United States Patent Office -- 3,279,918 Patented Oct. 18, 1966 2 3.279,918 trophotographic reproduction methods is obtained if in ELECTROPHOTOGRAPHIC MATERIAL the manufacture of the photoconductive layer compounds Paul Maria Cassiers, Jean Marie Nys, and Jozef Frans are used having the general formula: Willems, Mortsel-Antwerp, Belgium, assignors to Gevaert Photo-Producten N.V., Mortsel, Belgium, a 5 X Belgian company R o/ NC-R NoDrawing. Filed Feb. 4, 1960, Ser. No. 6,627 r Claims priority, application Great Britain, Feb. 5, 1959, -C-N 4,147/59; Belgium, Dec. 11, 1959, 39,426/59, Patent wherein: 585,555 2 Claims. (C. 96-1) 10 X=an oxygen or sulphur atom, a methylene or N-R- The present invention relates to an electrophotographic E. yogen atom or an alkyl radi s material,material consistingand more particularlyof a support to andan electrophotographica photoconductive R1 and R2=each a hydrogen atom, an alkyl or aryl radi layer which contains an organic photoconductive Sub- 15 cal either substituted or not, or together the missing stanceyer orIcn. which consistsa of 9.an organicpng photoconductiveo atomstituted necessary t; and to close an arylene nucleus either sub substance,Electrophotographic materials are already known which R.A.F.A.cal AEEfilia an alkyl,y , aryl or heterocyclic radiradl consist of a support and a photoconductive layer contain- s ing as photoconductor an inorganic Substance Such as 20 with the understanding that at most one of the symbols selenium or zinc oxide or an organic substance such as R1, Ra and R3 represents a hydrogen atom or an alkyl anthracene, benzidine or a heterocyclic compound of a radical either substituted or not. determined type. Some compounds according to the above formula, Now we have found that electrophotographic material which seemed to be particularly suitable for the manu with particularly favorable properties and suitable to be 25 facture of the electrophotographic material according to used in the application of the most widely varying elec- the present invention are given hereinafter in Table 1. TABLE 1. Com- X R R R Prepared according M.P., pound to- o C. 1..........CH: off OH, CHs ------------------------ 59 cH 2--------- O {X- H -(> E. Fischer, Ber. 29 -------- (1896), 205. Hic, CHs 3.0 HC N-( >-H -(D-NCN CH -- 4---------- O { X- H -( > J. Llster & R. Rob- - ( > inson,Soc. 101 J. (1912)Chem. 1306. O 5---------- O { X- H -( > 1. { X F.al., Newton J. Am. Hayes Chem. et ----- N- Soc. 77 (1955) 1850. CH 2 N. CH 6.--------- O CE -( >-N / U.S.P. 2,793.192--------------- c cH- YoHs CH 7---------- O -K X-N B. Schiedt, J. prakt. -------- N Chem. 157 (1941) CE 221. O 8,279,918 TABLE -CoIntinued Com R R R pound H O. Davidson et al., J. -------- NH SEE Chem. 2 (1938) 10--------- NEH CH Ibid.-------------------------- ill--------- NH Ibid.-------------------------- CH3 12.-------- NH - -N { X-NC CH NO A. H. Cook & D. G. -------- 18--------- NE Jones, J.C.S. 194i, 282. 14-------- NB Ibid.-------------------------- A. H. Cook & D. G. -------- 15.--------- NH Siles, J.C.S. 1941, COOE 16--------- NH B. Radziszewski, ------- 17.------ NH Chem. Zentr. (1909) 1883-4. 18--------- NH - - - - - - - - - - - - - - - - - - - - - - 232-233 19--------- NE 20--------- NH CH 3,279,918 TABLE 1-Continued Prepared according Com- X R1 R; Rs pound 21--------- NE ( >- { X- / S r NN &H, BC H. Bredereck & The Eg, Ber. 86 (1953) 2. NH ( >- HSC N-( >-H HC 120 2. NH K X- H3C N-K X-CH, H3C CHs N 222 24--------- NH - N- - m N H3C CH SO3H H3C 2. NH K >- H3C N-( )-- HC 2. NH ( )- HCDN-( )--( ) OE 2. NH K)- Hic,DN-K )--K 28 3C -"|C HC *-C-|x 99 80--------- NH. H.CO-( Y H, co-( >- -(D-och, 98 "-" I - -( > 82.-------- NH - OO CE 2 N D. Jerchel et al., Ann. 38--------- NI pH - NH 575 (1952) 162-73. c ScH. / G. Leandri et al., 2 CH, CH, Gazz. Chim. Ital. 85 (1955) 780. 34---------| NH ofbH Y -(D-NC CH S / CH 2 CHQ NE H. Boganz, Angew, 85--------- NH CH N/N Chem, 68 (1956) 15-2. ScH. Yé 3,279,918 TABLE -Continued Com- X R R pound R3 Prepared according M.P., to- o C. 36.-------- NH E. A. Steck & A. R. Day J. Am. Chem. Soc. 65 (1943) 452-6. (CH, 37--------- NH O -( > Ibid.-------------------------- 38--------- S EI {D- -( ) Ann. 259,237------------------ / S 8.s ( )- H - - British Specification ----- 722.543, CHQ 40--------- S CH U.S.P. 2.793.192--------------- CH ScH / CH 4--------- S 3C-C Fierz-David H.A., Fundamental Proc cn / esses of Dye Chem CB istry p. 333 (1949), Interscience Pub lishers, New York. 42.-------- S Hic, N 2 or U.S.P. 2.793.192--------------- HC cn / C Compound 3 is prepared by refluxing for about 6 hours Compound 7 is also prepared by boiling up for 2 at N-(p-dimethylaminobenzoyl)-p-dimethylaminophena hours 7.8 g. of chrysoquinone, 4.5 g. of p-dimethyl cylamine solution in an excess of phosphorus oxy 55 aminobenzaldehyde and 24 g. of crystallized ammonium chloride until no hydrochloric acid vapors evolve any acetate in 200 cm.8 of acetic acid. The precipitate formed more. Next, the excess of phosphorus oxychloride is is sucked off and recrystallized from benzene. Melting distilled off on water-bath and the residue is treated with point: 285 C. ice-cold water. The yellow-orange solution is slightly Compound 8 is prepared as compound 7 but 4.5 g. of alkalized whereafter the formed precipitate is sucked off. 60 p-dimethylaminobenzaldehyde is replaced by 7 g. of 5 This precipitate is washed with water and in the presence acenaphthaldehyde and the recrystallization of the precipi of active carbon recrystallized from a mixture of piperi tate formed occurs from xylene. Melting point: above dine and water. A yellow product melting at 219-220 260° C. C. is obtained. The compounds 12, 13, 15-32, 36 and 37 can be Compound 4 is also prepared by treating an anhydrous 65 prepared according to O. Davidson, M. Weiss and M. etheric solution of equimolar amounts of alpha-naph Jelling, J. Org. Chem. 2 (1938), 325-6. For some of thaldehyde and benzaldehyde cyanohydrin with dry hy these compounds similar or other methods of synthesis drochloric acid gas in order to precipitate the oxazole are given in Table 1. hydrochloride. If no further precipitate is formed any Compound 14 is obtained by catalytic hydrogenation more, the hydrochloride is quickly sucked off, washed 70 under pressure and at about 40° C. of compound 13 dis with a little anhydrous ether and next dissolved in al solved in acetic acid. Melting point: 217-218 C. cohol. By addition of water to this solution the free For the manufacture of the electrophotographic mate oxazole precipitates. It is finally sucked off, washed with rial according to the present invention, a photoconductive water, dried and recrystallized from hexane. Melting layer containing at least one of the compounds according point: 110° C. 75 to the above general formula or mainly consisting of at 3,279,918 9 O least one of the compounds according to the above gen rays from a determined part of the spectrum can also be eral formula is applied to a suitable support. present in the photoconductive layers. The photoconductive layers according to the present Thus, for instance the general sensitivity and/or the invention can contain besides one or more of the com sensitivity to electromagnetic rays from the visible part pounds according to the above general formula still one of the spectrum can markedly be increased by adding to or more other photoconductive compounds with similar the photoconductive layer one or more compounds se or different photoelectric, mechanical or other physical lected from one or more of the following classes, prefer properties; moreover, there can be present in the photo ably in an amount of 0.1 to 5% in respect of the weight conductive layer other compounds which confer the of compound used as photoconductor according to the properties desired to the photoconductive layer and/or O above general formula. to the composition wherefrom this layer is formed. A. Triarylmethane dyestuffs without ring closure, i.a.: Thus, in the manufacture of the photoconductive layers (1) Those according to the general formula according to the present invention one or more macro 2. molecular compounds can be added as binding agents -- to the composition wherefrom the photoconductive layer 5 is formed; preferably, macromolecular compounds with high specific resistivity (i.e., with a specific resistivity higher than 109 ohm-cm.) are used for this purpose; macromolecular compounds particularly suitable as bind ing agent for the photoconductive layers are e.g., natural 20 resins, such as dammar resin, elemi-resins, gum arabic, manila gum and Sandarac resin; micro-crystalline waxes; modified natural substances such as cellulose diacetate wherein R, R2, R3, R1, R5, Re and Z each represents a and cellulose triacetate, cellulose acetobutyrate, ethyl hydrogen atom or a methyl group and X a hydroxyl cellulose, ethyl cellulose stearate or other cellulose deriva 5 group or a chlorine atom, such as for instance Fuchsine tives pentaerythrite polyesters or other modified colopho (C.I. 42510), Waxoline Red A25 (C.I. 42510B), Crystal nium resins and ester gums; polymerizates such as poly Violet (C.I. 42555) and Crystal Violet Base (C.I. ethylene, polystyrene and copolymers of styrene, poly 42555B); vinylacetate and copolymers of vinyl acetate, polyvinyl (2) Those according to the general formula acetals of formaldehyde, acetaldehyde, butyraldehyde, 30 polyacrylic acid esters and polymethacrylic acid esters CH3 and coumarone-indene resins; and polycondensates such as glycerol-phthalate resins and other glyceryl polyesters, alkyd resins, polyethylene glycol esters, diethylene glycol H2N- >--(O-NHR'sona polyesters, formaldehyde resins and silicone resins; par 3 5 Y ticularly good results can be attained by using the poly esters described in U.S.