JP3018906B2 - Semiconductive polymer elastic member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging member having an antistatic function, a shock absorbing member, and a semiconductive polymer elastic member used in electronic processes and the like.

[0002]

2. Description of the Related Art In recent years, with the progress of electronic technology, there has been an increasing demand for antistatic techniques for packaging materials and shock absorbers for protecting electronic components. In addition, with the advance of electrophotographic technology, a semiconductive elastic roller has attracted attention as a contact charging member for a transfer material and toner of a dry electrophotographic apparatus, and is used for a developing roller, a copying roller, and the like. The semiconductive elastic roller has an advantage that a required charge amount can be given to a transfer material or the like at a low power supply voltage as compared with a conventionally used corotron charger. For the elastic roller used for these purposes, a polymer elastomer such as rubber or urethane or a polymer foam material is usually used, and a roller obtained by blending a conductive material such as carbon black with the desired conductivity is provided. Had been used.

The semiconductive member used for such an application has not only a predetermined electric resistance value, but also a small variation in the electric resistance position, a small dependence of the electric resistance on the applied voltage, and a continuous energization. It is necessary that the fluctuation range of the electric resistance at the time of performing the operation is small.

[0004]

The problem of the present invention is that 1 × 10 ⁵ to 1 × necessary for the electrophotographic process by mixing carbon black or the like.
It is difficult to produce a constant resistance in a medium resistance region of 10 ¹⁰ [Ωcm], and a predetermined resistance is obtained by mixing a filler such as metal or metal oxide powder, whisker and / or carbon black. A polymer member such as a polymer elastomer or a polymer foam adjusted to a value has a problem that the position variation of the electric resistance is large and the measured voltage dependence of the electric resistance is large.

Therefore, a roller having a constant resistance in a medium resistance region is manufactured by mixing an ion conductive substance such as sodium perchlorate. However, if such a roller is continuously operated for a long time in an energized state, the resistance gradually increases, and when used for electrophotography, there is a problem that an image defect is caused. Accordingly, an object of the present invention is to solve the drawbacks of the conventional semiconductive elastic material and to provide a semiconductive elastic member having the above-mentioned various characteristics.

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, a polymer material as a base material and an organic ionic material (here,
Excludes ammonium perchlorate. ), The electrical resistance is 1 × 10 ⁵ to 1 × 10 ¹⁰ [Ωcm] at a measurement voltage of 1000 V at a temperature of 28 ° C. and a relative humidity of 85%, and when the current is continuously supplied for 8 hours under the same conditions. The electric resistance is less than 5 times the initial resistance, and the electric resistance at a measurement voltage of 10 V under the same temperature / humidity condition is a measurement voltage of 5000 V
If it is a semiconductive polymer elastic member whose electric resistance is not more than twice the electric resistance of the electrophotographic photosensitive member such as a developing roller or a copying roller, even if it is energized for a long time, its performance will not decrease due to an increase or fluctuation in the resistance value. The present inventors have found that they can be suitably used as a conductive roller, and have completed the present invention.

Accordingly, the present invention comprises a polymer material as a base material, to which an organic ionic material (excluding ammonium perchlorate) is added as a conductive agent. Measurement voltage 1 at ℃, relative humidity 85%
1 × 10 ⁵ to 1 × 10 ¹⁰ [Ωcm] at 000 V,
In addition, the electric resistance when continuously energized for 8 hours under the same conditions is less than 5 times the initial resistance, and the electric resistance at a measurement voltage of 10 V under the same temperature / humidity condition is not more than twice the electric resistance at a measurement voltage of 5000 V. An object of the present invention is to provide a semiconductive polymer elastic member.

Hereinafter, the present invention will be described in more detail. As described above, the semiconductive polymer elastic member according to the present invention has an electric resistance of 1 × 10 ⁵ to 1 × 10 ¹⁰ [Ω at a measurement voltage of 1000 V at a temperature of 28 ° C. and a relative humidity of 85%.
cm], and the electrical resistance when continuously energized for 8 hours under the same conditions is less than 5 times the initial resistance, and the electrical resistance at a measurement voltage of 10 V under the same temperature / humidity condition is an electrical resistance at a measurement voltage of 5000 V Is twice or less.

The polymer used in the present invention includes:
It can be obtained by a general method in which a polyhydroxyl compound and a polyisocyanate compound are mixed and cured by heating. In this case, as the polyhydroxyl compound, polyols used in the production of general flexible polyurethane foams and elastomers, that is, polyether polyols having terminal polyhydroxyl groups, polyester polyols, and polyether polyester polyols which are copolymers of both are used. In addition, general polyols such as a so-called polymer polyol obtained by polymerizing an ethylenically unsaturated monomer in a polyol can be used.

It is preferable to use mainly a hydrophilic urethane base material containing hydrophilic polyols such as polyether polyol, polyester polyol and polytetramethylene ether glycol as constituents. Here, if a hydrophobic polyol such as polyisoprene polyol, polybutadiene polyol or hydrogenated polybutadiene polyol is mainly used, it is difficult to impart conductivity satisfying the requirements.

Examples of the polyisocyanate compound include polyisocyanates which are also used for producing general flexible polyurethane foams and elastomers, that is, tolylene diisocyanate (TDI), crude TDI, 4,4-diphenylmethane diisocyanate (MDI), crude MD
I, aliphatic polyisocyanates having 2 to 18 carbon atoms, alicyclic polyisocyanates having 4 to 15 carbon atoms, and mixtures and modified products of these polyisocyanates, such as prepolymers obtained by partially reacting with polyols Is used.

The organic ionic substance used as a conductive agent in the present invention, specifically, as a cationic surfactant, lauryl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride,
Octadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, modified aliphatic dimethylethylammonium ethosulfate, etc., as amphoteric surfactants, lauryl betaine, stearyl betaine, dimethylalkyl lauryl betaine, etc., and borofluoride Examples thereof include quaternary ammonium salts such as tetrabutylammonium, tetraethylammonium borofluoride, and tetrabutylammonium chloride. Among these, lauryl trimethyl ammonium chloride,
Cationic surfactants such as stearyltrimethylammonium chloride, octadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, modified aliphatic dimethylethylammonium ethosulfate, and quaternary ammonium salts such as tetrabutylammonium borofluoride Is particularly preferably used. However, ammonium perchlorate salts such as tetraethylammonium perchlorate and tetrabutylammonium perchlorate are not used as the organic ionic substance.

[0013] By mixing the above-mentioned various organic ionic substances with the above-mentioned base material, the volume resistivity is set to 1 × 10 ⁵ to
It can be adjusted to a medium resistance region of 1 × 10 ¹⁰ [Ωcm]. It is also preferable to form these into a foam. The method of foaming is not limited, but a method of mixing and using a foaming agent or a method of mixing bubbles by mechanical stirring is preferably used.

The method for producing urethane is not limited, but may be polyether polyol, polyester polyol, polytetramethylene ether glycol, polyol obtained by addition polymerization of polyethylene oxide or polypropylene oxide to glycerin, ethylene glycol, propanediol, butanediol, and the like. Hydrophilic chain extender and tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate (crude MDI), urethaneimine-modified MD
I, a cross-linking agent such as isophorone diisocyanate, for imparting conductivity, after mixing with a conductive agent such as a quaternary ammonium salt to be added, and a reinforcing agent such as carbon black if necessary, a cross-linking reaction catalyst, A method of curing by heating is preferably used.

The electroconductive roller for electrophotography, which is a main field of application of the present invention, is suitably used as a roller for development, transfer, etc., but is not limited to these applications. Any member can be applied as long as the member can be used. In addition, the form is not limited to the roller shape shown in FIG. 1, and may be, for example, a brush shape, a plate shape, a block shape, or another shape. Normally, the core is plated with iron, or a core such as stainless steel is coated with the conductive material of the present invention, and the outside thereof is further subjected to conductivity and / or semi-conductivity and / or depending on the application.
Or it may be painted with an insulating paint, in short it forms a protective film on the surface of the conductive roller layer depending on the application,
The roller layer can be formed in a plurality of layers. In any case, the semiconductive elastic member of the present invention used for the electrophotographic conductive roller is usually 1 × 10 ⁵ to 1 × 10 ^10.
It shows a stable resistance value in a medium resistance region of [Ωcm].

An example of a transfer device using the present conductive roller will be described. As shown in FIG. 1, a conductive roller 1 having a conductive roller layer 1b formed outside a cored bar 1a is replaced with a photosensitive drum or the like. Of the transfer member (not shown) such as paper, and a voltage is applied between the transfer member 1 and the member to be charged 2 by a power source 3 to thereby charge the member to be charged and the transfer member. A developer such as toner on the member to be charged 2 is transferred to a transfer material by generating an electric field therebetween. When the semiconductive member is incorporated in an electrophotographic apparatus such as a copying machine, it is applied to an electrostatic image developing section, a toner or developer transfer section, and the like.

Here, a predetermined voltage is applied to a urethane conductive roller to which an inorganic salt such as lithium perchlorate, sodium perchlorate, or calcium perchlorate is added as a conventionally used ionic conductive material. 3, when the operation is continued while continuously maintaining the same polarity potential, the resistance of the conductive roller increases, and when applying a predetermined current, a considerably high potential is not applied. In some cases, the predetermined current cannot be secured.

Although the mechanism relating to the increase in resistance is not clear, rollers having conductivity by adding salts such as lithium perchlorate, sodium perchlorate, calcium perchlorate and lithium borofluoride have the same polarity. It is considered that, when continuous application is performed, dissociation and polarization of the ionic substance occurs, and it becomes difficult for a current to flow, so that resistance increases.

In fact, as shown in an experimental example to be described later, a voltage of a fixed polarity is applied to a conductive roller using sodium perchlorate as a conductive material, and sodium at the inner portion and the outer portion of the roller whose resistance value has increased is increased. When the amount and the amount of perchloric acid were quantified, compared to a standard sample to which no voltage was applied,
Perchloric acid increased with decreasing sodium in the inner part, while sodium increased in the outer part. From this, electrophoretic polarization of sodium perchlorate due to voltage application was observed.

Lauryl, which is an organic ionic substance (excluding ammonium perchlorate) instead of inorganic salts such as lithium perchlorate, sodium perchlorate and calcium perchlorate as the ion conductive substance. Trimethylammonium chloride, stearyltrimethylammonium chloride, octadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride,
By adding one or more selected from the group consisting of quaternary ammonium salts such as denatured fatty acid / dimethylethylammonium ethosulfate, tetrabutylammonium borofluoride, tetraethylammonium borofluoride, and tetrabutylammonium chloride, the volume is increased. It is possible to obtain a urethane material having a specific resistance of 1 × 10 ⁵ to 1 × 10 ¹⁰ [Ωcm] and a stable resistance even when energized for a long time.

In this case, the molecular weight of the quaternary ammonium salt is preferably 140 or more, more preferably 200 to 600. In this case, it is essentially important to add the above quaternary ammonium salt to the long-term stability of the current flow of the resistor. However, as long as the effect of the present invention is not impaired,
An inorganic salt such as conventionally used lithium perchlorate, sodium perchlorate or calcium perchlorate or carbon black may be used in combination. Here, the hydrophilic polyurethane has a resistance at a temperature of 15 ° C. and a relative humidity of 10% which is 100 times or more the resistance at a temperature of 28 ° C. and a relative humidity of 85% without a conductive agent. Even if an ammonium salt is added, the resistance value is still 20 times or more. Therefore, when inorganic ions such as lithium perchlorate and carbon black are used together, the resistance fluctuation between low temperature and low humidity and high temperature and high humidity can be reduced. . It is also preferable to use a quaternary ammonium salt dissolved in a solvent such as various ethers and alcohols.

There is no limitation on the negative ion species forming the quaternary ammonium salt, but Cl ⁻ , F ⁻ , Br ⁻ , I ⁻ , Cl
O ₄ ⁻ , BF ₄ ⁻ , SO ₄ ²⁻ , and C ₂ H ₅ —SO ₄ ⁻ are used, and C ₄ is particularly preferable in terms of solubility in hydrophilic urethane.
_{^{lO 4 -, BF 4 -,}} C 2 H 5 -SO 4 - is preferably used.

Hereinafter, a conductive roller which is an embodiment of the semiconductive elastic member of the present invention will be described. However, the present invention is not limited to the following embodiment. Prior to Examples and Comparative Examples, an experimental example on a mechanism of increasing the resistance of the conductive member due to voltage application will be described.

[Experimental Example] Polarization transfer of an ionic substance was quantified by ion chromatography. The sample used was 20 parts by weight of TDI-100 (Sumitomo Bayer Urethane Co., Ltd., Sumidur T-100) and polyether polyol (Exenol 828, manufactured by Asahi Glass Co., Ltd.) having a molecular weight of 5000 by adding propylene oxide and ethylene oxide to glycerin. ) 100 parts by weight, 1,3-butanediol 6.3 parts by weight, silicone-based surfactant (SF2935F, manufactured by Nippon Yunika)
Parts by weight, 0.03 parts by weight of dibutyltin dilaurate, and 0.02 parts by weight of a 33% solution of sodium perchlorate in diethylene glycol monomethyl ester were mixed in a Modmix.
The mixture was foamed with a foaming injection machine manufactured by the company, and the mixture was poured into a mold having a roller cored bar arranged at the center and cured at 80 ° C. for 12 hours. After curing, buffing was performed to a predetermined size to obtain a conductive roller. The diameter of the conductive roller was 16.5 mm.

Next, a voltage of +1000 V was applied to the core metal of the conductive roller for 8 hours using a Model 610C power supply manufactured by Treck with an aluminum drum having a diameter of 30 mm as an opposite electrode. The environment at the time of voltage application is temperature 28 ° C,
Humidity was 85%. The initial resistance was about 2 × 10 ⁷ Ω, but increased with the application of voltage, and after 8 hours, about 1 × 1 Ω
Up to about 0 ⁸ Ω resistance value has increased.

A sample (hereinafter referred to as an inside) 0.5 g of a portion of the roller from the metal core cut to a thickness of 2 mm and a sample (hereinafter referred to as an outside) 0 mm of a surface portion of the roller cut to a thickness of 2 mm 0.5 g and 0.5 g of a standard sample to which no voltage was applied were immersed and extracted in 1.4 ml of distilled water for 24 hours, respectively, and quantified by ion chromatography. The equipment used was Toyo Soda CCPD pump, Waters U-6.
The flow rate was 3 ml / min using a K injector, Wescan electrical conductivity detector, Shimadzu IC-A1 (for anion analysis) or IC-G1 (for cation analysis) column. The mobile phase was phthalate buffer (4 mM, pH
6.2), a nitric acid aqueous solution (2 mM) was used for cation analysis. The results are shown in Table 1, and the results support the hypothesis that the resistance increases due to the polarization of the ionic substance.

[0027]

[Table 1]

Example 1 The formulation shown in the above experimental example, ie, TDI-100
0 parts by weight, 100 parts by weight of a polyether polyol having a molecular weight of 5,000 by adding propylene oxide and ethylene oxide to glycerin, 6.3 parts by weight of 1,4-butanediol, a silicone-based surfactant (SF2935F, manufactured by Nippon Yunika) ) 4 parts by weight, 0.03 parts by weight of dibutyltin dilaurate, and modified aliphatic dimethylethylammonium ethosulfate (in place of 0.02 parts by weight of a 33% solution of sodium perchlorate in diethylene monomethyl ester in the above experimental examples) H _{[CH 2] 4-20
C 2 H 5 N [CH 3} ] 2 C 2 H 5 SO 4, molecular weight 466
550) 0.5 parts by weight of the mixture was foamed with a foam mixer made by Monomix Co., Ltd., and the mixture was poured into a mold having a roller cored bar arranged in the center and cured at 80 ° C. for 12 hours. After curing, the conductive roller was buffed to a predetermined size to obtain a conductive roller.

In the apparatus shown in FIG. 1, the above roller having a diameter of 16.5 mm is used as one semiconductive elastic material member.
Was used such that an aluminum drum having a diameter of 30 mm was used, and the rotation speed of the aluminum drum was set to 17 rpm.
Next, as a constant current generating power supply 3, Mod manufactured by Treck
el 610C, and a constant current of 2 μA was applied. FIG. 2 is a graph in which the voltage value at this time is observed, the roller resistance is determined from the conversion to the current value, and the roller resistance is plotted against the energization time. As a result, almost no increase in the resistance of the conductive roller was observed, indicating that good continuous operation was possible.

[Comparative Example 1] Sodium perchlorate (NaClO ₄ , molecular weight 122.5) was used in place of the modified aliphatic dimethylethylammonium ethosulfate 0.5 part by weight as the ion conductive material to be blended.
An experiment was conducted in the same manner as in Example 1 except that the concentration of the 33% diethylene glycol monomethyl ester solution was changed to 0.02 parts by weight.
It was shown to. In this case, the initial resistance was about 2 × 10 ⁷ Ω and increased with the application of the voltage.
^The resistance value has risen to ⁸ Ω or more. As a result, in order to secure a current amount equal to the initial value, a voltage five times the initial value must be applied.

Example 2 Lauryltrimethylammonium chloride (C ₁₂ H) was used in place of 0.5 parts by weight of modified aliphatic dimethylethylammonium ethosulfate as the ion conductive material to be blended.
₂₅ N [CH ₃ ] ₃ Cl, molecular weight 249.5) 20%
An experiment was conducted in the same manner as in Example 1 except that the isopropanol solution was changed to 1 part by weight, and FIG. 4 shows changes in the resistance of the conductive roller with respect to time. As a result, almost no increase in the resistance of the conductive roller was observed, indicating that good continuous operation was possible.

Example 3 Same as Example 1 except that the ion conductive material to be blended was changed to 0.5 parts by weight of modified aliphatic dimethylethylammonium ethosulfate and 0.2 parts by weight of tetrabutylammonium borofluoride. FIG. 5 shows a change in the resistance of the conductive roller with respect to time. There was almost no increase in the resistance of the conductive roller, indicating that good continuous operation was possible.

Comparative Example 2 An experiment was carried out in the same manner as in Example 1 except that the ionic conductivity imparting agent was changed to 0.5 parts by weight of modified aliphatic dimethylethylammonium ethosulfate and 2 parts by weight of acetylene black. Was. When the voltage fluctuation when a constant current of 2 μA was supplied from the power supply 3 was measured by the apparatus shown in FIG. 1, the voltage was periodically changed from 50 V to 4 with the rotation of the roller.
It fluctuated between 00V. Such a phenomenon is not observed in the examples.

Example 4 An ionic conductivity-imparting agent to be blended was added to 0.5 parts by weight of modified aliphatic dimethylethylammonium ethosulfate, and sodium perchlorate (NaClO ₄ , molecular weight 122.
The experiment was carried out in the same manner as in Example 1 except that 0.01% by weight of the 33% diethylene glycol monomethyl ester solution of 5) was used. 2 μA from 3 power supplies by the device shown in FIG.
When the voltage fluctuation when the constant current was supplied was measured, the phenomenon that the voltage periodically fluctuated with the rotation of the roller was not observed, and the resistance stability during continuous energization was also good.

Example 5 Example 1 was repeated except that the ion conductive material to be blended was added to 0.5 parts by weight of modified aliphatic dimethylethylammonium ethosulfate and further to 4 parts by weight of oil furnace carbon black (HAF grade). An experiment was performed in the same manner as in the above. FIG.
When the voltage fluctuation when a constant current of 2 μA was supplied from the power supply 3 was measured by the apparatus shown in the above, no phenomenon that the voltage periodically fluctuated with the rotation of the roller was observed, and the resistance stability during continuous energization was also observed. It was good.

Comparative Example 3 18.2 parts by weight of 2,4-tolylene diisocyanate and hydrogenated 1,2-polybutadiene polyol (molecular weight: 20
00) 100 parts by weight, 6.3 parts by weight of 1,4-butanediol, a silicone-based surfactant (SF, manufactured by Nippon Yunika)
2935F) 4 parts by weight, dibutyltin dilaurate 0.
01 parts by weight, modified aliphatic dimethylethyl ammonium ethosulfate _{(H [CH 2] 14-20 C} 2 H 5 N
_{[CH 3] 2 C 2 H} 5 SO 4, molecular weight 466 to 550)
0.5 parts by weight of the mixture was foamed with a foaming and pouring machine manufactured by Monomix Co., Ltd., and the mixture was poured into a mold having a roller cored bar disposed at the center and cured at 80 ° C. for 12 hours. After curing, it was buffed to a predetermined size to obtain an elastic roller. The resistance of this roller was 2 × 10 ¹² Ω, and no conductivity could be imparted.

Example 6 As an organic ionic conductive agent, lauryl trimethyl ammonium chloride (C ₁₂ H) was used in place of 0.5 parts by weight of modified aliphatic dimethyl ethyl ammonium ethosulfate.
₂₅ N [CH ₃ ] ₃ Cl, molecular weight 249.5) 20%
A conductive roller was manufactured in the same manner as in Example 1 except that the isopropanol solution was changed to 1 part by weight, and an experiment was performed in the same manner as in Example 3 to examine a change in the resistance of the conductive roller with respect to time.

As a result, the initial resistance is about 2.8 × 10 ⁷ Ω
After 8 hours, the resistance value was about 4.3 × 10 ⁷ . As a result, there was almost no increase in the resistance of the conductive roller, and it was confirmed that good continuous operation was possible.

[0039]

As described above, according to the conductive roller using the material of the present invention, a roller having no increase in resistance even when used continuously can be obtained. A good image can be stably obtained even when used for a long time.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a charging system using a semiconductive elastic member of the present invention.

FIG. 2 is a graph showing a change in resistance value due to continuous use of a conductive roller manufactured using the semiconductive elastic member according to Example 1.

FIG. 3 is a graph showing a change in resistance value due to continuous use of a conductive roller of Comparative Example 1 manufactured using a conventional conductive material.

FIG. 4 is a graph showing a change in resistance value due to continuous use of a conductive roller manufactured using a semiconductive elastic member according to Example 2.

FIG. 5 is a graph showing a change in resistance value due to continuous use of a conductive roller manufactured using a semiconductive elastic member according to Example 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Charging roller (conductive member) 1a Core 1b Conductive roller layer (main body) 2 Photoconductor roll (charged body) 3 Power supply

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-4-232980 (JP, A) JP-A-6-313422 (JP, A) JP-A-6-248174 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C08L 1/00-101/14 F16C 13/00 G03G 15/08-15/16

Claims (6)

(57) [Claims] An organic ionic substance (excluding an ammonium perchlorate salt) is added as a conductive agent to a polymer material as a base material.
1 × 10 at a measurement voltage of 1000 V at a relative humidity of 85%
⁵ to 1 × 10 ¹⁰ [Ωcm], and the electrical resistance when continuously energized for 8 hours under the same conditions is less than 5 times the initial resistance, and the electrical resistance at a measurement voltage of 10 V under the same temperature / humidity conditions , The electric resistance at 5000 V
A semi-conductive polymer elastic member, wherein the length is not more than twice. 2. The semiconductive polymer elastic member according to claim 1, wherein the polymer substance is polyurethane. 3. The semiconductive polymer elastic member according to claim 2, wherein the polyurethane is hydrophilic. 4. The semiconductive polymer elastic member according to claim 1, wherein the organic ionic substance is a cationic and / or zwitterionic surfactant. 5. The semiconductive polymer elastic member according to claim 1, wherein an inorganic ionic substance and / or carbon black is added to the polyurethane in addition to the organic ionic substance. 6. The semiconductive polymer elastic member according to claim 1, which is an elastic roller for an electrophotographic process.