DE2155630A1 - Photo-sensitive polymers - contg cyano-and/or thiocyano -substd 9-vinylcarbazol units - Google Patents

Abstract

Polymer contains cyano- and/or thiocyano-substd. 9-vinylcarbazol units of formula I (where R is H, Cl, Br, I or NO2). The polymer may be a (thio) cyano-substd. (halogenated) poly-9-vinylcarbazol or a (thio)cyano-substd. copolymer of 9-vinylcarbazol with (meth)acrylate(s) and/or sytrene. Used in electrophotography, having high photo-sensitivity, low residual potential on exposure.

Description

"Photosensitive polymer with cyan and / or thiocyanate-substituted 9-vinylcarbazole units, process for its preparation and its use as organic, photoconductive material in photosensitive elements for electrophotography " The invention relates to light-sensitive materials, as organic photoconductive materials polymers useful in photosensitive elements for electrophotography, a process for their manufacture and their use for the stated purpose.

There are various organic photoconductive materials for electrophotographic confesses light-sensitive elements. Conventional organic photoconductive materials point however, only a low sensitivity and could with regard to their photosensitivity also not without destruction or impairment of the light-sensitive layer, the uniformity of the glassy resp.

amorphous structure and flexibility can be improved.

There are also organic photoconductive materials made of high molecular weight Known polymers. Examples are polymers with heterocyclic molecular parts, such as carbazole rings, and polymers called polynuclear aromatic rings, such as Naphthalene rings, Änthracene rings and the like. Contained in the molecule.

These organic, high molecular weight, photoconductive polymers have various merits such as transparency, light weight, and film-forming ability so that it could be assumed that they would find widespread use. Nevertheless, they are not used in practice because of their sensitivity to light disadvantageously far less and their physical properties are not are better than the inorganic photoconductor.

The invention is therefore based on the object of a photosensitive Material for electrophotography with high sensitivity and exposure to create low residual potential that has good physical properties.

This object is achieved according to the invention by a photosensitive polymer with cyano- undo or thiocyanine-substituted 9-vinylcarbazole units of the formula in which R is a hydrogen, chlorine, bromine or iodine atom or a nitro group.

Representative examples of polymers with repeating cyano-substituted 9-vinylcarbazole units are cyan-substituted poly-9-vinylcarbazoles, cyan-substituted Copolymers of 9-vinylcarbazole and acrylic acid ester (s), methacrylic acid ester (s) and / or Styrene, as well as cyano-substituted, halogenated poly-9-vinylcarbazoles.

Representative examples of polymers according to the invention with repeating thiocyanine-substituted 9-vinylcarbazole units are thiocyanine-substituted poly-9-vinylcarbazoles, thiocyanate-substituted copolymers of 9-vinylcarbazole and acrylic acid ester (s), methacrylic acid ester (s) and / or styrene, as well as thiocyanate-substituted, halogenated 9-vinylcarbazole homo- or copolymers.

The incorporation of suitable comonomer units serves to improve the Film formability, flexibility and solubility of the polymers according to the invention.

If the comonomer units do not have their own photoconductivity, the photosensitivity of the obtained by incorporating these comonomers Copolymers are generally reduced, however, in the case of the polymers of the invention this reduction in sensitivity by cyanation or thiocyanation, i. compensated by the introduction of cyano or thiocyanate groups.

The Mechanism on which the High Sensitivity and Photoconductivity of the electrophotographic photosensitive materials according to the invention is based, is not clear, but it is believed that the 9-vinylcarbazole ring moiety acted as donor and the cyano and thiocyanate groups as acceptor, so that an intramolecular Charge transfer takes place.

Copolymers according to the invention with cyano- and / or thiocyanine-substituted In addition to the aforementioned, 9-vinylcarbazole units can also contain the following monomer units contain: 2-vinylpyridine, vinylanthracene, vinylnaphthalene, styrene, acrylonitrile, Methyl acrylate, ethyl acrylate, vinyl acetate, vinylidene chloride, vinyl carbazole, halogen, nitro- or amino-substituted vinyl carbazole, vinyl stearate, n-butyl acrylate, acryloxyethyl diethylamine, Vinyl cinnamate, ethylene, vinyl pyrrolidone, vinyl chloride and the like.

The copolymers of the invention may other than cyano or thiocyanine substituted Vinyl carbazo ionomer units, two or more kinds of different monomer units contain.

The polymers of the invention can be prepared by means of various organic Synthesis methods are produced. Representative examples of suitable syntheses are: 1) homo- or copolymerization of halogen-substituted 9-vinylcarbazoles or 9-vinylcarbazole derivatives and subsequent reaction of the polymer with a Cyanide.

2) Halogenation of homo- or copolymers of 9-vinylcarbazole or 9-vinyl carbazole derivatives by conventional methods and subsequent conversion of the reaction product mixture with a cyanide.

It was found that in the above reactions 1) and 2) halogen atoms located in the 3- or 6-position as the carbazole nucleus, in particular bromine and allow iodine atoms to be smoothly exchanged for a cyano or nitrile group, respectively, if ian the carbazole ring in a non-proton-active polar solvent such as dimethylformamide, Dimethylacetamide, N-methylpyrrplidone and the like, in the presence of copper-I-cyanide heated. The percentage of halogen atom exchange achieved depends on on the nature of the halogen atoms and the reaction conditions ib, but amounts to optimal Conditions close to 100%.

The above-mentioned implementation takes place during implementation hardly ever gel formation after the reaction and after the formation of the final product.

Examples of homo- and copolymers of 9-vinylcarbazole or 9-vinylcarbazole derivatives, into which cyano or thiocyanate groups are to be introduced according to the invention are: A) Homopolymers of 9-vinylcarbazoles with halogen substituent (s): homopolymers of Monomers such as 3-bromo-9-vinylcarbazole, 3-iodo-9-viiylcarbazole, 3-chloro-6-bromo-9-vinylcarbazole, 3, 6-Diiodo-9-vinylcarbazole, 3-chloro-9-vinylcarbazole, 3, 6-I? Ichlor-9-vinylcarbazole, 3-chloro-6-iodo-9-vinylcarbazole and the like.

B) Copolymers of 9-vinylcarbazole with halogen substituent (s): copolymers of the monomers mentioned under A).

with monomers such as 2-vinylpyridine, vinyl anthracene, vinylnaphthalene, Styrene, Acrylonitrile, methyl acrylate, ethyl acrylate, vinyl acetate, vinylidene chloride, Vinyl carbazole, nitro-substituted vinyl carbazole, amino-substituted vinyl carbazole, halogen-substituted vinyl carbazole (excluding combinations with the same as mentioned under A)), vinyl atearate, n-butyl acrylate, acryloxydiethyl amine, vinyl cinnamate, Ethylene, vinyl pyrrolidone, vinyl chloride and the like.

C) Homopolymers of 9-vinylcarbazole derivatives with one halogen substituent (s): Homopolymers of monomers such as 3-bromo-6-nitro-9-vinyl carbazole and 3-chloro-6-nitro-9-vinylcarbazole.

D) Copolymers of monomers mentioned under C) with monomers mentioned under B) (as a copolymer of 9-vinyl carbazole derivative (s).

3) Cyano groups can be found in homo- or copolymers of 9-vinylcarbazole or 9-vinylcarbazole derivatives also by reaction with cyanogen bromide (cyanogen bromide) according to Friedel-Crafts.

The following examples illustrate the preparation of the invention cyano-substituted poly-9-vinylcarbazoles.

Example 1 5.0 g of poly-9-vinylcarbazole are dissolved in 50 ml of pyridine, whereupon 6.6 g of iodine are added and the mixture is stirred at 110 ° C. for 3 hours. After this To cool the solution is poured into a large amount of methanol to prevent the reaction precipitate obtained polymer. The bollard is filtered off, dried and through Purified reprecipitation from pyridine-methanol.

The polymer thus obtained is an encoded poly-9-vinylcarbazole and contains, contrary to the results of the elemental analysis, 20.49% iodine.

2.0 g of this iodinated poly-9-vinylearbazole are dissolved in 50 ml of N-ethyl-2-pyrrolidone dissolved, whereupon 0.5 g of copper (I) cyanide is added and the mixture is heated for 6 hours at 150.degree stirs. After cooling, the reaction mixture is poured into a large amount of methanol to precipitate the polymer obtained in the reaction. The thereby precipitated polymer is filtered off, dried and stimulated by reprecipitation in pyridine-ethanol, wherein a white polymer is obtained. This white polymer is in organic Solvents, such as tetrahydrofuran, pyridine, chlorobenzene and the like. Soluble. The infrared absorption spectrum this polymer shows at 2210 cm (charaiiteri.table for cyano or nitrile groups) and 890 cm 1 and 805 cm 1 (characteristic of one in the 3-position on the carbazole ring sitting substituents) absorption bands. Elemental analysis shows that the polymer contains 9.65% nitrogen but no iodine. This result agrees match the calculated values.

It follows that the implementation is quantitative and that with this one Reaction obtained polymer mainly from cyano-substituted poly-9-vinyicarbazole which contains an average of 0.39 cyano or nitrile groups per carbazole ring, which sit in the 3-position on the carbazole ring.

Example 2 Analogously to Example 1, numerous different iodized Poly-9-vinylcarbazoles with cyano or. Nitrile substituents produced.

The degree of nitrile substitution can be adjusted by adjusting the reaction conditions be managed. The following are general relationships between the implementation or manufacturing conditions and the degree of cyan substitution.

The degree of iodine substitution in poly-9-vinylcarbazole can be less regulated as 1.35 atoms per vinyl carbazole ring will. Below the degree of substitution is given per vinyl carbazole ring. Lm present Example is a poly-9-vinylcarbazole with a degree of iodine substitution as the starting material from 0.183 to 0.706 atoms used. The degree of conversion or degree of exchange of Iodine in or against cyano or nitrile groups can, depending on the chosen reaction or manufacturing conditions are 90 to 95%. As a solvent are for the production of iodinated poly-9-vinylcarbazoles, preferably pyridine (the cyano-substituted Polymers with up to about 0.7 cyan or

Can dissolve nitrile groups per carbazole ring), tetrabydrofuran (the cyano-substituted Polymers with; can dissolve up to about 0.6 nitrile groups per Carbazolrign) and monochlorobenzene (the cyano-substituted polymer with up to about 0.4 nitrile groups per orarbazole ring can solve) used.

N-methylpyrrolidone is particularly preferred as the reaction solvent, but pyridine is also preferred and preferred. The reaction temperature is 1500C when using N-methylpyrrolidone. A white polymer is obtained which is easily soluble in solvents. The degree of conversion or degree of exchange of iodine atoms for nitrile groups is 20 to 95% and the desired sample is obtained by a 6 to 8 hour reaction. The conversion or. The degree of exchange for a 2-hour reaction at 2000C is even 100%, but a colored polymer with low solubility is formed. Copper-I-cyanide is preferably used in amounts of up to 2 Nol per gram atom of iodine. By using higher than the stated amounts of copper (I) cyanide, an improvement in the degree of substitution of iodine atoms for nitrile groups can hardly be achieved. The reaction conditions used in the present preparation examples and the elemental analysis values obtained are listed in the table below, in which the percentages relate to weight. No. Analysis: Iodine content CuCN / J- Resk- Cyanated PVCZ Solubility Color Iodine% in the iodine ratio CN content J content chlorine tetra pyri- ten PVCZ * 1 nis time * 2 * 3 benzene hydride furan (Hours.) 1-1 2.67 0.183 2 6 0.140 0.043 0 0 0 white 1-2 3.43 0.287 2 4 0.231 0.056 0 0 0 white 1-3 1.82 0.327 2 6 0.298 0.009 # 0 0 white-light- 1-4 11.84 0.392 2 2 0.183 0.109 0 0 0 white brown 1-5 4.94 0.405 2 4 0.323 0.082 X 0 0 white 1-6 3.91 0.405 5 4 0.339 0.066 # 0 0 white 1-7 5.10 0.416 2 3 0.331 0.085 # 0 0 white 1-8 1.97 0.416 2 8 0.384 0.032 X 0 0 white 1-9 2.18 0.610 2 6 0.574 0.036 X 0 0 white 1-10 1.78 0.610 2 8 0.580 0.030 X # 0 white The reaction is carried out at 150 ° C. in N-methyl-2-pyrrolidone as solvent.

0 s easily soluble.

soluble.

X: sparingly soluble.

PVCZ: poly-9-vinylcarbazole * 1: iodine atoms / carbazole ring * 2: CN groups / lt * 3 s iodine atoms / lt Example 3 5.0 g of brominated poly-9-vinylcarbazole with a Bromine content of 43.28% are produced by adding Po17-9rvinyl carbazole the Wohl-Ziegler reaction or brominated with bromine in pyridine. This brominated poly-9-vinylcarbazole is dissolved in 50 ml of pyridine. whereupon 0.8 g of copper-I-cyanide is added to the solution and the mixture is allowed to react at 110 ° C. for 8 hours. After cooling, the reaction will solution poured into a large Mengo of methanol to form the resulting polymer precipitate, which is filtered off, dried and by reprecipitation in pyridine-methanol is cleaned to obtain a white polymer. The infrared absorption spectrum this polymer, like that obtained in Example 1, has remarkable characteristics Absorption bands at 2210 cm-1, 890 cm-1 and 805 cm-1 and, according to deia The result of the elemental analysis shows a bromine content of 24.7%. So it is in the case of the polymers obtained as the product of this reaction to form a cyano-substituted, brominated poly-9-vinylcarbazole with an average of 0.94 nitrile groups and an average of 0.89 bromine atoms per carbazole ring, the substituents being mainly sit in the 3 and 6 positions on the carbazole ring.

The reaction of brominated poly-9-vinylcarbazole with copper-I-cyanide lasts longer than that of iodinated poly-9-vinylcarbazole with copper-I-cyanide. The conversion or. Degree of exchange of the bromine substituent for cyano or

Nitrile groups is lower than that of iodine substituents versus nitrile groups. Another example can be found in its essential data in the table below. Br content in. mission Romated Poly-9- Brominated N-Methyl- CuCN CuCN / Br- inylcarbazole poly-9-vinyl-pyrrolidone ratio Atoms / carbazole ring) carbazole nis * , 706 5 g 125 ml 2.67 g 4 * Mole to atom ratio Reaction conditions Cyan-substituted poly-9-vinylcarbaiol Reaction reaction CN content Br content temperature time .. (Groups / Carba- (Atoms / Carbazole- Oa h zolring) ring) 150 40 0.223 0.483 solubility colour Pyridine THF monochlorine benzene weak easily soluble brown soluble soluble Example 4 50 ml of pyridine are treated with 5.0 g of chlorinated and iodinated poly-9-vinylcarbazole with a chlorine content of 4.07% and an iodine content of 13.33%, which is obtained by reacting 10 g by chlorinating poly -9-vinylcarbazole with sulfuryl chloride obtained chlorinated poly-9-vinylcarbazole with a chlorine content of 4.69% with 8.4 g of iodine in the manner described in Example 1 is prepared.

1.2 g of copper (I) cyanide are added to this mixture, whereupon it is allowed to react at 110 ° C. for 10 hours. The product obtained in this way becomes' amalog Example 1 treated further, using a white, cyars @ bstituierter, chlorinated Poly-9-vinylcarbazole with a halogen content found by elemental analysis of 4.61% and a nitrogen content of 8.48% received. The above elementary analyzes agree with those under the approach, that all the iodine is exchanged for nitrile groups, calculated values for the halogen and nitrogen content match.

@us follows the above result of the elemental analysis, that the average degree of substitution or content of nitrile groups or chlorine atoms per carbazole ring is 0.25 and 0.27, respectively.

Example 5 5.0 grams of iodized poly-9-vinylcarbazole with an iodine content of 20.49%, i.e. one of the iodinated poly-9-vinylcarbazole described in Example 1 corresponding polymer are dissolved in 125 ml of N-methyl-2-pyrrolldon, whereupon one 0.80 g of copper (I) cyanide are added to the solution and the reaction mixture is added for 8 hours 1500C and then further treated analogously to Example 1, whereby a white, in polymer soluble in organic solvents, the infrared absorption spectrum this polymer has an absorption band characteristic of nitrile groups at 2210 cm1 as well as for substituents in the 3-position on the carbazole ring Absorption bands at 890 and 805 cm 1. Elemental analysis reveals an iodine content of 6.80%.

These characteristics show that the polymer thus obtained actually made from cyan-substituted iodinated poly-9-vinylcarbazole with average 0.28 nitrile groups and 0.12 iodine atoms in 3-position.

Polymers with cyano-substituted 9-vinylcarbazole units can be also by cyanating 9-vinylcarbazole or 9-vinylcarbazole derivatives and then Prepare polymerization of the cyanated monomers.

Example 6 3.2 g by iodizing 9-ß-chloroethylcarbazole and dehydrating 3-iodine-9-vinylcarbazole produced with potassium hydroxide with a melting point of 194 ° C (decomposition) are dissolved in 50 ml of N-methyl-2-pyrrolidone, whereupon the solution with 2.0 g of Cu ~ CN and a small amount of rydroquinone are added and the mixture is then poured into heated to 150 ° C in a nitrogen atmosphere. The reaction mixture is in water poured, filtered, washed with water, dried and the reaction product then recrystallized three times, giving 1.5 g of 3-cyano-9-vinylcarbazole. Analysis: Found; 11.5 a; Ber .; 12.9% 0.5 g of the 3-cyano-9-vinylcarbazole thus obtained and 1.0 6 9-Vinylcarbazol are then given a Polyaerissionsrchr, with Azobisisobutyronitril added and heated to 80 ° C. for 8 hours in a nitrogen atmosphere. That included The polymer obtained is dissolved in tetrahydrofuran and precipitated in methanol. Included receives a white polyzer, which is easily soluble in tetrahydrofuran, which is about 31 Contains% 3-cyano-9-vinylcarbazole units.

Thiocyanated polymers according to the invention can, for example, such as can be prepared as follows: (1) Introducing thiocyanate groups into poly-9-vinylcarbazoles or 9-vinylcarbazole copolymers, (2) thiocyanating halogenated 9-vinylcarbazole homo- or copolerer.

(3) Halogenation of bomo- or copolymers of thiocyanated 9-vinylcarbazole.

The thiocyanation reaction can be carried out according to the "Organic Reactions", Volume 3, page 240 ff (edited by R.

Adams) described, optionally modified methods be: As relevant: suitable methods are to be mentioned: a) relocating a 9-vinyl carbazole polymer solution with a solution of free thiocyan in benzene, chlorobenzene, Chloroform or methylene chloride wFd b) carrying out a reaction by electrolytic or chemical (e.g. from alkali metal thiocyanate and halogen) formation or generation of thiocyan. Some poly-9-vinylcarbazoles heavily substituted with thiocyanate groups are insoluble in benzene and monochlorobenzene, which is why it is advantageous in these cases is to carry out the reaction in tetrahydrofuran or dioxane. Furthermore you can thiocyanate the homo- or copolymers mentioned above under A) to B). Nan can also be thiocyanated 9-vinyl carbazole or thiocyanated 9-vinyl carbazole derivatives polymerize.

In the following examples, the preparation is thiocyanate 9-vinylcarbazole homo- and copolymer explained.

Example 7 3.9 g of poly-9-vinylcarbazole are dissolved in 180 ml of monochlorobenzene dissolved, whereupon the solution is a solution of lead thiocyanate and an equivalent Amount of bromine produced thiocyan in nonochlorobenzene with stirring at -5 to -10 ° C added and the mixture allowed to react for 3 hours.

The reaction mixture is then poured into methanol in order to precipitate the resulting polymer, which is then washed further with methanol and finally dried under reduced pressure. Thiocyanate reaction yield amount of temperature Polymer (1) 0.58 g 200C 4.1 g "(2) 1.16 g 200C 4.4 g Elemental analysis of the resulting polymers: N% S% Polymer (1) 8.24 3.85 Easily soluble in monochlorine benzene Polymer (2) 9.50 7.18 " In the infrared absorption spectrum of these polymers, 860 cm 1 and 790 cm 1 (1,3,4-substituted benzene nucleus) appear at 2145 cm 1 (SC- * N) absorption bands, the position of which indicates that the SCN groups are mainly in the 3-position on the Carbazole ring are bound.

Example 8 2.0 g by adding an aqueous copper (II) sulfate solution with potassium thiocyanate, filtering off the precipitate which separates out and washing of the precipitate with ethanol and then with ether obtained Supfer-II-thiocyanate are in a solution of 3.9 g of poly-9-vinylcarbazole in 180 ml of monochlorobenzene and 25 ml of glacial acetic acid suspended, whereupon the suspension is stirred at 30 to 500C. When the black copper (II) thiocyanate has turned almost white, the reaction liquid becomes centrifuged to separate insolubles and then poured into methanol in order to precipitate the polymer formed during the reaction, which is filtered off, with methanol washed and dried under reduced pressure.

Analysis of the polymer thus obtained: Found: N 9.50 %; s 7.02%.

Example 9 10 g of 9-vinylcarbazole-ethyl acetate copolymer (71 mol% 9-vinylcarbazole) are in 200 ml of monochlorobenzene and 20 ml Pyridine dissolved, whereupon one of this solution with stirring at 100C 40 ml of benzene containing 2.5 g of thiocyan, drips. When the addition is complete, the reaction is left at the same temperature Continue to run for 2 hours, and then pour the reaction liquid into a large amount Methanol to precipitate the copolymer. The copolymer is washed with methanol and dried under reduced pressure.

Analysis: Found: N 7.92%; S 6.05%.

Analogous to the above-described Arbeitsswelse, but instead of of the 9-vinylcarbazole-ethyl acrylate copolymer as the starting material is a 9-vinylcarbazole-styrene-C opolymer (95 mol% of 9-vinylcarbazole units) is used, a thiocyanated 9-vinylcarbazole-styrene copolymer, which has the following analytical characteristics: N 9.30%; S 7.41%.

Example 10 A solution of 4 g of poly-9-vinylcarbazole in 200 ml of dry Methylene chloride are 5 ml of methylene chloride containing 1.4 g of sulfuryl chloride at 00C, added dropwise.

The reaction is then allowed to run for 3 hours at 200.degree. C. and the water is poured The reaction mixture is then poured into a large amount of methanol Precipitate polymer, which is then filtered off and dried. The yield is 4.3 g.

Analysis: Cl 8.38%; N 6.40%.

21 g of the chlorinated poly-9-vinylcarbazole thus obtained are dissolved in 50 ml of monochlorobenzene, whereupon the solution is stirred at 1000 5 ml of a solution of 0.6 g of thiocyan in benzene are added dropwise.

After the addition has ended, the reaction mixture is stirred at the same time Temperature further for 2 hours and then pour the reaction mixture into a large amount Methanol.

The resulting polymer product is isolated and recrystallized Purified in monochlorobenzene-methanol.

Analysis: N 8.64%; Cl 7.39%; S 6.72%.

Leave from the polymers prepared as described above electrophotographic photosensitive members can be made, e.g., by coating a conductive support with a solution of one of these polymers and then Drying the applied solution or by melt-coating a conductive one Carrier with one of these polymers or by making a self-supporting one Polymer film by means of melt extrusion or evaporation of the solvent from a Polymer solution.

The polymers can be used as electrophotographic photosensitive Elements in the form of self-supporting Films or fabrics or in Use the form of thin films on conductive substrates. For example, you can use to manufacture electrophotographic photosensitive members made from polymers of the present invention coat a glass plate with a polymer solution, the solution layer on the Dry the glass plate and peel off the remaining film, a polymer melt-through Extrude spinnerets into fibers which are then woven, or a conductive one Coat the carrier with a polymer solution.

The polymers can contain additives for adjusting the photographic Properties or characteristic data, e.g. sensitizers, and additives for setting the physical properties, such as plasticizers and opacifiers (opacifying Medium), can be added. Examples of sensitizers are Lewis acid sensitizers, e.g., polynitro compounds such as 1,3,5-trinitrobenzene, picric acid, 5-nitroacetonaphthalene and 2,4,7-trinitrofluorenone, carboxylic acids such as acetic, trifluoroacetic, trichloroacetic and salicylic acid, sulfonic acids, such as benzenesulfonic and p-toluenesulfonic acid, sulfonic acid chlorides, such as p-toluenesulfonic acid chloride, and optical sensitizers such as crystal violet, Malachite green, methylene blue, brilliant green and quinizarin should be mentioned.

Suitable plasticizers are, for example, dibutyl phthalate, dioctyl phthalate, Tricresyl phosphate and chlorieSes polyphenyl should be mentioned.

Organic photoconductive materials are usually used in combination used with a color sensitizer or a Lewis acid sensitizer as itself the most photosensitive organic photoconductive materials are still considerable are less sensitive to light than inorganic photoconductive materials.

The organic photoconductive materials of the invention also have with respect to the discharge characteristics upon exposure and the photosensitivity excellent properties, but are still preferred in practice used in combination with various color sensitizers and Lewis acids.

One of the most effective ways to sensitize those of the invention organic photoconductive polymer is sensitization with free radicals forming substances (radical sensitization). Radical awareness can be how be carried out as follows: The organic photoconductive material according to the invention is a substance which forms free radicals in an amount of about 1 to 30% by weight, based on the weight of the organic photoconductive polymer added, whereupon the mixture is exposed to radiation for a few to a few tens of minutes, e.g. UV radiation or colored or visible light. The achieved thereby The sensitivity to light is similar to that of dye-sensitized zinc oxide to compare.

Representative examples of free radical generating compounds are Polyhalogen compounds such as CBr4, CJ4, CHJ3, C2Cl6, CBrCl3, CCl4, CHBr3, CHCl3, C2Br6, C2HBr5, C6H5CBr3, CJBr3, CJCl3, CHJCl2, CHJBr2, CBrCl3, CHBrCl2, α, α, α-trichlorotoluene, α, α, α-tribromoacetophenone and dgl-A suitable means for further or npch, stronger sensitization is it, the hadikal sensitization in the presence of the sensitizers of the following. listed type to be carried out leuco bases or carbinol It @@ em @on triphenylmethane dyes, w e leuco malachite green, leuco crystal violet, leucomethyl violet, beukoopal blue and Carbinolm @ lachite green styryl color bases, such as 4 - (@ - dimethylaminophenyl-1,3-butadienyl) -quinoline, 4-p-dimethyl @ minostyrylquinoline, 2-p-dimethylaminostyrylquinolime, 2- (4-dimethylaminophenyl-1, 3-butadienyl) quinoline and 2-p-dimethylstyrylbenzothiazole.

Cyanine color base, such as 2- [3- (1-ethyl-2- (1H) -quinolylidene) -propenyl] -quinoline, 2- [2-Mathyl-3- (3-ethyl-2- (3H) -benzothiazolylidene) -propenyl) benzathiazole and 4 - [(- ethyl-2 (1H) -quinolylidene) methyl] -c @ imoline.

Merocyanine color bases, such as 3-ethyl-5- [3-ethyl-2- (3H) -benzoxazolylidene] -rhodanine, 1-ethyl-3- [3-ethyl-2 (3H) -benzoxazolylidene ] oxyindole and 4- [3-ethyl-2 (3H) -benzoxazolylidene] -3-phenyl-5- (4H) -isooxazolone.

Secondary or tertiary arylamines, such as diphenylamine, N-methylamine, N, N-dimethylaniline, N-ethylaniline, N, N-diethylaniline, phenyl-α-naphthylamine, Phenyl-ß-naphthylamine, triphenylamine, N-methyldiphenylamine and N-benzylaniline.

Carbazoles, such as carbazole, N-ethylcarbazole, N-methylcarbazole, N-phenylcarbazole, N-benzylcarbazole, N-vinylcarbazole, 3,6-dibromo-N-vinylcarbazole and 3-chloro-N-ethyl carbazole.

Indoles, such as indole, 2-methylindole, 1,2-dimethylindole, 1-phenylindole, 4-chloroindole and N-vinylindole.

The radical sensitization can not only occur in the liquid phase but also in the solid phase, e.g. by irradiating a solid photosensitive film be performed.

The electrophotographic photosensitive material of the present invention can be used to generate images using various known means or means. Methods related to charging and development, e.g. corona discharge, magnetic brush development and / or electrophoretic development can be used.

The following examples serve to further explain the invention, however, are in no way to be understood as a limitation.

Example 11 A sandblasted aluminum plate is mixed with a mixture the end Ethers and alcohol degreased using a rotary coating device a liquid of the composition given below in an amount or

Starch coated so that an 8μ thick film remains after drying and dried with a stream of warm air.

Composition of the material used to coat the sandblasted aluminum plate Liquid used: poly-9-vinyl carbazole.

(Luvican M-170, Rand-fr name, product of B)) (as a comparison) or cyanated poly-9-vinylcarbazole with a nitrogen content of 2.0 as specified in the following table @@ ter (1) to (5) g chlorobenzene 40 ml crystal violet 2.0 mg The photosensitive plate obtained is momtiert on a rotary electrometer to charge it negatively and exposed to a tungsten lamp. The irradiation time that has elapsed until the original potential has dropped to 1/3 and 1/10 is measured and the reciprocal value of the irradiation time is specified as the "sensitivity" parameter. The so defined "sensitivity" of various samples is given in the table below. The initial potential at the beginning of the irradiation or exposure is in each case about 500 volts. Cyanated poly-9 sensitivity: vinylcarbazole: waste on Nitrogen content 1/3 1/10 (1) 8.51% 1.50 1.95 (2) 9.60% (Example 1) 2.30 2.75 (3) 11.89% 5.35 5.95 (4) 14.59% 8.80 10.5 (5) 20.41% 8.85 10.5 Poly-9-vinyl carbazole (Comparison or Reference substance) 0 1.0 The cyanated poly-9-vinylcarbazoles listed above under (1) and (3) are prepared by reacting an iodinated poly-9-vinylcarbazole with a sufficient amount of copper-I-cyanide analogously to Example 1 and the above under (4) and (5) listed cyanated poly-9-vinylcarbazoles prepared by reacting a brominated poly-9-vinylcarbazole with a sufficient amount of copper-I-cyanide analogous to Example 3.

Example 12 One of Polymers No. 1 to No. 10 of Example 2 2.0 g crystal violet 5 mg 2,4,? - trinitrofluorenone 2 mg diphenyl chloride 0.5 g chlorobenzene 40 ml.

By coating an art paper with a mixture of the above specified composition in an amount that a strong 8 P after drying Leaves film behind, a photosensitive paper is made. This photosensitive Paper is charged in the dark and then using a 500 W tungsten lamp equipped enlarger exposed through a positive microfilm original image. The latent image thus created is developed using a liquid developer, whereby good positive images are obtained. The optimum amount of exposure light is 300 Lux x ~ seconds.

Example 13 Cynated polymer as under (1) to (4) in the following Table indicated 2.0 g carbon tetrabromide 100 mg 9-vinylcarbazole 180 mg chlorobenzene 40 ml.

A solution of the ingredients listed above is provided in an Erlenmyerko, made of hard glass and stirring a photochemical Treatment by exposure for 5 minutes with a 100 arranged at a distance of 10 cm W subjected to high pressure mercury lamp. Then you put the reaction liquid 2 mg of 2,4,7-trinitrofluorenone, whereby one photosensitive With the light-sensitive liquid thus obtained, a high quality paper that adheres to its surface. with a polyvinyl alcohol layer is provided, coated so that an 8 P film remains after drying.

The photosensitive paper obtained in this way is then made using a corona discharge in the dark and exposed analogously to Example 12. That The resulting electrostatic latent image is then made using a liquid Developed into a positive image.

The amount of exposure light required in each case to achieve sharp and clear positive images is given in the table below for each of the cyanated polymers (1) to (4) as "optimal exposure" in lux × seconds. Cyanated polymer nitrogen optimal salary exposure (%) (Lux. Sec.) (1) Cyanated Poly-9 vinyl carbazole 8.51 150 (2) Cyanated Poly-9 vinylcarbazole (manufactured represents according to example 1) 9.60 130 (3) Cyanated Poly-9 vinyl carbazole 11.89 120 (4) Cyanated and chlorinated Poly-9-vinyl carbazole (prepared according to Example 4) 8.36 95 The cyaiiized poly-9-vinylcarbazoles listed above under (1) and (3) are prepared analogously to Example 1.

Example 14 Example 1 is repeated using a coating liquid with the following composition: poly-9-vinylcarbazole (Luvican M-170) (comparison) or a photosensitive polymer prepared according to Example 7 or 8, 2.0 g of tetrahydrous per 40 ml 2,4,7-trinitrofluorenone 1.0 mg The following results are obtained: Thiocyanated Poly-9 Sensitivity: Decrease vinylcarbazole: 1/3 1/10 Sulfur content 3.85% 2.2 2.6 7.18% 5.3 5.9 Poly-9-vinylcarbazole 1.0 1.0 (Comparison) Example 15 To produce a photosensitive paper, a photosensitive liquid is applied to a high quality paper (60 g / m 2) with a polyvinyl alcohol layer in such an amount that an 8 P film remains after drying.

The photosensitive liquid is cyanated by dissolving 2 g 9-vinylcarbazole-ethyl acrylate copolymer or cyanated 9-vinylcarbazole-styrene copolymer (prepared according to Example 9) in 40 ml of monochlorobenzene, replace Wer solution with 100 mg carbon tetrabromide and 2 mg triphenyl bismuthine, irradiate for 5 minutes this solution with a 100 W high pressure mercury lamp arranged at a distance of 10 cm (for the purpose of triggering a photochemical reaction) and then adding 5 mg of 2,4,7-trinitrofluorenone prepared. The resulting photosensitive Paper is charged by corona discharge in the dark and then by means of a a photographic enlarger equipped with a 500 W tungsten lamp an original positive microfilm image-wise exposed.

The electrostatic image created in this way becomes with a liquid developer to obtain high-contrast positive images. The optimal exposure is 155 lux x seconds in the case of the former cyanated Copolymer and 110 lux x seconds in the case of the second cyanated copolymer. the optimum exposure when repeating the above experiments using the corresponding non-cyanated copolymers is 465 lux x seconds or 310 lux x seconds.

Example 16 Thiocyanated polymer 2 g carbon tetrabromide 100 mg 9-vinylcarbazole 50 mg triphenylbi smuthin 2 mg monochlorobenzene 40 ml A solution with the composition given above is treated photochemically analogously to Example 15 and under the same conditions and then treated with 2 mg crystal violet, whereupon analogously Example 15 produces a photosensitive paper from the photosensitive liquid obtained in this way, which paper is also tested analogously to Example 15 for its suitability for the production of images. The following results are obtained: Thiocyanated polymer Optimal exposure Uhiocyanated poly-9 vinylcarbazole; 105 lux. Seconds Sulfur content: 3.85% Thiocyanated copolymer, manufactured provides 160 lux according to example 3. Seconds Thiocyanated polymer, manufactured represents 90 lux seconds according to example 4 The polymers with a low sulfur content, for example a sulfur content of 3.85%, give satisfactory results even if triphenylbismuthine is omitted from the formulation given above.

The invention further relates to photosensitive elements for Electrophotography, the basic embodiment of which is shown in the single figure of the enclosed Drawing is reproduced and consists of a conductive support 1 and a photosensitive Layer 2 consists, and is characterized in that the photosensitive layer at least one polymer according to the invention as the organic photoconductive material with repeating units of the formula I contains.

Claims (5)

P a t e n t a n s p r ü c h e Polymer with cyano- and / or thiocyanine-substituted 9-vinylcarbazole units of the formula in which R is a hydrogen, chlorine, bromine or iodine atom or a nitro group. 2. Polymer according to claim 1, d a d u r c h g e k e n n -z e i c h n e t that there is a cyano or thiocyanate substitui @ @es poly-9-vinylcarbazole, cyano or thiocyanate-substituted, halogenated poly-9-vinylcarbazole, cyano- or thiocyanine-substituted Copolymer of 9-vinylcarbazole and acrylic acid ester (s), methacrylic acid ester (s) and / or Styrene is. 3. Process for the preparation of cyan-substituted polymers according to Claim 1 or 2, d a d u r c h g e -k e n n z e i c h n e t that one is a halogen-substituted one 9-vinylcarbazole homo- or copolymer with copper-I-cyanide to form a polymer with cyan-substituted 9-vinylcarbazole units. 4. Process for the preparation of thiocyanate-substituted polymers according to claim 1 or 2, d u r c h g e n n n z e i c h n e t that one optionally halogen-substituted 9-vinylcarbazole homo- or copolymer with thiocyan or copper (II) thiocyanate to form a polymer with thiocyanate-substituted 9-vinylZ carbazole units implements 5. Use of polymers according to claim 1 or 2 as photosensitive organic material in photosensitive elements for electrophotography.