| abstract |
The present invention relates to the use of water-soluble copolymers which, in statistical distribution, contain 5 to 60% by weight of residues of the formula 1 2 to 40% by weight consist of radicals of the formula 11, and also their derivatives obtainable by partial hydrolysis, where R 'and R 2 are the same or different and hydrogen, methyl, ethyl or optionally together trimethylene, Y the radical -CO-NH -C (CH 3 ) 2 -CH 2 - or a direct bond and X⊕ is a cation, as an aid in the de-oiling of mineral oil-containing sand and rock masses. Some of the copolymers are new. The new copolymers and their production are also the subject of the invention. and 38 to 93% by weight of residues of the formula 111 |