Copolymers comprising a-olefins and olefin dicarboxylic acid esters, production thereof, and use thereof as pour point depressants for crude oils, mineral oils, or mineral oil products

A process for preparing a copolymer (X) comprising, as monomers, at least

• (A) 40 to 60 mol %, based on the amount of all monomers, of at least one α-olefin (A) of the formula H2C═CH—R1
• where R1 is at least one linear, cyclic or branched, aliphatic and/or aromatic hydrocarbyl radical having 14 to 50 carbon atoms, and
• (B) 60 to 40 mol %, based on the amount of all monomers, of monoethylenically unsaturated dicarboxylic acids or derivatives thereof,
• wherein the monomers (B) are
• (B1) at least one monomer (R2OOC)R5C═CR6(COOR4),
• (B2) at least one monomer (R3OOC)R5C═CR6(COOR4) and
• (B3) optionally at least one monomer selected from the group of
• (HOOC)R5C═CR6(COOH) (B3a) and
• where
• R2 is a linear alkyl radical having 16 to 36 carbon atoms,
• R3 is a radical selected from the group consisting of
• R3a:
• linear 1-alkyl radicals having 1 to 10 carbon atoms,
• R3b:
• branched and/or secondary alkyl radicals having 4 to 30 carbon atoms,
• R3c:
• unsubstituted or alkyl-substituted, cyclic alkyl radicals having 5 to 18 carbon atoms, and
• R3d:
• unsubstituted or alkyl-substituted, aromatic hydrocarbyl radicals having 6 to 36 carbon atoms,
• R4 in each case independently is a radical selected from the group of H, R2 and R3, with the proviso that at least 50 mol % of the R4 radicals are H,
• R5 and R6 are each H,
• the proportion of the R3 radicals based on the sum total of the R2 and R3 radicals is 5 mol % to 45 mol %,
• the proportion of the monomers (B1)+(B2) based on the sum total of all monomers (B) is at least 50 mol %, and
• the weight-average molecular weight Mw of the copolymers (X) is 2000 g/mol to 25 000 g/mol, said process comprising:
• I) providing a polymeric reactant by polymerizing at least the following monomers:
• 40 to 60 mol %, based on the amount of all α-olefin monomers H2C═CH—R1 (A) used, where R1 is at least one linear, cyclic or branched, aliphatic and/or aromatic hydrocarbyl radical having 14 to 50 carbon atoms, and
• 60 to 40 mol % of (B3b)
• where the number-average molecular weight Mn of the polymeric reactant is 1000 g/mol to 15 000 g/mol,
• II) polymer-analogous esterification of the polymeric reactant provided in stage I at 130° C. to 180° C. with
• at least one alcohol R2OH where R2 is a linear alkyl radical having 18 to 36 carbon atoms, and
• at least one alcohol R3OH, selected from the group consisting of
• R3aOH where R3a represents linear 1-alkyl radicals having 1 to 10 carbon atoms,
• R3bOH where R3b represents branched and/or secondary alkyl radicals having 4 to 36 carbon atoms,
• R3cOH where R3c unsubstituted or alkyl-substituted, cyclic alkyl radicals having 5 to 18 carbon atoms, and
• R3dOH where R3d is an unsubstituted or alkyl-substituted aromatic hydrocarbyl radical having 6 to 36 carbon atoms,
• where the proportion of the alcohols R3OH based on the sum total of the alcohols R2OH and R3OH is 1 mol % to 49 mol %, and
• the amount of the alcohols R2OH and R3OH used together is 0.5 to 1.5 mol/mol of (B3b).