Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording-members for original recording by exposure, e.g. to light, to heat or to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/02—Charge-receiving layers
  • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
  • G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
  • G03G5/0601—Acyclic or carbocyclic compounds
  • G03G5/0612—Acyclic or carbocyclic compounds containing nitrogen
  • G03G5/0614—Amines
  • G03G5/06142—Amines arylamine
  • G03G5/06144—Amines arylamine diamine

Definitions

• This invention relates to photographic reproduction and more particularly to a new group of organic photoconductors and to electrophotographic processes, namely processes in which an electrostatic latent image is produced by utilizing the property of photoconduction (i.e., a variable conductivity dependent on the intensity of illumination).
• the electrostatic latent image may be produced in a conventional exposure operation, for example by means of a lens-projected image or by contact-printing techniques, whereby a nonvisible electrostatic charge pattern (the so-called electrostatic latent image) is created on a surface, in which pattern the charge density at any point is related to the intensity of illumination obtained at the point during the exposure.
• The. latent image may be develo ed (i.e., rendered visible) by means of a triboelectric powder or liquid toner.
• Said powder such as a pigmented synthetic resin, fixes the resulting visible image by rendering the powder permanently adherent to a support on which the image is desired, for example in suitable cases by heating to soften or melt the powder particles.
• the liquid toner particles which are washed over the surface are caused to adhere permanently by the drying oil component of the liquid toner.
• the electrostatic latent image is commonly formed on the surface of a photoconductive insulating layer carried on a support.
• material comprising such support and photoconductive layer may be charged by applying a uniform surface charge to the free surface of the photoconductive layer.
• the charge can be applied by conventional means such as corona discharge or the like.
• the charge is retained due to the substantial insulating character, i.e., the low conductivity, of the insulating layer in the dark.
• the photoconductive property of the layer causes the conductivity to increase in the illuminated areas to an extent which is proportional to the intensity of illumination. This results in a leakage of the surface charge in the illuminated areas while the charge in the unilluminated areas remains. This is what constitutes the aforementioned charge pattern or electrostatic latent image.
• Electrophotographic processes have become of increasing importance in recent years, especially in connection with office duplicating processes. Consequently, there has been much interest aroused and much effort has been made to obtain suitable materials for making the support and photoconductive insulating layers used in such copying processes.
• the invention is also directed to a new electrophotographic material which is quickly and easily imaged by exposure to commonly employed light sources.
• N,N,N,N'-substituted-1,3-phenylenediamines of the present invention have been found to be very stable and do not discolor appreciably when exposed to light and oxygen for substantial periods of time.
• electrophotographic sheets or plates having a coating containing the substituted-1,3-phenylenediamines of the present invention can be exposed to light and oxygen for long periods of time without the coatings turning dark yellow or brown.
• R represents l,3-phenylene, 4-methyl-l ,3-phenylene, 4-halol ,3-phenylene, 4-ethyll,3-phenylene, 4-isopropyll ,3-phenylene, 4-methoxyl ,3- phenylene, 2-halo-l,3-phenylene and 4,6-dimethyl-l,3-phenylene and Z represents benzyl, monomethylbenzyl, dimethylbenzyl, trimethylbenzyl, tetramethylbenzyl, monohalobenzyl or dihalobenzyl; however, when R represents l,3-phenylene, Z must represent monomethylbenzyl, dimethylbenzyl, trimethylbenzyl, tetramethylbenzyl, monohalobenzyl, or dihalobenzyl; Z
• alkyl and halo as employed in the present specification and claims represent an alkyl moiety having from one to six carbon atoms, inclusive, and a halogen selected from the group consisting of bromine or chlorine.
• the new N,N,N,N'-tetrabenzyl-l,3phenylenediamines and N,N-dialkyl-N ,N-dibenzyll ,3-phenylenediamines of the present invention are hereinafter referred to as substituted l,3-phenylenediamines for the sake of convenience.
• substituted 1,3-phenylenediamines are oils, noncrystalline solids or crystalline solids which are soluble in various common organic liquids and substantially insoluble in water.
• the new N,N,N',N'-tetrabenzyl-l,3-phenylenediamines of the present invention corresponding to the formula are prepared by reacting a 1,3-phenylenediamine corresponding to the fonnula H,N-R-Nl-l, with a benzyl halide corresponding to the formula Z-X, where X represents bromine or chlorine.
• the reaction between the l,3phenylenediamine and benzyl halide takes place readily in an inert organic solvent as reaction medium and at temperatures within the range of from 40 to 150 C. with the production of the desired substituted l,3-phenylenediamine product and the hydrogen halide of reaction.
• the temperature of the reaction mixture is maintained within the reaction temperature range for from 1 to 4 hours and conveniently until there is a substantial cessation in the production of the hydrogen halide of reaction.
• the proportions of the reactants to be employed are not critical, some of the desired product being produced when the reactants are contacted together in any proportions.
• the reaction consumes 4 molar proportions of a benzyl halide such as benzyl chloride or benzyl bromide for each molar proportion of l,3-phenylenediamine; however, in a preferred procedure the benzyl halide is employed in an amount slightly in excess (about percent) of the stoichiometric amount necessary to react with all of the 1,3-phenylenediamine.
• the use of a larger excess of the benzyl halide does not adversely affect the yield or the desired product.
• the benzyl halide and 1,3-phenylenediamine are dispersed in the inert organic reaction medium in any order or fashion.
• Representative inert organic liquids include ethanol, methyl cellosolve, 2-propanol, and methanol. It is preferred that the solvents be at least slightly polar in nature.
• a base such as sodium hydroxide or potassium hydroxide is added to the reaction mixture in order to neutralize the reaction mixture and prevent the formation of the hydrohalide salt of the 1,3-phenylenediamine starting material.
• the temperature of the reaction mixture is maintained within the reaction temperature range until there is a substantial cessation in the production of hydrogen halide byproduct as indicated by the amount of base, preferably an aqueous base, needed to neutralize the reaction mixture.
• the water added to the reaction mixture with the aqueous base can be removed by azeotropic distillation with additional inert organic solvent being added to the reaction mixture to replace the solvent lost during the distillation.
• additional inert organic solvent being added to the reaction mixture to replace the solvent lost during the distillation.
• the desired product can be isolated from the reaction mixture by conventional procedures.
• the oily product is separated by decantation and thereafter dissolved in an organic solvent such as acetone.
• the solvent solution is filtered to remove the salt byproduct formed during the neutralization procedure and cooled.
• the product separates as an oil, noncrystalline solid, or crystalline solid. This product can then be further purified by such conventional procedures as washing, crystallization, distillation or recrystallization.
• the N ,N-disubstitutedl ,3-phenylenediamine starting material is prepared by the condensation of 1,3-phenylenediamine with the appropriate benzyl alcohol (Z-OH) according to the method of Y. Sbluac, J. Am. Chem. Soc., 78, 3207( 1956).
• the reaction between the N,N- disubstituted-l,3-phenylenediamine and benzyl halide takes place in an inert organic solvent as the reaction medium and occurs readily at temperatures of from 40 to C. and preferably at the boiling temperature of the reaction mixture.
• the group of new N,N'-dialkyl-N,N-dibenzyl-l,3-phenylenediamine compounds corresponding to the formula are prepared by reacting together N,N'-dialkyl-l ,3-phenylenediamine and a benzyl halide corresponding to the formula Z-X, dispersed in an inert organic solvent such as ethanol, methyl cellosolve, or 2-propanol as reaction medium.
• the reaction proceeds readily at temperatures from 40 to 150 C., with the temperature of the reaction mixture being maintained within the reaction temperature range for from about 1 to 4 hours.
• the reaction mixture is neutralized by the addition of aqueous base as previously described.
• the desired product is isolated from the reaction mixture and further purified using the same procedures as previously described for the production ofthe N,N,N',N'-tetrabenzyll ,3phenylenediamines.
• N,N'-diethyl-N,N-dibenzyl-1,3- phenylenediamine is prepared by ethylation of the appropriate N,N-dibenzyl-l,S-phenylenediamine corresponding to the formula
• the ethylation is carried out in an excess of the ethylating agent as reaction medium.
• Representative ethylating agents include triethylphosphate and diethyl sulfate.
• the reactants are contacted together at temperatures of from 150 to 250 C. for from 1 to 4 hours. However, in a convenient procedure, the reaction mixture is maintained at the reflux temperature for from 1 to 4 hours. Following the reaction period, the reaction mixture is treated with an aqueous base to hydrolyze the polyphosphates formed during the reaction period and to facilitate the isolation of the desired product. During the hydrolysis procedure, the desired product separates in the reaction mixture as an oily residue which is then extracted from the reaction mixture with ether. The ether extract is then dried and fractionally distilled to obtain the desired product.
• the new substituted-1,3-phenylenediamine products of the present invention are oils, noncrystalline solids or crystalline solids. It has been found that when seed crystals for the oils and noncrystalline materials are obtained, the oils and noncrystalline products can be caused to readily crystallize.
• the oils and noncrystalline solids are conveniently prepared for use as photoconductors as follows: the oil or noncrystalline solid is dissolved in an organic solvent and the solvent solution washed with water to remove any salt remaining in the product. In those cases where it is found that the product does not form a crystalline solid the reaction mixture is diluted with water to remove ionic materials. The recovered oil is then washed with an alcohol such as methanol or ethanol.
• the washed oil is then dissolved in chloroform and the chloroform solution dried, filtered, stripped of low boiling constituents to yield the product as an oily residue.
• This residue can then be dissolved in an organic solvent and employed as a photoconductor as described in the present specification and claims.
• benzyl halides to be employed as starting materials for the production of the substituted l,3-phenylenediamines include 4-chlorobenzyl chloride, 4-methy1- benzyl chloride, 2,5-dimethylbenzyl chloride, 4-bromobenzyl bromide, 2,3,5,6-tetramethylbenzyl bromide, 2,3,4,5- tetramethylbenzyl chloride, 2-chlorobenzyl chloride, 3,4- dichlor Tavernzyl chloride, 3,5-dibromobenzyl bromide and 3- chlorobenzyl chloride.
• the new electrophotographic material of the present invention is comprised of a conductive support layer, being coated on at least one surface thereof with a photoconductive insulating layer, said photoconductive insulating layer being comprised of an insulating resin binder, and a substituted 1,3- phenylenediamine or N,N,N,N-tetrabenzyl-1,3 phenylenediamine.
• the substituted 1,3-phenylenediamines correspond to one of the formulas as previouly defined and N,N,N',N-tetrabenzyl-l,3-phenylenediamine and N,N'-di-oxylylene-l,3,-phenylenediamine have been found to be useful as organic photoconductors.
• the new substituted 1,3-phenylenediamines, N,N '-di-o-xylylenel ,3-phenylenediamine and N,N,N',N'-tetrabenzyl-l,3-phenylenediamine will be referred to as TSMPD for the sake of convenience.
• the TSMPD compounds generally absorb the lower end of the ultraviolet spectrum (i.e., 3300 A. and below). Therefore, when it is desired to shift the spectral response of the electrophotographic product of the present invention to a longer wavelength, an electron-accepting sensitizing agent is added to the TSMPD- containing photoconductive layer.
• the sensitizer compounds serve as electron acceptors, and in addition to shifting the spectral response, these sensitizers facilitate mobile charge carrier transport, thereby increasing the efiiciency of the system.
• sensitizers are the substituted fluorene compounds such as 9-fluorenone, 2,4,7-trinitro-9-fluorenone and 2-nitrofluorene; and substituted stilbenes such as 2,4,3- trinitrostilbene, 2,4-dinitrostilbene, and 2,4,6-trinitrostilbene and substituted benzothiazoles such as Z-styrylbenzothiazole, 3-nitrophenylbenzothiazole, 2-phenylbenzothiazole, 2-(3'- nitrophenyl)-benzothiazole, 2-(4-dimethylamino)- benzothiazole, 4-phenylbutadienyl-Z-benzothiazole, 2- styrylquinoline, p-nitroacetophenone, l,l-dicyano-4-phenylbutadiene, 9,10-phenanthrenedione, 3,5-dinitromethyl benzoate, 2,4-dinitrophenyl sulfide, 2,4,4-trinitro
• the TSMPD compounds and the sensitizer, if utilized, are em ployed in association with a resin or synthetic polymer, for example: natural resins, synthetic resins (including copolymers) such as the polystyrenes or polystyrene copolymers including styrene-butadiene, styrene-butadiene-acrylonitrile; acrylates, polyvinyl acetals, polycarbonates, polyphenylene oxide, phenoxy resins, polysulfones, polyesters and other synthetic polymeric resinous materials.
• a resin or synthetic polymer for example: natural resins, synthetic resins (including copolymers) such as the polystyrenes or polystyrene copolymers including styrene-butadiene, styrene-butadiene-acrylonitrile; acrylates, polyvinyl acetals, polycarbonates, polyphenylene oxide, phenoxy resins, polys
• the TSMPD photoconductive substances and sensitizers when used for preparation of the photoconductive insulating layer are preferably so used in solution in organic solvents, such as for example ethanol, benzene, chloroform, acetone, toluene, methylene chloride, methyl ethyl ketone or ethylene glycol monomethyl ether. Mixtures of two or more TSMPD compounds may be employed. Mixtures of solvents may also be used. It is also possible to employ the photoconductive substances in association with other organic photoconductive substances.
• organic solvents such as for example ethanol, benzene, chloroform, acetone, toluene, methylene chloride, methyl ethyl ketone or ethylene glycol monomethyl ether.
• the TSMPD compound or mixture thereof is employed in an amount equivalent to from 0.01 to 200 or more percent by weight with respect to the resinous binder. in many cases the photoconductive TSMPD compound or mixture thereof may be employed at greater than 200 percent with advantageous results.
• the amount of TSMPD to be employed will depend upon the system in which the product is being utilized, i.e. the particularly light source, the length of exposure, the particular TSMPD compound being used, etc.
• the amount of electron-acceptor sensitizing agent to be utilized will vary depending upon Such factors as the sensitizer, the TSMPD, the light source and the length of exposure.
• the TSMPD compounds of the present invention can be employed without the use of a sensitizer at 3600 A. or below. However, it is generally desirable to employ a sensitizer to shift the spectral response. In such cases the amount employed will be within the range of from 0.01 to 20 percent by weight ofthe TSMPD compound.
• the support may be of any material suitable for use in electrophotographic processes, for example, aluminum or other metal plates or foils, plastic foil and preferably paper sheets or webs.
• paper When paper is to be used as a support for the photoconductive layer, it is preferable that it shall have been pretreated against penetration by the coating solution, for example with methyl-cellulose in aqueous solution; polyvinyl alcohol in aqueous solution; a solution in acetone and methyl ethyl ketone of a mixed polymer of acrylic acid methyl ester and acrylonitrile; or with solutions of polyamides in aqueous alcohols or a coating containing some conductive polymer such as polyvinylbenzyltrimethylammonium chloride. Solutions of the photoconductive substances and insulating resins in organic solvents are applied to the support by known methods (for example, by spraying, reverse-roll coating, or whirl coating). Following the coating procedure, the coating thus prepared is dried.
• the photoconductive layers are usually charged positively or negatively by means of a corona discharge.
• the light sensitivity of the thus obtained photoconductive layers lies mainly in the range of 3,000 to 7,000 A.
• Very good images may be obtained by a short exposure using a positive or negative to a conventional electrophotographic light source such as a highpressure mercury vapor lamp, tungsten lamp or the like.
• the latent image so produced may be developed in known fashion by the application ofdry powder or liquid toner.
• the filtrate was allowed to cool whereupon an oily product began to separate. Acetone was added to the filtrate to keep the oily product in solution. The filtrate was then cooled in an ice bath and seed crystals were added to initiate the crystallization of the desired product.
• the solid product was isolated by filtration and recrystallized from a solution of equal parts of acetone and ethanol. The recrystallized N,N,N,N'-tetrabenzyl-1,3-phenylenediamine was found to melt at 99-l00 C.
• N,N ,N ,N -tetra-(4-methylbenzyl)-1,3-pheny1enediamine (m.p. 101B 103 C.) N,N,N,N'-tetra-(2-chlorobenzy1)-1,3- phenylenediamine (m.p. l73175C.).
• the following new compounds of the present invention are prepared by reacting (a) 4- 45 b. N,N,N',N'-tetrabenzyl-(4-chloro-1,3-phenylenediamine) 60 (m.p.107.5109.5 C.)
• N,N,N,N-tetra-(2,5-dimethy1benzy1)-4-chloro-l ,3-phenylenediamine (m.p. 15 8-160 C.)
• N,N,N',N-tetrabenzy1-(4-isopropyl-l ,3-phenylenediamine) (m.p.112-1 14 C.)
• N,N,N',N-tetra-(4-methylbenzyl)-4-isopropy1-1,3-phenylenediamine oil
• N ,N,N',N-tetrabenzyl-(4-methoxy-l ,3-pheny1enediamine) m.p.1l5-117C.
• N,N-diisopropyl1,3-phenylenediamine (4grams, 0.0021 mole) and 2,5-dimethy1benzyl chloride (7.16 grams, 0.0046 mole) were dispersed in milliliters of ethanol.
• the reaction mixture thus prepared was heated at the reflux temperature for 1.5 hours. During the reflux period the reaction mixture was periodically neutralized by the addition of aqueous sodium hydroxide. Following the reaction period, the reaction mixture was filtered while hot and the filtrate cooled. The oily product which separated from the filtrate was washed with water and ethanol.
• the oily product was then dissolved in chloroform, dried over sodium sulfate, and distilled under reduced pressure to remove the low-boiling constituents and obtain the N,N'-diisopropyl-N,N'-di-(2,5-dimethylbenzyl)- 1,3-phenylenediamine product as an oil.
• N,N-di-sec.-butyl-N,N'-di(2-chlorobenzyl) phenylenediamine (an oil) by reacting together N ,N'-di-sec.-buty1- 1,3-phenylenediamine and 2-chlorobenzyl chloride.
• N,N'-diisopropy1-N,N'-dibenzyl-l,3-phenylenediamine (an oil) by reacting together N,N'-diisopropyl-1,3-phenylenediamine and benzyl chloride.
• Example 3 N,N'-diisopropy1-N,N'-dibenzyl-l,3-phenylenediamine (an oil) by reacting together N,N'-diisopropyl-1,3-phenylenediamine and benzyl chloride.
• N,N-dibenzyl-l,3-phenylenediamine (10 grams, 0.035 mole) and 2,5-dimethylbenzyl chloride (12.5 grams, 0.08 mole) were dispersed in 50 milliliters of isopropanol and the resulting mixture heated at the reflux temperature for 2.5 hours.
• Aqueous potassium hydroxide was periodically added to the reaction mixture.
• the oil which separated in the reaction mixture during the reflux period was taken up in hot acetone and the hot acetone solution was filtered.
• N,N'-dibenzy1-l,3-phenylenediamine grams, 0.087 mole) and triethyl phosphate (15.9 grams, 0.087 mole) were placed in a reaction vessel and heated until the exothermic reaction started, whereupon the heat was removed. The reaction was allowed to proceed for about 10 minutes and then phenylenediamine was heated at the reflux temperature for about minutes. Following the reflux period, aqueous sodium hydroxide (12 grams NaOH in 50 ml. of water) was added 5 to the reaction mixture and the mixture thereafter heated for 1 hour. During the heating period an oily product separated in the aqueous mixture. Following this heating period the aqueous mixture and oily product were allowed to cool.
• a photoconductive insulating coating was prepared by mixmg Toluene ll 9 liters Polystyrene (Dow Chemical Co. 23 kilograms Styron 666U) N,N,N' N'-tetrabenzyl-I,3- 10.6 kllogram phenylcnediamine 9 l0-phenanthrenedionc 4 grams (dissolved in 200 milliliters of chloroform) The above-listed constituents were thoroughly mixed to provide a uniform coating composition.
• This coating composition was applied by means of a reverse-coil coater to one side of a 34-pound paper base stock having on each side thereof a l-pound base coating of clay, titanium dioxide, polyvinyl alcohol and electrically conductive polyvinyl benzyl trimethyl ammonium chloride.
• the photoconductive insulating coating was applied in an amount equivalent to pounds dry weight of coating per ream (25 inches X 38 inches-500 sheets).
• This paper yielded a clear image upon exposure using ZOO-watt high-pressure mercury light source (microfilm projection exposure) for 5 seconds. The imaged paper was very stable showing barely discernable discoloration after 30 minutes in a Fade-ometer Microfilm projection exposures were effected using silver, Kalvar and diazo microfilms.
• N,N,N,N'-tetra-(2-methylbenzyl)-I,3-phenylenediamine (0.25 grams), tetramethylthiuram disulfide, toner set, (007 grams) and 2-styrylbenzothiazole (0.03 gram) were dissolved in 20 grams of a polymer solution comprised of polystyrene (Dow Chemical Company, Styron 666U) dissolved in 108 milliliters of chloroform.
• the coating composition was mixed thoroughly and thereafter applied to a paper base sheet by means of a No. 20 Meyer bar.
• the coating was then dried, charged by means ofa corona discharge and imaged through a transparency by means ofa high-pressure mercury vapor lamp for a period of seconds.
• the imaged surface was then treated with a standard, commercial liquid toner.
• a sample of the paper thus produced was placed in the Fade-ometer for 30 minutes with only very slight discoloration.
• a coating composition is prepared by mixing 1 part by weight of N,N,N',N-tetra-(4-methylbenzyl)-l ,3-phenylenediamine, 3 parts by weight of polysulfone P-4700 (manufactured by the Union Carbide Corporation), 0.0005 part by weight of 2,4,3'-trinitrostilbene, and parts by weight of toluene as a solvent.
• This coating composition is applied to a suitable paper substrate which has been base-coated with 8 pounds (dry weight) per team inches X 38 inches500 sheets) ofa coating comprised of 70 parts by weight of polyvinyl alcohol, 20 parts by weight of calcium carbonate and 10 parts by weight of polyvinyl benzyl trimethyl ammonium chloride.
• a positive print is made by negatively charging the coated paper by means of a corona discharge, and subsequently exposing the paper sheet through a positive transparency to a ill
• the latent electrostatic image thus produced is developed by applying thereto a dry, positively charged thermoplastic resinous toner (comprising carbon black particles coated with thermoplastic resin).
• the toner thus applied is attracted to the latent image areas producing a visible image which is permanently fixed by heating the thermoplastic toner on the sheet surface at a temperature of C for short time which solidly fuses the toner.
• the clear print thus prepared shows no appreciable discoloration when placed in a Fade-ometer for 30 minutes. developing produced the positively
• all steps are repeated as described above except that the coated paper is positively charged, and the developing toner is negatively charged. Clear images are produced when the positively charged paper is developed with the negative toner.
• a coating composition is prepared by mixing 2 parts by Weight of tetrabenzyl-l ,3 phenylenediamine, 3 parts by weight of polyvinyl butyral (Butvar 8-76, manufactured by the Monsanto Chemical Company) as a resinous binder, 0.002 parts by weight of a sensitizing dye (ethyl red), and 15 parts by weight of a solvent for the above composition, which solvent component is comprised of9 parts by weight of toluene and 6 parts by weight of methyl ethyl ketone.
• a sensitizing dye ethyl red
• This coating composition is applied to one side of a web of bleached paper bodystock having a basis weight of 40 pounds per ream, and previously coated with 3 pounds (dry weight) per ream of the base coating described in Example 8.
• the paper sheet thus coated is negatively charged by means of a corona discharge, and charged sheet is then exposed through a positive transparency to a 60-watt tungsten lamp at a distance of22 cm. for 15 seconds,
• the latent image thus produced in selected areas of the copy sheet is developed by applying to the exposed surface a positively charged liquid toner comprised of an oxidizing oil which has been intimately admixed with a colored body (carbon black), this composition having been dispersed in a strongly insulating liquid (deodorized kerosene).
• a positively charged liquid toner comprised of an oxidizing oil which has been intimately admixed with a colored body (carbon black), this composition having been dispersed in a strongly insulating liquid (deodorized kerosene).
• the particles of oil and carbon black are attracted to the laten image areas in the exposed sheet, and a clear, sharp visible image is produced. No heat-fusing step is necessary in this method as the oil quickly hardens and adheres permanently upon expo sure to air.
• the thus produced is placed in a. Fade-ometer for 60 minutes with only very slight discoloration.
• TSMPD compounds and sensitizers listed below were made into coating compositions by dissolving 0.5 gram of the TSMPD and 1.5 grams of polystyrene in l2 milliliters of chloroform. In the resulting solution the sensitizer was dissolved in a quantity expressed as percent weight based on the weight of TSMPD present. In each case the solution was spread on a paper base sheet by means of a No. 20 Meyer bar, about 3 to 4 pounds dry weight per ream, being applied.
• TSM PD Compounds Sensitizer Sensitrzer in 71 of TSMPD N.N,N',N'-tetra(Z,5-d
• a photoconductive coating was prepared by combining N,N,N,N'-tetra-(2,5-dimethylbenzyl)-1,3-phenylenediamine (0.5 gram), polyvinyl butyral (21.5 grams ofa solution comprised of 12 grams of polymer in l08 ml. chloroform) and 2-(-4-diethylaminobenzylidene)- picolinc methiodide.
• the coating thus prepared was applied to the base stock described in example 6 by means of a No. 20 Meyer bar. The sheet was charged to 800 volts and showed little dark decay and retained 15 volts after seconds of exposure to visible light. No discoloration was observed after minutes in the Fade-ometer.
• the Fade-ometer employed to test the electrophotographic materials of the present invention is an Atlas Color Fade-ometer, Type FDA-R sold by Atlas Electric Devices Company.
• the starting 1,3-phenylenediamine and benzyl halide starting materials employed in the present invention are all produced in accordance with procedures well known in the art.
• the N,N-dialkyl-l,3-phenylenediamine starting materials are prepared by a modification of the Jones and Cowie method (German Pat. No. 927,165).
• the modified procedure comprises reacting a ketone such as acetone, methyl ethyl ketone, cyclohexanone and the like with a l,3-phenylenediamine in the presence of platinum oxide as a catalyst.
• the reaction is carried out for 8 hours in an excess of the ketone as reaction medium in a high-pressure reactor at a temperature of 160 C. and under hydrogen at a pressure of 300 pounds per square inch.
• 1,3-phenylenediamine (2.80 grams, 0.26 mole) and 04,01 dichloro-o-xylene 10 grams, 0.057 mole) were dispersed with stirring in 40 milliliters ofmethyl cellosolve.
• the reaction mixture was heated at 90 C. for l hour. During the heating period aqueous sodium hydroxide was periodically added to the reaction mixture. The product precipitated as a crystalline solid in the reaction mixture during the heating period.
• the reaction mixture was filtered and the filter cake washed with water to remove the salts, and remaining solid product was recrystallized from chloroform-ethanol mixture.
• the recrystallized N,N'-di-o-xylylene-l,3-phenylenediamine product was found to melt at 232-235C.
• An electrophotographic material comprising a relatively more conductive support having a photoconductive insulating layer thereon which comprises a photoconductor selected from the class consisting of N,N-di-o-xylylene-l ,3-phenylenediamine and substituted 1,3-phenylenediamines having the general formula:
• R is a divalent arylene group selected from the class consisting of 1,3-phenylene; 4-methyl-l-3,phenylene; 4-ethyl- 1,3-phenylene; 4-halo-l,3phenylene; 4-isopropylene-l,3- phenylene;4-methoxy-l,3phenylene; 2-halo-l,3-phenylene; 5 and 4,6-dimethyl-l,3-phenylene; R is a divalent arylene group selected from the class consisting of 1,3-phenylene; 4- methyl-1,3-phenylene; 4-ethyl-l,3-phenylene and 4-isopropyl- 1,3-phenylene; Z is an aralkyl group selected from the class consisting of benzyl, monomethylbenzyl, dimethylbenzyl, trimethylbenzyl, monohalobenzyl and dihalobenzyl; and alkyl represents an alkyl
• the photoconductive insulating layer comprises a photoconductor having the general formula N-R-N wherein R is a divalent arylene group selected from the class consisting of l,3phenylene, 4-methyl-l,3-phenylene, 4-ethyl- 1,3-phenylene, 4-halol ,3-phenylene, 4-isopropyl-l ,3-phenylene, 4-methyloxy-l,3-phenylene, 2halo-l,3-phenylene and 4,6-dimethyl-l,3-phenylene and Z is an aralkyl group selected from the class consisting of benzyl, monomethylbenzyl, di methylbenzyl, trimethylbenzyl, tetramethylbenzyl, monohalobenzyl and dihalobenzyl.
• R is a divalent arylene group selected from the class consisting of l,3phenylene, 4-methyl-l,3-phenylene, 4-ethyl- 1,3-phenylene
• the photoconductive insulating layer comprises a photoconductor having the general formula wherein R is a divalent arylene group selected from the class consisting of 1,3-phenylene, 4-methyll,3-phenylene, 4-ethyl- 1,3-phenylene, 4-halo-l,3-phenylene, 4-isopropyl-l,3-phenylene, 4-methyoxy l,3-phenylene, 2-halo-l.3-phenylene and 4,6-dimethyl-l,3-phenylene;
• Z is an aralkyl group selected from the class consisting of benzyl, monomethylbenzyl, dimethylbenzyl, trimethylbenzyl, and tetramethylbenzyl, monohalobenzyl and dihalobenzyl; and Z is a dissimilar aralkyl group selected from the group designated by Z.
• photoconductive insulating layer comprises a photoconductor having the general formula alkyl /ulkyl N-RN ⁇ Z 7,
• An electrophotographic material as claimed in claim 2 dimethylbenzyl)-l,3-phenylenediamine. wherein the electron acceptor 1S gfluorenone 10.
• An electrophotographic material as claimed in claim 2 trinitrofluorenone, or 2-nitrofluorenone.
• An electrophotographic material as claimed in claim 3 wherein the photoconductor is N,N,N,N'-tetra-(4-methyl- 5 benzyl)-1,B-phenylenediamine or N,N,N,N'-tetra(2,5-
• the electron acceptor is 2,4,3-trinitrostilbene, 2,4- dinitrostilbene or 2,4,6trinitrostilbene.

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• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Photoreceptors In Electrophotography (AREA)

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Cited By (157)

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• 1968
  • 1968-04-25 US US724224A patent/US3615404A/en not_active Expired - Lifetime
• 1969
  • 1969-04-24 GB GB21077/69A patent/GB1218000A/en not_active Expired
  • 1969-04-24 BE BE732021D patent/BE732021A/xx unknown
  • 1969-04-25 DE DE19691921273 patent/DE1921273A1/de active Pending
  • 1969-04-25 FR FR6913167A patent/FR2006937A1/fr not_active Withdrawn
  • 1969-04-25 CH CH634569A patent/CH486724A/fr not_active IP Right Cessation
  • 1969-04-25 NL NL6906419.A patent/NL160953C/xx active

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