Copolymers based on maleic anhydride and .alpha., .beta.-unsaturated compounds a process for their preparation and their use as paraffin inhibitors

A composition comprising a mineral oil and a copolymer based on maleic anhydride and .alpha., .beta.-unsaturated compound having bivalent structural units as follows:

• A. 20 to 95 mole percent of the structural element ##STR27## B. 0 to 40 mole percent of the structural element ##STR28## C. and 2 to 40 mole percent of the structural element ##STR29## the sum of the mole percents of (A), (B) and (C) being 100, and wherein R.sup.1 and R.sup.2 are identical or different and denote hydrogen, straight chain or branched alkyl with 1 to 12 carbon atoms, unsubstituted or substituted aryl having 6 to 12 carbon atoms and wherein the substituents of the aryl are selected from C.sub.1 -to-C.sub.6 alkyl, halogen, and C.sub.1 -to-C.sub.6 alkoxy or the ester group ##STR30## in which R.sup.4 represents alkyl with 1 to 20 carbon atoms,
• R.sup.3 denotes an alkyl with 1 to 20 carbon atoms, cycloalkyl with up to 20 carbon atoms, or unsubstituted or substituted aryl radical with up to 20 carbon atoms wherein the substituents of the aryl are selected from C.sub.1 -to-C.sub.6 alkyl, halogen and C.sub.1 -to-C.sub.6 alkoxy, and
• X and Y are identical or different and represent the group
• --O--R.sup.5
• in which
• R.sup.5 denotes hydrogen, a cation or alkyl with 1 to 40 carbon atoms, or
• X and Y represent the group
• --NHR.sup.3
• in which R.sup.3 has the above-mentioned meaning,
• and at least one of the radicals in the radicals X and Y containining at least 18 carbon atoms.