JP2008274286A - Conductive polymer composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive polymer composition which contains an ionic conductive additive salt, prevents the deposit of the salt, when an electric field is applied, and the increase of resistance, when energized, has excellent resistance to the environmental dependency, temporal change and the like of electric resistance, and has stable electric characteristics. <P>SOLUTION: This conductive polymer composition is characterized by comprising a continuous phase 1' and a non-continuous phase 2', forming a sea-island structure from the continuous phase and the non-continuous phase, and unevenly distributing a salt capable of being dissociated into a cation and an anion in the non-continuous phase, wherein a polymer constituting the non-continuous phase has higher affinity with the salt capable of being dissociated into the cation and the anion than that of a polymer constituting the continuous phase, thereby inhibiting the migration of the salt on the outside of the phase. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a conductive polymer composition, specifically, in an ion conductive polymer composition containing an ion conductive additive salt, preventing salt precipitation when applying an electric field, resistance increase during continuous energization, and the like, Furthermore, it is intended to improve the environmental dependency and change with time of the electrical resistance value and obtain stable electrical characteristics.

  As a method of imparting conductivity to various conductive members, a method using an electronic conductive polymer composition in which a conductive filler such as a metal oxide powder or carbon black is blended in a polymer, urethane, acrylonitrile butadiene rubber ( NBR), and an ion conductive polymer composition such as epichlorohydrin rubber.

  In the case of using an electroconductive polymer composition obtained by blending a conductive filler such as metal oxide powder or carbon black, the electrical conductivity is increased by a slight change in addition amount particularly in the required semiconductive region. Since the resistance value changes abruptly, it becomes very difficult to control. For this reason, since it is difficult to uniformly disperse the conductive filler in the polymer composition, when the roller or belt-like conductive member is used, the resistance value is increased in the circumferential direction and longitudinal direction of the roller and in the plane of the belt. This causes the problem of variation.

  There is a problem that the variation in the electrical resistance value is not only within one product but also between products. Furthermore, the electrical resistance value of the conductive roller or conductive belt obtained from the conductive polymer composition depends on the applied voltage and does not show a certain resistance value. In particular, when carbon black is used as the conductive filler, these tendencies appear remarkably. Such a phenomenon may make mechanical control difficult and increase costs in an image forming process such as charging, development, transfer, and fixing. In addition, when carbon is used, there is a problem that it cannot be colored freely. From the above points, ion conductive members tend to be preferred, and various proposals have been made.

  For example, in Japanese Patent Application Laid-Open No. 10-169641, a semiconductive polymer elastic member in which a quaternary ammonium salt is added to a polymer material as a base material and a resistance value at the time of continuous energization is defined while considering the use environment Has been proposed.

Japanese Patent Laid-Open No. 10-169641

However, in the above-mentioned Japanese Patent Application Laid-Open No. 10-169641, by adding a quaternary ammonium salt having a specific anion, an attempt is made to reduce an increase in resistance value during continuous energization generated in an ion conductive member. However, there is a problem that the environmental dependency (temperature dependency + humidity dependency) of the electrical resistance value cannot be sufficiently reduced. Further, the salt to be mixed may move to the surface and contaminate contact substances such as a photoreceptor.
As described above, in the conductive member, not only the increase in the resistance value during continuous energization is reduced, but also the environmental dependency of the electrical resistance and the problem of migration contamination to contact substances such as salt to be mixed with the photosensitive member. It is also necessary to consider.

  As an ionic conductive conductive agent, there are conductive oligomers and conductive plasticizers containing a polyether structure such as polyethylene oxide (both Mn <10000), but these are not fixed in the polymer composition, There is a problem that causes bleed and bloom. In particular, in the case of conductive rollers, conductive belts, and the like for copying machines and printers, they may migrate to contaminate the photoreceptor, stain the image, and in the worst case, alter and destroy the photoreceptor.

In addition, in systems using metal salts such as lithium perchlorate and ionic conductive addition salts such as various quaternary ammonium salts, the ion from which the salt is dissociated depends on the blending amount and compatibility with the base polymer. However, since it moves toward the electrode during continuous energization, the resistance value may increase considerably over time. In addition, added salt or the like may be deposited on the surface of the conductive member, and depending on the substance, the photoreceptor may be contaminated.
In particular, when a medium composed of a low molecular weight polyether compound or a low molecular weight polar compound is used to disperse the added salt, the salt easily moves in the polymer and the conductivity is improved. Precipitates easily. Furthermore, these low molecular weight media used also migrate to the surface, and when used for a long time, there may be a problem that migration contamination and toner sticking occur, resulting in loss of practicality. When used continuously for a long time as an actual product, these points often cause problems.

  The present invention has been made in view of the above-described problems, reduces the environmental dependency (temperature dependency + humidity dependency) of electrical resistance while maintaining a sufficiently low resistance value, and resistance during continuous energization. It is an object of the present invention to provide an ion conductive polymer composition with a small increase.

In order to solve the above problems, the present invention is a conductive polymer composition comprising an ion conductive additive salt,
It is composed of a continuous phase and one or more discontinuous phases, and the continuous phase and the discontinuous phase have a sea-island structure.
At least one of the discontinuous phases is a first discontinuous phase in which a salt dissociable into a cation and an anion is unevenly distributed, and the polymer constituting the first discontinuous phase constitutes the continuous phase. The present invention provides a conductive polymer composition characterized in that the affinity of the salt capable of dissociating into the cation and the anion is higher than that of the polymer, and the movement of the salt to the outside is suppressed. Yes.

  As a result of intensive studies by the inventors, the inventors focused on the arrangement of salts that can achieve low electrical resistance and the affinity between the salt and the polymer, and studied and experimented on polymer materials and ionic conductive additive salts to be blended. This is based on the finding of a phase structure capable of preventing the migration of the salt to the outside of the composition while maintaining good electrical characteristics due to ions.

  As described above, it has a sea-island structure consisting of a continuous phase and one or more discontinuous phases, a salt dissociable into a cation and an anion is unevenly distributed in the discontinuous phase, and has high conductivity and electricity. Since the polymer constituting the discontinuous phase in which the salt capable of dissociating into the cation and the anion having a large resistance lowering ability has a higher affinity with the salt than the polymer constituting the continuous phase, The degree of freedom of the salt in the continuous phase can be increased, and the migration of the salt out of the system when an electric field is applied can be suppressed while maintaining a low electrical resistance. Thus, by suppressing the transfer of salt, it is possible to prevent an increase in resistance during continuous electrokinetics and transfer contamination outside the system. Furthermore, since the salt is present in the discontinuous phase, it is hardly affected by the environment such as temperature and humidity. Moreover, due to ionic conduction, variations in electrical resistance and voltage dependence are small.

Conventionally, in order to reduce the resistance value of the entire composition as much as possible, attempts have been made to distribute the salt to the continuous phase. However, the present invention relates to the affinity between the salt and the polymer and the arrangement of the salt. Paying attention to the above configuration, reducing the environmental dependency (temperature dependency + humidity dependency) of electrical resistance while maintaining a sufficiently low resistance value, and reducing the increase in resistance during continuous energization Made possible.
In particular, in the present invention, a salt having a high degree of ion dissociation and a high conductivity is used, and even if an electric field is continuously applied, the salt is hardly transferred out of the system. Without greatly increasing the value, excellent conductivity can be obtained with a small amount of a salt having excellent conductivity. Therefore, the influence on other physical properties such as compression set and hardness can be reduced as much as possible.

  The phase structure of the polymer composition such as the continuous phase and the discontinuous phase can be observed, for example, with a phase mode of an atomic force microscope (AFM) type scanning probe microscope (SPM).

Two phases, the first discontinuous phase and the second discontinuous phase, are provided as the discontinuous phase, and the salt is hardly added to the second discontinuous phase and the continuous phase.
In addition, the affinity of each phase with the polymer salt is first discontinuous phase> continuous phase> second discontinuous phase, and the electric resistance value (volume resistivity) of each phase is first discontinuous phase> continuous phase. > The second discontinuous phase is preferred. The affinity between the polymer of each phase and the salt is evaluated based on the volume resistivity described later of the polymer of each phase and the volume resistivity of the polymer of each phase in a state including a salt, and these volume resistivity is low. It can be said that the affinity between the polymer and the salt is high.
By setting it as the said structure, the ratio of the 1st discontinuous phase in which the dissociable salt is unevenly distributed can be suppressed, without impairing electroconductivity very much. As a result, a low volume resistivity can be maintained as a whole composition even if the amount of dissociable salt is reduced.
The first discontinuous phase is preferably present so as to surround the second discontinuous phase.
The first discontinuous phase, the second discontinuous phase, and the continuous phase may each be composed of two or more kinds of polymers, and even if each of them is finely divided into a plurality of phases, the gist and utility of the present invention can be obtained. It doesn't matter if it is satisfied.

Assuming that the volume resistivity of the polymer constituting the first discontinuous phase in which salts dissociated into cations and anions are unevenly distributed is R1, and the volume resistivity of the polymer constituting the continuous phase is R2, 0.2 ≦ log ₁₀ R2-log ₁₀ R1 ≦ 5 may be satisfied, but this log ₁₀ R2-log ₁₀ R1 is preferably 0.5 or more and 4 or less, and most preferably 1 or more and 3 or less.
This is because, when the above value is smaller than 0.2, a salt that can be dissociated into the continuous phase is easily transferred. On the other hand, if the above value is larger than 5, it is difficult to realize low resistance as a whole. In addition, when the polymer which comprises one phase is made into the blend of two or more types of polymers, it is set as the volume resistivity of the blended polymer. Moreover, the volume resistivity here is a volume resistivity of only the polymer containing no salt.

The weight ratio of the polymer constituting the discontinuous phase and the polymer constituting the continuous phase is (polymer constituting the discontinuous phase: polymer constituting the continuous phase) = (5:95) to (75:25). It is preferable.
If the blending ratio of the polymer constituting the discontinuous phase is less than the above range, the volume fraction of the discontinuous phase is too low, so the volume resistivity of the entire composition, or a roller or belt molded from the composition, etc. The resistance value cannot be lowered sufficiently. On the other hand, if the blending ratio of the polymer constituting the continuous phase is less than the above range, even if a technique such as dynamic crosslinking is used, it cannot be present as the continuous phase.
The weight ratio is more preferably (10:90) to (60:40), and more preferably (20:80) to (45:55).
In the present invention, the electric resistance value can be controlled to some extent by changing the ratio of the continuous phase and the discontinuous phase while keeping the blending amount of the dissociable salt fixed. If dynamic crosslinking is used, a relatively high fraction component can be brought into the discontinuous phase, and the ratio of the polymer constituting the discontinuous phase can be increased.
The volume fractions of the continuous phase, the first discontinuous phase, and the second discontinuous phase are preferably continuous phase> second discontinuous phase> first discontinuous phase.

The salt capable of dissociating into a cation and an anion is preferably blended at a ratio of 0.01 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the total polymer component.
This is because if the amount is smaller than 0.01 parts by weight, a sufficient effect of reducing the electric resistance cannot be obtained. If the amount is larger than 20 parts by weight, the cost is increased. This is because it becomes difficult to obtain. In addition, More preferably, it is 0.2 to 10 weight part, More preferably, it is 0.4 to 6 weight part.

The salt dissociable into a cation and an anion was measured in a propylene carbonate (PC) / dimethyl carbonate (DME) mixed solvent (volume fraction 1/2) at a salt concentration of 0.1 mol / l at 25 ° C. The conductivity is 2.3 mS / cm or more, preferably 3.5 mS / cm or more. This conductivity is proportional to the concentration of dissociated ions and their mobility. In addition, although the said electrical conductivity is so preferable that it is large, the upper limit of the electrical conductivity of the salt which exists actually is about 4.5 mS / cm.
Examples of the salt in such a range include CF ₃ SO ₃ Li, C ₄ F ₉ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, (C ₂ F ₅ SO ₂ ) ₂ NLi, and (C ₄ F ₉ SO ₂ ) (CF ₃ SO ₂ ) NLi, (FSO ₂ C ₆ F ₄ ) (CF ₃ SO ₂ ) NLi, (C ₈ F ₁₇ SO ₂ ) (CF ₃ SO ₂ ) NLi, (CF ₃ CH ₂ OSO ₂ ) ₂ NLi, (CF ₃ CF ₂ CH ₂ OSO ₂ ) ₂ NLi, (HCF ₂ CF ₂ CH ₂ OSO ₂ ) ₂ NLi, ((CF ₃ ) ₂ CHOSO ₂ ) ₂ NLi, (CF ₃ SO ₂ ) ₃ CLi, CF ₃ CH ₂ OSO ₂ ) ₃ CLi, LiPF _{6 and the} like.

  When a salt having a high conductivity as described above is used, a very low electric resistance value can be obtained with a small amount of addition. On the other hand, when such a salt with a high conductivity is used, the salt is particularly in the system. It becomes easy to move. Therefore, when the salt having high conductivity is not used to suppress the salt migration of the present invention, the resistance increase during continuous use tends to be significantly larger than that of the salt having low conductivity. Therefore, when a salt with good conductivity is used, particularly when the structure of the present invention is configured to suppress the salt migration, a remarkable effect can be exhibited.

  Further, as the salt capable of dissociating into the cation and the anion, a salt having an anion having a fluoro group and a sulfonyl group is preferably used. In such a salt, since functional groups such as a fluoro group and a sulfonyl group have electron withdrawing properties, anions are more stabilized and ions have a higher degree of dissociation. Thereby, a very low electric resistance value can be obtained with a small amount of addition.

  The anion having a fluoro group and a sulfonyl group is an ion selected from at least one of the group consisting of a bis (fluoroalkylsulfonyl) imide ion, a tris (fluoroalkylsulfonyl) methide ion, and a fluoroalkylsulfonic acid ion. Is preferred. Thereby, environmental dependency such as volume resistivity can be improved, the degree of dissociation is very large, and the phase with a polymer constituting a discontinuous phase such as EO-PO-AGE copolymer or epichlorohydrin rubber. It is also preferable from the viewpoint of high capacity. In particular, when a salt made of bis (fluoroalkylsulfonyl) imide ion or tris (fluoroalkylsulfonyl) methide ion is used, environmental dependency such as volume resistivity can be made extremely small.

The cation of the salt having an anion having a fluoro group and a sulfonyl group is preferably an alkali metal, group 2A, transition metal or amphoteric metal cation. Alkali metals are particularly preferable because they have a low ionization energy and can easily form stable cations. In addition to the metal cation, a salt having a cation represented by the following chemical formula (Chemical Formula 1, Chemical Formula 2) may be used. In the formula, R _{1 to} R ₆ are each an alkyl group having 1 to 20 carbon atoms or a derivative thereof, and R _{1 to} R ₄ , and R ₅ and R ₆ may be the same or different. Among these, a salt composed of a trimethyl-type quaternary ammonium cation, in which three of R _{1 to} R ₄ are methyl groups and the other is composed of an alkyl group having 7 to 20 carbon atoms or a derivative thereof, is an electron donor. It is particularly preferable because three positively charged methyl groups can stabilize the positive charge on the nitrogen atom and other alkyl groups or derivatives thereof can improve compatibility with the polymer. In addition, in the cation of the chemical formula 2, R ₅ or R ₆ is preferably a methyl group or an ethyl group because it is easier to stabilize the positive charge on the nitrogen atom if it has an electron donating property. In this way, by stabilizing the positive charge on the nitrogen atom, the stability as a cation can be increased, and the salt can have a higher degree of dissociation and thus excellent conductivity imparting performance.

  For the reasons described above, salts having an anion having a fluoro group and a sulfonyl group are alkali metal salts of bis (trifluoromethanesulfonyl) imide, alkali metal salts of tris (trifluoromethanesulfonyl) methide, alkali of trifluoromethanesulfonic acid. Most preferably, the salt is selected from at least one of the group consisting of metal salts.

  Salts having anions consisting of bis (fluoroalkylsulfonyl) imide ions and tris (fluoroalkylsulfonyl) methide ions, especially bis (trifluoromethanesulfonyl) imide lithium, have been used in the past because they are stable even at very high temperatures. Unlike lithium perchlorate and perchloric acid quaternary ammonium salts, etc., there is no need for measures such as making them explosion-proof. From this point, the manufacturing cost can be reduced and the safety can be ensured, which is very good.

The salt capable of dissociating into a cation and an anion is preferably blended without a medium comprising a low molecular weight polyether compound having a molecular weight of 10,000 or less or a low molecular weight polar compound. When such a medium is used, there is a case where the electric resistance value increases greatly when used continuously for a long time, or the medium precipitates together with ions, and the photosensitive member is likely to be contaminated.
A known method can be used as a method of blending a dissociable salt without using the above medium. For example, after dry blending with a Henschel mixer, tumbler, etc., a blend containing a dissociable salt and polymer is melt-mixed with a single or twin screw extruder, Banbury mixer, kneader, etc. I can do it. In addition, when a dissociable salt is blended at a high temperature in a polymer system of a thermoplastic resin or a thermoplastic elastomer, it may be used under an inert gas atmosphere such as nitrogen for the purpose of preventing deterioration of the polymer, etc. Mixing (mixing) can also be performed.

  The conductive polymer composition of the present invention is preferably a vulcanized rubber composition, a urethane rubber composition, or a thermoplastic elastomer composition because it can impart appropriate elasticity and the like, but in addition, a resin is used as the polymer. Also good.

The polymer constituting the first discontinuous phase in which the salt capable of dissociating into a cation and an anion is unevenly distributed can strongly stabilize a cation generated from the salt by an ether bond or a cyan group. It is preferable that the main component is at least one of a polyoxyalkylene copolymer, a cyan group-containing polymer, and an epihalohydrin polymer.
Thus, by increasing the affinity between the polymer constituting the first discontinuous phase and the salt, the resistance value of the entire composition can be effectively reduced, and the precipitation of the salt out of the system and the continuous An increase in resistance value during use can be prevented.
Specifically, it is preferable to use ethylene oxide-propylene oxide-allyl glycidyl ether copolymer (EO-PO-AGE copolymer) or / and epichlorohydrin rubber as the polymer constituting the first discontinuous phase. . As epichlorohydrin rubber, epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer, epichlorohydrin-ethylene oxide-propylene oxide-allyl glycidyl ether copolymer, epichlorohydrin-ethylene oxide-propylene oxide copolymer And epichlorohydrin-allyl glycidyl ether copolymer.
In addition, a polyethylene oxide block polyamide copolymer and a polyether ester amide copolymer also have high affinity with the salt used in the present invention, and are preferably used as a polymer constituting the first discontinuous phase.

  When the EO-PO-AGE copolymer is used, the copolymerization ratio can be set so that the volume resistivity can be reduced while maintaining the physical properties (compression set, hardness) of the composition. In the copolymer, the ethylene oxide ratio is preferably 55 mol% or more and 95 mol% or less. Ionic conductivity is exhibited because oxonium ions and metal cations in the polymer (for example, cations such as lithium ions in the added salt) are stabilized by ethylene oxide units and propylene oxide units. , By being transported by the segmental motion of the molecular chain of that part. In general, the ethylene oxide unit has higher stability than the propylene oxide unit. Therefore, a higher ratio of the ethylene oxide unit can stabilize more ions and realize a lower resistance.

  The polymer constituting the continuous phase is preferably a low nitrile NBR or / and a medium / high nitrile NBR or a polyester-based thermoplastic elastomer. As a result, the resistance value as a whole can be made as low as possible, and the dissociable salt can be prevented from shifting out of the composition and from increasing in resistance during continuous energization. As the material of the continuous phase, since the electrical resistance value is low to some extent and the Tg is low, the temperature dependence of the viscoelasticity near room temperature is small, thereby making it possible to reduce the environmental dependence of the volume resistivity. Particularly preferred are low nitrile NBR and the like. The Tg of these polymers is -40 ° C or lower, more preferably -50 ° C or lower.

The second discontinuous phase that does not disperse a salt that can dissociate into a cation and an anion is preferably mainly composed of a low-polar rubber. Specifically, the low polarity rubber is at least one rubber selected from ethylene propylene diene copolymer rubber (EPDM), ethylene propylene rubber (EPM), butyl rubber (IIR), and styrene butadiene rubber (SBR). Is preferred. Thereby, ozone resistance can be provided to a composition. For example, even when used for a conductive member or the like used in an image forming apparatus, ozone resistance can be secured against ozone generated in the apparatus.
Furthermore, in order to reduce the temperature dependence of the viscoelasticity of the entire system near room temperature and to reduce the environmental dependence of the electrical resistance value, not only the polymer used for the continuous phase but also the polymer used for the second discontinuous phase. However, those having a lower Tg are preferred. The same applies to the polymer used for the first discontinuous phase. The Tg of these polymers is preferably −40 ° C. or lower, more preferably −50 ° C. or lower.

  In the present invention, a part of the ions generated from the salt to be added can be converted into a single ion using an anion adsorbent or the like to stabilize the conductivity or improve the conductivity when added in a small amount. As an anion adsorbent, synthetic hydrotalcite mainly composed of Mg and Al, inorganic ion exchangers such as Mg-Al, Sb, and Ca, and ion sites that fix anions in the chain (co-current). ) Known compounds such as polymers are useful. Specifically, synthetic hydrotalcite (manufactured by Kyowa Chemical Industry Co., Ltd., trade name Kyoward 2000, Kyoward 1000), anion exchange ion exchange resin (manufactured by Nippon Nensui Co., Ltd., trade name Dyanon DCA11) Is mentioned.

  When a polymer containing halogen such as chlorine is used as the polymer, it is preferable to incorporate an acid acceptor such as hydrotalcite in order to prevent deterioration of the polymer due to dehydrochlorination reaction and rusting of the kneader. In the case of synthetic hydrotalcite, the blending amount is 1 to 15 parts by weight, preferably 3 to 12 parts by weight, based on 100 parts by weight of the halogen-containing polymer.

As the vulcanizing agent to be added, sulfur is particularly preferable because low electrical resistance can be realized. In addition to sulfur and organic sulfur-containing compounds, peroxides can be used, and these can be used in combination. In particular, when EPDM or EPM is used as the low-polar rubber forming the second discontinuous phase, the peroxide phase can effectively vulcanize the phase composed of these rubbers.
Examples of the organic sulfur-containing compound include tetraethylthiuram disulfide and N, N-dithiobismorpholine. Examples of the peroxide include dicumyl peroxide and benzoyl peroxide. Of these, when foaming is performed together with vulcanization, it is preferable to use sulfur from the viewpoint of improving the balance between the vulcanization speed and the foaming speed. The addition amount of the vulcanizing agent is 0.5 to 5 parts by weight, preferably 1 to 3 parts by weight, based on 100 parts by weight of the polymer component.

Moreover, you may mix | blend a vulcanization accelerator and can use inorganic promoters, such as slaked lime, magnesia (MgO), and risurge (PbO), and the organic promoter described below.
Examples of organic accelerators include thiazoles such as 2-mercapto-benzothiazole and dibenzothiazyl disulfide, sulfenamides such as N-cyclohexyl-2-benzothiazylsulfenamide, tetramethylthiuram monosulfide, and tetramethylthiuram. Thiurams such as disulfide, tetraethylthiuram disulfide, and dipentamethylenethiuram tetrasulfide, and thioureas can be used in appropriate combination.
The vulcanization accelerator is preferably 1 part by weight or more and 5 parts by weight or less, and more preferably 2 parts by weight or more and 4 parts by weight or less with respect to 100 parts by weight of the polymer component.

Further, a vulcanization acceleration aid may be blended, and examples thereof include metal oxides such as zinc white, fatty acids such as stearic acid, oleic acid, and cottonseed fatty acid, and other conventionally known vulcanization acceleration aids.
You may mix | blend a chemical foaming agent in the ratio of 3 to 12 weight part with respect to 100 weight part of polymer components for provision of a softness | flexibility etc. In addition, you may mix | blend softeners, such as oil, anti-aging agent, etc.
Further, for the purpose of improving the mechanical strength, a filler can be blended as necessary within a range not impairing the electrical characteristics and other physical properties. Examples of the filler include powders such as silica, carbon black, clay, talc, calcium carbonate, magnesium carbonate, and aluminum hydroxide. The filler is preferably 60 parts by weight or less with respect to 100 parts by weight of the polymer.

The conductive polymer composition of the present invention is more preferably non-chlorine or non-bromine without using a salt having chlorine or bromine.
Specifically, a composition that does not contain chlorine or bromine as a polymer, and does not use a salt containing chlorine or bromine such as lithium perchlorate, sodium perchlorate or quaternary ammonium perchlorate, By using a non-chlorine or non-bromine composition as a whole, there is no risk of corroding, rusting or contaminating the metal surface such as the shaft of the conductive roller. Furthermore, an incineration process after use can be performed very easily, and an environmentally friendly composition can be obtained.

  The conductive polymer composition of the present invention described above was measured at a measurement temperature of 70 ° C., a measurement time of 22 to 24 hours, and a compression ratio of 25% in the permanent strain test method of vulcanized rubber and thermoplastic rubber described in JIS K6262. The magnitude of the compression set is preferably 30% or less. This is because when the ratio is larger than 30%, the dimensional change becomes too large when the composition is molded and used as a conductive member such as a roller or a belt, which is not suitable for practical use. In addition, More preferably, it is 25% or less, and it is so good that it is small.

The volume resistivity described in JIS K6911 measured under an applied voltage of 100 V is preferably less than 10 ^10.0 [Ω · cm]. This is because if the volume resistivity is larger than 10 ^10.0 Ωcm, good conductivity cannot be obtained when a conductive member or the like is used, and it is not suitable for practical use. In addition, when the composition is molded into a roller, a belt, or the like, the efficiency of transfer, charging, toner supply, etc. is likely to decrease. The volume resistivity is more preferably 10 ^4.0 Ωcm or more and 10 ^9.5 Ωcm or less.

Furthermore, the volume resistivity ρ _V [Ω · cm] when a constant voltage of 1000 V was continuously applied to a sample having a thickness of 0.25 mm for 5 hours in an environment of 23 ° C. and 55% relative humidity was measured. It is preferable that the resistivity increase Δlog ₁₀ ρ _V = log ₁₀ ρ _V (t = 5 hr.) − Log ₁₀ ρ _V (t = 0 hr.) Is 0.5 or less. This is because if the index value of the increase in volume resistivity is greater than 0.5, the resistance increase during continuous use will increase when molded into a conductive member or the like, which may impede practical use. is there.

Furthermore, the volume resistivity ρ _V [Ω · cm] under the conditions of 10 ° C. relative humidity 15%, 32.5 ° C. relative humidity 90% was measured, and the environmental dependency of volume resistivity Δlog ₁₀ ρ _V = log ₁₀ The value of ρ _V (10 ° C. relative humidity 15%) − log ₁₀ ρ _V (32.5 ° C. relative humidity 90%) is 1.7 or less, preferably 1.4 or less, more preferably 1.2 or less, most preferably Is preferably 1.1 or less.
This is because, when the index value of the environmental dependency of the volume resistivity is greater than 1.7, the resistance value changes greatly due to the environmental change when molded into a conductive member or the like, and a larger power supply is required. This is because the power consumption and product cost of the image forming apparatus using the conductive member increase.

  Although the conductive member is formed using the conductive polymer composition described above, it is particularly suitably used for a conductive roller, a conductive belt, or the like.

  As is clear from the above description, according to the present invention, a salt having a phase structure composed of a continuous phase and one or more discontinuous phases and dissociating into a cation and an anion is unevenly distributed in the discontinuous phase. In addition, a polymer that forms a discontinuous phase in which a salt that can dissociate into a cation and an anion is unevenly distributed has a higher affinity for a salt that can dissociate into a cation and an anion than a polymer that forms a continuous phase. Is high. For this reason, it is possible to suppress the outflow of salt out of the system when an electric field is applied while increasing the degree of freedom of salt in the discontinuous phase and maintaining low electrical resistance. It is possible to prevent an increase in resistance during continuous electrodynamics. Furthermore, since salt is unevenly distributed in the discontinuous phase, it is not easily affected by the environment such as temperature and humidity, and due to ionic conduction, variation in electric resistance and voltage dependency are small.

  In addition, even if the electric field continues to be applied, it is suppressed that the salt migrates and appears on the surface, or the resistance value rises. Therefore, it is possible to use a salt with excellent conductivity, and the salt with excellent conductivity can be used. Excellent conductivity can be obtained even in a small amount. Therefore, problems such as bleed, bloom, photoconductor contamination and migration contamination do not occur, and the influence on other physical properties such as compression set and hardness can be reduced as much as possible.

Embodiments of the present invention will be described below.
FIG. 1 is a schematic diagram showing the structure of an ion conductive polymer composition according to a first embodiment of the present invention that forms a conductive layer. The ion conductive polymer comprises a continuous phase 1, a first discontinuous phase 2, It consists of the second discontinuous phase 3 and the three phases have a sea-island structure. The first discontinuous phase 2 and the second discontinuous phase 3 exist substantially uniformly in the continuous phase 1, and the first discontinuous layer 2 exists so as to surround the second discontinuous phase 3.
In addition, the 2nd discontinuous phase 3 does not necessarily need to exist so that it may be seen in the description about 2nd Embodiment mentioned later.

FIG. 2 shows the morphology (one side of 10 μm) of the conductive polymer composition observed in a phase mode with an atomic force microscope (AFM) scanning probe microscope (SPM). In FIG. 2, the continuous phase 1 has the lightest color, the first discontinuous phase 2 has the darkest color, and the second discontinuous phase 3 has a medium color density. In the figure, the dark portion has a high elastic modulus, and the light portion has a low elastic modulus.
In addition, as shown in FIG. 2, the volume fraction is as follows: continuous phase 1> second discontinuous phase 3> first discontinuous phase 2.

In order to exhibit the sea-island structure as shown in FIG. 1 and FIG. 2, the type and amount of the polymer in each phase are defined, and the amount of salt to be added and the addition method are defined.
The ion conductive polymer composition is added with 0.01 to 20 parts by weight of a salt capable of dissociating into a cation and an anion with respect to 100 parts by weight of the total polymer, and the first discontinuous phase 2 is added. In the second discontinuous phase 3 and the continuous phase 1, almost no salt is added.

  The polymer of the first discontinuous phase 2 has a higher affinity for the dissociable salt than the polymer constituting the continuous phase 1, and the polymer constituting the continuous phase 1 does not add a dissociable salt. The affinity with the dissociable salt is higher than that of the polymer constituting the second discontinuous phase 3. That is, the affinity of each phase with the polymer salt is such that first discontinuous phase 2> continuous phase 1> second discontinuous phase 3.

  Specifically, as shown in Example 2 described later, in the first embodiment, for example, an EO-PO-AGE copolymer (EO: PO: AGE =) is used as a polymer constituting the first discontinuous phase 2. 90: 4: 6) 10 parts by weight, 63 parts by weight of low nitrile NBR as the polymer constituting the continuous phase 1, and low polarity as the polymer constituting the second discontinuous phase 3 with almost no dissociable salt added 27 parts by weight of EPDM, which is an ozone resistant rubber, is used. That is, the affinity with the dissociable salt is EO-PO-AGE copolymer> low nitrile NBR> EPDM.

The volume resistivity of the EO-PO-AGE copolymer of the first discontinuous phase 2 is R1, the volume resistivity of the low nitrile NBR of the continuous phase 1 is R2, and the volume resistivity of the EPDM of the second discontinuous phase 3 is R3. Then, log ₁₀ R1 is 7.9, log ₁₀ R2 is 10.2, log ₁₀ R3 is 14.8, and the value of (logR2-logR1) is 2.3.
The weight ratio of the polymer constituting the first and second discontinuous phases 2 and 3 to the polymer constituting the continuous phase 1 is 37:63.

1.1 parts by weight of lithium-bis (trifluoromethanesulfonyl) imide, which is a salt having an anion having a fluoro group and a sulfonyl group, as a salt dissociable into a cation and an anion added to the conductive polymer ing. This salt has a conductivity of 4.0 mS / cm measured in a PC / DME mixed solvent (volume fraction 1/2) at a salt concentration of 0.1 mol / l at 25 ° C. Moreover, it mix | blends without passing through the medium which consists of a low molecular weight polyether compound with a molecular weight of 10,000 or less and a low molecular weight polar compound.
Lithium-bis (trifluoromethanesulfonyl) imide is disclosed in Japanese Patent Publication No. 1-33871 (application from Amber, etc.) or Japanese Patent Application Laid-Open No. 9-173856 (application from Noguchi Laboratory and Asahi Kasei Corporation). Or Japanese Patent No. 3117369, Japanese Patent Application Laid-Open No. 11-209338 (Application of Central Glass Co., Ltd.), or Japanese Patent Application Laid-Open No. 2000-86617, Japanese Patent Application Laid-Open No. 2001-139540 (Application of Kanto Denka Kogyo Co., Ltd.) ), Or those synthesized by a conventionally known method such as JP-A-2001-288193 (filed by Morita Chemical Co., Ltd.).
Lithium tris (trifluoromethanesulfonyl) methane is disclosed in US Pat. No. 5,554,664, or JP 2000-219692 (filed by Noguchi Laboratory and Asahi Kasei Corporation), or JP 2000- The one synthesized by a conventionally known method such as 226392 (Kanto Denka Kogyo Co., Ltd. application) was used.

  The conductive polymer composition contains 9 parts by weight of carbon black as a filler, 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 1.5 parts by weight of powdered sulfur as a vulcanizing agent, and two types of vulcanization accelerators. Each consists of a vulcanized rubber composition blended with 1.5 parts by weight and 0.5 parts by weight.

  FIG. 3 shows a conductive roller 10 having a conductive layer 11 formed from the conductive polymer composition. The conductive roller 10 includes a cylindrical metal core 12 having conductivity and the conductive layer 11 on the surface side of the core 12, and the core 12 is provided in a hollow portion of the cylindrical conductive layer 11. Press-fit and install.

The conductive roller 10 is manufactured by the following method.
First, a dissociable salt and an EO-PO-AGE copolymer were kneaded at 60 ° C. for 3 minutes using a kneader, and low nitrile NBR, EPDM, and other various compounding agents were added to the kneaded product obtained here. It mix | blends and again knead | mixes with an open roll, a closed kneader, etc. at 60 degreeC for 4 minutes, and produces a conductive polymer composition.

This conductive polymer composition is put into a single screw extruder having a diameter of 60 mm, extruded into a hollow tube shape at 60 ° C. and preformed, and the raw rubber tube is cut into a predetermined size to obtain a preform. When this preform is put into a pressurized steam vulcanizing can and foamed, the chemical foaming agent is gasified and foamed, and vulcanized at a temperature at which the rubber component crosslinks (15 to 70 minutes at 160 ° C.). Obtained vulcanized rubber tube.
Vulcanization conditions are measured with a curast meter or the like, and are appropriately adjusted with a 95% torque rise time t95 [minute] as a guide.
In order to reduce the photoreceptor contamination and compression set, it is desirable to set the conditions so that a sufficient vulcanization amount can be obtained.

  After preparing the core metal 12 and applying the hot melt adhesive to the outer peripheral surface thereof, the core metal is inserted into the vulcanized rubber tube obtained above, heated and bonded, and then the surface is polished to form the conductive layer 11. Finished to the target dimensions. The dimensions of the conductive layer 11 of the conductive roller 10 are an inner diameter of 6 mm, an outer diameter of 14 mm, and a length of 218 mm.

The conductive layer 11 has a compression set value of 17% measured at a measurement temperature of 70 ° C. for a measurement time of 24 hours in the permanent strain test method for vulcanized rubber and thermoplastic rubber described in JIS K6262, and an applied voltage of 100V. the volume resistivity according to JIS K6911 were measured under is 10 ^9.0 [Ω · cm].

Further, for example, the conductive polymer composition described in Example 2 constituting the conductive layer of the conductive roller 10 has an environment where the volume resistivity at an applied voltage of 100 V is 10 ^9.0 Ω · cm, the temperature is 23 ° C., and the relative humidity is 55%. Below, volume resistivity ρ _V [Ω · cm] when a constant voltage of 1000 V is continuously applied to a sample having a thickness of 0.25 mm for 5 hours is measured, and an increase in volume resistivity Δlog ₁₀ ρ _V = log ₁₀ ρ _V (t = 5 hr.) − Log ₁₀ ρ _V (t = 0 hr.) Is 0.08, and volume resistance under conditions of 10 ° C. relative humidity 15%, 32.5 ° C. relative humidity 90% The ratio ρ _V [Ω · cm] is measured, and the volume resistivity is dependent on the environment Δlog ₁₀ ρ _V = log ₁₀ ρ _V (10 ° C. relative humidity 15%) − log ₁₀ ρ _V (32.5 ° C. relative humidity 90% ) Is 0.8.

  The conductive layer 11 of the conductive roller 10 manufactured by the above method includes the continuous phase 1, the first discontinuous phase 2, and the second discontinuous phase 3, and the first discontinuous phase 2 and the second discontinuous phase 3. To surround. As described above, the high-performance salt that can control the morphology and reduce the resistance value in a small amount is unevenly distributed in the first discontinuous phase 2 mainly composed of the EO-PO-AGE copolymer. It is possible to obtain a low electrical resistance value necessary for practical use while preventing the salt from moving out of the product when added and the resistance increase during continuous energization.

Therefore, while maintaining low electrical resistance, changes in the electrical resistance due to the environment and changes due to continuous use are reduced, and variations in the electrical resistance due to the roller parts are reduced, so that stable and good images can be formed. A gentle conductive roller can be obtained. Therefore, it is suitable for a developing roller, a charging roller, a transfer roller, and the like. In particular, it is suitable as a conductive roller for color copiers or color printers that require high image quality.
A foaming agent is blended, the expansion ratio is 100% or more and 500% or less, preferably 150% or more and 300% or less, and the hardness measured with a type E durometer described in JIS K6253 is 60 degrees or less, preferably 40 degrees. It can also be set as the foaming roller which has the following foaming layers.

  The conductive layer 11 is provided with a second discontinuous phase 3 in which almost no salt is distributed, and the second discontinuous phase 3 is surrounded by the first discontinuous phase 2 in which salt is unevenly distributed. Therefore, the volume fraction of the first discontinuous phase 1 in which the salt is unevenly distributed can be suppressed without significantly impairing the conductivity. Thereby, even if the addition amount of the salt and the polymer of the first discontinuous phase 1 that actively distributes the salt is reduced, a low volume resistivity and a product resistance value of the roller can be obtained as a whole. In addition, since the salt having an anion having a fluoro group and a sulfonyl group used as a salt capable of dissociating into a cation and an anion is expensive, the increase in cost can be suppressed by reducing the amount of the salt added. be able to.

4 and 5 show a second embodiment, which shows a form in which a conductive belt 13 formed using the conductive polymer composition of the present invention is used as a transfer belt.
The conductive belt 13 is stretched by two pulleys 14 and carries and conveys a sheet material 16 such as paper on a linear portion 15 on the upper side of the rotating conductive belt 13. The toner image formed above is transferred to the sheet material 16.

Although the said electroconductive belt 13 is not limited only to such a form, it consists only of the electroconductive layer 21 formed from the electroconductive polymer composition of one layer of seamless belt shape. As shown in FIG. 5, the conductive layer 21 is composed of a single continuous phase 1 ′ and a single first discontinuous phase 2 ′. The continuous phase 1 ′ and the first discontinuous phase 2 ′ It has a sea-island structure.
Only the first discontinuous phase 2 'has a salt dissociable into a cation and an anion, and the polymer constituting the first discontinuous phase 2' can be dissociated more than the polymer constituting the continuous phase 1 '. It has a high affinity with various salts.

  Specifically, 30 parts by weight of a resin-type antistatic agent made of a polyethylene oxide block nylon 12 copolymer is used as a polymer constituting the first discontinuous phase 2 ′ in which dissociable salts are unevenly distributed, and the continuous phase 1 ′ is used. As a constituent polymer, 100 parts by weight of a polyester-based thermoplastic elastomer composed of a soft segment made of polyether and a hard segment made of polyester is used.

When the volume resistivity of the resin-type antistatic agent constituting the first discontinuous phase is R1, and the volume resistivity of the polyester thermoplastic elastomer constituting the continuous phase is R2, log ₁₀ R1 is 9.0, and log ₁₀ R2 is 13.4, and the value of (log ₁₀ R 2 -log ₁₀ R 1) is 4.4. The weight ratio of the polymer constituting the first discontinuous phase 2 ′ to the polymer constituting the continuous phase 1 ′ is 23:77.

  As a salt dissociable into a cation and an anion, 1.5 parts by weight of lithium-bis (trifluoromethanesulfonyl) imide, which is a salt having an anion having a fluoro group and a sulfonyl group, is used. This salt has a conductivity of 4.0 mS / cm measured at a salt concentration of 0.1 mol / liter at 25 ° C. in a PC / DME mixed solvent (volume fraction 1/2), and has a molecular weight of 10,000 or less. It is blended without a medium composed of a low molecular weight polyether compound or a low molecular weight polar compound.

The conductive belt 13 is manufactured by the following method.
The detachable salt and the resin-type antistatic agent are dry blended using a tumbler. This dry blend is immediately fed into a twin screw extruder. After kneading at 170-210 ° C. for 2 minutes, the mixture is cooled and pelletized. The pellets of the kneaded product obtained here are dry-blended with polyester thermoplastic elastomer pellets in the same manner as described above, and again kneaded at 210-270 ° C. for 2 minutes using a twin-screw extruder, cooled, and electrically conductive. A pellet of the functional polymer composition is prepared. The pellets of the conductive polymer composition are formed into a belt shape by an extruder for resin.

The conductive belt 13 has a volume resistivity of 10 ^9.6 [Ω · cm] described in JIS K6911 measured under an applied voltage of 100V.

The conductive belt 13 has a volume resistivity ρ _V [Ω · when a constant voltage of 1000 V is continuously applied to a sample having a thickness of 0.25 mm in an environment of 23 ° C. and a relative humidity of 55% for 5 hours. cm], the volume resistivity increase Δlog ₁₀ ρ _V = log ₁₀ ρ _V (t = 5 hr.) − log ₁₀ ρ _V (t = 0 hr.) is set to 0.36, and the relative humidity at 10 ° C. The volume resistivity ρ _V [Ω · cm] under the condition of 15%, 32.5 ° C. and 90% relative humidity was measured, and the environmental dependency of volume resistivity Δlog ₁₀ ρ _V = log ₁₀ ρ _V (relative to 10 ° C. The value of humidity 15%) − log ₁₀ ρ _V (32.5 ° C. relative humidity 90%) is set to 1.4.

  The conductive belt 13 includes a conductive layer 21 in which a salt that can be dissociated into a cation and an anion is unevenly distributed in the first discontinuous phase 2 ′, and a salt that can reduce the resistance value with a small amount as a salt to be added. In addition, the polymer used for each phase is appropriately selected, so that it is necessary for practical use while preventing the salt from moving out of the system when an electric field is applied and the increase in resistance during continuous energization. A low electrical resistance value can be obtained. Moreover, it has moderate flexibility in the thickness direction, but hardly stretches in the length direction. And when it is set as a non-chlorine and a non-bromine type composition like Example 9, 10, it is an electroconductive belt which was good for the environment and excellent in practicality.

  In the above-described embodiment, the case where the conductive belt of the present invention is used as a transfer belt has been described in detail. However, for example, an intermediate transfer belt, a fixing belt, a developing belt, and a conveyance belt used in an image forming apparatus may be used. Can be used. In particular, when a white belt is used, toner adhesion can be easily visually checked, so that it is suitable for evaluation of cleaning performance and can be suitably used as an intermediate transfer belt.

  In addition to the above embodiment, various materials can be used for the polymer constituting the continuous phase, the polymer constituting the discontinuous phase, and the dissociable salt as described above. Various compounding materials can be changed as necessary to optimize the electrical characteristics according to the required performance. The types and amounts of various compounding materials can be set as appropriate. Kneading can be performed by a method other than the above, and a conductive polymer composition can be produced and a conductive member can be formed by a conventionally known method.

Hereinafter, the Example of a conductive member formed using the conductive polymer composition of this invention and a comparative example are explained in full detail.
First, examples of the conductive roller and comparative examples will be described.
For Examples 1 to 6 and Comparative Examples 1 to 5, each compounding material described in Tables 1 and 2 is kneaded, extruded, vulcanized, molded, and polished by the same method as in the above embodiment, and a conductive roller. Was made. A conductive roller for a transfer roller equipped with a Laser Jet 4050 type laser beam printer manufactured by Hewlett-Packard Company was used.

In parallel with this, the rubber removed from the kneader is extruded by a roller head extruder and formed into a sheet shape. After being vulcanized in a vulcanizer at 160 ° C for an optimal time, the thickness is about 2 mm. This was sliced to obtain a vulcanized rubber slab sheet for volume resistivity (volume resistivity value) evaluation. Tables 1 and 2 show the evaluation results obtained using these rollers and rubber slab sheets and various evaluations as rollers described later.
In measuring the resistance increase during continuous energization, a sliced slice having a thickness of about 0.25 mm was prepared and used in order to match the conditions with the example of the conductive belt.

(Examples 1-6)
An EO-PO-AGE copolymer or epichlorohydrin rubber is used as the polymer constituting the discontinuous phase, and lithium-bis (trifluoromethanesulfonyl) imide or lithium-tris (which can be dissociated into a cation and an anion) (Trifluoromethanesulfonyl) methane was unevenly distributed. Low nitrile NBR was used as the continuous phase and EPDM was used as the other non-continuous phase. A foaming roller was used except for Example 2.

(Example 7)
Epichlorohydrin rubber (50 phr), NBR, calcium carbonate, hydrotalcite, zinc white and stearic acid were mixed and kneaded in a closed kneader preheated to 120 ° C. A thiourea crosslinking agent (vulcanizing agent 2) master batch of epichlorohydrin rubber (for 10 phr) prepared in advance while kneading and a crosslinking accelerator (vulcanization accelerator 3) for the thiourea crosslinking agent were added and dynamically crosslinked. Crosslinking proceeded while looking at the kneading torque chart, and kneading was once completed near the torque peak. Then, it cooled to 50 degreeC, sulfur, the vulcanization accelerator 1, and the vulcanization accelerator 2 were mixed with the kneader, and the dynamic crosslinking composition was obtained. This was extruded into a tube shape in the same manner as in Examples 1 to 6, preformed, and the tube cut was vulcanized at 160 ° C. for 10 to 70 minutes to obtain a conductive layer.

(Comparative Examples 1-5)
Comparative Example 1 did not use a salt that can be dissociated into a cation and an anion. Comparative Examples 2 and 3 have a two-phase structure of a continuous phase composed of low nitrile NBR and a discontinuous phase composed of EPDM, and a salt that can dissociate into a cation and an anion is unevenly distributed in the continuous phase. Comparative Examples 4 and 5 had a structure of only one phase composed of one kind of polymer, and a salt capable of dissociating into a cation and an anion was added to the one phase. Comparative Examples 1 and 2 were foam rollers.

  As the EO-PO-AGE copolymer or epichlorohydrin rubber, one previously kneaded with a dissociable salt was used. In the combined system of carbon black and EPDM, carbon black was previously kneaded into EPDM and used as a master batch. In Example 6, carbon black was kneaded into NBR in advance to form a master batch. Vulcanization accelerator 1 was dibenzothiazyl disulfide, vulcanization accelerator 2 was tetramethylthiuram monosulfide, and blowing agent 1 was 4,4'-oxybis (benzenesulfonylhydrazide).

The volume resistivity R1 of the polymer constituting the discontinuous phase in which salts dissociable into cations and anions are unevenly distributed, the volume resistivity R2 of the polymer constituting the continuous phase, and the salt dissociable into cations and anions The volume resistivity R3 of the polymer constituting the non-continuous phase not unevenly distributed was measured without adding salt.
For example, in Example 1 or Example 2, 100 parts by weight of ZSN8030, 9 parts by weight of Seest 3, 5 parts by weight of silver candy R, 1 part by weight of stearic acid 4931, 1.5 parts by weight of powdered sulfur, Noxeller DM The volume resistivity of a composition containing 1.5 parts by weight and 0.5 parts by weight of Noxeller TS was measured. During measurement, the applied voltage was 100 V, the measurement environment was 23 ° C., and the relative humidity was 55%.

  Moreover, the Example of an electroconductive roller using a urethane composition and a comparative example are explained in full detail. About Example 8 and Comparative Examples 6-8, the conductive layer was produced using the material which consists of a mixing | blending of following Table 3 and Table 4, respectively.

(Example 8)
Two kinds of polyether polyols 1 and 2 were used, and lithium-bis (trifluoromethanesulfonyl) imide, which is a salt dissociable into a cation and an anion, was used.
The polyether polyol 1 and the polyether polyol 2 are both PPG-based polyols, have the same hydroxyl value, and have almost the same basic structure. Therefore, they are uniformly compatible to form one phase.
The continuous phase consists of a liquid polybutadiene polymer (terminal isoazonate prepolymer 1) that has a much lower affinity with the salt and has a log ₁₀ R2 of 14.1.
The discontinuous phase was composed of a PPG polyol having a relatively high affinity with the salt as described above. log ₁₀ R1 is 11.1, and log ₁₀ R2−log ₁₀ R1 is 3.0.
As described above, in the polyurethane composition formed by reacting the isocyanate prepolymer and the polyol, the ratio of the discontinuous phase to the continuous phase is about 40:60, and the conductive polymer composition of the present invention can be obtained.
Specifically, a conductive layer was produced as follows.
After the polyether polyol 1 and the polyether polyol 2, the aromatic diamine, the antifoaming agent, the leveling agent, and the like are weighed, the mixture is stirred and uniformly mixed at room temperature using a rotary stirrer or the like. Thereafter, the mixture was degassed under reduced pressure. Similarly, the terminal isocyanate prepolymer defoamed under reduced pressure is mixed with the previously prepared mixed solution, stirred and defoamed again, and then poured into slabs for evaluating physical properties and various molds for producing conductive rollers. After pouring into the mold, heating is performed at 150 ° C. for 60 minutes, thereby causing a curing reaction and obtaining a desired slab or conductive roller.
In addition, when used for a conductive roller, when a metal shaft is coated with a urethane primer, a mixture of the polyol-containing mixture and an isocyanate prepolymer is poured into a mold. good.
As a primer for urethane, for example, a mixture of SBU polyol 0759 manufactured by Sumika Bayer Urethane Co., Ltd. and Sumijoule 44V20 in a weight ratio of 1: 2 manufactured by Sumika Bayer Urethane Co., Ltd. is preferably used. .
The volume resistivity of the urethane composition and its environmental dependency were measured using a 130 × 130 × 2 mm slab, but the resistance increase during continuous energization was 130 × 130 × 0.25 mm.

(Comparative Examples 6-8)
Comparative Examples 6 and 7 did not contain a dissociable salt. In Comparative Example 8, a PPG polyol (polyether polyol 1, 2) and a PPG prepolymer (terminal isocyanate prepolymer 2) were used, but a liquid polybutadiene prepolymer having a lower affinity for salt than PPG was not used. Basically, the composition is composed of only a phase having a relatively high affinity with a dissociable salt. In either case, a conductive layer was prepared by the same method as in the example.

(Measurement of volume resistivity)
It measured on the measurement sheet | seat produced as mentioned above on the constant temperature and humidity conditions of 23 degreeC relative humidity 55% using the ultra high resistance microammeter R-8340A made from Advantest Corporation. The measurement method was in accordance with the volume resistivity (volume resistivity) measurement method described in JIS K6911, and the applied voltage at the time of measurement was 100V. The common logarithm value is displayed in the table. As for Examples and Comparative Examples of the conductive belt, resulting the conductive belt used as it is, measured in the same manner as described above with a total of 20 points in the circumferential direction 4 points × longitudinal five points of the belt, log ₁₀ The average value of ρ _V [Ω.cm] is shown in the table.

(Roller resistance value)
As shown in FIG. 6, the conductive layer 41 through the cored bar 42 is abutted and mounted on a φ30 aluminum drum 43 and connected to the + side of the power supply 44 in an atmosphere at a temperature of 23 ° C. and a relative humidity of 55%. The end of the conducting wire having resistance r (100Ω to 10 kΩ) was connected to one end surface of the aluminum drum 43 and the leading end of the conducting wire connected to the negative side of the power source 44 was connected to the other end surface of the conductive layer 41 to conduct electricity. The conductive roller 40 was indirectly rotated by applying a load F of 500 g to both ends of the core metal 42 and rotating the aluminum drum 43 while applying a voltage of 1000 V between the core metal 42 and the aluminum drum 43. At this time, resistance measurement was performed 36 times in the circumferential direction, and the average value was obtained. The value of the internal resistance was adjusted so that the significant figure of the measured value was as large as possible according to the level of the resistance value of the roller. In the apparatus of FIG. 6, when the applied voltage is E, the roller resistance value R is R = r × E / V−r, but the term of −r is regarded as very small this time, and R = r × E / V. The roller resistance value R was calculated from the detected voltage V applied to the internal resistance r. In the table, the average logarithmic value of the roller resistance value is used.

(Volume specific resistance environment dependence)
In Examples and Comparative Examples of conductive belts, in the environment of 10 ° C. relative humidity 15% (LL environment) and 32.5 ° C. relative humidity 90% (HH environment), 100 V is applied in the same manner as described above. The volume resistivity of the conductive belt was measured.
And, the volume resistivity is dependent on the environment: Δlog ₁₀ ρ _V (LL-HH) [Ω.cm] = log ₁₀ ρ _V (10 ° C., 15% rh.)-Log ₁₀ ρ _V (32, 5 ° C., 90 % Rh.)
According to the equation, environmentally dependent numerical values are calculated, and the values are shown in Tables 5 and 6. It is not preferable that this value exceeds 1.7.

(Roller resistance unevenness)
Using the apparatus shown in FIG. 6, in an atmosphere of 23 ° C. and 55% relative humidity, a load F of 500 g is applied to both ends of the metal core, and the conductive roller is rotated by rotating the aluminum drum at a rotation speed of 30 rpm. In this state, when an applied voltage of 1000 V was applied, the circumferential unevenness (ratio of (maximum value of electrical resistance in the circumferential direction / minimum value of electrical resistance in the circumferential direction)) within one circle was determined. The circumferential unevenness is 1.0 to 1.3, more preferably 1.0 to 1.2, and still more preferably 1.0 to 1.15.

(Resistance increase during continuous energization)
By measuring roller resistance.
[Examples 1-7], [Comparative Examples 1-5]
A constant voltage of 1000 V was continuously applied to the roller for 96 hours in an environment of 23 ° C. and relative humidity of 55% in the same state as when the roller resistance value [Ω] was measured. At this time, the roller resistance value R (t = 0) immediately after voltage application and the roller resistance value R (t = 96 hr.) After application for 96 hours were measured in the same manner as described above, and these values were used. The amount of increase in resistance during continuous energization: Δlog ₁₀ R (t = 96-0 hr.) [Ω] = log ₁₀ R (t = 96 hr.)-Log ₁₀ R (t = 0) was calculated. Numerical values are shown in Tables 1-4. Since the rotation speed of the aluminum drum is 30 rpm and the diameter is 30 mmφ, the linear velocity during rotation is 94 mm / min.

(Resistance increase during continuous energization)
By measuring volume resistivity.
A digital ultra-high manufactured by Advantest Corporation in a conductive belt or at a point with a slab of 0.25 mm in thickness in the same condition as when measuring volume resistivity in an environment of 23 ° C. and 55% relative humidity. A constant voltage of 1000 V was continuously applied for 5 hours using a resistance microammeter R-8340A. At this time, the volume specific resistance value ρV (t = 0) of the belt or slab immediately after voltage application and the volume specific resistance value ρV (t = 5 hr.) Of the belt or slab after application for 5 hours are expressed as above. Measured in the same manner, and using these values, the amount of increase in resistance during continuous energization: Δlog ₁₀ ρ _V (t = 5-0 hr.) [Ω.cm] = log ₁₀ ρ _V (t = 5 hr.)-Log ₁₀ ρ _V (t = 0) was calculated. Numerical values are shown in each table.

(In-plane unevenness)
The measurement of the in-plane unevenness of the conductive belt is performed by dividing the maximum value of the 20 specific volume resistivity values obtained in one belt by the minimum value. The calculated values were calculated and listed in Tables 5 and 6. Thus, it can be seen that the belts in Examples and Comparative Examples are very uniform with almost no unevenness. On the other hand, this value can be about 2 to 10 for a carbon conductive belt, and about 100 for a large belt.
Regarding the in-plane unevenness of the volume resistivity of the rubber composition for the conductive roller and the urethane composition, Mitsubishi Chemical Co., Ltd. has a total of 20 points in the produced 130 × 130 × 2 mm slab: 5 points in length × 4 points in width. Measurement was performed using a Hiresta UP and URS type probe, and a value obtained by dividing the maximum value by the minimum value was calculated and described in each table.

(Compression set)
Using the test piece obtained by cutting the conductive roller obtained above with a width of 10 mm parallel to the end face, according to the vulcanized rubber and thermoplastic rubber permanent strain test method described in JIS K6262, a measurement temperature of 70 ° C., a measurement time The measurement was performed at a compression rate of 25% for 22 to 24 hours. If this compression set value exceeds 30%, the dimensional change when it becomes a roller becomes so large that it is likely not to be suitable for practical use.

(Photoconductor contamination test)
In Examples 1 to 8 and Comparative Examples 1 to 8, the test was performed by the following method.
With the vulcanized rubber slab sheet of Example / Comparative Example pressed against the photoreceptor set in the cartridge (cartridge type C4127X) of Laser Jet 4050 type laser beam printer manufactured by Hewlett-Packard Company, 32.5 ° C, relative Store at 90% humidity for 2 weeks. Thereafter, the vulcanized rubber slab sheet was removed from the photoconductor, halftone printing was performed with the printer using the photoconductor, and whether or not the printed material was stained was examined according to the following criteria.
○: No contamination as long as the printed product is visually observed. △: Mild contamination (contamination with no problem in use that can be removed to the extent that it cannot be seen visually by imprinting within 5 sheets)
×: Severe contamination (contamination that reveals abnormalities by visual inspection of printed matter even when 5 or more sheets are imprinted)
For the conductive belts of Examples 9 and 10 and Comparative Examples 9 and 10, a section of the obtained conductive belt, a laser beam printer DocuPrint 180 manufactured by Fuji Xerox Co., Ltd., and its cartridge (product code CT350035). Evaluation was performed in the same manner as described above using the photoconductor set in (1). However, the storage conditions were 45 ° C. and 80% relative humidity.

(Measurement of hardness)
About the electroconductive roller, the hardness under the load of 500 g was measured using the type E durometer described in JIS K6253 (durometer E hardness). However, for the solid roller, the load was 1000 g.

  As shown in Tables 1 and 2, the conductive rollers obtained from the conductive polymer compositions of Examples 1 to 7 are unevenly distributed with a dissociable salt in the required one-phase first discontinuous phase. For this reason, all of them were excellent in electrical characteristics, and problems such as migration contamination did not occur. In particular, the electrical resistance was less dependent on the environment, and the resistance increase during continuous energization was small. In addition, the conductive polymer composition reduced in hardness by foaming or the foaming roller using the conductive polymer composition was good because the resistance increase during energization was small.

  On the other hand, since Comparative Example 1 did not contain a dissociable salt, the volume resistivity value and the roller resistance value were too high. In Comparative Examples 2 and 3, since the dissociable salt was unevenly distributed in the continuous phase, the increase in resistance during continuous energization was not suitable. Since Comparative Examples 4 and 5 used a salt that can be dissociated in a one-phase system, the resistance increase during continuous energization was not suitable.

  Moreover, FIG. 2 mentioned above was the morphology which observed Example 2 in the phase mode in the scanning probe microscope (SPM) of an atomic force microscope (AFM) type. The morphology of Comparative Example 3 (one side: 10 μm) is shown in FIG. Comparative Example 3 is composed of one continuous phase and one discontinuous phase, and the dissociable salt is unevenly distributed in the continuous phase.

  Furthermore, FIG. 8 shows the resistance change during continuous energization of the conductive roller made of the conductive polymer composition of Example 1 and Comparative Example 2. The horizontal axis is the energization time, and the vertical axis is the roller resistance value. In Example 1 and Comparative Example 2, the roller resistance values in the initial state are almost the same, but as shown in FIG. 8, the resistance in Comparative Example 2 is significantly increased by continuous energization, whereas in Example 1, Only a slight increase.

  As shown in Tables 3 and 4, in the conductive urethane rubber composition of Example 8 and the conductive roller using the same, a salt that can be dissociated only in the required first discontinuous phase is unevenly distributed. Therefore, both of them were excellent in electrical characteristics and did not cause problems such as migration contamination. In particular, the electrical resistance was less dependent on the environment, and the resistance increase during continuous energization was small.

  On the other hand, since Comparative Examples 6 and 7 did not contain a dissociable salt, the resistance value was high and unsuitable. Since Comparative Example 8 basically used a salt that can be dissociated in a substantially one-phase system, the increase in resistance during continuous energization was not suitable.

Next, examples and comparative examples of conductive polymer compositions for conductive belts are shown.
Each compounding material described in Table 5 and Table 6 was compounded and kneaded using the tumbler and twin-screw extruder by the method described above, and then extruded by a resin extruder, and the inner diameter was 168 mm, the average thickness was 0.25 mm, A conductive belt for an intermediate transfer belt having a width of 350 mm was produced. Tables 5 and 6 show the evaluation results and various evaluations as the belt described above.

(Examples 9 and 10)
A resin comprising a polyethylene oxide block nylon 12 copolymer or a polyether ester amide copolymer having a very high affinity between the cation and the anion-dissociable salt used in the present invention as a polymer constituting the discontinuous phase Using a type antistatic agent, lithium-bis (trifluoromethanesulfonyl) imide, which is a salt dissociable into a cation and an anion, was unevenly distributed. As the continuous phase, a polyester-based thermoplastic elastomer composed of a polyether soft segment and a polyester hard segment, which has a smaller affinity with the salt than the above resin-type antistatic agent, but has a little affinity. A master batch with the above resin-type antistatic agent was prepared and used so that the concentration of lithium-bis (trifluoromethanesulfonyl) imide was 5 wt%. In addition, since the value of R2 in the data of Comparative Example 10 and the volume specific resistance value of the composition show a reasonably low value, the thermoplastic elastomer (perprene) used in these Examples is the present invention. It can be seen that the salt used has a certain affinity.

(Comparative Examples 9 and 10)
In Comparative Example 9, 20 wt% of lithium-bis (trifluoromethanesulfonyl) imide dissolved in dibutoxyethoxyethyl adipate was added to a polyester-based thermoplastic elastomer (polyether-polyester block copolymer Perprene P90BD). Using. The amount of salt was 0.5 parts by weight. In Comparative Example 10, lithium-bis (trifluoromethanesulfonyl) imide was directly dispersed in one phase of a polyester-based thermoplastic elastomer without using a medium composed of a low molecular weight polyurethane compound or a low molecular weight polar compound.

  The resin-type antistatic agent 1 has a polyethylene oxide block nylon 12 copolymer as a main component. The resin-type antistatic agent 2 contains a polyether ester amide copolymer as a main component.

  As shown in Tables 5 and 6, in Examples 9 and 10, since the dissociable salt is unevenly distributed in the required first discontinuous phase, all of them have excellent electrical characteristics and problems such as migration contamination. Also did not occur. In particular, the electrical resistance was less dependent on the environment, and the resistance increase during continuous energization was small.

  On the other hand, Comparative Example 9 uses a salt that can be dissociated in a one-phase system, and such a salt is dispersed using a medium composed of a low molecular weight polar compound. It was unsuitable. In Comparative Example 10, the increase in resistance during continuous energization was large, and the environmental dependency was slightly large.

It is a schematic diagram which shows the structure of the conductive polymer composition of 1st Embodiment of this invention. It is a figure which shows the phase structure (morphology) of the conductive polymer which forms the conductive member of Example 2 of 1st Embodiment. It is the schematic of the conductive roller provided with the conductive layer formed from the conductive polymer of 1st Embodiment. It is the schematic of the electroconductive belt formed using the electroconductive polymer composition of 2nd Embodiment of this invention. It is a schematic diagram which shows the structure of the conductive polymer composition of 2nd Embodiment. It is the schematic of the measuring apparatus of the electrical property of rollers, such as a roller resistance value. It is a figure which shows the phase structure (morphology) of the conductive polymer which forms the conductive member of the comparative example 3. It is a graph which shows the resistance change at the time of continuous energization of the roller of Example 1 and Comparative Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1 'continuous phase 2, 2' 1st discontinuous phase 3 2nd discontinuous phase 10 Conductive roller 11, 21 Conductive layer 12 Core metal 13 Conductive belt

Claims (13)

A conductive polymer composition comprising an ion conductive additive salt,
It consists of a continuous phase and one discontinuous phase, and the continuous phase and the discontinuous phase form a sea-island structure,
The polymer constituting the continuous phase is a polyester-based thermoplastic elastomer, the polymer constituting the discontinuous phase is a polyoxyalkylene copolymer, and the polymer constituting the discontinuous phase has a cation reducing ability. And a salt capable of dissociating into an anion, and the polymer constituting the discontinuous phase has a higher affinity for the salt capable of dissociating into the cation and the anion than the polymer constituting the continuous phase. The salt is unevenly distributed in the continuous phase, the salt is hardly dispersed in the continuous phase, and the movement of the salt to the outside is suppressed,
The weight ratio of the polymer constituting the discontinuous phase and the polymer constituting the continuous phase is (the polymer constituting the discontinuous phase: the polymer constituting the continuous phase) = (20:80) to (45: 55)
The salt capable of dissociating into the cation and the anion is blended at a ratio of 0.01 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the total polymer component, and is a thermoplastic elastomer composition. A conductive polymer composition.   The conductive polymer composition according to claim 1, wherein the polyoxyalkylene copolymer is a polyethylene oxide block nylon copolymer or a polyether ester amide copolymer. When the volume resistivity of the polymer constituting the first discontinuous phase is R1, and the volume resistivity of the polymer constituting the continuous phase is R2,
The conductive polymer composition according to claim 1, wherein 2.3 ≦ log ₁₀ R 2 −log ₁₀ R 1 ≦ 4.4.   The salt capable of dissociating into a cation and an anion was measured at a salt concentration of 0.1 mol / l at 25 ° C. in a propylene carbonate (PC) dimethyl carbonate (DME) mixed solvent (volume fraction 1/2). The conductive polymer composition according to any one of claims 1 to 3, wherein the electrical conductivity is 2.3 [mS / cm] or more.   The conductive polymer composition according to any one of claims 1 to 4, wherein the salt capable of dissociating into a cation and an anion is a salt having an anion having a fluoro group and a sulfonyl group.   The anion having a fluoro group and a sulfonyl group is an ion selected from at least one selected from the group consisting of a bis (fluoroalkylsulfonyl) imide ion, a tris (fluoroalkylsulfonyl) methide ion, and a fluoroalkylsulfonic acid ion. Item 6. The conductive polymer composition according to Item 5.   The conductive cation according to claim 5 or 6, wherein a cation of the salt having an anion having a fluoro group and a sulfonyl group is a cation of an alkali metal, a group 2A, a transition metal, or an amphoteric metal. Polymer composition.   The salt having an anion having a fluoro group and a sulfonyl group comprises an alkali metal salt of bis (trifluoromethanesulfonyl) imide, an alkali metal salt of tris (trifluoromethanesulfonyl) methide, and an alkali metal salt of trifluoromethanesulfonic acid. The conductive polymer composition according to any one of claims 5 to 7, which is a salt selected from at least one of the group.   The salt capable of dissociating into a cation and an anion is blended without using a medium composed of a low molecular weight polyether compound having a number average molecular weight (Mn) of 10,000 or less or a conductive plasticizer which is a low molecular weight polar compound. The conductive polymer composition according to any one of claims 1 to 8.   The electroconductive member which consists of an electroconductive roller or an electroconductive belt formed from the electroconductive polymer composition of any one of Claim 1 thru | or 9.   A conductive roller comprising: a cylindrical metal core having conductivity; and a conductive layer formed by cylindrically forming the conductive polymer composition on the surface of the core. Item 11. The conductive member according to Item 10.   The conductive member according to claim 10, wherein the conductive polymer composition comprises a conductive belt formed into a seamless single-layer belt shape. It is a manufacturing method of the conductive polymer composition according to claim 1 or 2,
Kneading the cation and anion dissociable salt to the polyoxyalkylene copolymer,
A method for producing a conductive polymer composition, wherein the kneaded product is produced by kneading the polyester-based thermoplastic elastomer.

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