by subjecting such a carbon material to a temperature in the range of 200 to 600 ° C. More preferably, it is obtained by contacting with fluorine gas at a temperature in the range of 300 to 500 ° C. At a reaction temperature lower than this range, the fluorination reaction progresses slowly, the degree of fluorination is hard to increase, and the thermal stability is not sufficient. However, problems such as the non-adhesiveness and lubricity of the fluorinated carbon black cannot be achieved. Conversely, if the reaction temperature is higher than this range, the pyrolysis reaction is likely to occur, and the The yield rate of fluorine carbon black will be reduced. Also, it is necessary to pay close attention to the fact that a sudden thermal decomposition reaction may occur and cause an explosion.

The fluorine gas used for the reaction may be diluted with an inert gas such as nitrogen, argon, helium, tetrafluorocarbon, or the like. In addition, it may contain hydrogen fluoride. Also, the reaction can be carried out at normal pressure, but it does not work at all even if the pressure is reduced or applied.

In addition to the above conditions, the reaction time, fluorine gas flow rate, etc., depend on the reactivity of the raw material carbon material with fluorine and the desired FZC (containing fluorine). The amount should be adjusted accordingly.

Next, (B) the fluorine-containing thermoplastic resin containing the component will be explained.

A feature of the present invention is to provide a fluorine-containing thermoplastic resin material which can be melt-extruded and formed. Conventionally, rubber materials such as fluorine rubber and silicone rubber have been used in this field, but materials mainly made of these rubbers are used. Cannot be melt extruded.

Fluoro-containing thermoplastics include tetrafluoroethylene (TFE) and at least one other species that can be co-polymerized with it. Ren-unsaturated monomers (eg, ethylene, propylene, etc., olefins, hexafluoropropylene, vinylidene) Fluoride, black mouth trifluorene, vinyl fluoride, etc., gen- erated olefins, pamphlets Copolymers with fluoroalkyl vinyl ethers, etc.), polyclonal trifluoroethylene, polyvinylidene Orid etc. are exposed. A particularly preferred fluorine-containing thermoplastic resin is a fluorine-containing thermoplastic resin having a hydrogen atom. The plastic resin is distinguished from the point that high strength is obtained and the point that it is excellent in additivity. Specific examples include ethylene (ET)-tetrafluoroethylene (TFE) copolymer (ETZTFE = 40Z60 to 60Z40; mole ratio), vinylide Fluoride-based polymers (for example, polyvinylidene-fluoride, vinylidene-fluoride) Propylene copolymer, vinylidene fluoridation □□ trifluoroethylene copolymer). In particular, ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoridation (PVdF), vinylidene Fluorofluorohexyl copolymers are preferred because of their high strength and high potency. When these fluorine-containing thermoplastic resins are used, they have superior heat resistance, non-adhesion, water and oil repellency, lubricity, and chemical resistance compared to general-purpose resins. The effect is obtained that a composition having the following is obtained. Such general-purpose resins include, for example, polyether ether ketone, thermoplastic thermoplastic polyimide, polyethylene naphthalate, and the like. , Polybutyrene, evening rate, polyethersulfone, polysulfone, polycarbonate, polyaryt, poly Non-fluorothermoplastic resins, such as polyethylene terephthalate and polyethernitrile, can be used.

The composition ratio of the component (A) and the component (B) is 1/99 to 20Z80 (weight ratio; the same applies hereinafter). When the amount of the component (A) decreases, the effect of adding the fluorinated carbon black cannot be achieved, and when the amount increases, the tensile strength increases. The mechanical strength tends to decrease. Also, the component (B) may be mixed with the non-fluorine-based thermoplastic resin in such an amount that the effect of the present invention is not impaired. The features of the melt-extrusion material of the present invention are that it has good extrusion moldability even without adding a plasticizer, and it does not require the addition of a surfactant. The point is that stable semiconductivity can be obtained. Therefore, in the past, leaching (bleeding) was a problem and was a source of contamination. And the addition of a fluorine-based surface active agent can be eliminated.

The composition of the present invention can be mixed and prepared by a usual method, for example, a simple method.

Resin and fluorinated carbon black and, if necessary, the minimum amount of additives, V-type blender, tumbler, henshermi After mixing with a mixer such as a kneader, the mixture is further mixed using a melting and kneading device such as a twin screw extruder to form a pellet. The pellets obtained by the extruder are used to form the desired shape, for example, a belt, plate, film, etc. It is formed.

The melt-extrusion material of the present invention has physical properties suitable as a material for forming a transfer layer of a photosensitive portion of an image forming apparatus.

That is, the coatings (tubes, films, etc.) obtained by melting and extruding the material of the present invention have the following physical properties.

(1) The surface has a specific volume resistivity of 10 ⁸ to 10 ¹³ Q * cm, preferably l O l O ^ Q 'cm. As long as it is within this range, excellent toner transfer will be performed. In addition, the ratio of the maximum value and the minimum value of the volume specific resistivity on the same coating surface is 10 or less, and the semiconductivity is uniform, so that dielectric breakdown does not occur. I

(2) The contact angle with water is 96 degrees or more, preferably 98 degrees or more. When the contact angle with water is large, the non-adhesiveness is good.

(3) Bow I Zhang Ying Hot (25 ° C) Force 350kgf Zcm ² or more, Child or 36 It is 0 to 600 kgf / cm ² .

Also, (4) the surface roughness (Ra) force is preferably 5 μππ or less, and more preferably 0.5 μππ or less. A smooth surface having a small surface roughness (R a) has little toner residue and is excellent in terms of image formation.

The transfer belt to which the present invention is applied takes a large amount of tension when rotating at high speed. Conventionally, transfer belts satisfying the characteristics of (1), (2), and (4) above and imparting a large tensile strength have been conventionally used. Rather, it has been achieved for the first time in the present invention.

The material of the present invention can provide various shaped articles by the melt extrusion molding method. For example, it can be formed into a film, a tube, a plate, a belt or the like. Such a melt extruded product cannot be homogeneous unless it is excellent in melt formability. In this regard, if the fluorinated force is combined with a bon black, as described above, it is melted due to the structure. The melt viscosity becomes remarkably large, the melt-kneading becomes insufficient, and the dispersion becomes uneven. The material of the present invention is preferably within a range where melt flow rate (MFR), which is one of the indicators of melt formability, is acceptable (0.5 gZlO or more). ETFE: 297 ° C, PVdF: 230 ° C, load 5 kg) あ It is dispersible (meltability) together with its melt formability. Is also good.

The present invention also relates to a transfer belt for a photosensitive section of an image forming apparatus.

The image forming apparatus used in the present invention may be an electronic photocopier, a facsimile machine, a laser printer, or a laser printer. Not limited to them, but based on electrostatic duplication Includes equipment for transferring toner.

In the image forming apparatus, for example, in the light-sensing section of an electronic photocopier, for example, a charging roller, a current image roller, and a transfer belt, which are usually semiconductive rollers, are usually used. Or roller) Powerful.

The transfer belt usually has an endless transfer belt.

By pressing the transfer paper against the photosensitive drum with three rollers, the toner image on the photosensitive drum is transferred to the transfer paper. I will do it.

Such a transfer belt is a single endless belt (typically 50 to 250 m thick) or a transfer layer (thickness) on a heat-resistant resin woven fabric. (About 10 to 50 / im), but the transfer belt of the present invention can be applied to those conventional structures. It is a thing.

In addition, the melt-extrusion material of the present invention is useful not only as a transfer belt but also as a resistor layer for a transfer roller, a charged roller, a current image roller, and the like. It is.

In such a roller, a conductive elastic layer is formed first on a conductive support. The material for the conductive elastic layer is not particularly limited, and may be silicone rubber, ethylene propylene rubber, or epoxy rubber. Conductive powders and conductive fibers (carbon black, gold, etc.) are contained in composite rubber such as chlorohydrin rubber, nitrile rubber, and urethane rubber. Powders, carbon fibers, etc.), and has a volume-specific resistivity of 10 ⁵ Q'cm or less. Is less than 10 ³ Q'cm and has a rubber hardness (JIS A) force S in the range of 20 to 50 degrees, preferably 25 to 40 degrees. . When mixing conductive powder, it is preferable to use a plasticizer or surface active agent for the purpose of resistance adjustment or rubber hardness adjustment. Absent . This means that these chemicals ooze out over time, contaminating the surface of photosensitizers and the like, and toner filming on the roller surface. This is a cause of the occurrence of the

The material of the conductive support is not particularly limited, and the alloy mainly composed of aluminum or aluminum is used. Can use stainless steel.

Then, the melt-extrusion material of the present invention is formed into a tube-like film by a usual melt-extrusion molding method. It may be stretched or heat-shrinkable if necessary, but usually does not have to be stretched or heat-shrinkable. The thickness of such a tube must be in the range of 0.01 to 0.15 mm, and it is preferable to deviate from this value. No part rollers are available.

Next, a specific example of the manufacture of the roller for the light-sensing unit according to the present invention will be described. That is, first, a core metal and a tube made of the melt-extrusion material according to the present invention are arranged inside the tubular molded body with a space between them. It is arranged so that the inner surface of the cylindrical molded body and the outer surface of the tube are in contact with each other, and the material for the conductive elastic layer is flowed through the above-mentioned space. The roller for the photosensitive portion of the present invention can be obtained by vulcanizing it if necessary and vulcanizing it if necessary. Of course, it is necessary to take out the roller part, including the coated tube, from the tubular molded body when necessary. At this time, in order to make it easy to come in contact with the rubber part on the inner surface of the tube, perform a pre-etching process, a brimmer process, etc. You can keep it. Alternatively, a conductive elastic layer may be prepared in advance, and the surface thereof may be covered with a tube to be placed in the present invention. In this case, it is better to use a heat-shrinkable tube. As described above, there is no particular limitation on the method of manufacturing the rollers. As described above, the melt-extrusion material of the present invention is applied to various types of rollers or belts of the photosensitive section of an image forming apparatus, and particularly to a transfer belt which requires a high strength. Good for rooting.

Next, the present invention will be described in more detail with reference to examples. The part indicates the weight part.

Example 1

Fluorine black (denka black manufactured by Electrochemical Engineering Co., Ltd .; average particle size: 0.04 m) is fluorine-filtered to obtain an FZC of 0.1. Fluorinated carbon black has been created.

The fluoridation power of 10 parts of the black block and 90 parts of the ETFE (ethylen Z tetrafluoroethylene = 48752; mole ratio) are 90 parts. After mixing at 30 ° C with Rumimixer, the mixture is melted at 300 ° C in a twin-screw extruder (Laboplasty mill made by Toyo Seiki Co., Ltd.). They were kneaded, extruded, and pelleted. This pellet is extruded into a film (300 °) with an extruder (30 単 single-axis extruder manufactured by Tanabe Plastics Co., Ltd.). C), A film with a thickness of 150 μιη was produced.

The physical properties of the obtained film were measured. The results are shown in Table 1.

(Volume-specific resistivity)

In accordance with JIS Κ 6911, a fan measurement cell (Registration Channel No.R12702A) manufactured by Advanst Co., Ltd. and a resistance meter (Digit Meter) Measure using a tall ultra-high resistance meter R 8340 A).

(Water contact angle)

Measured with a contact angle meter manufactured by Kyowa Kyokai Kagaku Co., Ltd.

(Tensile strength)

Measure according to ASTM D 638. (Surface roughness)

Using a surface roughness measuring instrument (Surfcom470A) manufactured by Tokyo Seimitsu Co., Ltd., a sample is obtained by a diamond pick-up with a 2 μm R stylus tip. 2.5mm pick-up speed 0.3mm

Automatic measurement in Z seconds. Ra is the center average roughness specified in JIS B 0601-1982.

In addition, in order to examine the melt formability of the molten extruded material of the present invention, the melt extrusion rate (MFR) (ETFE 297 ° C, PV d F: 230 ° C, load 5kg). The results are shown in Table 1.

Examples 2 to 6

Except for using the fluorinated carbon black having the FZC shown in Table 1 as shown in the table, the pellets were melted and extruded in the same manner as in Example 1. A film was formed by molding, and each physical property was measured. The results are shown in Table 1.

Example 7

Except that ETFE was replaced by polyvinylidene fluoride (PVdF), the pellets were melted and pressed in the same manner as in Example 1. Films were produced by molding and each physical property was measured. The results are shown in Table 1.

Comparative Example 1

In Example 1, a film was produced by melt-extrusion molding using ETFE alone without combining a fluorine-containing carbon black film, and measuring the properties of the film. Specified. Table 1 shows the results.

Comparative Examples 2-3

In Example 1, in place of the fluorinated carbon black, a non-fluorinated raw material carbon black (manufactured by Denki Kagaku Kogyo Co., Ltd.) The average particle size is 0.04 μm). In the same manner as in Example 1, the blended amounts shown in Table 1 were melt-extruded to form films, and the physical properties were measured. Table 1 shows the results.

Comparative Example 4

Table 1 shows the complete fluorinated carbon black (F / C = l.l) in place of the fluorinated carbon black in Example 1. In the same manner as in Example 1, the mixture in the amounts shown was melt-extruded to produce a film, and each physical property was measured. The results are shown in Table 1.

Industrial availability

As is evident from Table 1, the melt-extrusion material of the present invention is excellent in melt formability (MFR), and the melt extruded material is also a fluoropolymer. The change in the volume specific resistivity is small even when the amount of the mixed metal is changed (Comparing Examples 1 and 2, 3 and 4, and 5 and 6), and the non-adhesive property (water contact) It provides molded products that have excellent strength and smoothness (surface roughness) and have sufficient strength and are suitable for transfer belts or rollers in the photosensitive area.

Claims

The scope of the claims

1. (A) A composition comprising at least a part of a fluorinated filler material and (B) a fluorine-containing thermoplastic resin. The surface of the resulting film has a specific volume resistivity of 10 ⁸ to 10 ¹³ Ωcm, a contact angle with water of 96 ° or more, and a tensile strength of the film of 400 kgf at 25 ° C. A melt-extruded material suitable for forming a transfer layer of a light-sensitive portion of an image forming apparatus characterized by being composed of a composition having Zcm ² or more.

2. The melt-extruded material according to claim 1, wherein the surface roughness Ra of a film obtained from the composition is 0.5 μπι or less.

3. (Α) shows that the ratio F / C of fluorine atoms to carbon atoms is 0.

The range of claims characterized by being a fluorinated carbon black having a value of 1 or more and less than 1.0. The melt-extrusion material as described in Paragraph 1 of the Claims. .

4. (Α) shows that the ratio F / C of fluorine atoms to carbon atoms is 0.

The scope of the claim, characterized in that it is a fluorinated carbon black having a value of 1 or more and less than 0.5.The melt extrusion described in Paragraph 1 Materials.

5. The molten extruded material according to claim 1, wherein the content of (ii) is 1 to 20% by weight.

6. The melt-extrusion material according to claim 1, wherein (ii) is a fluorine-containing thermoplastic resin containing hydrogen atoms.

7. Make sure that (Β) is an ethylene-tetrafluoroethylene copolymer or a vinylidenefluoride polymer. The melt-extruded material described in Paragraph 1 of the scope of the claim.

8. A transfer belt for a light-sensitive portion of an image forming apparatus formed by using the melt-extrusion material according to claim 1.