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US 4,786,699 AGranted
Preparation of polyvinylpyrrolidone
AssigneeBASF SE
InventorsAdolf Nuber, Siegfried Lang, Axel Sanner, Gerd Schroeder
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Abstract
Polyvinylpyrrolidone having a Fikentscher K value of from 14 to 95 is prepared at from 50.degree. to 95.degree. C. in aqueous solution with hydrogen peroxide as starter, the solution being maintained at pH 7-11 by means of NaOH, KOH, their carbonates or bicarbonates.
Claims3
A process for preparing polyvinylpyrrolidone having a Fikentscher K value of from 14 to 95 which comprises:
- heating an aqueous solution of vinylpyrrolidone at a temperature of 50.degree. to 95.degree. C. in the presence of hydrogen peroxide as a starter and in the presence of free heavy metal ions in a concentration range of from 1 ppb to 2 ppm, based on the vinylpyrrolidone, with said heavy metal being selected from the group consisting of copper, iron, silver and cobalt, and maintaing the pH of the solution at from 7-11 by the addition of NaOH, KOH, their carbonated or bicarbonates.
Dependencies are inferred from the claim text.