JP2001105545A - Conductive stretched multi-layer film and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive stretched film having low surface resistance and improved mechanical strength by orientation with the use of a resin composition containing a fluorocarbon resin and conductive powder and a method for producing the film. SOLUTION: In a conductive stretched multi-layer film, a conductive stretched multi-layer film comprising a stretched multi-layer film in which a fluorocarbon resin composition layer A containing 12-35 volume % of conductive powder is arranged at least on one side of a fluorocarbon resin layer B, and the surface resistance of the layer A is 1×1010 Ω or below. A method for producing the conductive stretched multi-layer film is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive stretched multilayer film which has excellent surface conductivity, can be formed into a thin film, and has good mechanical strength. The present invention relates to a conductive stretched multilayer film in which a fluororesin composition layer containing a base resin and a conductive powder is disposed as a surface layer. The conductive stretched multilayer film of the present invention makes use of surface conductivity, for example,
It is suitable as a charge control member such as a charge removing belt and a charge removing film in an electrophotographic image forming apparatus. Also,
The conductive stretched multilayer film of the present invention is suitable for applications utilizing the conductivity, antistatic properties, dust absorption preventing properties, etc., for example, as electronic component packaging materials, wallpaper, OA equipment exterior materials, antistatic partitions, and the like.

[0002]

2. Description of the Related Art In the field of electric and electronic equipment, the surface resistivity of a synthetic resin molded article is reduced to provide conductivity, antistatic property,
It is required to provide a charge control function such as a dust adsorption preventing property. For example, in an image forming apparatus such as an electrophotographic copying machine or an electrostatic recording device, it is necessary to strictly control the charge such as charging the surface of the photoreceptor or removing electricity after copying. Therefore, a charge control member having a low surface resistivity, such as a static elimination belt or a static elimination film, is used. When the electronic component packaging material made of synthetic resin adsorbs dust due to generation of static electricity, the quality of electronic components such as ICs and LSIs is impaired. OA device exterior materials made of synthetic resin, when adsorbed with dust, impair the appearance or cause a failure of the device body. Therefore, these packaging materials and exterior materials are required to have low surface resistivity and to be hardly charged.

[0003] In addition, a synthetic resin molded article having a charge control function has low surface resistivity, heat resistance, chemical resistance, solvent resistance, and ozone resistance in view of use conditions and use environment. It is required to be excellent in stain resistance, non-adhesion, moldability and the like. Further, a synthetic resin molded product having a charge control function is required to be in a thin film form depending on the application field. Such a conductive film can be used not only as a charge control member by itself, but also as a composite material by constituting a surface layer of various molded articles.

On the other hand, fluororesins such as polyvinylidene fluoride resins are excellent in heat resistance, chemical resistance, solvent resistance, ozone resistance, stain resistance, non-adhesion, moldability, etc. Attention has been paid to resin materials for control members.
However, since the fluororesin itself is an insulator, to reduce the surface resistivity of the molded product, for example, (1) a method of applying an antistatic agent to the surface of the molded product, (2) an antistatic There are known a method of kneading an agent, (3) a method of blending a conductive powder such as a conductive carbon black with a resin, and the like.
However, the method of applying the antistatic agent to the surface of the molded article has a problem that the antistatic agent easily falls off by wiping or cleaning the surface of the molded article. In the method of manufacturing a molded article using a resin composition in which an antistatic agent is kneaded into a fluororesin, the antistatic agent bleeds out or a large amount of the antistatic agent is mixed, thereby impairing the inherent properties of the resin. Problem.

[0005] In the method of blending a conductive powder with a fluororesin, it is necessary to blend a relatively large amount of the conductive powder, so that the molding processability of the resin is reduced and the mechanical strength of the molded product is reduced. . In particular, when a resin composition in which a relatively large amount of conductive powder is mixed with a fluororesin is formed into a thin film such as a sheet or a film, it is difficult to obtain sufficient mechanical strength. In general, mechanical strength can be improved by stretching a synthetic resin sheet or film. However, when a stretched film is prepared from a resin composition mixed with a conductive powder, the conductive powder in the resin is dispersed by the stretching, so that the conductivity is significantly reduced. In order to increase the conductivity of the stretched film, it is necessary to add a larger amount of conductive powder to the resin.

However, in the case of a fluororesin, particularly a polyvinylidene fluoride resin, an unstretched sheet is prepared using a resin composition containing a large amount of conductive powder, and this sheet is stretched uniaxially or biaxially. If this is attempted, the sheet will break during the stretching, and therefore the film cannot be stretched or a stretched film having a high draw ratio cannot be produced. In the case of a resin such as polypropylene having excellent stretchability, even if a large amount of conductive powder is blended, it is possible to find out the stretching conditions under which a stretched film having a high stretch ratio can be obtained. However, in the case of a polyvinylidene fluoride resin, if the conductive powder is blended in a proportion of 12% by volume or more, the unstretched sheet becomes extremely brittle, so that the sheet is easily broken during stretching, and a satisfactory stretched film can be obtained. Cannot be manufactured.

On the other hand, as a method for forming a conductive fluororesin film, a solution obtained by dissolving or dispersing a fluororesin and a conductive powder in an appropriate solvent is formed into a thin film by a casting method or a spin coating method. Methods are known. However, this method requires handling solvents,
The manufacturing process is complicated and there is a problem of environmental pollution. Moreover, the film produced by this method is an unstretched film and is not oriented, and therefore has poor mechanical strength.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition containing a fluororesin such as a polyvinylidene fluoride resin and a conductive powder, having a low surface resistivity,
Another object of the present invention is to provide a conductive stretched film having improved mechanical strength by orientation and a method for producing the same.

The present inventors have conducted intensive studies to achieve the above object, and as a result, laminated an unstretched fluororesin composition layer containing a conductive powder on one or both sides of the unstretched fluororesin layer. An unstretched multilayer sheet is prepared, and then the unstretched multilayer sheet is stretched in at least one direction, thereby forming a stretched fluororesin containing a relatively large amount of conductive powder on one or both sides of the stretched fluororesin layer. It has been found that a conductive stretched multilayer film comprising a stretched multilayer film having a composition layer disposed thereon and having a low surface resistivity can be obtained. According to this method, even if the fluororesin composition layer is highly filled with the conductive powder, the degree of orientation of the stretched multilayer film can be increased, so that a conductive stretched multilayer film having excellent mechanical strength is obtained. be able to. The present invention has been completed based on these findings.

[0010]

According to the present invention, 12 to 12 conductive powders are coated on one or both surfaces of the fluororesin layer (B).
Fluororesin composition layer (A) containing 35% by volume
Is provided, and the surface resistivity of the fluororesin composition layer (A) is 1 × 10 ¹⁰ Ω or less.

Further, according to the present invention, the fluorine-based resin layer (B
1) On one or both sides, 12 to 35% by volume of conductive powder
Producing a non-stretched multilayer sheet laminated with a fluorine-containing resin composition layer (A1) containing at a ratio of, and then a method for producing a conductive stretched multilayer film in which the unstretched multilayer sheet is stretched in at least one direction is provided. You.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Fluorine-based resin Examples of the fluorine-based resin used in the present invention include polyvinylidene fluoride (PVDF) -based resin, polyvinyl fluoride (PVF) -based resin, ethylene tetrafluoride / perfluoro (alkyl vinyl ether) copolymer (PFA) ) -Based resin, ethylene / tetrafluoroethylene copolymer (ETFE)
And a resin having a structural unit derived from a fluoromonomer such as a tetrafluoroethylene / propylene hexafluoride copolymer (FEP) resin. Among them, polyvinylidene fluoride resin is particularly preferable from the viewpoint of balance between stretchability and various physical properties.

These fluorine-based resins may contain other copolymerizable monomer units in addition to the fluorine-based monomer units constituting each fluorine-based resin. In that case, each fluorine-based monomer unit constituting each fluorine-based resin is a main constituent unit, preferably at least 80 mol%, more preferably at least 90 mol%, particularly preferably at least 95 mol%. Is desirable.

The vinylidene fluoride resin may be a homopolymer of vinylidene fluoride (PVDF) or a copolymer of vinylidene fluoride having vinylidene fluoride as a main constituent unit and another copolymerizable monomer. You may. As the vinylidene fluoride-based copolymer, for example, vinylidene fluoride-
Hexafluoropropylene copolymers, vinylidene fluoride-tetrafluoroethylene copolymers, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymers, and vinylidene fluoride-chlorotrifluoroethylene copolymers are preferred. Can be These polyvinylidene fluoride resins can be used alone or in combination of two or more.

Among polyvinylidene fluoride resins, PVDF, which is a homopolymer of vinylidene fluoride, is preferred from the viewpoints of stain resistance, ozone resistance and solvent resistance. From the viewpoint of flexibility and tear strength, a vinylidene fluoride copolymer having vinylidene fluoride as a main component alone is used,
Alternatively, it is preferable to use it by blending with PVDF. In order to improve the adhesiveness, a vinylidene fluoride copolymer having a functional group introduced is preferably used. As the polyvinylidene fluoride-based resin, another thermoplastic resin such as an acrylic resin or another fluororesin may be blended and used as long as the object of the present invention is not hindered.

Although the molecular weight of the polyvinylidene fluoride resin is not particularly limited, the melt flow rate used as a standard is preferably 0.5 to 40 g / 10 min, more preferably 3 to 30 g / 10 min, and particularly preferably 6 to 30 g / 10 min. ~ 25g / 1
It takes about 0 minutes. Melt flow rate is 235
It is the amount of outflow determined by ASTM D1238 at a temperature of 5 ° C. and a load of 5 kg / cm ² .

As the PFA resin, the molar ratio of ethylene tetrafluoride to perfluoro (alkyl vinyl ether) is usually 80:20 to 99.5: 0.5, preferably 90:20.
PFA of 10-99: 1 can be mentioned. As perfluoro (alkyl vinyl ether), perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether), perfluoro (propyl vinyl ether), perfluoro (n-heptyl vinyl ether)
And the like. Among them, perfluoro (propyl vinyl ether) is preferable in view of the properties of the copolymer. As the PFA resin, in addition to the above two components,
Further, one or more of a small amount of a third component such as a fluorine-containing olefin or a hydrocarbon-based olefin may be copolymerized. As the third component, for example, α-olefins such as propylene and 1-butene; vinyl fluoride,
Vinylidene fluoride, (perfluorobutyl) ethylene,
Fluorinated olefins such as trifluorochloroethylene; and the like. When these third components are copolymerized, it is sufficient to modify PFA, and it is generally preferable to copolymerize at a ratio of 10 mol% or less.

Although the molecular weight of the PFA-based resin is not particularly limited, the melt flow rate used as a standard is 0.5 to 4%.
About 00 g / 10 minutes is preferable. Melt flow rate was measured at 380 ° C using a Koka flow tester.
This is the amount of outflow from a nozzle having a load of 7 kg / cm ² and a diameter of 2 mm and a length of 8 mm.

As the ETFE resin, the molar ratio of ethylene tetrafluoride to ethylene is usually 30:70 to 70:30,
Preferably, PTFE having a ratio of 40:60 to 60:40 can be used. As the PTFE-based resin, in addition to the above two components, one or more third components such as a fluorine-containing olefin or a hydrocarbon-based olefin may be further copolymerized. Examples of the third component include α-olefins such as propylene and 1-butene; fluorinated olefins such as hexafluoropropylene, vinylidene fluoride, (perfluorobutyl) ethylene, and trifluorochloroethylene; Fluorinated vinyl ethers such as ethyl vinyl ether) and perfluoro (methyl vinyl ether); fluorinated acrylates; and the like.

The molecular weight of the ETFE-based resin is not particularly limited.
About 00 g / 10 minutes is preferable. Melt flow rate was measured at a temperature of 300 ° C using an advanced flow tester.
This is the amount of outflow from a nozzle 1 mm in diameter and 2 mm in length under a load of 30 kg / cm ² .

As the FEP resin, the molar ratio of ethylene tetrafluoride to propylene hexafluoride is usually 70:30 to 9
9: 1, preferably 80:20 to 95: 5 FEP. As the FEP resin, in addition to the above two components, one or more third components such as fluorine-containing olefins and hydrocarbon olefins may be further copolymerized. As the third component, for example,
Α-olefins such as propylene and 1-butene; fluorinated olefins such as hexafluoropropylene, vinylidene fluoride, (perfluorobutyl) ethylene and trifluorochloroethylene; perfluoro (ethyl vinyl ether), perfluoro (methyl vinyl ether) Fluorinated vinyl ethers; fluorinated acrylates;
And the like. When these third components are copolymerized, it is sufficient to modify the FEP.
It is preferable to copolymerize at a ratio of not more than mol%.

The molecular weight of the FEP resin is not particularly limited.
About 00 g / 10 minutes is preferable. Melt flow rate was measured at 380 ° C using a Koka flow tester.
This is the amount of outflow from a nozzle having a load of 7 kg / cm ² and a diameter of 2 mm and a length of 8 mm.

2. Conductive Powder The conductive powder used in the present invention is not particularly limited, and examples thereof include metal powders such as copper powder, iron powder, silver powder, and aluminum powder; potassium titanate, tin oxide, antimony oxide, and indium oxide. Metal oxide powder; conductive carbon black such as acetylene black, oil furnace black, thermal black, and channel black; and graphite powder. These conductive powders can be used alone or in combination of two or more. The shape of the conductive powder is not particularly limited, for example, spherical, fiber, whisker,
The shape may be any shape such as a scaly shape and an irregular shape. The particle size of the conductive powder is usually 10 μm or less, and preferably 1 μm or less.
μm or less.

The conductive powder preferably has good dispersibility in a fluororesin so as not to impair the appearance of the molded article. Particularly preferred conductive powders have a DBP oil absorption of usually 100 ml / 100 g or more, preferably 100 ml / 100 g or more.
~ 400ml / 100g, average particle size is usually 1 ~ 100
nm, preferably 10 to 50 nm, and the ash content is usually 0.2.
% Or less, preferably 0.1% or less of conductive carbon black. The DBP oil absorption indicates ml of dibutyl phthalate contained per 100 g of carbon black (measured with a dibutyl phthalate absometer).
The average particle size represents a particle size (D _50). From the viewpoint of the appearance of the molded article and the dispersibility, acetylene black is particularly preferred as the conductive powder used in the present invention.

As the conductive powder, commercially available conductive carbon black can be used. Examples of acetylene black include Denka Black manufactured by Denki Kagaku Kogyo KK. Examples of the conductive oil furnace black include Vulcan XC-72 and Vulcan P manufactured by Cabot Corporation, and Ketjen Black EC manufactured by Lion Corporation.

3. Other components The conductive stretched multilayer film of the present invention has a fluorine-based resin layer.
It is a stretched multilayer film in which a fluororesin composition layer (A) containing a conductive powder is disposed on one or both surfaces of (B). Fluorinated resin composition layer (A) and fluorinated resin layer (B)
May optionally contain an additive.
Examples of additives include talc, mica, silica, alumina, kaolin, ferrite, zinc oxide, magnesium hydroxide, calcium carbonate, nickel carbonate, calcium sulfate, barium sulfate, aluminum hydroxide, glass powder,
Granular or powdery fillers such as quartz powder, inorganic pigments, and organic metal salts can be used. These fillers can be appropriately blended according to the purpose of use within a range not to impair the purpose of the present invention.

As additives, for example, antioxidants, lubricants, plasticizers, coloring agents, ultraviolet absorbers, surfactants, inorganic acids, organic acids, pH adjusters, crosslinking agents, coupling agents, etc. It can be appropriately compounded within a range that does not impair the object of the present invention. The fluorine-based resin layer (B) preferably contains no conductive powder from the viewpoint of stretchability, but may contain a small amount of conductive powder of 10% by volume or less, if necessary. .

4. Conductive stretched multilayer film The conductive stretched multilayer film of the present invention comprises a fluororesin layer.
(B) is a stretched multilayer film in which a fluorine-based resin composition layer (A) is arranged on one side or both sides, and both layers are stretched. The proportion of the conductive powder in the fluororesin composition layer (A) is 12 to 35% by volume, preferably 15 to 30% by volume, and more preferably 18 to 28% by volume. The ratio of the fluorine resin in the fluorine resin composition layer (A) is usually 6
It is 5 to 88% by volume, preferably 70 to 85% by volume, more preferably 72 to 82% by volume. However, when the fluorine-based resin composition layer (A) contains various additives and the like,
The proportion of the fluorine-based resin can be usually 50 to 88% by volume. If the proportion of the conductive powder in the fluororesin composition layer (A) is too small, a stretched multilayer film having a low surface resistivity cannot be obtained. If the proportion of the conductive powder in the resin composition layer (A) is too large, stretching becomes difficult.

The conductive stretched multilayer film of the present invention may be at least uniaxially oriented. Although the degree of orientation is not particularly limited, in the case of a conductive stretched multilayer film using, for example, polyvinylidene fluoride-based resin as the fluorine-based resin, the degree of orientation in at least one axis direction is 60%.
It is preferable that it is above. This degree of orientation is more preferably at least 65%, still more preferably at least 70%, particularly preferably at least 75%. The degree of orientation can be increased to 90-95%. The larger the degree of orientation, the better the mechanical strength and the thickness of the conductive stretched multilayer film of the present invention can be reduced.

In the conductive stretched multilayer film of the present invention, the surface resistivity of the fluororesin composition layer (A) disposed on one side or both sides is 1 × 10 ¹⁰ Ω or less. This surface resistivity is preferably 1 × 10 ¹ to 1 × 10 ¹⁰ Ω. The conductive stretched multilayer film of the present invention is used, for example, in a electrophotographic image forming apparatus in a neutralizing member (static film or belt).
When used as, the surface resistivity of the fluororesin composition layer (A) is preferably 1 × 10 ¹ to 1 × 10 ⁶ Ω,
More preferably, it is in the range of 1 × 10 ² to 1 × 10 ⁵ Ω. If the surface resistivity of the conductive stretched multilayer film is too high, the charge elimination ability is reduced, and if it is too low, it is difficult to uniformly remove the charge. In the conductive stretched multilayer film of the present invention, the surface resistivity can be arbitrarily adjusted according to the purpose of use.

The layer structure of the conductive stretched multilayer film of the present invention comprises: a fluorine-based resin composition layer (A) / a fluorine-based resin layer (B);
And fluorine-based resin composition layer (A) / fluorine-based resin layer
(B) / Fluorine-based resin composition layer (A). The ratio of the thickness of the fluororesin composition layer (A) is usually in the range of 1 to 95% based on the total thickness of the stretched multilayer film. However, on both surfaces of the fluororesin layer (B), the fluororesin composition layer
When (A) is arranged, this thickness ratio means the total ratio of both fluororesin composition layers (A). The ratio of the thickness of the fluororesin composition layer (A) is preferably from 5 to 90.
%, More preferably 10 to 80%, particularly preferably 20%
~ 70%. In many cases, a fluororesin composition layer
Good results can be obtained when the thickness ratio of (A) is about 30 to 60%. If the ratio of the thickness of the fluorine-based resin composition layer (A) is too small, the surface resistivity increases or the in-plane variation of the surface resistivity increases. Fluorine resin composition layer
If the thickness ratio of (A) is too large, stretching becomes difficult.

The thickness of the conductive stretched multilayer film of the present invention is usually 5 to 150 μm, preferably 10 to 100 μm.
m, more preferably 15 to 80 μm. If the thickness is too small, the durability is reduced, and if it is too large, the flexibility is impaired.

5. Method for Producing Conductive Stretched Multilayer Film To produce the conductive stretched multilayer film of the present invention, first, a conductive powder is contained on one or both sides of the fluororesin layer (B1) in a proportion of 15 to 35% by volume. An unstretched multilayer sheet is prepared by laminating the fluororesin composition layer (A1), and the unstretched multilayer sheet is stretched in at least one direction.

The method of blending the conductive powder with the fluororesin is not particularly limited, and a known mixing method, for example,
Methods such as melt kneading using a Banbury mixer, a roll mill, and an extruder can be employed. As a method of producing an unstretched multilayer sheet, for example, (i) separately forming an unstretched fluorine-based resin layer (B1) and an unstretched fluorine-based resin composition layer (A1), and thermocompression bonding these Lamination method, (i
i) a method of laminating a fluorine-based resin and a fluorine-based resin composition containing a conductive powder by co-extrusion.

The thickness of each layer and its ratio in the unstretched multilayer sheet are adjusted so as to become the thickness of each layer and its ratio after stretching. As the stretching method of the unstretched multilayer sheet,
Free-width uniaxial stretching, constant width uniaxial stretching, sequential biaxial stretching, simultaneous biaxial stretching, stretching by an inflation method, and the like can be employed. In the case of uniaxial stretching, the stretching ratio is usually 1.2 to 15 times, preferably 1.5 to 10 in the uniaxial direction.
And more preferably about 2 to 5 times. The stretching ratio in the case of biaxial stretching is 1.2 in each of the longitudinal and transverse directions.
It is about 15 times, preferably about 1.5 to 10 times, more preferably about 2 to 5 times.

6. Applications The conductive stretched multilayer film of the present invention can be used, for example, as a charge control member such as a static elimination belt and a static elimination film in an electrophotographic image forming apparatus by utilizing the surface conductivity. The conductive stretched multilayer film of the present invention makes use of conductivity, antistatic properties, dust absorption preventing properties, etc., for example, electronic component packaging materials, wallpaper, OA equipment exterior materials,
It can be used as an antistatic partition or the like. The conductive stretched multilayer film of the present invention can be used as it is in the shape of the film, but may constitute the surface layer of various molded articles and members.

[0037]

The present invention will now be described more specifically with reference to examples and comparative examples. In addition, the measuring method of physical properties is as follows. (1) Thickness The thicknesses of the sheet and the film were measured with a dial gauge thickness meter (trade name: DG-911, manufactured by Ono Sokki Co., Ltd.).

(2) Degree of orientation The degree of orientation (unit:%) of the film was measured using an X-ray diffractometer (trade name: RAD-RB type, manufactured by Rigaku Corporation), a wide-angle goniometer, a scintillation counter, and a fiber sample table. P
It was calculated by β measurement of VDF (110). Details of the measuring method and the calculating method are as follows. Sample preparation method A sample film was adhered in the thickness direction with the stretching axis aligned to prepare a sample piece having a length of 40 mm, a thickness of 2 mm, and a width of 0.3 mm. Adhesive (Toa Gosei Co., Ltd., trade name:
Aron Alpha) was used. In the case of a uniaxially stretched film, so that the stretching direction matches the length direction of the sample,
In the case of a sequentially biaxially stretched film, the direction of the secondary stretch axis was made to coincide with the length direction of the sample piece.

Measurement conditions X-ray: Cu Kα ₁ (voltage: 30 kV, current: 150 mA) Scanning speed: 10 ° / min β step width: 0.2 ° Scanning range: -90 to 270 ° Incident direction: Calculation method from edge The degree of orientation = [(360−ΣWi) / 360] × 100 Wi is the half-width of the peak in degrees. The unit of the degree of orientation is%.

(3) Surface resistivity In the present invention, a sample having a surface resistivity of 10 ⁸ Ω or more is
Residency cell having a ring-shaped electrode (trade name:
HP 16008B, manufactured by Hewlett-Packard Company, inner electrode diameter 26.0 mm, outer electrode inner diameter 38.0
mm, the outer diameter of the outer electrode is 40.0 mm), the sample is sandwiched with a load of 7 kg, and the surface resistivity ρ _S when a voltage of 10 V is applied in the surface direction for 1 minute between the inner electrode and the outer electrode is measured. (Hiresta IP, manufactured by Mitsubishi Chemical Corporation). The details of such a method of measuring the surface resistivity by the ring electrode method are described in JIS-K6911.

In the present invention, a sample having a surface resistivity of less than 10 ⁸ Ω is measured using a four-probe probe (trade name: PSP probe, manufactured by Mitsubishi Chemical Corporation, pin interval 1.5 mm) and a resistivity measuring device (trade name: (Loresta HP, manufactured by Mitsubishi Chemical Corporation) to determine the surface resistivity ρs. Details of such a surface resistivity measurement method using the four-point probe method are described in JIS-K7194.

[Example 1] Polyvinylidene fluoride [KF # 1000 pellets manufactured by Kureha Chemical Industry Co., Ltd .; melt flow rate (measurement method described in the text) 8.8 g / 10 min]
And acetylene black [manufactured by Denki Kagaku Kogyo KK, trade name: Denka Black; DBP oil absorption = 190 ml / 100
g, average particle size (D ₅₀ ) = 42 nm, ash content = 0.06%]
And 250 ° C., 50 r using a mixer tester [Labo Plast Mill manufactured by Toyo Seiki Co., Ltd.] according to the formulation shown in Table 1.
pm, kneading for 6 minutes, temperature 250 ° C, initial pressure 1M
A sheet (A1) having a thickness of 0.2 mm was produced by press molding with Pa. On the other hand, polyvinylidene fluoride (same as above) was press-molded at a temperature of 250 ° C. and an initial pressure of 1 MPa to produce a 0.15 mm thick sheet (B1).

The sheet (A1) and the sheet (B1) were overlaid and press-molded at a temperature of 200 ° C. and an initial pressure of 0.1 MPa to obtain an unstretched multilayer sheet having a thickness of 0.3 mm. This unstretched multilayer sheet was simultaneously and biaxially stretched 2.5 times vertically and horizontally by a tenter clip type stretching machine adjusted to 180 ° C. to obtain a biaxially stretched film having an average thickness of 45 μm. This biaxially stretched film is a conductive multilayer stretched film of a biaxially stretched film (A) (thickness 26 μm) from the sheet (A1) and a biaxially stretched film (B) (thickness 19 μm) from the sheet (B1). there were. The biaxially stretched film (A) had a surface resistivity of 3.2 kΩ. Further, this conductive stretched multilayer film was flexible and excellent in mechanical strength, and could not be easily torn by hand. Table 1 shows the physical properties of the obtained conductive stretched multilayer film.

[Example 2] A compounding formulation shown in Table 1 of polyvinylidene fluoride (KF # 1000 powder, manufactured by Kureha Chemical Industry Co., Ltd.) and acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd., same as above) Was extruded from a 30 mmφ twin-screw extruder in which the extruder tip temperature was 270 ° C. and the die setting temperature was 270 ° C., to obtain composite pellets. The composite pellet and polyvinylidene fluoride (KF # 1000 pellet manufactured by Kureha Chemical Industry Co., Ltd.) are extruded from a two-layer T-die having a set temperature of 260 ° C. and cooled on a cooling drum having a surface temperature of 90 ° C. Solidifies to a thickness of 24
0 μm [resin composition layer (A1) = 100 μm, PVDC layer (B
1) = 140 μm]. The unstretched multilayer sheet is stretched 3.5 times in the machine direction by a tenter clip type stretching machine adjusted to 180 ° C., and then stretched 3.5 times in the transverse direction to obtain an average thickness of 20 μm [resin composition Layer (A) = 8 μm, PVDC layer (B) = 12 μm] to obtain a biaxially stretched film. The surface resistivity of the biaxially stretched film on the resin composition layer (A) side was 12.5 kΩ. This biaxially stretched film was excellent in flexibility and mechanical strength. Table 1 shows the physical properties of the obtained stretched film.

Example 3 An unstretched multilayer sheet having the composition shown in Table 1 was obtained in the same manner as in Example 1. This unstretched multilayer sheet is stretched 3.5 times in the machine direction by a tenter clip type stretching machine adjusted to 180 ° C. to have an average thickness of 7
4 μm [resin composition layer (A) = 43 μm, PVDC layer (B)
= 31 μm] to obtain a uniaxially stretched film. The surface resistivity of the biaxially stretched film on the resin composition layer (A) side was 1.5%.
It was kΩ. This biaxially stretched film was excellent in flexibility and mechanical strength. Table 1 shows the physical properties of the obtained stretched film.

COMPARATIVE EXAMPLE 1 Polyvinylidene fluoride (KF # 1000 pellets, manufactured by Kureha Chemical Industry Co., Ltd.) and acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd., same product) are shown in Table 1. Using a mixer tester (Labo Plast Mill, manufactured by Toyo Seiki Co., Ltd.)
After kneading at 0 rpm for 6 minutes, press molding was performed at a temperature of 250 ° C. and an initial pressure of 1 MPa to obtain an unstretched sheet having a thickness of 0.2 mm. Simultaneous biaxial stretching of the unstretched sheet was attempted using a tenter clip type stretching machine adjusted to 180 ° C., but the sheet was broken immediately after stretching, and a stretched film was not obtained.

COMPARATIVE EXAMPLE 2 Polyvinylidene fluoride (KF # 1000 powder, manufactured by Kureha Chemical Industry Co., Ltd.) and acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd., same product) are shown in Table 1. Was extruded from a 30 mmφ twin screw extruder in which the extruder tip temperature was 270 ° C. and the die set temperature was 270 ° C., to obtain composite pellets.
The composite pellet was extruded from a single-layer T-die having a die set temperature of 260 ° C., and cooled and solidified on a cooling drum having a surface temperature of 90 ° C. to obtain an unstretched sheet having a thickness of 240 μm.
When the unstretched sheet was subjected to uniaxial stretching using a tenter clip stretching machine adjusted to 180 ° C., it was broken immediately after stretching, and a stretched film was not obtained.

Comparative Example 3 An average thickness of 45 μm was obtained in the same manner as in Example 1 except that the mixing ratio of polyvinylidene fluoride and acetylene black was changed as shown in Table 1.
m [resin composition layer (A) = 26 μm, PVDC layer (B) = 1]
9 μm]. The surface resistivity of the stretched film on the resin composition layer (A) side was 1.0 × 1
0 ¹³ Ω. Table 1 shows the physical properties of the obtained stretched film.

Comparative Example 4 An unstretched multilayer sheet was prepared in the same manner as in Example 1 except that the mixing ratio of polyvinylidene fluoride and acetylene black was changed as shown in Table 1. Although simultaneous biaxial stretching of the unstretched multilayer sheet was attempted, it was broken immediately after stretching, and a stretched film was not obtained.

[0050]

[Table 1]

[0051]

According to the present invention, there is provided a conductive stretched multilayer film which is excellent in surface conductivity, can be formed into a thin film, and has good mechanical strength, and a method for producing the same. The conductive stretched multilayer film of the present invention can be used in a wide range of fields as a static elimination film, an antistatic film, a conductive film, and the like. In addition, the conductive stretched multilayer film of the present invention can form a surface layer of various molded articles and components requiring surface conductivity.

Continued on the front page F-term (reference) 2H071 DA00 DA07 DA13 EA00 4F100 AA37B AA37C AA37H AK17A AK17B AK17C AK19A AK19B AK19C BA02 BA03 BA06 BA10B BA10C BA16 DE01B DE01C DE01H EA061 GB03 EJ01G02J01 EJ013 YY00B YY00C 4J002 BD121 BD131 BD141 BD151 BD161 DA026 DA036 DA066 DE046 FD116 GF00 GQ00 GQ02 5G301 DA18 DA47 DD05 DD08 DE10

Claims (9)

[Claims] 1. A stretched multilayer film comprising a fluororesin composition layer (A) containing a conductive powder in a ratio of 12 to 35% by volume disposed on one or both sides of a fluororesin layer (B). A conductive stretched multilayer film in which the surface resistivity of the fluororesin composition layer (A) is 1 × 10 ¹⁰ Ω or less. 2. The conductive stretched multilayer film according to claim 1, wherein the fluororesin constituting the fluororesin composition layer (A) and the fluororesin layer (B) are both polyvinylidene fluoride resins. 3. The conductive stretched multilayer film according to claim 1, wherein the conductive powder is conductive carbon black. 4. The conductive stretched multilayer film according to claim 2, wherein the stretched multilayer film has a degree of orientation in at least one uniaxial direction of 60% or more. 5. The stretched multilayer film has a thickness of 5 to 150 μm.
The conductive stretched multilayer film according to any one of claims 1 to 4, wherein m is m. 6. The ratio of the thickness of the fluororesin composition layer (A) is from 1 to 9 based on the total thickness of the stretched multilayer film.
The conductive stretched multilayer film according to any one of claims 1 to 5, which is in a range of 5%. 7. The conductive stretched multilayer film according to claim 1, which is a charge control member mounted on an electrophotographic image forming apparatus. 8. An unstretched multilayer sheet in which a fluororesin composition layer (A1) containing a conductive powder in a ratio of 12 to 35% by volume is laminated on one or both sides of a fluororesin layer (B1). And then, stretching the unstretched multilayer sheet at least uniaxially. 9. The production of a conductive stretched multilayer film according to claim 8, wherein the fluororesin constituting the fluororesin composition layer (A1) and the fluororesin layer (B1) are both polyvinylidene fluoride resins. Method.