Patent ID: 7728093

Claim:
A method for solvent deparaffinization of paraffinic mineral oil distillates, comprising: adding a dewaxing additive and a solvent to said paraffinic mineral oil distillates, to obtain a solvent-paraffinic mineral oil mixture; stirring until a clear solution results; cooling the solution to below −20° C. at a defined rate, thereby forming paraffin crystals which form a filter cake which is porous and permeable to the solution; and separating said paraffin crystals from said solution by filtration; increasing a filtration volume per filtration time compared to the filtration volume per filtration time using no dewaxing additive; and obtaining deparaffinized mineral oil distillates; wherein said dewaxing additive comprises a copolymer of the following free-radically polymerizable monomers of Formulae A and B: wherein R 1 =H or CH 3 , R 2 =phenyl, benzyl, naphthyl, anthranyl, phenanthryl, N-pyrrolidonyl, N-imidazolyl, 2-pyridyl, 4-pyridyl or an alkyl-substituted aromatic substituent or R 2 =COOR 3 where R 3 =H or R 3 is a linear or branched alkyl radical of C 1 -C 10 or R 3 is a heteroatom-substituted radical —(CH 2 ) n X where X=OH or X=N(R 4 ) 2 wherein n=1-10 and R 4 is in each case independently H or R 4 =C 1 -C 4 -alkyl or R 3 is —(CH 2 CH 2 O) m R 5 wherein m=1-90 and R 5 =H or R 5 =C 1 -C 18 or R 3 is a benzyl, phenyl or cyclohexyl radical or R 2 =CONHR 6 wherein R 6 =H or R 6 is a linear or branched alkyl radical of C 1 -C 10 or R 6 is a heteroatom-substituted radical —(CH 2 ) n X where X=OH or X=N(R 4 ) 2 wherein n=1-10 and R 4 is in each case independently H or R 4 =C 1 -C 4 -alkyl; wherein R 7 =H or CH 3 , and R 8 radical=linear or branched alkyl radicals of C 12 -C 40 , and, optionally further customary dewaxing additives.