DE1497182C2 - Electrophotographic recording material - Google Patents

Description

—CH, -CH, -

consists.

The invention relates to an electrophotographic recording material having a photoconductive one Layer containing a polymeric 9-vinyl anthracene as photoconductor, optionally a binder and optionally contains a sensitizer.

It is known anthracene derivatives (German Auslegeschrift 11 09 032) or polycondensation products of hydrocarbons with anthracene units (French patent specification 12 82 559) as photoconductors in to use electrophotographic recording materials.

The disadvantage of these known recording materials is that their ease of manufacture, stability, ease of use and photosensitivity is unsatisfactory.

It is also known to use polyvinyl anthracene in electrophotographic To use recording materials (British patent specification 9 41 069). This polyvinyl anthracene however, it is extremely low in sensitivity and therefore hardly practical use.

The object of the invention is to provide an electrophotographic recording material which is stable and has excellent photosensitivity.

The subject matter of the invention is based on an electrophotographic recording material a photoconductive layer which may contain a polymeric 9-vinyl anthracene as a photoconductor Contains binder and optionally a sensitizer, and is characterized in that the Photoconductor made from a poly-9-vinylanthracene with units the formula

-CH

consists.

OH2 CH

The electrophotographic recording material of the present invention thus contains either poly-9,10-dimethylene anthracene or a polymer with 9,10-dimethylene anthracene units in the main chain.

The invention achieves that a stable electrophotographic recording material which is extremely sensitive to light after charging.

The table serves to compare the photosensitivities of the recording materials according to the invention with the commercially available zinc oxide and selenium plates.

The polymer A is a poly-9-vinylanthracene composed of units of the formula

-CH ₇ -CH-

It has a characteristic absorption band at 1285 nm (infrared), which is based on 9-ethyl-substituted Anthracene is due (see Fig. 1).

The polymer C consists of units of the formula

CH,

or

60 It has no absorption band at 1285 nm.

From the infrared spectrum (Fig. 1) it follows that polymer C is poly-9,10-dimethylene-anthracene.

The polymer B has a mixed structure of

Polymer A and polymer C, as can be seen from the in FIG. 1 results in the infrared spectrum shown.

The respective proportion can be derived from the ratio of the strength of the infrared absorption at 1285 and 1325 nm can be calculated. 5 to 40% of the polymer B consist of a structure corresponding to polymer C.

Photoconductor

Polymeric Ä

Polymer A (sensitized).

Polymer B

Polymer B (sensitized).

Polymer C

Polymer C (sensitized).

zinc oxide

Zinc oxide (sensitized) ...
selenium

exposure
in lux seconds,
until the surface potential is halved
is decreased

47000

3,300

300

70

2 to 3
280

12 to 30
7th

The lower the exposure in lux · seconds, the greater the photosensitivity of the photoconductive ones Layer. The procedure for measuring photosensitivity is in Bulletin of the Chemical Society of Japan, Vol. 37, No. 6, pp. 842 to 844 (by A. A η a m i et al.).

In Fig. 2 is the relationship between the proportion of 9,10-dimethylanthracene units in polymer B. and its photosensitivity (not sensitized) explained. It can be seen that a proportion below 5% greatly reduces photosensitivity; a proportion over 40% makes the polymer insoluble.

The polymer B is soluble in organic solvents. By coating a transparent A transparent recording material is obtained from the support. .

The polymer C is insoluble in solvents and is therefore in the form of a dispersion in a Binder solution used to produce photoconductive layers. Examples of binders are Polystyrene, polyvinyl chloride, polyvinyl chloride copolymers, Polyvinyl butyral, polyvinyl acetate, phenolic resin, rosin and dammar resin. These binders are in an amount of 10 to 500 parts by weight, preferably 50 to 80 parts by weight, per 100 parts by weight of polymer C used.

The photosensitivity of the photoconductive layers with the polymers B and C can by Sensitizing dyes and sensitizers are increased.

Examples of sensitizing dyes are crystal violet (C.I. 42 555), rhodamine (C. I. 45 150), rhodamineB extra (CI. 45 170), rhodamine 6 G (CI. 45 160), rose bengal (CI. 45 440) and methyl violet (C.I. 42 535). Their proportion is 0.1 to 1 percent by weight, based on the polymer.

Examples of sensitizers are the electron acceptors tetracyanoethylene, tetracyanoquinodimethane, Bromanil, chloranil, benzoquinone, naphthoquinone, anthraquinone or anthraquinone derivatives. Their proportion is 1 to 20 percent by weight, based on the polymer. You can also get the strength and increase the elasticity of the photoconductive layer by additives.

Examples of additives are chlorinated paraffin, chlorinated diphenyl, cinnamic acid, hydrocinnamic acid and polyvinyl benzoate. The proportion of additives is 50 to 200 percent by weight, based on weight on the polymer.

The following are suitable as a layer carrier: plates made of aluminum or zinc, paper, in which the coating liquid cannot penetrate, plastic films whose electrical resistance is due to an antistatic Means is decreased by two or three orders of magnitude lower than that of the photoconductive layer or its surface with metal, e.g. B. vacuum-coated silver or copper iodide or glass plates, the surface of which is vacuum-coated with metal or copper iodide.

The coating can be done by immersion, flow, spray or centrifugal processes. Any conventional Process can be used to create a charge image on the photoconductive layer of the to produce recording material according to the invention. The photoconductive layer can be positive or are charged negatively. A particularly high sensitivity to light can be achieved through positive charging can be achieved.

Preparation of the polymer A

Poly-9-vinylanthracene is obtained in 99% yield, if you dissolve 10 g of 9-vinylanthracene in 100 ml of dry toluene and 2 mol percent titanium tetrachloride, based on the 9-vinylanthracene, adds.

The preparation of 9-vinylanthracene is known from the Journal of Chemical Society, Vol. 1957, pp. 3858-3862. The polymer has a molecular weight of 2400, a melting point of 210 to 220 ⁰ C and is soluble in benzene, methyl ethyl ketone, tetrahydrofuran and methylene chloride.

A similar polymer can also be made using benzoyl peroxide and di-tert-butyl peroxide can be produced as a catalyst. For example, 29 mg of di-tert-butyl peroxide are placed in an ampoule to 4 g of 9-vinylanthracene. The resulting mixture is cooled to -70 ° C and placed in a nitrogen atmosphere brought. Then the ampoule is closed under reduced pressure and the polymerization Performed 72 hours at 140 ° C. The product is dissolved in benzene and precipitated with ethanol, a pale yellow polymer being obtained in a yield of 64%.

A similar polymer can be made by adding 10 g of refined 9-vinylanthracene in 30 ml Dissolved toluene and 2 mole percent of a Friedel-Crafts catalyst [e.g. B. boron trifluoride, sulfuric acid, anhydrous aluminum chloride, anhydrous tin (IV) chloride or titanium tetrachloride] can be added. The mixture is placed in an ampoule and the ampoule is sealed in a nitrogen atmosphere. The polymerization is carried out at -70 ° C for 24 hours. The product is dissolved in benzene and with Precipitated ethanol. A pale yellow polymer which is soluble in benzene is obtained in a yield of 76 to 93%:

Each of these manufacturing processes gives polymer A.

Preparation of the polymer B

To a solution of 10 g of 9-vinylanthracene in 50 ml of dry benzene, 2 mol percent titanium

tetrachloride, based on the 9-vinylanthracene, was added. The mixture is reacted at -70 ° C for 2 hours. After that, over the course of an hour warmed to room temperature. The yield of the yellow soluble in benzene and tetrahydrofuran Polymers is 90 to 95%.

A similar polymer can be made in the presence of boron trifluoride, anhydrous aluminum chloride or anhydrous tin (IV) chloride. The yield in this case is 40 to 95%.

A similar polymer can also be prepared by adding 0.5 to 2 mol percent titanium tetrachloride, based on the amount of polymer A, to a solution of 20 g of polymer A in 100 ml of benzene. The mixture is placed in an ampoule, which is sealed under reduced pressure. The mixture is then reacted at a temperature of 5 to 20 ^{° C. for 0.5 to 4 hours.} The reaction mixture is then poured into alcohol, whereupon the polymer precipitates. The yield is 90 to 98%.

Each of these manufacturing processes gives the polymer B.

Preparation of the polymer C

To a solution of 10 g vinyl anthracene in 50 ml dry benzene add 2 mol percent titanium tetrachloride, based on the amount of 9-vinylanthracene added. Then the mixture is 24 hours reacted at a temperature of 20 to 70 ° C. This gives an insoluble in solvents, pale brown polymer. The yield is 90 to 99%.

A similar polymer can also be produced at a temperature of 20 to 70 ^° C. using boron trifluoride, anhydrous aluminum chloride or anhydrous tin (IV) chloride. The yield in this case is 90 to 99%.

A similar polymer can be prepared by adding 0.1 ml of a 10% strength solution of titanium tetrafluoride in η-hexane to a solution of 3 g of refined 9-vinylanthracene in 10 cm ^{3 of benzene.} The mixture is reacted for 80 hours at room temperature and normal pressure. This gives poly-9-vinylanthracene in almost stoichiometric yield. The product is not soluble in solvents. After washing the polymer with dilute hydrochloric acid, water and alcohol, a pale yellow powder is obtained, which is then dried.

A similar polymer can be prepared by adding 0.5 to 3 mol percent titanium tetrachloride to a solution of 20 g of polymer A in 50 ml of benzene and reacting the mixture at a temperature of 20 to 70 ^° C. for 24 hours. The yield is 90 to 99%.

A similar polymer can be made by dissolving polymer A in methylene chloride and then precipitated with an excess of trifluoroacetic acid. The yield is 99%.

A similar polymer can be prepared by adding to a solution of 20 g of polymer A in 100 ml benzene 2 mole percent titanium tetrachloride, anhydrous aluminum chloride, anhydrous tin (IV) chloride or boron trifluoride, is added. The mixture is in a sealed ampoule at 25''C and reduced pressure. The viscosity gradually increases and begins after 1 to 2 hours to form a precipitate that eventually solidifies. After standing for 24 hours, the product becomes in Alcohol — hydrochloric acid poured with alcohol and water washed and dried. It is washed again with benzene. After drying, one obtains a yellow polymer in 96 to 99% yield.

In all of the above-described reaction processes, the reaction rate at temperatures below 20 ^° C. is so low that the desired reaction product is not obtained. On the other hand, at a temperature above 70 ° C, the reaction product is strongly colored and the photoconductivity is reduced.

Each of these manufacturing processes yields the polymer C.

The representation gives the

9-vinyl anthracene

Polymer B

Polymer C

Polymer A

Ways of making the polymer A, B and C on. example 1

Ig polymer B and 0.5 g of chlorinated diphenyl are dissolved in 15 ml of benzene, applied to an aluminum plate using a centrifugal method and dried. A photoconductive layer 3 μm thick was obtained. After this through Corona discharge was positively charged, it was placed under a positive master copy and By a 100 watt tungsten filament lamp for 1 second exposed with an illuminance of 1500 lux. Then a powder developer was put over it distributed, whereby a positive toner image with strong contrasts was obtained, which was obtained by heating was fixed.

B e i s ρ i e 1 2

1 g of polymer B, 0.5 g of chlorinated diphenyl and 0.1 g of 2-methylanthraquinone were dissolved in 15 ml of chlorobenzene dissolved, spun onto an aluminum plate and dried. Included became a photoconductive layer 3 μm thick obtain. After this was positively charged by corona discharge, it became under a positive one Copy original exposed for 1 second with an illuminance of 1000 lux. After development a positive toner image was obtained, which was fixed by heating.

Example 3

1 g of Polymer B, 0.5 g of polyvinyl cinnamate, 0.1 g of 2-methylanthraquinone, and 0.5 mg of crystal violet dissolved in 4 ml of chlorobenzene, on a sheet of paper that has been pretreated against penetration by solvents was applied and dried. A photoconductive layer with a thickness of 8 μm was thereby obtained obtain. It was loaded for 1 second with an illuminance of 600 lux using the reflex method.

clears. A positive toner image is obtained through powder development.

Example 4

The same solution as in Example 3 is applied to a thin polyester sheet previously coated with copper iodide vacuum coated. After drying, a photoconductive layer of 10 μm thickness obtained. This was through a positive master copy exposed for 1 second with an illuminance of 600 lux. By powder development gives a positive toner image.

Example 5

1 g of finely powdered polymer C was dissolved in a solution of 1 g of polyvinyl butyral in 5 ml of benzyl alcohol dispersed. The dispersion was applied to an aluminum plate with a blade and then dried. A 7 μm thick photoconductive layer was obtained. The photoconductive Layer is then positively charged by a corona discharge (6 kV) and through for 1 second a positive master copy is exposed to an illuminance of 50 lux. After development a positive toner image is obtained.

Example 6

0.3 g of polyvinyl butyral, 0.1 g of 1,2-benzanthraquinone and 0.5 mg of methylene blue were dissolved in 5 ml of benzyl alcohol dissolved. 1 g of Polymer C was added to the solution and mixed thoroughly with it. The dispersion was made using a blade on a sheet of paper that had previously been protected against the ingress of solutions has been treated. After drying, a 7 μm thick layer was obtained. After this When this was positively charged by a corona discharge (6 kV), it was reflexively charged for 1 second exposed with an illuminance of 3 lux. After developing it became a positive Obtained a toner image fixed by heating.

Example 7

0.25 g of polystyrene, 0.5 mg of phthalic anhydride and 0.1 g of 2-methylanthraquinone were dissolved in 5 ml of benzene dissolved. One gram of polymer C was mixed thoroughly with the solution. The dispersion was by means of A blade is applied to a sheet of paper that has previously been treated to prevent the ingress of solutions and dried. A 7 μm thick layer was obtained. The photoconductive layer was charged in a conventional manner and exposed to an illuminance of 3 lux. To a visible, true-to-life image was obtained after developing.

Example 8

5 g of finely powdered polymer C and 5 g of polybutyral were mixed thoroughly in 10 ml of benzene, on one Aluminum plate poured on and dried. A 7 μm thick layer was obtained. after the When the layer was negatively charged with the help of a corona discharge, it was charged for 2 seconds by a positive master copy exposed with an illuminance of 100 lux. After powder development a positive toner image was obtained, which was fixed by heating.

Example 9

5 g of finely powdered polymer C was thoroughly mixed with 3 g of polybutyral, 1 g of 2-methylanthraquinone and 50 mg Crystal violet mixed in 20 ml of ethanol. The mixture was then applied to a sheet of paper that was previously made has been treated against ingress of solutions. After drying, a uniform, 5 μπι thick photoconductive layer obtained. It was reflex-exposed for 0.7 seconds, with one Illuminance of 10 lux has been set. A positive resulted after powder development Toner image that has been fixed in the heat.

Example 10

5 g of polymer C was mixed thoroughly with 5 g of polybutyral in 10 ml of benzene, the mixture to one Aluminum plate poured on and dried. A 7 μm thick layer was obtained. after the Layer was positively charged by means of a corona discharge (6 kV), it became 1 second long exposed by a positive master copy with an illuminance of 10 lux. After powder development a positive toner image resulted. It was fixed by heating.

Example 11

0.5 g of polymer C, 0.3 g of 2-methylanthraquinone, 50 mg of crystal violet and 3 g of polybutyral were in 20 ml of benzyl alcohol mixed thoroughly and applied to a sheet of paper, previously protected against penetration had been treated by solutions. A uniform photoconductive layer of 5 μΐη Thickness (measured dry) obtained. It was reflex-exposed for 0.4 seconds, with an illuminance of 10 lux was set. After the powder development, a positive toner image was created, which is shown in the heat was fixed.

For this purpose 2 sheets of drawings

509 612/367

Claims (1)

Claim: Electrophotographic recording material with a photoconductive layer which is a poly- CH, - meres 9-vinylanthracene as photoconductor, if appropriate contains a binding agent and optionally a sensitizer, characterized in that that the photoconductor consists of a poly-9-vinylanthracene with units of the formula