to example 7 the following amounts are used 1 014 g of demineralized water are initially introduced at room temperature into a 2 1 plane ground flask having jacket heating and a stirrer and 50 5 g of starch a solids content 82 2 are suspended therein with stirring the apparatus is then placed under nitrogen nitrogen atmosphere and stirring are maintained for the entire further reaction sequence the starch suspension is heated to 85 u00b0 c the starch glutenizing and forming a slightly turbid solution after 85 u00b0 c have been reached stirring is continued for 15 min and then 0 5 g of glacial acetic acid is added thereafter the following two solutions are metered in uniformly and simultaneously over 90 min at 85 u00b0 c 23 35 g of aetac as an 80 strength aqueous solution aetac after the end of the metering operations stirring is continued for 45 min at 85 u00b0 c after which 15 0 g of a 2 strength aqueous solution of ammonium peroxodisulphate are added for subsequent activation stirring is effected for a further 45 min at 85 u00b0 c after which the polymer solution is cooled to room temperature the ph is adjusted to 7 1 with about 7 g of 10 strength sodium hydroxide solution and furthermore 1 4 g of the biocide preventol u00ae d 2 bayer ag are added finally the polymer solution is filtered through a 100 u03bcm polyamide filter cloth the stated amounts in the following examples are specified as percentages by weight unless stated otherwise all stated amounts represent the content of dry polymer based on dry paper 0 5 or 1 5 of each of the polymers from the preceding preparation examples.