JPH11181270A - Semiconducting thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition having volume resistivity of semiconducting region in which the change due to moisture is small, scarcely exhibiting corrosive property to metal and useful as a static charge member, etc., for electrophotographic type image forming apparatus by including a polyalkylene oxide and a specific alkali metal salt, etc., at a specific ratio. SOLUTION: This thermoplastic resin composition normally comprises (A) 2-99.9 wt.% polyalkylene oxide (e.g. polyethylene oxide) having 1,000-10,000,000 weight-average molecular weight, (B) 0-97.9 wt.% other thermoplastic resin, preferably vinylidene fluoride-based resin (e.g. polyvinylidene fluoride) and (C) 0.1-5 wt.% alkali metal salt having <=1 g/L solubility to water at 23 deg.C, preferably cesium perfluoroalkylsulfonate (e.g. cesium perfluorooctanesulfonate). The composition is useful for antistatic films for packaging electronic parts and dust absorption preventing members for various OA equipment, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductive resin composition, and more particularly to a semiconductive resin composition having a volume resistivity of a semiconductive region, a small change in volume resistivity due to humidity, and
The present invention relates to a semiconductive resin composition having no metal corrosion property. The semiconductive resin composition of the present invention is used in fields where semiconductivity and antistatic properties are required, for example, antistatic films for packaging electronic components, dust adsorption preventing members used for various OA equipment, and the like.
It can be suitably used for a charge removing member, a conductive member, and the like. A semiconductive thermoplastic resin composition has a volume resistivity of 1
It refers to a thermoplastic resin composition of about 0 ⁵ to 10 ¹² Ωcm.

[0002]

2. Description of the Related Art Polyalkylene oxides such as polyethylene oxide are widely known to be good conductors of ions because they have high water absorption and are good solvents for electrolytes. Utilizing this property, an antistatic resin composition in which a polyalkylene oxide and a specific metal salt are added to an insulating resin such as polystyrene or polyester has been proposed (for example, JP-A-53-149246). No.
JP-A-2-233743, etc.). It is known that a resin composition obtained by adding a lithium salt to polyethylene oxide has excellent ionic conductivity (for example, JP-A-4-323260, JP-A-7-65860, etc.).

Conventionally, electrolytes used in combination with polyalkylene oxides include the alkali metal or alkaline earth metal sulfonates, carboxylates, alkylsulfonates, alkylcarboxylates, and halogens described above. And the like. Resin compositions in which these electrolytes are blended with polyalkylene oxide, or resin compositions in which these electrolytes are blended with other thermoplastic resins together with polyalkylene oxide, reduce the volume resistivity to a semiconductive region. Can be. However,
Resin compositions containing these electrolytes, due to the high water absorption of polyalkylene oxide,
There is a disadvantage that the volume resistivity greatly changes due to a change in environment such as humidity. In addition, when an electrolyte that is easily dissolved in water is used, a molded article made of a resin composition containing the electrolyte easily bleeds out to the surface of the molded article, which impairs the appearance of the molded article and mechanical strength. And the volume resistivity fluctuates. Furthermore, when a lithium salt or the like bleeds out, there is a problem in that the bleed-out material corrodes the contacted metal.

On the other hand, in the field of electric and electronic equipment, a resin material capable of precisely controlling static electricity is required. For example, in an image forming apparatus such as an electrophotographic copying machine or an electrostatic recording apparatus, at least a surface layer of a charging member such as a charging roll or a charging belt, a developing roll, a transfer roll, or a transfer belt is semiconductive. However, at the same time, it is required that the change in volume resistivity due to humidity be small. If the volume resistivity of these charging members changes significantly due to changes in humidity, it becomes difficult to precisely control static electricity in various processes such as charging, development, and transfer.
High-quality images cannot be stably formed.

[0005] In addition, the exterior materials and parts of various electric and electronic devices absorb dust and toner due to static electricity.
It may damage the appearance or cause a failure. Films, containers and device parts for packaging electronic parts such as ICs and LSIs, if dust is absorbed by static electricity, will impair the quality of the electronic parts. Therefore, resin materials used in these applications are required to have a volume resistivity of a semiconductive region in order to prevent static charge. In addition to it,
In the resin materials used in these applications, various additives blended to lower the volume resistivity bleed out, impairing the appearance, sticking the surface, reducing the mechanical strength, It is required not to contaminate an article to be packaged or corrode a metal member or metal product that comes into contact. However, as described above, a conventional resin composition based on a polyalkylene oxide and an electrolyte cannot satisfy these required performances.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductive thermoplastic resin composition based on a polyalkylene oxide and an alkali metal salt, which has a semiconductive region of 10 ⁵ to 10 ¹² Ωcm. The volume resistivity can be stably and accurately reproduced within the range of, the change in volume resistivity due to environmental humidity fluctuation is small, and the bleed out of alkali metal salts and the resulting metal corrosiveness are small. An object of the present invention is to provide a semiconductive thermoplastic resin composition. The present inventors have conducted intensive studies to overcome the problems of the prior art, and as a result, by adding an alkali metal salt having low solubility in water to polyalkylene oxide, the volume resistivity of the semiconductive region was reduced. It has been found that a semiconductive thermoplastic resin composition which has a small change in volume resistivity due to humidity and has low metal corrosiveness due to bleed out of an alkali metal salt can be obtained. The resin composition may contain a thermoplastic resin other than the polyalkylene oxide. The present invention has been completed based on these findings.

[0007]

Thus, according to the present invention, (A) 2-99.9% by weight of a polyalkylene oxide, (B) 0-97.9% by weight of another thermoplastic resin, and (C) (3) A semiconductive thermoplastic resin composition containing 0.1 to 5% by weight of an alkali metal salt having a solubility in water at 23 ° C of 1 g / L or less. According to the present invention, the following preferred embodiments are provided. (1) The above-mentioned semiconductive thermoplastic resin composition wherein the alkali metal salt (C) is a cesium salt. (2) The above-mentioned semiconductive thermoplastic resin composition, wherein the cesium salt is a cesium perfluoroalkylsulfonic acid salt. (3) The semiconductive thermoplastic resin composition described above, wherein the thermoplastic resin (B) is a vinylidene fluoride resin. (4) The semiconductive thermoplastic resin composition for a charging member in an electrophotographic image forming apparatus.

[0008]

DETAILED DESCRIPTION OF THE INVENTION (Polyalkylene oxide) The polyalkylene oxide used in the present invention usually has a weight average molecular weight of 1,000 to 10,000.
Those in the range of 0000 can be used. Further, the weight average molecular weight is 1,000 to 10,000.
A cross-linked polyalkylene oxide obtained by cross-linking a polyalkylene oxide having a molecular weight in the range of 0.000 by an appropriate method can also be used. Examples of the polyalkylene oxide used in the present invention include polymers obtained by polymerizing one or more alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, styrene oxide, and epichlorohydrin. The method for polymerizing the alkylene oxide and the method for crosslinking the polyalkylene oxide are not particularly limited, and known methods can be used. A commercially available polyalkylene oxide or a crosslinked polyalkylene oxide may be used. The blending ratio of the polyalkylene oxide is 2 to 99.9% by weight, preferably 5 to 99.8% by weight, and more preferably 8 to 99.5% by weight, based on the total amount of the semiconductive thermoplastic resin composition. %. If the blending ratio of the polyalkylene oxide is too small, sufficient conductivity cannot be imparted. If the blending ratio is too large, the expression of conductivity becomes insufficient.

(Alkali Metal Salt) The alkali metal salt used in the present invention has a solubility in water at 23 ° C. of 1
g / L or less, preferably 0.6 g / L or less, more preferably 0.3 g / L or less. Since polyalkylene oxide has high water absorption, the water content fluctuates due to changes in environmental humidity. When the solubility of the alkali metal salt in water is large, the change in the volume resistivity of the resin composition becomes large depending on the water content of the polyalkylene oxide. On the other hand, if the solubility of the alkali metal salt in water is too high, bleed-out is liable to occur and metal corrosivity is liable to occur. 23 of the alkali metal salt used in the present invention
There is no lower limit to the solubility in water at 23.degree. C., and the solubility in water at 23.degree.

Examples of such alkali metal salts include alkali metal alkylsulfonates, alkylcarboxylates, alkylphosphates, perfluoroalkylsulfonates, etc., which have a solubility in water at 23 ° C. It is selected from those of 1 g / L or less. Examples of the alkali metal include lithium, sodium, potassium, and cesium. Among the alkali metal salts, lithium salts and cesium salts having low ionization energy are preferable, and cesium salts are particularly preferable. An alkali metal salt having a lower ionization energy tends to have a greater conductivity-imparting effect.

Further, as the alkali metal salt, a perfluoroalkyl sulfonate is preferable, and cesium perfluoroalkyl sulfonate is particularly preferable. The number of carbon atoms of the perfluoroalkyl group in the perfluoroalkyl sulfonate is usually 5 to 20, preferably 5 to 1
5, more preferably 6 to 8. If the number of carbon atoms in the perfluoroalkyl group is too small, the perfluoroalkyl sulfonate easily bleeds out of the resin composition, and the metal corrosivity also increases. If the number of carbon atoms in the perfluoroalkyl group is too large, the effect of imparting conductivity is reduced. The compounding ratio of the alkali metal salt is 0.1 to 5% by weight, preferably 0.2 to 5% by weight, more preferably 0.3 to 4% by weight, based on the total amount of the semiconductive thermoplastic resin composition. %. If the blending ratio of the alkali metal salt is too small, the expression of conductivity becomes insufficient. If the blending ratio is too large, the alkali metal salt undissolved in the polyalkylene oxide causes cloudiness of the resin composition.

(Other Thermoplastic Resins) Other thermoplastic resins other than the polyalkylene oxide used in the present invention are not particularly limited, and include, for example, fluororesins, polyamides, polyvinyl chloride, polystyrene, polyesters and the like. be able to. These other thermoplastic resins can be used for modifying a resin composition mainly composed of polyalkylene oxide, but a resin composition mainly composed of another thermoplastic resin and provided with semiconductivity. It can also be used to get things. Therefore, the other thermoplastic resin can be used in any mixing ratio within the range of 0 to 97.9% by weight based on the total amount of the semiconductive thermoplastic resin composition.

[0013] Among other thermoplastic resins, a fluororesin is preferred from the viewpoint of the effect of imparting conductivity and the application. As the fluororesin, for example, polyvinyl fluoride (PV
F), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA), ethylene-tetra Examples thereof include fluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), and ethylene-chlorotrifluoroethylene copolymer (ECTFE). These fluororesins can be used alone or in combination of two or more.

Among these fluororesins, vinylidene fluoride resins such as PVDF are particularly preferred from the viewpoints of moldability and mechanical properties. Examples of the vinylidene fluoride resin include, in addition to PVDF, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, and the like. A vinylidene fluoride copolymer having vinylidene fluoride as a main constituent unit can be given. These vinylidene fluoride resins can be used alone or in combination.
More than one species can be used in combination.

When a resin composition containing a vinylidene fluoride resin is used for an application such as a charging member in an electrophotographic image forming apparatus, the mixing ratio of the vinylidene fluoride resin is determined by using a semiconductive thermoplastic resin. Usually from 70 to 97.9% by weight, preferably from 80 to 97.9% by weight, based on the total amount of the composition.
94.8% by weight, more preferably 85 to 91.7% by weight
It is. Even if the blending ratio of the vinylidene fluoride-based resin is such a large amount, the polyalkylene oxide and the alkali metal salt are used in combination to have a desired volume resistivity in the semiconductive region, and It is possible to obtain a semiconductive thermoplastic resin composition in which the change in resistivity due to humidity is small.

(Other Additives) The semiconductive thermoplastic resin composition of the present invention may contain other additives, if desired. As other additives, for example, silica, alumina, kaolin, talc, mica, ferrite, potassium titanate, titanium oxide, zinc oxide,
Aluminum hydroxide, magnesium hydroxide, calcium carbonate, nickel carbonate, calcium sulfate, barium sulfate,
Granular or powdery fillers such as glass powder, quartz powder, metal powder, carbon black, graphite, inorganic pigments, and organic metal salts; carbon fiber, glass fiber, asbestos fiber, silica fiber, alumina fiber, zirconia fiber, boron nitride fiber,
Fibrous fillers such as silicon nitride fibers, boron fibers, and potassium titanate fibers; These fillers can be appropriately compounded according to the purpose of use within a range not to impair the purpose of the present invention. In addition, the semiconductive thermoplastic resin composition of the present invention includes, for example, an antioxidant, a lubricant, a plasticizer, an organic pigment, an inorganic pigment, an ultraviolet absorber, a surfactant, an inorganic acid, an organic acid, and a pH adjuster. General-purpose additives such as a crosslinking agent and a coupling agent can be appropriately compounded within a range that does not impair the object of the present invention.

(Semiconductive Thermoplastic Resin Composition) The method for preparing the semiconductive thermoplastic resin composition of the present invention is not particularly limited, and suitable methods include, for example, (1) powder or pellets. Mixing a resin component in a powder form, a powdered alkali metal salt, and optionally other additives with a mixer mixer or the like; (2) mixing each component with a mixer, and then subjecting the mixture to a melt extrusion method Pelletizing method,
(3) Each component is dissolved or dispersed in water or a mixed solvent of water and a water-soluble solvent (eg, acetone, alcohol, etc.), mixed with a mixer such as a mixer, and then dried (including drying under reduced pressure). And a method of melt-extruding the obtained dried product into pellets.

The semiconductive thermoplastic resin composition of the present invention comprises:
Press molding, melt extrusion, injection molding, solution casting,
By various molding methods such as a coating method, it can be molded into various molded articles or coated molded articles. Alternatively, a masterbatch in which a polyalkylene oxide contains a high concentration of an alkali metal salt may be prepared, and a molding process may be performed by diluting the polyalkylene oxide with a resin component to a necessary concentration during molding. The semiconductive thermoplastic resin composition of the present invention is suitably used for an antistatic film for packaging electronic components, a dust adsorption preventing member used for various OA devices, a static elimination member, a conductive member, and the like. The molding method and shape of the semiconductive thermoplastic resin composition of the present invention are not particularly limited, and are formed into a sheet or a thread by a known molding method such as injection molding or melt extrusion. It is possible. The semiconductive thermoplastic resin composition of the present invention may be used alone, or may be used as a laminated sheet by being combined with another resin layer or the like as necessary.

[0019]

The present invention will be described below more specifically with reference to examples and comparative examples. In addition, the measuring method of physical properties is as follows. (1) Thickness measurement The thickness of the molded product was measured with a dial gauge thickness meter (trade name “DG-911” manufactured by Ono Sokki Co., Ltd.). The arithmetic average of the measured values of the 20 sheet samples was determined and defined as the thickness of the molded product. (2) Volume resistivity The volume resistivity was measured according to JIS K6911. More specifically, a sample is sandwiched between a resiliency cell having a ring-shaped electrode [Hewlett Packard Co., Ltd., product name "HP16008B"] with a load of 7 kgf, and a voltage of 10 V is applied between the inner electrode and the counter electrode. Was applied in the thickness direction for one minute, and the volume resistivity was measured. The outer diameter of the inner electrode is 26.0 mm, the inner diameter of the outer counter electrode is 38.0 mm, and the outer diameter of the counter electrode is 40.0 mm. The volume resistivity was determined by a measuring device (trade name “HP4339A High Resistance Meter”) manufactured by Hewlett-Packard Co., Ltd. Each sample was kept at 23 ° C. at a relative humidity (RH) of 12%, 50%, and 80% at a constant temperature and humidity [Nagano Kagaku Kikai Seisakusho Co., Ltd., trade name “LH30-13M”]. ) For 24 hours, and then the volume resistivity was measured in a thermo-hygrostat under the same relative humidity and temperature conditions. The arithmetic mean value of the measured values of the 20 sheet samples was determined and defined as the volume resistivity. Further, the ratio (a / b) between the volume resistivity value (a) measured under the 12% RH condition and the volume resistivity value (b) measured under the 80% RH condition was calculated, and the volume due to the change in humidity was calculated. The index was used to indicate the degree of change in resistivity. (3) Metal Corrosion After metal aluminum was formed on the sample surface by the vacuum evaporation method, it was left for one week in an environment of a temperature of 23 ° C. and a relative humidity of 50%, and changes in the aluminum evaporation film were observed.

[Synthesis Example 1] 53.8 g of potassium perfluorooctanesulfonate [trade name “F110”; manufactured by Dainippon Ink and Chemicals, Incorporated; C ₈ F ₁₇ SO ₃ K] is 700 c.
C was dissolved at 50 ° C. in a mixed solution of acetone / water (mixing ratio = 70 cc / 630 cc) to obtain a solution A. On the other hand, 20 g of cesium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 300 cc of water (5
(0 ° C.). The solution A and the solution B were mixed and stirred to precipitate a white precipitate. After removing water-soluble components from this precipitate by filtration, 3000 cc
, And then dried under reduced pressure at 90 ° C to obtain cesium perfluorooctanesulfonate [C ₈ F
₁₇ SO ₃ Cs]. The solubility of this cesium perfluorooctanesulfonate in water at 23 ° C. was 0.2 g / L.

[Example 1] Polyethylene oxide (trade name "Aqua Coke" manufactured by Sumitomo Seika Co., Ltd.) was dried at 60 ° C under reduced pressure for 25 hours. This polyethylene oxide 9
9.5% by weight and 0.5% by weight of cesium perfluorooctanesulfonate prepared in Synthesis Example 1 were rotated using a melt kneader (trade name “Laboplast Mill” manufactured by Toyo Seiki Co., Ltd.). Kneading temperature 150 ° C for 8 minutes at several 50 rpm
To prepare a resin composition. Then, the resin composition was press-molded at 150 ° C. to obtain a sheet having a thickness of 300 μm. Table 1 shows the results.

Example 2 A 300 μm thick sheet was prepared in the same manner as in Example 1 except that the formulation was changed to 96.0% by weight of polyethylene oxide and 4.0% by weight of cesium perfluorooctanesulfonate. I got something.
Table 1 shows the results.

Example 3 10.0 wt% of polyethylene oxide, 89.5 wt% of polyvinylidene fluoride (trade name "KF # 2300", manufactured by Kureha Chemical Industry Co., Ltd.), and perfluorooctane sulfone A sheet having a thickness of 300 μm was obtained in the same manner as in Example 1 except that the composition was changed to 0.5% by weight of cesium acid and the kneading temperature was changed to 180 ° C. Table 1 shows the results.

Comparative Example 1 Instead of cesium perfluorooctanesulfonate, potassium perfluorooctanesulfonate [C ₈ F ₁₇ SO ₃ K; solubility in water at 23 ° C. = 3.7 g / L, Dainippon Ink and Chemicals, Ltd. A sheet having a thickness of 300 μm was obtained in the same manner as in Example 1 except that trade name “MegaFac F110” manufactured by Kogyo Co., Ltd. was used. Table 1 shows the results.

Comparative Example 2 Lithium perfluorooctanesulfonate [C ₈ F ₁₇ SO ₃ Li; solubility in water at 23 ° C. = 50 g / L or more instead of cesium perfluorooctanesulfonate, Dainippon Ink and Chemicals, Ltd. (stock)
The product was manufactured in the same manner as in Example 1 except that the product name “MegaFac F116” was used to obtain a sheet having a thickness of 300 μm. Table 1 shows the results.

[Comparative Example 3] Lithium chloride (solubility in water at 23 ° C = 50 g / L or more) was used instead of cesium perfluorooctanesulfonate.
In the same manner as in Example 1, a sheet having a thickness of 300 μm was obtained. Table 1 shows the results.

Comparative Example 4 The procedure of Example 1 was repeated except that polyethylene oxide was used alone.
A sheet having a thickness of 00 μm was obtained. Table 1 shows the results.

[0028]

[Table 1]

(Footnotes) (1) PEO: polyethylene oxide [Sumitomo Seika Co., Ltd.
(2) PVDF: polyvinylidene fluoride [KF # 230 manufactured by Kureha Chemical Industry Co., Ltd.] (3) PFS-Cs: cesium perfluorooctanesulfonate (Synthesis Example 1) (4) PFS-K: par Potassium fluorooctanesulfonate [MegaFac F manufactured by Dainippon Ink and Chemicals, Inc.
110] (5) PFS-Li: lithium perfluorooctanesulfonate [MegaFac F116 manufactured by Dainippon Ink and Chemicals, Inc.]

As is clear from the results in Table 1, the semiconductive thermoplastic resin compositions of the present invention (Examples 1 to 3) all have a volume resistivity of the semiconductive region, and In addition, a change in volume resistivity due to a change in humidity is small, and there is no metal corrosion. On the other hand, the resin composition using an alkali metal salt having a solubility in water at 23 ° C. of more than 1 g / L (Comparative Examples 1 to 3) has a large change in volume resistivity due to a change in humidity, and lithium. When a salt was used (Comparative Examples 2 and 3), metal corrosion was observed.
When polyethylene oxide is used alone (Comparative Example 4), the volume resistivity cannot be sufficiently reduced.

[0031]

According to the present invention, 10 ⁵ to 10 ¹² Ωcm
Within the range, the specified volume resistivity is reproduced stably and accurately, and the change of the volume resistivity due to the fluctuation of environmental humidity is small,
A semiconductive thermoplastic resin composition having low metal corrosiveness due to bleed out of an alkali metal salt is provided. Since the semiconductive thermoplastic resin composition of the present invention has semiconductivity, it is suitable for use as a charging member such as a charging roll, a charging belt, a developing roll, and a transfer roll in an electrophotographic image forming apparatus. It is. In addition, the semiconductive thermoplastic resin composition of the present invention has an antistatic property,
It can be suitably used as an antistatic film for packaging electronic parts, a dust adsorption preventing member used for various OA equipment, a static elimination member, a conductive member, and the like.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiyoshi Teramoto 18-13, Kamitamari, Tamari-mura, Niigata-gun, Ibaraki Pref.Resin Processing Technology Center, Kureha Chemical Industry Co., Ltd. 18-13 Kamitamari Kureha Chemical Industry Co., Ltd.Resin Processing Technology Center (72) Inventor Hisaaki Terashima 18-13 Kamitamari, Tamari Village, Shinji-gun, Ibaraki Pref.Kureha Chemical Industry Co., Ltd.

Claims (5)

[Claims] (A) polyalkylene oxides 2 to 9
9.9% by weight, (B) 0 to 97.9% by weight of other thermoplastic resin, and (C) solubility in water at 23 ° C. is 1 g / L.
A semiconductive thermoplastic resin composition containing 0.1 to 5% by weight of the following alkali metal salt. 2. The semiconductive thermoplastic resin composition according to claim 1, wherein the alkali metal salt (C) is a cesium salt. 3. The semiconductive thermoplastic resin composition according to claim 2, wherein the cesium salt is a cesium perfluoroalkylsulfonic acid salt. 4. The semiconductive thermoplastic resin composition according to claim 1, wherein the thermoplastic resin (B) is a vinylidene fluoride resin. 5. The semiconductive thermoplastic resin composition according to claim 1, which is used for a charging member in an electrophotographic image forming apparatus.