JP2007297438A - Composition for forming semiconducting urethane elastomer and semiconducting roll produced by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for forming a semiconducting urethane and having excellent stability of the stock solution and a semiconducting roll produced by using the composition and free from the bleed-out of the conductive agent even under a severe condition. <P>SOLUTION: The composition for forming a semiconducting urethane elastomer is composed of (A) a base material containing an isocyanate-terminated urethane prepolymer obtained by reacting (a1) a polyether polyol with (a2) an organic polyisocyanate and (B) a curing agent containing (b1) a polyol, (b2) a conductive agent composed of a conductive carbon and (b3) an antistatic agent composed of a specific ionic compound, wherein the content of the component (b2) is 0.1-1 mass% and that of the component (b3) is 0.001-10 mass% based on the sum of the base material (A) and the curing agent (B). The invention further provides a semiconducting roll produced by using the composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a semiconductive urethane elastomer-forming composition having excellent raw material liquid stability without bleeding of an antistatic agent composed of an ionic compound even under severe conditions, and semiconductive using the composition The present invention relates to a roll, and is suitable for a developing roll, a charging roll, a transfer roll and the like in an electrophotographic apparatus such as a copying machine or a printer.

  Conventionally, conductive fine powder is generally added as a means for imparting conductivity to rubber. As the conductive fine powder, carbon (carbon black), metal, metal oxide and the like are generally used.

  On the other hand, the bias application roll in the electrophotographic apparatus is required to be non-staining to the photoreceptor and toner. In order to prevent physical, chemical and electrical contamination, conductive coating such as polyamide (nylon) or alkyd resin is generally applied to the rubber roll surface layer (Patent Document 1, Patent Document 2, Patent) Reference 3 etc.).

  However, when such a structure is adopted, there is a disadvantage that the process becomes complicated and the manufacturing cost increases.

  As a means for easily solving these problems, a method of chemically treating the inside of the roll surface has been proposed (see Patent Document 4).

  Although this treatment method is effective, there is a problem that it is easily affected by the surface resistance of the substrate.

  On the other hand, when the electrical resistance of the substrate is controlled by the dispersion of conductive fine particles such as carbon black, the variation due to the environment such as temperature and humidity is small, but the dispersion of the conductive fine particles is insufficient. Variation is a problem. The effect of this variation was not emphasized in the low-resolution area, but improvement has been demanded as the image quality of electrophotographic apparatuses such as printers and copiers increases.

  As another means for conducting, there is a method using an ionic conductive material. In this method, since the ionic conductive material is dispersed at the molecular level in the polymer matrix of the electric resistance adjusting layer, the electric resistance is lower than that of the above method in which the conductive pigment is dispersed in the electric resistance adjusting layer. The variation is small, and therefore, partial charging failure does not cause a problem in image quality. However, since the ionic conductive material has a migratory property, it bleeds out to the surface of the charging roller over time and contaminates the photosensitive drum, thereby causing an image defect. In addition, ionic conductive materials are often difficult to disperse in urethane resins due to the nature of ionic salts, and in particular, are often poorly compatible with polyether polyols. Furthermore, since many ionic conductive materials have high hygroscopicity, it absorbs moisture in the atmosphere at the time of molding, and it is difficult to obtain a good molded product. In addition, there is a problem that the electrical resistance changes depending on the environment such as temperature and humidity.

  As means for solving such a problem, it has been proposed to provide a protective layer having a barrier function on the surface of the electric resistance adjusting layer. This protective layer is required to be thin and uniform and have good surface properties so as not to impair the function as a charging roller. As a material constituting the protective layer, a fluororesin, a silicone resin, a polyamide resin, a polyurethane resin, a polyethylene resin, and the like have been proposed (see Patent Document 5).

  However, when these charging rollers are mounted on an image forming apparatus and used for a long period of time, the resin material that is the main component of the surface protection layer of the charging roller is not a little sticky. Residual toner, paper dust, and the like are picked up from the photosensitive drum and contaminated, which causes problems such as charging failure and image unevenness.

JP-A-1-66674 JP-A-4-67067 Japanese Patent Laid-Open No. 7-20684 JP-A-5-158341 Japanese Patent No. 2947019

  However, a production method capable of easily producing a single-layer semiconductive urethane elastomer satisfying all of these characteristics has not been realized.

  In view of such circumstances, the present invention provides a semiconductive urethane elastomer-forming composition and a semiconductive roll using the composition without using a conventional multilayer structure such as tube coating or coating. This is the issue.

  As a result of repeated studies, the present inventors have found that the above problem can be solved by using an antistatic agent composed of conductive carbon and a specific ionic compound, and the present invention has been completed.

That is, the aspect of the present invention
A main agent (A) containing an isocyanate group-terminated urethane prepolymer obtained by reacting a polyether polyol (a1) and an organic polyisocyanate (a2), a polyol (b1), a conductive agent (b2), and an antistatic agent ( In the semiconductive urethane elastomer-forming composition comprising the curing agent (B) containing b3),
The conductive agent (b2) is conductive carbon, and the antistatic agent (b3) is a quaternary ammonium cation having an aliphatic unsaturated hydrocarbon group having 10 to 20 carbon atoms and one hydroxyalkyl group, and bis (trifluoromethane). (Sulfonylimide) an ionic salt comprising an anion, each content of the conductive agent (b2) and the antistatic agent (b3) in the total amount of the main agent (A) and the curing agent (B) is (b2) : 0.1 to 1% by mass, (b3): 0.001 to 10% by mass, a semiconductive urethane elastomer-forming composition.

The second aspect of the present invention is:
Main agent (A) containing an isocyanate group-terminated urethane prepolymer obtained by reacting polyether polyol (a1) and organic polyisocyanate (a2), polyol (b1), conductive agent (b2), and antistatic agent ( In the semiconductive urethane elastomer-forming composition comprising the curing agent (B) containing b3),
The conductive agent (b2) is conductive carbon, and the antistatic agent (b3) is an aliphatic unsaturated hydrocarbon group having 10 to 20 carbon atoms and a quaternary ammonium cation having two hydroxyalkyl groups and bis (trifluoromethane). (Sulfonylimide) an ionic salt comprising an anion, each content of the conductive agent (b2) and the antistatic agent (b3) in the total amount of the main agent (A) and the curing agent (B) is (b2) : 0.1 to 1% by mass, (b3): 0.001 to 10% by mass, a semiconductive urethane elastomer-forming composition.

The third aspect of the present invention is:
3. The semiconductive urethane elastomer-forming composition according to claim 1, wherein the conductive agent (b3) is ketjen black.

The fourth aspect of the present invention is:
It is a semiconductive roll using any of the aforementioned semiconductive urethane elastomer-forming compositions.

  According to the present invention, it is possible to provide a semiconductive urethane elastomer having semiconductivity, low temperature dependence of electrical resistance, and no bleeding out of the antistatic agent even under severe conditions, and high performance semiconductivity. It became possible to provide rolls.

  The present invention includes a main agent (A) containing an isocyanate group-terminated urethane prepolymer obtained by reacting a polyether polyol (a1) and an organic polyisocyanate (a2), a polyol (b1), a conductive agent (b2), and It is a semiconductive urethane elastomer-forming composition comprising a curing agent (B) containing an antistatic agent (b3).

  The main agent (A) contains an isocyanate group-terminated urethane prepolymer obtained by reacting the polyether polyol (a1) and the organic polyisocyanate (a2).

  When a polyester polyol is used instead of the polyether polyol (a1), not only the hydrolysis resistance of the resulting semiconductive urethane elastomer is lowered, but also the resilience is lowered. For this reason, when it is used as a roll, it deforms moderately when stress is applied, and when the stress is released thereafter, quick recovery is necessary, but this is insufficient.

  The number average molecular weight of the polyether polyol (a1) used in the present invention is preferably more than 500 to 5,000, particularly preferably 1,000 to 3,000.

  Specifically, an active hydrogen group-containing compound shown below is used as an initiator, such as ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), butylene oxide, amylene oxide, methyl glycidyl ether and the like. It can be obtained by addition polymerization of EO alone or a mixture of EO and other monomers from a cyclic ether monomer such as alkyl glycidyl ether or phenyl glycidyl ether, or a cyclic ether monomer such as tetrahydrofuran. In the present invention, poly (oxytetramethylene) polyol (hereinafter abbreviated as PTMG) is preferable in consideration of the strength, impact resilience, and the like of the obtained semiconductive urethane elastomer.

Examples of the initiator include those shown below.
Low molecular polyols:
Ethylene glycol (hereinafter abbreviated as EG), 1,2-propanediol (hereinafter abbreviated as 1,2-PD), 1,3-PD, 1,2-butanediol (hereinafter abbreviated as 1,2-BD) ), 1,3-BD, 1,4-BD, 1,5-pentanediol, 1,6-hexanediol (hereinafter abbreviated as 1,6-HD), 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol (hereinafter abbreviated as MPD), neopentyl glycol (hereinafter abbreviated as NPG), 1,8-octanediol, 1,9-nonanediol, decamethylene glycol, diethylene glycol, diethylene glycol Propylene glycol, 2,2-diethyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol (hereinafter abbreviated as DMH), , 2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-n-hexadecane-1,2-ethylene glycol, 2-n-eicosane-1,2-ethylene glycol 2-n-octacosane-1,2-ethylene glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, 3-hydroxy-2,2-dimethylpropyl-3-hydroxy-2,2- Dimethylpropionate, dimer acid diol, bisphenol A, hydrogenated bisphenol A, ethylene oxide or propylene oxide adduct of bisphenol A, hydrogenated bisphenol A, trimethylolpropane, glycerin, hexanetriol, quadrol, pentaerythritol, sorbitol, Close, glucose, fructose and low molecular polyamines:
Low molecular amino alcohols such as ethylenediamine, propylenediamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine, isophoronediamine, and diethylenetriamine:
Other active hydrogen group-containing compounds such as monoethanolamine, diethanolamine and triethanolamine:
ammonia

  Examples of the organic polyisocyanate (a2) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, , 5-naphthylene diisocyanate, 1,4-naphthylene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, tetramethylxylylene diisocyanate, 4 , 4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, Aromatic diisocyanates such as 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, 3,3'-dimethoxydiphenyl-4,4'-diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate Aliphatic diisocyanates such as 2-methyl-1,5-pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, lysine diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate , Alicyclic diisocyanates such as hydrogenated tetramethylxylylene diisocyanate and cyclohexyl diisocyanate, polyphenylene poly Polyisocyanates such as tylene polyisocyanate and crude tolylene diisocyanate, mixtures of two or more of these, urethane modified products, allophanate modified products, urea modified products, biuret modified products, uretdione modified products, uretoimine modified products of these organic diisocyanates, An isocyanurate modified body, a carbodiimide modified body, etc. are mentioned.

  The isocyanate group-terminated urethane prepolymer used in the main agent (A) used in the present invention is obtained by reacting at least the aforementioned polyether polyol (a1) and the organic polyisocyanate (a2). In this case, the isocyanate group / hydroxyl molar ratio (R value) is preferably 1.1 to 10, and more preferably 1.5 to 5. The reaction temperature is 30 to 100 ° C, preferably 50 to 80 ° C.

Isocyanate group-terminated urethane prepolymer obtained in this way, an isocyanate content of 1 to 15 wt%, a viscosity of 75 ° C. is 100~5,000mm / s ^2.

  The curing agent (B) used in the present invention contains a polyol (b1), a conductive agent (b2), and an antistatic agent (b3).

  Examples of the polyol (b1) include a low molecular polyol having a number average molecular weight of 500 or less and a high molecular polyol having a number average molecular weight of more than 500 to 3,000.

  Low molecular polyols having a number average molecular weight of 500 or less include EG, DEG, 1,2-PG, 1,3-PG, 1,3-BD, 1,4-BD, NPG, 1,6-HG, hydrogen Additional bisphenol A, glycerin, TMP, hexanetriol can be mentioned. These can be used alone or in combination of two or more. A preferred low molecular polyol in the present invention is TMP.

  Examples of the polymer polyol having a number average molecular weight of more than 500 to 3,000 include polyether polyol, polyester polyol, and polycarbonate polyol. In selecting the type of the polymer polyol, it is preferable to select the same component as the polymer polyol used for the main agent in consideration of the compatibility with the main agent (for example, the main component using the polyether polyol is a polyether. Select a polyol). In the present invention, poly (oxytetramethylene) polyol is particularly preferable among these from the viewpoint that suitable mechanical properties can be obtained in the molded product desired in the present invention.

  Examples of the conductive carbon as the conductive agent (b2) used in the present invention include acetylene black, ketjen black, furnace black, thermal black, lamp black, channel black, gas black, disk black, etc. There are various types of products. In the present invention, ketjen black having high conductivity is preferable when blended with a polyol and considering moldability.

  The compounding quantity of a electrically conductive agent (b2) is 0.1-1 mass% with respect to the total amount of a main ingredient (A) and a hardening | curing agent (B), and 0.3-0.8 mass% is especially preferable. . When there are too few compounding quantities of a electrically conductive agent (b2), the temperature dependence of the electroconductivity in the urethane elastomer obtained becomes large. Moreover, when there are too many compounding quantities, the viscosity of a liquid will increase and shaping | molding itself will become difficult.

  The antistatic agent (b3) used in the present invention comprises a quaternary ammonium cation having an aliphatic unsaturated hydrocarbon group having 10 to 20 carbon atoms and one or two hydroxyalkyl groups and bis (trifluoromethanesulfonyl). It is an ionic salt composed of (imide) anion.

Examples of the aliphatic unsaturated hydrocarbon group having 10 to 20 carbon atoms are those represented by the following general formula (1), and specific examples include an oleyl group and a linoleyl group.

  When the number of carbon atoms of the aliphatic unsaturated hydrocarbon group is less than 10, the compatibility with the main agent is lowered, and the antistatic agent is difficult to uniformly disperse in the molded product.

  When the hydrocarbon group having 10 to 20 carbon atoms is a saturated hydrocarbon group, the crystallinity of the antistatic agent increases, and the antistatic agent is added to the curing agent whose main component is a high molecular weight polyether polyol. There are problems such as easy precipitation.

The hydroxyalkyl group is represented by the following general formula (2), and specific examples include a methylol group, a hydroxyethyl group, a hydroxypropyl group, and the like.

  When the hydroxyalkyl group is a simple alkyl group, the antistatic agent may bleed over time. On the other hand, since it is a hydroxyalkyl group in the present application, the antistatic agent is taken into the urethane skeleton, so it can be said that the antistatic agent is not likely to bleed.

  Specific examples of the quaternary ammonium cation having an aliphatic unsaturated hydrocarbon group having 10 to 20 carbon atoms and one or two hydroxyalkyl groups that satisfy the above requirements are as follows. Is mentioned.

  When the anion is an anion other than the bis (trifluoromethanesulfonylimide) anion, it is difficult to maintain a liquid state in a normal state, and the compatibility with the main agent and the curing agent tends to be lowered. Moreover, it is often water-soluble, and there are problems with hygroscopicity and environmental stability of the resulting conductive elastomer.

  The blending amount of the antistatic agent (b3) is 0.001 to 10% by mass, particularly preferably 0.01 to 5% by mass, based on the total amount of the main agent (A) and the curing agent (B). When the blending amount of the antistatic agent (b3) is too small, the conductivity of the molded product is insufficient, and when it is too large, the conductivity reaches the peak with respect to the blending amount, which is not economical, and the physical properties. There is a risk of bleed due to decrease or aging.

  In the present invention, if necessary, a curing catalyst and various additives such as a plasticizer, an antifoaming agent, a leveling agent, a matting agent, a flame retardant, a thixotropic agent, a tackifier, a thickener, a lubricant, a charging agent. Inhibitors, conductive agents such as carbon and lithium salts, surfactants, reaction retarders, dehydrating agents, antioxidants, UV absorbers, hydrolysis inhibitors, weathering stabilizers, dyes, inorganic pigments, organic pigments, extender pigments Etc. can be used as appropriate.

  As a curing catalyst, triethylamine, tripropylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, dimethylbenzylamine, N, N, N ′, N′-tetramethylhexamethylenediamine, N, N, N ′ , N ′, N ″ -pentamethyldiethylenetriamine, triethylenediamine, bis- (2-dimethylaminoethyl) ether, tertiary amine such as 1,8-diaza-bicyclo (5,4,0) undecene-7, dimethylethanol Reactive tertiary amines such as amines, N-trioxyethylene-N, N-dimethylamine, N, N-dimethyl-N-hexanolamine or organic acid salts thereof, 1-methimidazole, 2-methylimidazole, 1 , 2-dimethylimidazole, 2,4-dimethylimidazole, 1-butyl- -Imidazole compounds such as methylimidazole, stannous octoate, dibutyltin dilaurate, dioctyltin dilaurate, organometallic compounds such as zinc naphthenate, 2,4,6-tris (dimethylaminomethyl) phenol, 2,4,6- Trimerization catalysts such as tris (dialkylaminoalkyl) hexahydro-S-triazine, potassium acetate, potassium 2-ethylhexanoate and the like can be mentioned.

  The semiconductive roll of the present invention is obtained by curing the aforementioned semiconductive urethane elastomer-forming composition. In order to obtain this semiconductive roll, the main agent (A) and the curing agent (B) are mixed uniformly, and the entrained air is removed as necessary (mixing). Next, the liquid is poured into a preheated mold (casting) and heated to cause a curing reaction. The preheating temperature of the mold is preferably 60 to 150 ° C. The curing conditions are preferably 3 to 10 hours at 60 to 200 ° C. In addition, it is preferable to further age at normal temperature after that for 1-7 days, and to harden | cure completely and to stabilize a physical property. Once cured, the cured product is removed from the mold (demolding).

  The mixing ratio of the main agent (A) and the curing agent (B) is a molar ratio of isocyanate group and hydroxyl group present in the system immediately after mixing, and is preferably isocyanate group / hydroxyl group = 90/100 to 115/100, 95/100 ˜110 / 100 is particularly preferred.

  The semiconductive roll obtained from the above has high rebound resilience, and the electrical resistance value also exhibits semiconductivity, and the temperature dependence of the electrical resistance is also small.

  Next, although the Example and comparative example of this invention are demonstrated in detail, this invention is not limited to these Examples. Unless otherwise specified, “%” in the examples means “% by mass”.

[Synthesis of isocyanate group-terminated urethane prepolymer for main agent]
Production Example 1
A volume of 1 L reactor equipped with a stirrer, thermometer, nitrogen seal tube, and condenser was charged with 727.3 g of polyol-1 and 272.7 g of MDI-1, and reacted at 85 ° C. for 3 hours. The isocyanate group terminal prepolymer (A-1) was obtained. The isocyanate content of A-1 was 6.1%, and the kinematic viscosity at 75 ° C. was 1,200 mm / s ² .

Production Examples 2 and 3
With preparations shown in Table 1, isocyanate group-terminated prepolymers A-2 and 3 were obtained in the same apparatus and procedure as in Example 1. The production results are also shown in Table 1.

Production Examples 1 to 3, in Table 1, Polyol-1: Poly (oxytetramethylene) polyol
Average number of functional groups = 2
Number average molecular weight = 2,000
Polyol-2: Poly (oxypropylene) polyol
Average number of functional groups = 2
Number average molecular weight = 2,000
Polyol-3: Poly (ethylene adipate) polyol
Average number of functional groups = 2
Number average molecular weight = 2,000
MDI-1: 4,4'-diphenylmethane diisocyanate

[Composition of curing agent]
Formulation Examples 1-15
In the ratios shown in Tables 2 and 3, polyol, conductive agent, antistatic agent and catalyst were mixed. The used ionic conductive agent is represented by the following general formula (5), and the specific contents are shown in Table 4. Tables 2 and 3 show the curing agent blending composition and the curing agent liquid stability results.

In Formulation Examples 1 to 15 and Tables 2 to 3, Polyol-4: Poly (oxytetramethylene) polyol
Average number of functional groups = 2
Number average molecular weight = 1,000
Polyol-5: Poly (oxypropylene) polyol
Average number of functional groups = 2
Number average molecular weight = 1,000
Polyol-6: Poly (oxypropylene) polyol
Average number of functional groups = 3
Number average molecular weight = 3,000
Polyol-7: Poly (ethylene adipate) polyol
Average number of functional groups = 2
Number average molecular weight = 1,000
TMP: Trimethylolpropane catalyst-1: N, N'-dimethylaminohexanol

  From the results of Table 3, in the anion portion of the ionic compound used for the antistatic agent, the substituent is a saturated aliphatic hydrocarbon group having 10 to 20 carbon atoms (B-13) and has a hydroxyl group. No (B-14) was found to have insufficient compatibility with the curing agent mainly composed of high molecular weight polyether polyol. Therefore, these curing agents (B-13 and 14) were not evaluated thereafter.

[Evaluation of cured product]
Examples 1-7, Comparative Examples 1-6
The main agent and the curing agent were mixed at the compounding ratios shown in Tables 5 and 6, the mixed solution was poured into a mold heated in advance after defoaming, and cured by heating to obtain a cured product. Curing conditions and various test methods are as shown below. After curing, appearance evaluation, mechanical property evaluation, and conductivity evaluation were performed. The results are shown in Tables 5 and 6.

Curing conditions The main agent and curing agent were each heated to 80 ° C, mixed with agitator at the blending ratio in the table (40 seconds), vacuum degassed, and preheated to 120 ° C in advance to a 2mm thick sheet mold. Cast. After being cured by heating in an oven at 120 ° C. for 10 hours, the mold was removed. Next, secondary curing was performed at room temperature for 1 week to obtain a measurement sample.

Evaluation Test Method Bleed Out Test A 2 mm thick sheet obtained by the above method was sandwiched between glass plates and allowed to stand under the conditions of temperature: 50 ° C., humidity: 90%: period: 1 week. Thereafter, the glass plate was removed from the sheet, and an evaluation was made based on whether or not a bleed-out substance could be confirmed on the glass plate.
◯: No bleed material was observed. X: Mechanical strength at which the bleed material was observed. A 2 mm thick sheet obtained by the above method was measured according to JIS-K7312. The compression set was evaluated under the conditions of 70 ° C. × 22 hours and 25% compression.
Volume resistance measurement The surface of the 2 mm-thick sheet obtained above was washed with methanol. Under LL (10 ° C. × 15%) conditions, NN (23 ° C. × 55%) and HH (28 ° C. × 85%) were used for 2 days. %) Conditions were measured after maintaining the state for one day. The measuring instrument was an R8340A digital superresistance meter manufactured by Advantest Corporation and a sample box for TR42 ultrahigh resistance, and the measurement voltage was 100 V and the measurement was performed 30 seconds after voltage application. The environmental dependence was evaluated by a logarithmic value of a value obtained by dividing the measured value of LL by the measured value of HH. The variation of the volume resistance value was evaluated by the ratio of the maximum measurement value and the minimum measurement value of 10-point measurement.

  From Tables 5 and 6, the semiconductive urethane elastomer (sheet) obtained from the semiconductive urethane elastomer-forming composition of the present invention showed good results. On the other hand, in Comparative Example, Comparative Example 1 had a low absolute value of volume resistance, and Comparative Example 2 had good mechanical properties and the like, but variation in volume resistance was very large. In Comparative Example 3, bleeding of the antistatic agent was observed, and in Comparative Example 4, the temperature dependence of the volume resistance was large. In Comparative Example 5, the variation in volume resistance was very large. In Comparative Example 6, the rebound resilience was a particularly small value compared to other molded products. In Comparative Example 3, the bleedability, which is the basic performance of the molded product, was poor, and hence no subsequent evaluation was performed.

[Evaluation of semiconductive roll]
Examples 8-14, Comparative Examples 7-10
Roll molding method The main agent and curing agent were each heated to 80 ° C, mixed with agitator (40 seconds) at the compounding ratio shown in Tables 7 and 8, and after degassing in vacuum, the diameter preheated to 120 ° C Cast into a roll mold of 19 mm in diameter with a 6 mm long and 270 mm long stainless steel rod. After being cured by heating in an oven at 120 ° C. for 10 hours, the mold was removed. Next, after secondary curing at room temperature for 1 week, the surface and the end portion were polished to obtain a roll having a diameter of 18 mm and a length of 230 mm.

Evaluation Method Roll Electrical Resistance Measurement The surface of the roll obtained above was washed with methanol, and under LL (10 ° C. × 15%) conditions for 2 days, NN (23 ° C. × 55%) and HH (28 ° C. × 85%). %) Conditions were measured after maintaining the state for one day. The measuring method is a method in which a roll is placed on an aluminum roll, a load of 500 g is applied to both ends of the shaft, and a resistance value between the shaft and the aluminum reference roll is measured. The measured value is an average value when two rotations are performed (the number of measurement points is 300 for two rotations, and theoretically, 2.4 measurement points). An R8340A digital super resistance meter manufactured by Advantest Corporation was used as a measuring instrument, and the measurement voltage was 100 V, and measurement was performed 30 seconds after voltage application. The variation in roll electric resistance value was evaluated by the ratio of the maximum measurement value and the minimum measurement value of 10-point measurement.

From Tables 7 and 8, the semiconductive roll of the present invention showed a good electrical resistance value. On the other hand, Comparative Example 7 still had a large absolute value of the electrical resistance value, and Comparative Examples 8 and 10 had large variations in measured values of electrical resistance (that is, non-uniform dispersion of the conductive agent). In Comparative Example 9, the electrical resistance value was highly dependent on the environment. In addition, although the comparative example 11 was a favorable result in Table 8, since the resilience elastic modulus is smaller than Table 6, actual use is difficult.

Claims (4)

Main agent (A) containing an isocyanate group-terminated urethane prepolymer obtained by reacting polyether polyol (a1) and organic polyisocyanate (a2), polyol (b1), conductive agent (b2), and antistatic agent ( In the semiconductive urethane elastomer-forming composition comprising the curing agent (B) containing b3),
The conductive agent (b2) is conductive carbon, and the antistatic agent (b3) is a quaternary ammonium cation having an aliphatic unsaturated hydrocarbon group having 10 to 20 carbon atoms and one hydroxyalkyl group, and bis (trifluoromethane). (Sulfonylimide) an ionic salt comprising an anion, each content of the conductive agent (b2) and the antistatic agent (b3) in the total amount of the main agent (A) and the curing agent (B) is (b2) : 0.1-1% by mass, (b3): 0.001-10% by mass, a semiconductive urethane elastomer-forming composition, A main agent (A) containing an isocyanate group-terminated urethane prepolymer obtained by reacting a polyether polyol (a1) and an organic polyisocyanate (a2), a polyol (b1), a conductive agent (b2), and an antistatic agent ( In the semiconductive urethane elastomer-forming composition comprising the curing agent (B) containing b3),
The conductive agent (b2) is conductive carbon, and the antistatic agent (b3) is an aliphatic unsaturated hydrocarbon group having 10 to 20 carbon atoms and a quaternary ammonium cation having two hydroxyalkyl groups and bis (trifluoromethane). (Sulfonylimide) an ionic salt comprising an anion, each content of the conductive agent (b2) and the antistatic agent (b3) in the total amount of the main agent (A) and the curing agent (B) is (b2) : 0.1-1% by mass, (b3): 0.001-10% by mass, a semiconductive urethane elastomer-forming composition,   The semiconductive urethane elastomer-forming composition according to claim 1 or 2, wherein the conductive agent (b3) is ketjen black. A semiconductive roll using the semiconductive urethane elastomer-forming composition according to any one of claims 1 to 3.