AT239057B - Electrophotographic material with a photoconductive layer made of poly (N-vinylcarbazole) - Google Patents

Description

  

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  Electrophotographic material with photoconductive
Layer of poly (N-vinylcarbazole)
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 (N-vinylcarbazole) Example 3: Production of polyvinylcarbazole by polymerization in solution, the polymerization being initiated by the formation of ions with sulfuric acid as a catalyst.



   A solution of 20 g of N-vinylcarbazole in 100 ml of toluene is cooled to -50 and, with vigorous stirring, 5 ml of sulfuric acid suspended in 20 ml of toluene are added dropwise. The temperature rises rapidly to 350. After cooling to -50 and stirring for one hour at this temperature, a further 50 ml of toluene are added to the reaction mixture. The mixture is then stirred for another 2 hours. The blue viscous solution thus obtained is poured into hexane and the precipitate formed is dried, washed with water and dried in vacuo. The polymer is purified by dissolving in benzene, filtering and precipitating in methanol.



   Yield: 8 g:
The suitability of the N-vinylcarbazole polymers obtained in this way for the production of light-sensitive layers for electrophotographic material is examined in the following example.



     Example: A paper base of 90 g / m2 is coated with a baryta layer that contains 10 g of barium sulfate per m2. Four strips (A, B, C and D) of this paper are each coated with a layer of a solution of 10 g of poly (N-vinylcarbazole) in 100 ml of methyl chloride, with each.



  Strip a poly (N-vinylcarbazole) of various origins is used.



   Strip A: Luvican M 170 (trademark for a poly (N-vinylcarbazole), manufactured by Badische Anilin- und Sodafabrik A. G., Ludwigshafen a / Rhein).



   Strip B: Poly (N-vinylcarbazole) prepared by emulsion polymerization according to Example 1 above.



   Strip C: Poly (N-vinylcarbazole), prepared by polymerization in solution with phosphorus pentoxide as catalyst according to Example 2 above.



   Strip D: Poly (N-vinylcarbazole), prepared by polymerization in solution with sulfuric acid as the catalyst according to Example 3 above.



   Each of these strips is negatively charged by a corona effect of high voltage and exposed for various times between 1 second and 5 minutes with a 100 watt lamp at a distance of 10 cm behind a slide.



   The latent images are visualized by dusting with a powder mixture of the following composition;
100 parts iron powder and 6 parts toner P 648 (a trademark for a dye developer made by General Photo Products Company, Chatam, N.Y.). The preliminary powder image is fixed by heat.



   For strips C and D, the minimum exposure time was only 1.5 seconds, while strips A and B required a minimum exposure time of 5 minutes.



    PATENT CLAIMS:
1. Use of poly (N-vinylcarbazole), which has been polymerized in solution and wherein the polymerization was initiated by ion formation, for the production of the photoconductive layer of an electrophotographic material.

 

Claims (1)

2. Use of poly (N-vinylcarbazole) in the polymerization of which phosphorus pentoxide has been used as a catalyst, for the purpose indicated in claim 1. 3. Use of poly (N-vinylcarbazole) in the polymerization of which sulfuric acid has been used as a catalyst, for the purpose indicated in claim 1.