Detergent Additive-Containing Mineral Oils Having Improved Cold Flow Properties

Abstract

The invention relates to the use of at least one oil-soluble compound B) which acts as a nucleating agent for paraffin crystallization and which is selected from comb polymers that carry alkyl side chains having on average a length of at least 18 C atoms per mole for improving the response of cold flow improvers for mineral oils C), which are different from B), in middle distillates that contain at least one ashless, nitrogenous detergent additive A), which is an oil-soluble, amphiphilic compound that comprises at least one alkyl or alkenyl group bound to a polar group, said alkyl or alkenyl group having 10 to 500 C atoms and the polar group having 2 or more nitrogen atoms.

1 . A method for improving the response behavior of mineral oil cold flow improvers C) in middle distillates which comprise at least one ashless nitrogen-containing detergent additive A) which is an oil-soluble amphiphilic compound which comprises at least one alkyl or alkenyl radical which is bonded to a polar group, where the alkyl or alkenyl radical comprises 10 to 500 carbon atoms and the polar group comprises 2 or more nitrogen atoms, comprising the step of nucleating a paraffin crystallization with at least one oil-soluble compound B) selected from comb polymers which bear alkyl side chains having a length of at least 20 carbon atoms wherein C) is different than B). 
   
   
       2 . A method as claimed in  claim 1 , wherein, based on one part by weight of the nitrogen-containing detergent additive A), 0.01 to 10 parts by weight of the oil-soluble compound B) are used. 
   
   
       3 . A method as claimed in  claim 1 , wherein the middle distillate contains 10 to 10 000 ppm of an ashless nitrogen-containing detergent additive A). 
   
   
       4 . A method as claimed in  claim 1 , wherein the ashless nitrogen-containing detergent additive A) has an alkyl radical having 15 to 500 carbon atoms. 
   
   
       5 . A method as claimed in  claim 4 , wherein the alkyl radical is derived from oligomers of lower olefins having 3 to 6 carbon atoms or mixtures thereof. 
   
   
       6 . A method as claimed in  claim 5 , wherein the alkyl radical is derived from a mixture of oligomers of lower olefins having 3 to 6 carbon atoms which contains more than 70 mol % of 2-methyl-2-butene, 2,3-dimethyl-2-butene and/or isobutene. 
   
   
       7 . A method as claimed in  claim 1 , wherein the ashless nitrogen-containing detergent additive A) is prepared using high-reactivity low molecular weight polyolefins which have molecular weights of 500 to 3000 g/mol having a proportion of terminal double bonds of at least 75 mol %. 
   
   
       8 . A method as claimed in  claim 1 , wherein the ashless nitrogen-containing detergent additive A) comprises a polar component which is derived from polyamines of the formula
   (R 9 ) 2 N-[A-N(R 9 )] q -(R 9 )   
     in which each R 9  is independently hydrogen, an alkyl or hydroxyalkyl radical having up to 24 carbon atoms, a polyoxyalkylene radical -(A-O) r — or polyiminoalkylene radical -[A-N(R 9 )] s -(R 9 ), wherein at least one R 9  is hydrogen, q is an integer from 1 to 19, A is an alkylene radical having 1 to 6 carbon atoms, and r and s are each independently integers from 1 to 50. 
   
   
       9 . A method as claimed in  claim 8 , wherein R 9  is hydrogen and q assumes values of at least 3. 
   
   
       10 . A method as claimed in  claim 1 , wherein the ashless nitrogen-containing detergent additive A) comprises an oil-soluble alkyl radical and a polar head group, and the oil-soluble alkyl radical and the polar head group are joined to one another via a C—N bond or via an ester, amide or imide bond. 
   
   
       11 . A method as claimed in  claim 1 , wherein the ashless nitrogen-containing detergent additive A) has a mean molecular weight determined by vapor pressure osmometry of more than 800 g/mol. 
   
   
       12 . A method as claimed in  claim 1 , wherein the cold flow improvers C) are copolymers of ethylene and 8 to 21 mol % of olefinically unsaturated compounds selected from the group consisting of vinyl esters, acrylic esters, methacrylic esters, alkyl vinyl ethers, alkenes, and mixtures thereof, wherein the olefinically unsaturated compounds may be substituted by hydroxyl groups and one or more of these comonomers may be present in the polymer. 
   
   
       13 . A method as claimed in  claim 12 , wherein the cold flow improvers C) are copolymers of ethylene and 8 to 21 mol % of vinyl esters of the formula 1
   CH 2 ═CH—OCOR 1   (1)   
     wherein R 1  is C 1  to C 30 -alkyl, and the alkyl groups may be substituted by one or more hydroxyl groups. 
   
   
       14 . A method as claimed in  claim 13 , wherein R 1  is a branched alkyl radical or a neoalkyl radical having 7 to 11 carbon atoms. 
   
   
       15 . A method as claimed in  claim 13 , wherein the ethylene copolymers contain vinyl acetate and at least one further vinyl ester of the formula 1 in which R 1  is C 4  to C 30 -alkyl. 
   
   
       16 . A method as claimed in  claim 1 , wherein the cold flow improvers C) are oil-soluble polar nitrogen compounds which are reaction products of compounds of the formula NR 6 R 7 R 8  in which R 6 , R 7  and R 8  may be the same or different, and at least one of these groups is C 8 -C 36 -alkyl, C 6 -C 36 -cycloalkyl, C 8 -C 36 -alkenyl, and the remaining groups are either hydrogen, C 1 -C 36 -alkyl, C 2 -C 36 -alkenyl, cyclohexyl or a group of the formula -(A-O) x -E or —(CH 2 ) n —NYZ in which A is an ethyl or propyl group, x is from 1 to 50, E=H, C 1 -C 30 -alkyl, C 5 -C 12 -cycloalkyl or C 6 -C 30 -aryl, and n=2, 3 or 4, and Y and Z are each independently H, C 1 -C 30 -alkyl or -(A-O) x , with compounds which contain at least one acyl group. 
   
   
       17 . A method as claimed in  claim 1 , wherein the cold flow improvers C) are alkylphenol-aldehyde resins which are condensation products of alkylphenols having one or two C 1 -C 18 -alkyl or -alkenyl radicals in the ortho and/or para positions to the OH group with aldehydes having 1 to 12 carbon atoms. 
   
   
       18 . A method as claimed in  claim 1 , wherein the comb polymers have a proportion of alkyl side chains having at least 20 carbon atoms in the total amount of the alkyl side chains of the comb polymer of at least 10 mol %. 
   
   
       19 . A method as claimed in  claim 1 , wherein the comb polymers have side chains of 22 to 60 carbon atoms. 
   
   
       20 . A method as claimed in  claim 1 , wherein the alkyl side chains of the comb polymers are linear. 
   
   
       21 . A method as claimed in  claim 1 , wherein the comb polymers contain a backbone composed of ethylenically unsaturated monocarboxylic acids, polycarboxylic acids or a mixture thereof. 
   
   
       22 . A method as claimed in  claim 1 , wherein the alkyl side chains of the comb polymers are bonded to the polymer backbone via an ester, amide, imide or ammonium group. 
   
   
       23 . A method as claimed in  claim 1 , wherein the comb polymers are polycondensates which contain structural units derived from alkylaromatics and have alkyl radicals having at least 20 carbon atoms. 
   
   
       24 . A method as claimed in  claim 23 , wherein the alkyl radicals are bonded to the aromatic via a C—C bond or via an ester or ether group. 
   
   
       25 . A method as claimed in  claim 1 , wherein the ratio between detergent additive A) and comb polymer B) is 0.01 to 10 parts by weight of nucleator per part by weight of detergent additive, based in each case on the active ingredient. 
   
   
       26 . An additive comprising
 a) at least one ashless nitrogen-containing detergent additive A) which is an oil-soluble amphiphilic compound comprising at least one alkyl or alkenyl radical bonded to a polar group, wherein the alkyl or alkenyl radical comprises 10 to 500 carbon atoms and the polar group comprises 2 or more nitrogen atoms,   and   b) at least one oil-soluble compound B) selected from comb polymers having alkyl side chains having a molar average length of at least 18 carbon atoms.   
   
   
       27 . The additive as claimed in  claim 26 , comprising a mineral oil cold flow improver C), wherein C) is different than B). 
   
   
       28 . The additive as claimed in  claim 26 , wherein the mineral oil cold flow improver C) is a copolymer of ethylene and 8 to 21 mol % of olefinically unsaturated compounds selected from the group consisting of vinyl esters, acrylic esters, methacrylic esters, alkyl vinyl ethers, alkenes, and mixtures thereof, wherein the olefinically unsaturated compounds may be substituted by hydroxyl groups and one or more of these comonomers may be present in the polymer. 
   
   
       29 . A middle distillate having a sulfur content of less than 100 ppm and a 90% distillation point of less than 360° C., comprising
 a) at least one ashless nitrogen-containing detergent additive A) which is an oil-soluble amphiphilic compound comprising at least one alkyl or alkenyl radical bonded to a polar group, where the alkyl or alkenyl radical comprises 10 to 500 carbon atoms and the polar group comprising 2 or more nitrogen atoms,   b) at least one oil-soluble compound B) selected from comb polymers having alkyl side chains having a molar average length of at least 18 carbon atoms,   and   c) at least one mineral oil cold flow improver C), wherein C) is different than B).   
   
   
       30 . The additive as claimed in  claim 26 , wherein the mineral oil cold flow improver C) is a copolymer of ethylene and 8 to 21 mol % of vinyl esters of the formula 1
   CH 2 ═CH—OCOR 1   (1)   wherein R 1  is C 1  to C 30 -alkyl, and the alkyl groups may be substituted by one or more hydroxyl groups.   
   
   
       31 . The additive as claimed in  claim 30 , wherein R 1  is a branched alkyl radical or a neoalkyl radical having 7 to 11 carbon atoms. 
   
   
       32 . The additive as claimed in  claim 30 , wherein the ethylene copolymers contain vinyl acetate and at least one further vinyl ester of the formula 1 in which R 1  is C 4  to C 30 -alkyl. 
   
   
       33 . The additive as claimed in  claim 26 , wherein the cold flow improvers C) are oil-soluble polar nitrogen compounds which are reaction products of compounds of the formula NR 6 R 7 R 8  in which R 6 , R 7  and R 8  may be the same or different, and at least one of these groups is C 8 -C 36 -alkyl, C 6 -C 36 -cycloalkyl, C 8 -C 36 -alkenyl, and the remaining groups are either hydrogen, C 1 -C 36 -alkyl, C 2 -C 36 -alkenyl, cyclohexyl or a group of the formula -(A-O) x -E or —(CH 2 ) n —NYZ in which A is an ethyl or propyl group, x is from 1 to 50, E=H, C 1 -C 30 -alkyl, C 5 -C 12 -cycloalkyl or C 6 -C 30 -aryl, and n=2, 3 or 4, and Y and Z are each independently H, C 1 -C 30 -alkyl or -(A-O) x , with compounds which contain at least one acyl group. 
   
   
       34 . The additive as claimed in  claim 26 , wherein the cold flow improvers C) are alkylphenol-aldehyde resins which are condensation products of alkylphenols having one or two C 1 -C 18 -alkyl or -alkenyl radicals in the ortho and/or para positions to the OH group with aldehydes having 1 to 12 carbon atoms.