EP0210521B1 - Electrophotographic recording material - Google Patents

Description

The invention relates to an electrophotographic recording material composed of an electrically conductive layer support, optionally an insulating intermediate layer and a photoconductive layer composed of at least one compound which produces a perylene-3,4,9,10-tetracarboximide derivative as charge carrier, photoconductor as charge transport compound, binder and conventional additives . The invention relates in particular to a recording material comprising an electrically conductive layer support, optionally an insulating intermediate layer, a dye layer with a perylene-3,4,9,10-tetracarboximide derivative as the charge-generating compound and an organic photoconductor as the charge transport compound layer.

The recording material according to the invention is advantageously suitable for a lithographic printing form or printed circuit which can be produced by electrophotographic means, consisting of a correspondingly suitable electrically conductive layer support and a photoconductive layer with binders which can be stripped of alkali.

The use of perylene-3,4,9,10-tetracarboxylic acid derivatives as charge-generating pigment compounds in organic photoconductor layers is known (US Pat. No. 3,904,407, DE-OS 22 37 539 corresponding to US Pat. No. 3 871 882, DE -OS 2314051 corresponding to US-PS 3, 972, 717 and EP-B 0 061 089).

From US-A-4, 514, 482 an electrophotographic material is known with a photoconductive layer which contains perylene pigment, the substituents of which can be alkyl or aryl groups. Although it is stated that the substituents can be different, all the particularly suitable compounds mentioned there are symmetrical in structure. Where an asymmetrically substituted compound is shown, as outlined in the formula in Example II, it can be seen from the description that the connection is rather symmetrical in nature. At no point is it stated how to get to compounds that are unsymmetrically substituted. With the usual manufacturing processes, only mixtures of differently substituted compounds are obtained.

US-A 4, 447, 514 discloses an electrophotographic recording material with a poly-N-vinylcarbazole / perylene pigment system as a photoconductive layer, which has better photosensitivity when it is mixed in certain quantities with a halogenated naphthoquinone and phenanthrene or pyrene. The formula given for the substituents R ₁ and R ₂ with hydrogen or alkyl or aryl, which may be substituted or unsubstituted, can also be formally derived from the fact that different substituents could be present in a compound. However, there is no reference to this in the description and examples. Only symmetrically substituted pigments are mentioned and used as suitable pigments. It is also mentioned how to proceed in order to expand the spectral sensitivity, namely by adding other pigments as usual.

Amending US-A-4,447,514, US-A-4,438,187 discloses the combination of poly-N-vinylcarbazole, perylene pigment and halogenated naphthoquinone as a photosensitive coating for electrophotographic material.

From the formula given for the perylene pigment, one can read formally that the substituents R ₁ and R ₂ could be different and should be hydrogen or alkyl or aryl, substituted or unsubstituted. Such an interpretation is in no way supported by description and examples. The pigments used are all symmetrically substituted. From the document it can be seen that such pigments are used that are commercially available. This only includes pigments that are symmetrically substituted.

As an advantage, this document points out that the poly-N-vinylcarbazole / pigment system can be adjusted more sensitive to light by additions. Additional pigments are required for a broader spectral sensitivity.

The known perylene-3,4,9,10-tetracarboxylic acid derivatives have, as red-colored dyes, photosensitivities which range approximately in the range from 620 to 650 nm. It was an object of the invention to find new perylene-3,4,9,10-tetracarboxylic acid derivatives which, if possible, also have good photosensitivity up to 700 nm.

• in der R - Wasserstoff, Alkyl, Hydroxyalkyl, Alkoxy-alkyl, Aryl oder Aralkyl und
• A - Phenylen, Naphthylen oder einen höher kondensierten aromatischen carbocyclischen oder heterocyclischen Rest, die jeweils durch Halogen, Alkyl, die Cyano- oder Nitro-Gruppe substituiert sein können, bedeuten,
  
• in der R und R' - ungleich voneinander sind und
• R Wasserstoff, Alkyl oder Aralkyl und
• R' Alkoxyalkyl, Cycloalkyl, Aryl, Aralkyl oder Heteroaryl, die jeweils durch Halogen, Alkyl, die Cyano-oder Nitrogruppe substituiert sein können,
• bedeuten, oder
  
  in der R - Wasserstoff, Alkyl, Hydroxyalkyl, Alkoxyalkyl, Aryl oder Aralkyl, die jeweils durch Halogen, Alkyl, die Cyano- oder Nitrogruppe substituiert sein können,
• bedeutet, enthält.
• Vorzugsweise bedeuten in Struktur I
• R - Niederalkyl oder Benzyl und
• A - Phenylen,
• in Struktur II
• R - Wasserstoff, Niederalkyl oder Benzyl und
• R' - Niederalkoxyalkyl, durch Niederalkyl substituiertes Phenyl, Benzyl oder Pyrenyl,
• und in Struktur 111
• R - Niederalkyl, Hydroxyniederalkyl, Niederalkoxyalkyl, Benzyl oder Phenylethyl.

The object is achieved according to the invention by an electrophotographic recording material of the type mentioned at the outset in that it contains a perylene-3,4,9,10-tetracarboxylic acid imide of the following structures in the photoconductive layer:

• in the R - hydrogen, alkyl, hydroxyalkyl, alkoxy-alkyl, aryl or aralkyl and
• A - phenylene, naphthylene or a more condensed aromatic carbocyclic or heterocyclic radical, which can each be substituted by halogen, alkyl, the cyano or nitro group,
  
• in which R and R '- are unequal to each other and
• R is hydrogen, alkyl or aralkyl and
• R 'alkoxyalkyl, cycloalkyl, aryl, aralkyl or heteroaryl, each of which can be substituted by halogen, alkyl, the cyano or nitro group,
• mean or
  
  in which R is hydrogen, alkyl, hydroxyalkyl, alkoxyalkyl, aryl or aralkyl, each of which can be substituted by halogen, alkyl, the cyano or nitro group,
• means contains.
• In structure I preferably mean
• R - lower alkyl or benzyl and
• A - phenylene,
• in structure II
• R - hydrogen, lower alkyl or benzyl and
• R '- lower alkoxyalkyl, phenyl, benzyl or pyrenyl substituted by lower alkyl,
• and in structure 111
• R - lower alkyl, hydroxy lower alkyl, lower alkoxyalkyl, benzyl or phenylethyl.

Examples of suitable carbocyclic or heterocyclic radicals are naphthylene-1,8- or pyridyl radicals. Cyclohexyl, for example, is suitable as the cycloalkyl.

It has surprisingly been found that the asymmetrical perylene-3,4,9,10-tetracarboximides according to the invention as charge-generating pigments with many organic photoconductors which are charge transport compounds and especially with binders are good photosensitive recording materials, both in double and in in a monolayer arrangement with pigment dispersed therein. Compared to the known perylimide dyes, the asymmetrical pigments according to the invention have high photosensitivity down to a range of almost 700 nm. This also allows their use in electrophotographic recording materials for He / Ne and LED laser light sources.

However, the variety of charge transport compounds and binders with which the asymmetrical pigments according to the invention can be combined to form highly sensitive photoconductor layers is particularly advantageous for the development of technically usable organic photoconductor layers.

worin in der Verbindungsklasse b der Substituent R bevorzugt Wasserstoff, Alkyl, wie Methyl bis Butyl, Hydroxyalkyl, wie 2-Hydroxyethyl, Alkoxyalkyl, wie 3-Methoxypropyl sowie Aralkyl, wie Benzyl sein kann. Die Derivate der Perylen-3,4,9,10-tetracarbonsäuremonoanhydridmonoimide (b) können auch mit Erfolg als Ladungsträger erzeugende Verbindungen eingesetzt werden. Wegen ihrer guten Alkalilöslichkeit sind sie bevorzugt in alkalisch entschichtbaren lithographischen Druckformen einsatzfähig.The preparation of the perylene-3,4,9,10-tetracarboximides according to the invention is known: The regulations for the perylene-3,4,9,10-tetracarboxylic acid monoanhydride monoimides required as starting products are in DE-OS 30 08 420 corresponding to US Pat 4,501,906 and DE-OS 30 17 185. The production processes of the perylene-3,4,9,10-tetracarboxylic acid monoanhydride monoalkali salts (a) and that of the perylene-3,4,9,10-tetracarboxylic acid monoanhydride monoimide (b) are given therein.

wherein in the compound class b the substituent R can preferably be hydrogen, alkyl, such as methyl to butyl, hydroxyalkyl, such as 2-hydroxyethyl, alkoxyalkyl, such as 3-methoxypropyl and aralkyl, such as benzyl. The derivatives of the perylene-3,4,9,10-tetracarboxylic acid monoanhydride monoimide (b) can also be used successfully as charge-generating compounds. Because of their good alkali solubility, they can preferably be used in alkali-strippable lithographic printing forms.

Starting from a compound of formula b), condensation with diamines [R (-NH ₂ ) _2] or primary amines (R-NH ₂ ) leads to the perylimidbenzimidazole (1) or peryldiimide (II) pigments according to the invention.

beschrieben. In derselben Veröffentlichung ist auch ein Pigment vom Typ (11) mit R = H und R' = 3,5-Xylidin dargestellt. Diese Verbindungen sind je nach Substitution rot - dunkelrot - dunkelviolett gefärbte Pigmente.For example, a compound of type (I) with R = CH ₃ and

described. A pigment of type (11) with R = H and R '= 3,5-xylidine is also shown in the same publication. Depending on the substitution, these compounds are red - dark red - dark violet colored pigments.

The structure of the electrophotographic recording material is explained schematically with the aid of the attached FIGS. 1 to 5. Position 1 indicates the electrically conductive layer support, position 2 indicates the charge layer producing dye layer, and position 3 indicates the charge transport layer. Position 4 indicates the insulating intermediate layer and position 5 shows layers which represent a charge carrier-producing dye layer in dispersion. Position 6 shows a photoconductive monolayer of photoconductor, perylene-3,4,9,10-tetracarboximide and binder.

Aluminum foil, optionally transparent, aluminum-vapor-coated or aluminum-clad polyester foil, is preferably used as the electrically conductive layer support, however, any other support material made sufficiently conductive (e.g. by soot, etc.) can also be used as the layer support. The arrangement of the photoconductor layer can also be on a drum, on flexible endless belts, e.g. made of nickel or steel etc. or on plates.

All materials known for this purpose can be used as carrier materials for the electrophotographic production of printing forms, e.g. Aluminum, zinc, magnesium, copper plates or multi-metal plates. Surface-coated aluminum foils have proven particularly useful. The surface refinement consists of mechanical or electrochemical roughening and, if appropriate, subsequent anodizing and treatment with polyvinylphosphonic acid in accordance with DE-OS 16 21 478, corresponding to US Pat. No. 4,153,461.

The aim of introducing an insulating intermediate layer, possibly also a thermally, anodically or chemically produced aluminum oxide intermediate layer (FIG. 3, position 4), is to reduce the charge carrier injection from the metal into the photoconductor layer in the dark. On the other hand, it should not hinder the flow of charge during the exposure process. The intermediate layer acts as a barrier layer, it also serves, if appropriate, to improve the adhesion between the layer support surface and the dye layer or photoconductor layer and should be able to be stripped off water or alcoholic-alkaline for the production of printing forms.

Different natural or synthetic resin binders can be used for the intermediate layer, but preference is given to using materials which are good on a metal, especially aluminum nium surface, adhere and are slightly dissolved when subsequent layers are applied. These include polyamide resins, polyvinyl alcohols, polyvinyl phosphonic acid, polyurethanes, polyester resins or specifically alkali-soluble binders, such as, for example, styrene-maleic anhydride copolymers.

The thickness of organic intermediate layers can be up to 5, that of an aluminum oxide intermediate layer is generally in the range from 0.01 to 1 μm.

The dye layer 2 or 5 according to the invention (FIGS. 2 to 5) has the function of a layer which generates charge carriers; the dye used determines the spectral photosensitivity of the photoconductive system through its absorption behavior.

The application of a homogeneous, densely packed dye layer is preferably obtained by evaporating the pigment onto the support in vacuo. Depending on the vacuum setting, the dye can be evaporated without decomposition under the conditions of 1.33 x 10-6 to 10-8 bar and a heating temperature of 240 to 290 _° C. The temperature of the substrate is below 50 _° C.

This gives layers with tightly packed dye molecules. This has the advantage over all other possibilities of producing very thin, homogeneous dye layers that an optimal charge generation rate can be obtained in the dye layer. The extremely finely dispersed distribution of the pigment enables a large concentration of excited dye molecules that inject charges into the transport layer. In addition, the charge transport through the dye layer is not or only slightly hampered by binders.

An advantageous layer thickness range of the evaporated dye is between 0.005 and 3 μm. A thickness range between 0.05 and 1.5 μm is particularly preferred since the adhesive strength and homogeneity of the vapor-deposited pigment are particularly favorable here.

In addition to vapor deposition of the dye, a uniform dye thickness can also be achieved by other coating techniques. This subheading includes mechanical rubbing of the finely powdered dye material into the electrically conductive substrate, electrolytic or electrochemical processes or electrostatic spray technology.

In combination with an intermediate layer or as a replacement for such, homogeneous, well covering dye layers with thicknesses of the order of 0.05 to 3 µm can also be obtained by grinding the dye with binder, in particular with cellulose nitrates and / or crosslinking binder systems, for example polyisocyanate-crosslinkable acrylic resins, Reactive resins, such as epoxies, DD lacquers, and then coating these dye dispersions according to position 5 in FIGS. 4 and 5. Furthermore, binders such as polystyrene, styrene-maleic anhydride copolymers, polymethacrylates, polyvinyl acetates, polyurethanes, polyvinyl butyrals, polycarbonates, polyesters etc. and mixtures thereof can be used.

The ratio of dye / binder can vary within wide limits, but preference is given to pigment primers with a pigment content of over 50% and correspondingly high optical density.

Another possibility is to produce a photoconductor layer according to FIG. 1, in which the charge generation centers (pigments) are finely dispersed in the transport layer medium. This arrangement has the advantage of a simpler production method than that of a double layer, and is particularly suitable for the production of lithographic printing forms. The pigment content in the photoconductor layer is preferably up to about 30%. The layer thickness of such arrangements is preferably 2 to 10 J.Lm.

The inverse arrangement of the charge carrier-generating layer 5 in FIG. 5 on the charge-transporting layer 3, when using a p-transport connection, provides photoconductor double layers which have a high photosensitivity when charged positively.

Organic materials which have an extensive m-electron system are particularly suitable as the material used for charge transport. These include both monomeric and polymeric aromatic or heterocyclic compounds.

The monomers used are in particular those which have at least one tertiary amino group and / or one dialkylamino group.

Heterocyclic compounds such as oxdiazole derivatives, which are mentioned in German patent 10 58 836 (corresponding to US Pat. No. 3,189,447), have proven particularly useful. These include, in particular, 2,5-bis (p-diethylaminophenyl) oxdiazole-1,3,4; unsymmetrical oxdiazoles, such as 5- [3- (9-ethyl) -carbazolyl] -1,3,4-oxdiazole derivatives (US Pat. No. 4,192,677), about 2- (4-dialkylaminophenyl -) - 5- [3 - (9-ethyl) -carbazolyl] -1,3,4-oxdiazole can be used successfully.

Other suitable monomeric compounds are arylamine derivatives (triphenylamine) and triarylmethane derivatives (DE-PS 12 37 900), e.g. Bis (4-diethylamino-2-methylphenyl) phenylmethane, more condensed aromatic compounds such as pyrene, benzo-condensed heterocycles (e.g. benzoxazole derivatives). Pyrazolines are also suitable, e.g. 1,3,5-triphenylpyrazolines or imidazole derivatives (DE-PS 10 60 714 or 11 06 599, corresponding to US-PS 3,180,729, GB-PS 938,434). This subheading also includes triazole, thiadiazole and especially oxazole derivatives, for example 2-phenyl-4- (2'-chlorophenyl) -5 (4'-diethylaminophenyl) oxazole, as described in German patents 10 60 260.12 99 296 , 11 20 875 (corresponding to US-PS 3,112,197, GB-PS 1,016,520, US-PS 3,257,203) are disclosed.

worin R = H-, Halogen-, Alkyl-, Alkoxy-Gruppen und R', R" = Alkyl-Gruppen sein können. Ihre Herstellung ist aus DE-OS 28 44 394 bekannt.4-Chloro-2 (4-dialkylaminophenyl) -5-aryloxazole derivatives are also of great interest,

where R = H, halogen, alkyl, alkoxy groups and R ', R "= alkyl groups. Their preparation is known from DE-OS 28 44 394.

gemäß US-PS 4,150,987, DE-OS 29 41 509, DE-OS 29 19 791, DE-OS 29 39 483 (entsprechend US-PS 4,338,388, US-PS 4,278,747, GB-PS 2,034,493) bewährt.Hydrazone derivatives of the following structures have also become a charge transport compound

according to US-PS 4,150,987, DE-OS 29 41 509, DE-OS 29 19 791, DE-OS 29 39 483 (corresponding to US-PS 4,338,388, US-PS 4,278,747, GB-PS 2,034,493) proven.

Formaldehyde condensation products with various aromatics, such as, for example, condensates of formaldehyde and 3-bromopyrene, have proven to be suitable as polymers (DE-OS 21 37 288 corresponding to US Pat. No. 3,842,038). In addition, polyvinyl carbazole or copolymers with at least 50% vinyl carbazole content as transport polymers, for example in a double layer arrangement, provide good photosensitivity (FIGS. 2 to 4).

Without the dye layer, the charge-transporting layer 3 has practically no photosensitivity in the visible range (420 to 750 nm). It preferably consists of a mixture of an electron donor compound (organic photoconductor) with a binder if negative charging is to be carried out. It is preferably transparent, but this is not necessary in the case of a transparent, conductive layer support. Layer 3 has a high electrical resistance of greater than 10 ¹² a. It prevents the discharge of electrostatic charge in the dark; when exposed, it transports the charges generated in the dye layer.

In addition to the charge generation and transport materials described, the added binder influences both the mechanical behavior, such as abrasion, flexibility, film formation, adhesion, etc., and to a certain extent the electrophotographic behavior, such as photosensitivity, residual charge and cyclic behavior.

Polyester resins, polyvinyl chloride / polyvinyl acetate copolymers, alkyd resins, polyvinyl acetates, polycarbonates, silicone resins, polyurethanes, epoxy resins, poly (meth) acrylates and copolymers, polyvinyl acetals, polystyrenes and styrene copolymers, cellulose derivatives, such as cellulose acetate etc., are used as binders. In addition, thermally post-crosslinking binder systems, such as reactive resins, which are composed of an equivalent mixture of hydroxyl-containing polyesters or polyethers and polyfunctional isocyanates, polyisocyanate-crosslinkable acrylate resins, melamine resins, unsaturated polyester resins, etc., have been used successfully.

Because of the good photosensitivity, flash sensitivity and high flexibility, the use of particularly viscous cellulose nitrates is particularly preferred.

In addition to the film-forming and electrical properties as well as those of the adhesive strength on the substrate when used for printing forms or printed circuits, solubility properties play a particularly important role in the selection of binders. Those binders which are soluble in aqueous or alcoholic solvent systems, optionally with the addition of acid or alkali, are particularly suitable for practical purposes. Suitable binders are then high molecular weight substances which carry alkali-solubilizing groups. Such groups are, for example, acid anhydride, carboxyl, phenol, sulfonic acid, sulfonamide or sulfonimide groups.

Copolymers with anhydride groups can be used with particularly good results. Copolymers of ethylene or styrene and maleic anhydride or maleic acid semiesters are very particularly suitable. Phenolic resins have also proven their worth.

Copolymers of styrene, methacrylic acid and methacrylic acid esters can also be used as alkali-soluble binders (DE-OS 27 55 851). In particular, a copolymer from 1 up to 35% styrene, 10 to 40% methacrylic acid and 35 to 83% methacrylic acid n-hexyl ester. A terpolymer made from 10% styrene, 30% methacrylic acid and 60% methacrylic acid n-hexyl ester is extremely suitable. Polyvinyl acetates (PVAc), in particular copolymers of PVAc and crotonic acid, can also be used.

The binders used can be used alone or in combination.

The mixing ratio of the charge transporting compound to the binder can vary. However, the requirement for maximum photosensitivity, i.e. as large a proportion of charge transport compound as possible and after crystallization to be avoided and increase in flexibility, i.e. as large a proportion of binders as possible, relatively certain limits. A mixing ratio of approximately 1: 1 parts by weight has generally proven to be preferred, but ratios between 4: 1 to 1: 4 are also suitable.

When using polymeric charge transport compounds such as bromopyrene resin, polyvinyl carbazole, binder proportions of around or below 30% are suitable.

The respective requirements of a copying machine for the electrophotographic and mechanical properties of the recording material can be met within a wide range by different adjustment of the layers, for example viscosity of the binder, proportion of the charge transport compound.

In addition to the transparency of the charge-transporting layer, its layer thickness is also an important factor for optimal photosensitivity: layer thicknesses between approximately 2 and 25 μm are generally used. A thickness range from 3 to 15 μm has proven to be particularly advantageous. However, if the mechanical requirements and the electrophotographic parameters (charging and development station) of a copying machine permit, the specified limits can be extended upwards or downwards in individual cases.

Leveling agents such as silicone oils, wetting agents, in particular nonionic substances, plasticizers of different compositions, such as, for example, those based on chlorinated hydrocarbons or those based on phthalic acid esters are considered to be customary additives. If necessary, conventional sensitizers and / or acceptors can also be added to the charge-transporting layer, but only to the extent that their optical transparency is not significantly impaired.

The invention is explained in more detail with the aid of the examples, without being restricted thereto.

example 1

An aluminized polyester film, the pigments are x 10- ⁷ bar deposited to 10-8 within 2 to 3 minutes at 250 to 260 _° C according to formula 1 and 2 (Appendix) in a vacuum vapor deposition at 1.33. Homogeneous pigment layers with layer weights in the range from 100 to 300 mg / m ^{z are obtained} . The layer support is completely covered.

A solution of equal parts by weight of 2,5-bis (4-diethylaminophenyl -) - oxdiazole-1,3,4 (To 1920, mp 149 to 150 _° C.) and a polyurethane resin (Desmolac ^R 2100, Bayer AG) is placed on these vapor deposition layers. spun in tetrahydrofuran (THF).

The layer is then dried in a forced-air drying cabinet at about 100 _° C. within 5 minutes. The layer thickness is then 7 to 8 µm, the layer adheres well. The photosensitivity is measured as follows:

To determine the light discharge curves, the test sample moves on a rotating plate through a charging device to the exposure station, where it is continuously exposed to a xenon lamp XBO 150 or halogen W lamp (150 W). A heat absorption glass and a neutral filter are installed upstream of the lamp. The light intensity in the measuring plane is in the range from 30 to 50 µW / cm ² or 5 to 10 µW / cm ² ; it is measured immediately after or parallel to the determination of the light decay curve with an optometer. The charge level and the photo-induced light decay curve are recorded by an electrometer using a transparent probe. The photoconductor layer is characterized by the charge level (Uo) and the time (T _1/2 ) after which half of the charge U _o / 2) has been reached. The product of Ti _{/ 2} [s] and the measured light intensity I [µW / cm ² ] is the half-value energy Ein [µJ / cm ² ].

The photosensitivity of the double layer is determined according to this characterization method:

The residual charge (U _R ) after 0.1 sec., Determined from the above bright discharge curves, is a further measure of the discharge of a photoconductor layer.

Example 2

The pigment layers with the asymmetrical perylimide dyes according to formula I, 1 and 2, are produced as described in Example 1. These vapor deposition layers are then coated with a solution of 65 parts by weight To 1920 and 35 parts by weight cellulose nitrate of the standard type 4E (DIN 53179) in THF. After drying, the layer thicknesses ranged from 7 to 8 and 12 to 13 µm.

The photosensitivity of these photoconductor double layers is determined according to Example 1:

The spectral photosensitivity of these photoconductor double layers is determined with the use of filters using the method given in Example 1: In the case of negative charging (500 to 550 V), the half-life (Ti / ₂ in msec) for the respective wavelength range is determined by exposure. The spectral photosensitivity curve of a photoconductor layer is obtained by plotting the reciprocal half-value energy (1 / E _1/2 cm ² / µJ) against the wavelength λ (nm). The half-value energy E _{1/2 / µJ / cm} 2 means the light energy that has to be irradiated in order to discharge the photoconductor layer to half the initial voltage U _o .

6 shows the spectral photosensitivities of photoconductor double layers with the pigments I, 1 and I, 2 (corresponding to curves 1 and 2) and a layer thickness of 12 to 13 μm.

Example 3

A pigment evaporation layer with pigment according to formula I, 1 is coated with a solution of equal parts by weight of 2-phenyl-4- (2'-chlorophenyl) -5 (4'-diethylaminophenyl) oxazole (Table: Layer 3 - 1) and a polyester resin ( Dynapol ^R L206) coated in THF. In a further coating solution, 2- (4'-diethylaminophenyl) -4-chloro-5 (4'-methoxyphenyl) oxazole was used instead of this oxazole derivative (Table: Layer 3 - 2). The two double layers with a layer thickness of 7 to 8 μ gave the following photosensitivity:

Example 4

The very good photosensitivity which is achieved by coating 50 parts by weight of To 1920 with 50 parts by weight of different binders in a thickness of 7 to 8 μm (solvent THF) on a pigment vapor deposition layer with an asymmetrical perylimide derivative (formula 1, 2) is as follows Table shown:

Example 5

A mixture of 65 parts by weight of pigment (formula I, 2), 25 parts by weight of cellulose nitrate of the standard type 4E (DIN 53179) and 10 parts by weight of epoxy resin (Epikote ^R 1001) are ground together intensively in THF for 2 to 3 hours in a ball mill. The finely dispersed solution is then homogeneously applied to a conductive support in thicknesses of approximately 210 mg / m ² and approximately 490 mg / m ² and dried.

To increase the photosensitivity, part of the pigment precoat was polished with cotton wool.

The pigment pre-coat (approx. 490 mg / m3), which is insoluble for the subsequent coating of the charge transport layer, is made with a solution of equal parts by weight To 1920 and a copolymer Styrene / butadiene (Pliolite ^R S5B) and coated with a solution of 98 parts by weight of polyvinyl carbazole (Luvican ^R M170, BASF) and 2 parts by weight of polyester resin (Adhesive ^R 49000) in THF. After drying, the double layer is 4 to 5 µm thick; their photosensitivity is determined according to Example 1:

Example 6

An aluminum-vapor-coated polyester film is vacuum-coated with the pigments according to formula 11, 1 and 2 in a thickness of approximately 200 mg / m ² . The homogeneous pigment layers are then coated with a solution of equal parts by weight of 2- (4-diethylaminophenyl) -4-chloro-5- (4-methoxyphenyl) oxazole and polycarbonate (Makrolon ^R 2405) in a thickness of about 8 μm after drying. The photosensitivity is measured analogously to Example 1:

Example 7

A pigment vapor deposition layer of approx. 135 mg / m ² thickness, consisting of a pigment according to formula II, 3, is produced according to Example 1 and with a solution of 98 parts of polyvinyl carbazole (Luvican ^R M170) and 2 parts of polyester resin (Adhesive ^R 49000) in THF coated. After drying, the double layer thickness is 7 µm. After measurement according to Example 1, with a negative charge of 510 V, a half-value energy Ei / 2 of 2.1 µJ / cm ^{2 is} present.

Example 8

Further vapor deposition layers are produced with the asymmetrical perylimide pigments II, 4 and 5. The thickness of these homogeneous dye layers is 185 and 150 mg / m ² .
A solution of equal parts by weight To 1920 and a copolymer of styrene and maleic anhydride (Scripset ^R 540) is applied in a thickness of approx. 8 µm. The measurement of the photosensitivity gives the following values:

Example 9

5 parts of pigment according to formula I, 2 are added to a solution of 45 parts of To 1920 and 50 parts of copolymer of syrene and maleic anhydride (Scipset ^R 550). This dispersion is ground very finely in a ball mill for about 2 hours and then layered on wire-brushed aluminum foil (a) and anodized aluminum foil (b) in a thickness of 7 to 8 μm.
The photosensitivity, measured analogously to Example 1 with a tungsten halogen lamp with positive and negative charging, can be seen from the following table:

Example 10

• a) 1,3,5-Triphenylpyrazolin,
• b) Bis(4-diethylamino-2-methylphenyl-)phenylmethan sowie
• c) 9-Ethylcarbazol-3-aldehyd-1,1-diphenylhydrazon

A solution of equal parts by weight of polycarbonate (Makrolon ^R 3200) and of the organic photoconductor compounds is applied to a vapor deposition layer (Pigment I, 1) according to Example 1

• a) 1,3,5-triphenylpyrazoline,
• b) bis (4-diethylamino-2-methylphenyl) phenylmethane and
• c) 9-ethylcarbazole-3-aldehyde-1,1-diphenylhydrazone

coated in 7 to 8 µm for a) and b) and 9 to 10 µm for c) thickness (dry). The photosensitivity is measured using a tungsten halogen lamp as described in Example 1:

Example 11

After preparation of the dye of the formula 111, 1 (DE-OS 30 17 185) will he bar aluminized in a vacuum vapor deposition was 1.3 x 10- ⁷ to 10- ⁸ within 7 minutes at about 250 _° C to a Evaporated polyester film. A homogeneous, red vapor deposition layer with a layer weight of 135 mg / m2 is obtained.

A solution of 65 parts by weight of To 1920 and 35 parts by weight of cellulose nitrate of standard type 4E is thrown into THF. After drying, the thickness of the charge transport layer is approximately 10 µm.

The photosensitivity is measured according to Example 1 with a halogen tungsten lamp (exposure intensity approx. 4.5 µW / cm ² ):

Charging (-) 320 V and E _1/2 = 0.92 µJ / cm ² . The spectral photosensitivity of this layer is shown in FIG. 7, it was mediated according to Example 2 with a negative charge of 300 to 350.

Example 12

Dye vapor deposition layers in a thickness range of 135 to 140 mg / m ² are produced with the compounds 111, 1 and II, 6, as described in Example 11. This is followed by a charge transport layer consisting of equal parts by weight To 1920 and a copolymer of styrene and maleic anhydride (Scipset ^R 550). The total layer thickness is approx. 10 µm. The photosensitivity is measured analogously to Example 1:

Example 13

• (+) Aufladung: 260 V Ei/₂ = 5,9 µJ/cm²
• (-) Aufladung: 510 V E_1/2 = 7,9 µJ/cm²

A solution of 45 parts of To 1920 and 50 parts of copolymer of styrene and maleic anhydride (ScripsetR 550) is mixed with 5 parts of dye according to formula III, 6 and very finely dispersed in a ball mill for about 2 hours. This dispersion is then layered on wire-brushed aluminum foil in a thickness of approx. 10 µm. The photosensitivity with positive (+) and negative (-) charging gives the following values (halogen-tungsten lamp).

• (+) Charging: 260 V Ei / ₂ = 5.9 µJ / cm ²
• (-) Charging: 510 VE _1/2 = 7.9 µJ / cm ²

Example 14

Evaporation layers with the perylene tetracarboxylic acid monoimides 111, 2 and 3 are produced in 115 and 110 mg / m ² thickness as described in Example 1. A solution of 66.7 parts To 1920 and 33.3 parts cellulose nitrate of standard type 4E (DIN 53179) in THF is layered on top. After drying, the layer thickness was 10 to 11 µm.
The photosensitivity of the two double layers is determined according to Example 1 (halogen-tungsten lamp):

Example 15

More advanced vapor deposition layers were produced with the perylene tetracarboxylic acid monoimides III, 4 and 5 on aluminum-coated polyester film in 120 and 105 mg / m ² thickness. The vapor deposition conditions were about 270 ° C and 10 minutes at 1.33 x 10- ⁷ to 10 sbar.

FORMELTABELLE

• 1 R = -CH ₃R' = H
• 2 R =
  
  R' = H
  
  
  
  

The homogeneous, strong red colored dye layers are coated with a solution of 50 parts To 1920, 25 parts polyester resin (Dynapol ^R L206) and 25 parts polyvinyl chloride-polyvinyl acetate copolymer (Hostaflex ^R M131) in a thickness of 8 to 9 µm. The photosensitivity according to Example 1, measured under halogen tungsten light, is:

FORMULA TABLE

• 1 R = -CH ₃ R '= H
• 2 R =
  
  R '= H
  
  
  
  

Claims (6)

1. An electrophotographic recording material comprising an electrically conductive support material, where appropriate an insulating intermediate layer, and a photoconductive layer comprising at least one layer containing a peryiene-3,4,9,10-tetracarbimide derivative as the charge carrier-generating compound, photoconductor as the charge transport compound, binder and customary additives, characterized in that a perylene-3,4,9,10-tetracarbimide responding to one of the following structural formulae is contained in the photoconductive layer of said material:

in which R denotes hydrogen, alkyl, hydroxyalkyl, alkoxyalkyl, aryl or aralkyl and

A denotes phenylene, naphthylene or a more highly fused aromatic carbocyclic or heterocyclic radical which can each be substituted by halogen, alkyl, the cyano group or the nitro group;

in which R and R' are different from each other and

R denotes hydrogen, alkyl or aralkyl and

R' denotes alkoxyalkyl, cycloalkyl, aryl, aralkyl or heteroaryl which can each be substituted by halogen, alkyl, the cyano group or the nitro group; or

in which R denotes hydrogen, alkyl, hydroxyalkyl, alkoxyalkyl, aryl or aralkyl which can each be substituted by halogen, alkyl, the cyano group or the nitro group.

2. An electrophotographic recording material comprising an electrically conductive support material, where appropriate an insulating intermediate layer, a dye layer with a perylene-3,4,9,10-tetracarbimide derivative as claimed in claim 1 as the charge carrier-generating compound, and a layer containing an organic photoconductor as the charge transport compound.

3. The recording material as claimed in claim 1 or 2, wherein, in formula I, R denotes lower alkyl or benzyl and A denotes phenylene.

4. The recording material as claimed in claim 1 or 2, wherein, in formula II, R denotes hydrogen, lower alkyl or benzyl and R_' denotes lower alkoxyalkyl, lower-alkyl-substituted phenyl, benzyl or pyrenyl.

5. The recording material as claimed in claim 1 or 2, wherein, in formula III, R denotes lower alkyl, hydroxy lower alkyl, lower alkoxyalkyl, benzyl or phenylethyl.

6. The recording material as claimed in claim 1 or 2, wherein the photoconductive layer contains a binder soluble in aqueous alkalis.

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