DE1254469B - Photoconductive layers - Google Patents

Description

GERMAN VjTffWW ^ PATENT OFFICE

EDITORIAL

German KJ .: 57 e - 5/06

Number: 1 254 469

File number: K 48294 IX a / 57 e Registration date: November 24, 1962

Readout set: November 16, 1967

The invention relates to photoconductive layers with an amino group-containing heterocyclic layer organic compound as a photoconductor.

It is known that organic substances such as anthracene, anthraquinone, benzidine, Oxdiazoles, triazoles, or the amino-containing heterocyclic compounds of German Auslegeschrift 1 109 032 can use.

A disadvantage of these known photoconductors is that they have a in the visible range of the spectrum have relatively low sensitivity and that they are only used in this area need to be sensitized.

In addition, the known photoconductors cannot be used to produce layers that show satisfactory homogeneity.

The object of the invention is to provide photoconductive layers of homogeneous structure which contain photoconductors which are sensitive in the visible range of the spectrum.

The subject matter of the invention is based on photoconductive layers with one containing amino groups heterocyclic organic compound as a photoconductor and is characterized in that it as a photoconductor at least one compound of the formula

, i CR ₁

i ^A i i

\ C - R »

contains, where A is a fused aromatic hydrocarbon radical which is associated with one or several unsubstituted or with aliphatic and / or aromatic radicals substituted amino groups and / or can be substituted with inert further radicals, and R and Ri are aryl, alkaryl, Alkoxyaryl, halogenated aryl, aminoaryl or with aliphatic and / or aromatic radicals substituted aminoaryl and wherein at least one aryl of the formula with a substituted or unsubstituted amino group must be substituted.

The photoconductors are quinoxalines. The fused aromatic hydrocarbon radical denoted by A may contain an N-containing one of the ones shown Represent ring fused phenyl, naphthyl or phenanthryl radical. This aromatic carbon hydrogen radical can be substituted one or more times, e.g. B. by an amino, AIkyIamino-, di-

Photoconductive layers

Applicant:

Kalle Aktiengesellschaft, Wiesbaden-Biebrich. Rheingaustr. 190-196

Named as inventor: Dr. Martha Tomanek, née Kunitzer, Wiesbaden-Biebrich

alkylamino, arylamino, diarylamino, arylalkylamino, alkyl, alkoxy or halogen radical. the aromatic rings of the aryl-containing substituents just mentioned can be replaced by halogen and / or be substituted by aliphatic hydrocarbon and / or alkoxy radicals having 1 to 4 carbon atoms.

The photoconductors can in a known manner by condensation of 1 mole of aromatic ortho-diamine, for. B. o-diaminobenzene, with 1 mole of an appropriately substituted benzil, e.g. B. 4-dimethylamino-benzil, in the presence of the dehydration promoting agents such as polyphosphoric acid or glacial acetic acid. The duration of the reaction is between 2 and 4 hours a temperature of 90 to 120 ° C. Then the reaction product is poured into water and the precipitated precipitate filtered off with suction after cooling, recrystallized from alcohol and dried. Reactions of this type are e.g. B. described in J. Am. Chem. Soc., 70: 904 (1948).

Suitable photoconductors are:

2-phenyl-3- (4'-dimethylaminophenyl) -quinoxaline,

2,3-bis- (4'-dimethylaminophenyl) -quinoxaline, 2-phenyl-3- (4 ^/ -diethylamino-phenyl) -quinoxaline, 2,3-bis- (4'-diethylaminophenyl) -quinoxaline, 2- {4'-methylaminophenyl) -3- (4'-methyl-propyl-

amino-phenyl) -quinoxaline, 2- (4'-phenylamino-phenyl) -3-phenyl-quinoxaline, 2- (4'-chlorophenyl> 3- (4'-dimethylamino-

phenylfquinoxaline, 2- (4'-Dimethylaminophenyl) -3- (4'-methoxy-

phenyl) -quinoxaline, 2- (4'-methyl-phenyI) -3- (4'-methylethylamino-

phenyl) -quinoxaline, 2-phenyl-3- (4'-dimethylaminophenyl) -6-methyl quinoxaline,

709 688 351

1

2-phenyl-3- (4'-dimethylaminophenyl) -7-chloroquinoxaline,

2-phenyl-3- (4'-dimethylaminophenyl) -6-meth-

oxy-quinoxaline,
2,3-bis- (4'-aminophenyl) -quinoxaline, 2,3-bis- (4'-aminophenyl) -6-aminoxaline.
2-phenyl-3-phenyl-6-amino-quinoxaline,
2,3-bis- (4'-methoxyphenyl) -6-amino-quinoxaline, 2,3-bis- (4'-chlorophenyl) -6-dimethylamino-

quinoxaline, 2-phenyl-3- (3'-methyl-phenyl) -7-methylpropyl-

amino-quinoxaline,
2,3-bis- (4'-bromophenyl) -6-phenylamino-quin-

oxaline.

2-phenyl-3- (4'-dimethylaminophenyI) -

6,7-benzo-quinoxaline or
2- (4'-methylpropylaminophenyl) -3-phenyl-

6.7-indeno- (2,3) -quinoxaline.

Mixtures of the photoconductors can also be used in the photoconductive layers according to the invention. You can also use one or more of the photoconductors in admixture with known inorganic or use organic photoconductors.

The invention achieves that photoconductive layers with a more homogeneous structure than are available so far. This homogeneous structure is due to the good solubility of the Photoconductor, which also creates high concentrations of photoconductors in the photoconductive layer - if this should be desired - can be achieved. The photoconductors are generally colorless to pale yellow in color. With the photoconductive layers, sharp images with large Achieve contrasts.

Another essential advantage of the photoconductor is that the maximum of their sensitivity to light is already in the visible range of the spectrum. This fact allows the possibility. Wf apply iiger or no optical sensitizers.

Furthermore, the photoconductive layer according to the invention has the advantage that it is both positive as can also be charged negatively, so that only by reversing the polarity with the same layer using positive images from both negative and positive originals from the same developer can be obtained.

To produce an electrophotographic recording material, the photoconductor is detached in benzene, acetone, methylene chloride, ethylene glycol monomethyl ether or in mixtures of these Solvents and thus coats a support in the usual way.

It is often advisable to use the photoconductor in a mixture with BimK agents. As a binder are called gL.: Balsam resin, rosin, shellac, phenolic resins modified with rosin, Coumarone resins, indene resins, cellulose ethers, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, Polyvinyl acetate, polyvinyl ether, copolymers of vinyl chloride, vinyl acetate and maleic acid, Polyacrylic ester, polymethacrylic ester. Polystyrene, copolymers of styrene and maleic anhydride, Phthalate resins. Polyester made from terephthalic acid or isophthalic acid and ethylene glycol, maleinate resins, mixed polyesters from maleic acid, rosin and higher alcohols, phenol-formaldehyde resins, 469

phenol-formaldehyde resins especially modified with rosin, urea-formaldehyde resins, Melamine formaldehyde resins. Aldehyde resins, ketone resins, xylene-formaldehyde resins, polyamides. Polyurethanes, low molecular weight polyethylene. Polypropylene. Poly-isobutylene or chlorinated rubber.

Mixture of 2 parts binder and 1 part photoconductor up to mixtures containing 2 parts photoconductor to contain 1 part binder are preferable. Particularly favorable results can be passed through Achieve application of mixtures in a weight ratio of 1: 1.

The spectral sensitivity of the photoconductive layers is essentially in the short-wave range of the visible spectrum and extends into the long-wave ultraviolet range. By adding sensitizing dyes, however, the spectral sensitivity of the photoconductive layers according to the invention can be increased in the visible region of the spectrum. Even quantities less than 0.0001 percent by weight produce good effects. However, the amount of the sensitizing dyes added to the photoconductive layer is generally from 0.001 to 5 "/», preferably from 0.01 to 3 "/». It is possible to add a larger amount of sensitizing dye, but in general no larger increases in sensitivity are obtained. Suitable sensitizing dyes are known from Belgian patent 558 078.

For the production of images on an electrophotographic recording material with a photoconductive layer according to the invention, the latter is charged as usual to 6000 to 7000 volts, exposed, developed and fixed.

As is known, the toner images can be converted into planographic printing forms, using as solvents alcohol, acetic acid or caustic soda is used for the photoconductive layer. at With the use of transparent substrates, the toner images can also be used as a master copy.

example 1

1 part (in the following all parts by weight are given) 2-phenyl-3- (4'-diethylamino-pheny!) -Quinoxaline (Formula 4) and 1.2 parts of a polyindene resin having a softening point of 80 ° C. are dissolved in 30 parts of chloroform, plus 0.002 parts Crystal violet in 0.4 part of methanol was added. The solution is on paper that is against the penetration organic solvent is pretreated, applied and dried. The so coated Paper is negatively charged by a corona discharge, then under a positive copy template exposed with a 100 watt light bulb and with a developer consisting of a carrier and a black toner, dusted in a known manner. The result is a positive toner image that is fixed and is then characterized by great contrast. If you use a transparent one Layer support, for example a cellulose acetate film or transparent paper, can be used for the toner image can be used as a master copy.

The preparation of 2-phenyl-3- (4'-diethylaminophenyD-quinoxaline can be done with the help of a method as described in J. Am. Chem. Soc., 70 (1948), p. 904, is done.

I 254

Example 2

1 part 2-PhenyI-3- (4'-dimethylaminophenyl) -quinoxaline (Formal). 1.5 parts of a ketone resin with a softening point of 76 to 82 C acid number 0, and 0.005 parts of brilliant green are in 19 parts Ethylene glycol monomethyl ether dissolved and the solution applied to aluminum cased paper. After the solvent has evaporated, it remains firmly adhering to the aluminum surface photoconductive layer. After being negatively charged by a corona discharge, the paper becomes under a positive master copy with a 100 watt lightbulb from a distance of 30 cm Exposed for 10 seconds. Development is then carried out as in Example 1. A positive toner image appears.

The compound according to formula 1 is prepared by boiling 25.3 parts of 4-dimethylaminobenzil for 3 hours and 10.8 parts of 1,2-diaminobenzene in 210 parts of glacial acetic acid. When the reaction has ended, the mixture is poured into 1 liter of water. The precipitate that separates out is filtered off with suction, washed with water and made up of 96% alcohol recrystallized.

Example 3

25th

5 parts of an equimolecular mixture are dissolved in 96.6 parts of ethylene glycol monomethyl ether 2-phenyl-3- (4'-dimethylamine-phenyl) -6-methoxyquinoxaline and 2-phenyl-3- (4'-dimethylamino-phenyl) -7-methoxy-quinoxaline (Formula 2). 5 parts of a styrene copolymer containing carbonyl groups with the decomposition point 200 to 210 C and the specific gravity L15 to 1.16 and 0.01 part Rhodamine B extra (C.I. 45 170) and uses it to coat a mechanically roughened, brushed one Aluminum foil, the brushing depth of which averages 5 to 7; j.m. After evaporation of the solvent, a photoconductive layer remains firmly adhering to the aluminum foil 4.7; xm thickness. The recording material produced in this way becomes negative as a result of a corona discharge charged and then in the cassette of a reproduction camera in which there is an erecting prism, exposed at f / 9 for 20 to 30 seconds, depending on the scale of the image. Be used as a light source eight nitraphot light bulbs of 500 watt each are used. A double-sided print serves as a master copy Book page. On these photoconductive layers, areas of DIN A4 format can be used with a Develop powder developer evenly without using magnetic brushes. The powder developer contains a toner mixture of kieselguhr and a toner that consists of a low-melting mixture made of polystyrene. Rosin. Soot and nigrosine are soluble in fuel.

After developing the charge image with this toner mixture (grain size 5 to 10 ^ m) the toner image is fixed by heating to 160 to 170 C in the course of 30 seconds. The toner image can be converted into a flat shape by wiping it over with a solution, which 40 percent by weight methanol, 10 percent by weight glycerine. 45 percent by weight glycol and 5 percent by weight Contains sodium silicate. The parts of the image not covered by the toner are dissolved away and become hydrophilic, while the image parts covered with toner take on a bold color, so that after clamping the planographic printing form obtained in this way can be printed in an offset printing machine.

The mentioned mixture according to formula 2 is prepared by heating 12.5 g for 3 hours 3.4-diaminotoluene and 25.3 g of 4-dimethylaminobenzil in 200 ml of polyphosphoric acid at 100 ° C After the reaction has ended, the mixture is poured into 2 l of water and the precipitate is filtered off with suction until the filtrate is neutral, washed, dried and recrystallized from alcohol. Since this is a mixture from two isomeric compounds (the methvi group in the 6- or 7-position), none is obtained sharp melting point. The two isomers are used in a mixture.

Example 4

1 part by weight of 2,3-bis- (4'-methoxypheny]) - 6-amino-quinoxaline is dissolved in 30 parts by weight of toluene (Formula 8). 1 part by weight of a resin-modified maleic acid resin and 0.006 part by weight of Eosin S. (C.I. 45 380) and applies the solution to a solvent-impermeable paper. To the remaining photoconductive layer adheres firmly to the evaporation of the solvent the paper. The procedure for producing an image is as described in Example 1 and this is obtained when using a positive copy, a positive toner image.

The compound according to formula 8 is prepared by catalytic reduction of 2,3-bis- (4'-methoxyphenyl) -6-nitro-quinoxaline. F. 190 to 191 C. with Raney nickel; the quinoxaline derivative was made analogously to the compound formula 1 from 4-nitro-1,2-diamino-benzene and 4,4'-dimethoxy-benzil.

Example 5

The procedure is as in Example 1, but the coated paper is positively charged after drying and exposed under a negative master copy. After developing and fixing as in Example 1 a positive toner image with sharp edges is obtained.

Example 6

0.6 part 2- (4'-chlorophenyl) -3- (4'-dimethylaminophenyD-quinoxaline (formula 5), 0.4 part 2-phenyl-3- (4'-dimethylaminophenyl) -6.7- benzo-quinoxaline (Formula 6) and 0.4 parts of 2,3-bis- (4'-methoxyphenyD-6-amino-quinoxaline (Formula 8) are in 38 parts Ethylene glycol monomethyl ether dissolved and the solution applied to a brushed aluminum foil. After the solvent has evaporated, a photoconductive layer remains firmly adhering to the aluminum foil Layer. The procedure is as in Example 1 and a toner image is obtained which is in a planographic printing form can be converted by wiping it with 80% alcohol, rinsing with water and rub in with greasy paint and ten percent phosphoric acid. A planographic printing form is obtained from which can be printed after clamping in an offset printing machine.

Example 7

1 part by weight of a mixture of 2-phenyl-3- (4'-dimethylaminophenyl) -6- and -7-chloroquinoxaline, 3 parts by weight of a mixture of 2-phenyl-3- (4'-dimethylaminophenyl) -6- and -7-methoxyquinoxaline (Formulas 3 and 9), 5 parts by weight of one

Phenol-formaldehyde resin with a softening point of 108 to 118 C and 0.008 parts by weight of patent blue AE (C.I. 42 045) are in a mixture of 50 parts by volume of benzene and 50 parts by volume of chloroform solved. The solution obtained in this way is used to create a paper that is protected against the penetration of solvents is coated. Toner images are formed on this paper in the same manner as in Example 1 generated. The paper is very sensitive, so that it can also be written on from both sides by episcopal means Master copies of images can be generated.

Example 8

H.N

15th

A mixture of 2 parts of 2-phenyl-3- (4'-dimethylamino-phenyl) -6,7-benzo-quinoxaline (formula 6), 2, parts of 2,5-bis (4'-diethylamino-phenyl) -l, 3,4-oxdiazole and 5 parts of a ketone resin is with 0.003 parts of methyl violet dissolved in 145 parts of ethylene glycol monomethyl ether and the solution applied to an aluminum-laminated paper. After the solvent has evaporated, a remains photoconductive layer firmly adhering to the aluminum surface. One loads the photoconductive Layer is positively applied by a corona discharge and exposed under a positive master copy. A very good positive toner image is obtained after development.

H _i N

H _i CO

- N (CHi) ₂

Formula 6

Formula 7

OCH »,

OCR _i

Formula 8

5- N (CH _s ) _i

Formula 9

N (CH _i ) _i

30th

Example 9

H »C-

N (CH ₁ ) _i

A mixture of 5 parts by weight of 2,3-bis (4'-aminophenyl) -quinoxaline, mp 258 to 259 C, and 5 parts by weight of a chlorinated rubber are dissolved in 100 GeFormel 1 35 parts by weight of toluene and 0.015 parts by weight of Rose Bengal (CI 45 440) added. The solution is printed on paper that has been pretreated to prevent the ingress of organic solvents. applied and dried. The procedure is continued as in Example 1 and high-contrast positive toner images are obtained.

Example 10

Formula 2 The procedure is as in Example 1, but a mixture of is used to coat the paper

1 part of an equimolecular mixture of 2-phenyl-N (CHs) _i 3- (4'-dimethylamino-phenyl) -6-amino-quinoxaline and

2 - phenyl - 3 - (4 '- Dimethylamine - phenyl) - 7 - aminoquinoxaline and 1 part of a converted natuer loan resin with the melting point 98-106 C. Formula 3 ^unc * ^c ^ ^he acid number 140/155. This mixture is dissolved in 37 parts of butanone.

The 2-phenyl-3- (4'-dimethylamino-phenyl-6- or -7-amino-quinoxalin is prepared by katalyti-N (C _i Ho) _i ^{55 scne} reduction of an alcoholic solution of

2-Phenyl-3- (4'-dimethylamino-phenyl) -6- or -7-nitro-quinoxaline with Raney nickel at 40 ° C. The nitro compound was obtained by boiling 4-nitro-1,2-diamino-benzoI obtained with 4-dimethylaminobenzil in formula 4 60 glacial acetic acid.

Example 11

Dissolve in 96 parts of ethylene glycol monomethyl ether 5 parts of 2,3-bis-phenyl-6-dimethylamino-quinoxaline, 5 parts of maleate resin with a melting point of 105 to 115 ° C and an acid number of 150 and 0.01 part RhodaminBextra (Cl. 45 170) and coated Formula 5 with a mechanically roughened, brushed aluminum

N (CH ₈ ) ₂

Claims (1)

minium foil, the brushing depth of which averages 5 to 7 am. After the solvent has evaporated What remains is a layer 4.7 x m thick, adhering firmly to the aluminum foil. The one made in this way The recording material is treated further as in Example 3. With the flat printing forme, very high editions and printed images of good quality can be produced. The 2,3-bis-phenyl-6-dimethylamino-quinoxaline, mp 188-190 ° C., is prepared from the compound Formula 7 by treatment with dimethyl sulfate. 29 g of the compound formula 7 are thereby Doused with 100 g of dimethyl sulfate and heated at 60 ° C. for 2 hours. Then you give alcohol and Add potassium hydroxide solution until a strongly alkaline reaction and boil under reflux for 4 hours. After this Cooling is poured into water, the precipitate which separates out is suctioned off, dried and removed Recrystallized ethyl alcohol. Claim: Photoconductive layer with an amino group-containing heterocyclic organic compound 10 as a photoconductor, characterized in that it is at least one photoconductor Compound of formula C-Ri C - R ₂ contains, wherein A is equal to a fused aromatic hydrocarbon radical which is associated with a or more unsubstituted or substituted by aliphatic and / or aromatic radicals Amino groups and / or can be substituted by inert further radicals, and R and Ri is aryl, alkaryl, alkoxyaryl. halogenated aryl, aminoaryl or with aliphatic and / or aromatic radicals are substituted aminoaryl and where at least one aryl of the formula must be substituted with a substituted or unsubstituted amino group. Considered publications:
German interpretative document No. 1 109 032.