Multifunctional Cooling Additives For Middle Distillates, Having An Improved Flow Capability

Abstract

The present invention relates to cooling additives for middle distillates, containing A) at least one comb polymer carrying hydroxyl groups, which can be produced by polycondensation of a polyol that contains two primary OH groups and at least one secondary OH group with a dicarboxylic acid or the anhydride or ester thereof, which carries a C 16 -C 40 alkyl radical or a C 16 -C 40 alkenyl radical, characterized in that the OH number of the comb polymer is at least 40 mg KOH/g, B) at least one copolymer of ethylene and of at least one ethylenically unsaturated ester, and C) at least one organic solvent.

1 . A cold additive for middle distillates comprising
 A) at least one comb polymer which has hydroxyl groups and wherein the comb polymer can be prepared by polycondensation of a polyol containing two primary OH groups and at least one secondary OH group, with a dicarboxylic acid, or the anhydride thereof or ester thereof, having a C 16 - to C 40 -alkyl radical or a C 16 - to C 40 -alkenyl radical, wherein the OH number of the comb polymer is at least 40 mg KOH/g,   B) at least one copolymer of ethylene and at least one ethylenically unsaturated ester, and   C) at least one organic solvent.   
     
     
         2 . The cold additive as claimed in  claim 1 , in which the dicarboxylic acid is according to the formula 1 
       
         
           
           
               
               
           
         
       
       wherein
 one of the R 1  to R 4  radicals is a linear C 16 -C 40 -alkyl or alkenyl radical and the rest of the R 1  to R 4  radicals are each independently hydrogen or an alkyl radical having 1 to 3 carbon atoms, and 
 R 5  is a C—C bond or an alkylene radical having 1 to 6 carbon atoms. 
 
     
     
         3 . The cold additive as claimed in  claim 2 , in which the dicarboxylic acid is alkylsuccinic acid, alkenylsuccinic acid or the anhydride thereof. 
     
     
         4 . The cold additive as claimed in  claim 1 , wherein the polyol is glycerol. 
     
     
         5 . The cold additive as claimed in  claim 1 , wherein the at least one comb polymer A) has an OH number between 40 and 500 mg KOH/g. 
     
     
         6 . The cold additive as claimed in  claim 1 , wherein the at least one copolymer B) is a copolymer of ethylene and 8 to 21 mol % of at least one olefinically unsaturated compound selected from the group consisting of vinyl esters, acrylic esters and methacrylic esters. 
     
     
         7 . The cold additive as claimed in  claim 1 , wherein the at least one solvent C) is selected from the group consisting of aliphatic hydrocarbons having 9 to 20 carbon atoms and aromatic hydrocarbons having 7 to 20 carbon atoms. 
     
     
         8 . The cold additive as claimed in  claim 1 , wherein the at least one solvent C) additionally comprises a solubilizer which contains 4 to 24 carbon atoms and is selected from the group consisting of alcohols, organic acids, ethers of organic acids, esters of organic acids, and mixtures thereof. 
     
     
         9 . The cold additive as claimed in  claim 1 , comprising 0.1 to 50% by weight of A), 1.5 to 73.5% by weight of B) and 25 to 95% by weight of C). 
     
     
         10 . The cold additive as claimed in  claim 1 , further comprising at least one further cold flow improver, selected from the group consisting of
 III) oil-soluble polar nitrogen compounds,   IV) resins of phenol derivatives bearing alkyl radicals with aldehydes,   V) comb polymers of the formula   
       
         
           
           
               
               
           
         
         
           in which 
           A is R′, COOR′, OCOR′, R″—COOR′, OR′; 
           D is H, CH 3 , A or R″; 
           E is H, A; 
           G is H, R″, R″—COOR′, an aryl radical or a heterocyclic radical; 
           M is H, COOR″, OCOR″, OR″, COOH; 
           N is H, R″, COOR″, OCOR, an aryl radical; 
           R′ is a hydrocarbyl chain having 8 to 50 carbon atoms; 
           R″ is a hydrocarbyl chain having 1 to 10 carbon atoms; 
           a is a number between 0.4 and 1.0; and 
           b is a number between 0 and 0.6, 
         
         VI) homo- and copolymers of olefins having 2 to 30 carbon atoms, and 
         VII) esters, ethers and ester/ethers of alkoxylated polyols, which have at least one alkyl radical having 12 to 30 carbon atoms. 
       
     
     
         11 . A process for improving the cold flow properties of fuel oils, comprising the step of adding a cold additive as claimed in  claim 1  to a middle distillate. 
     
     
         12 . A fuel oil comprising a middle distillate and at least one cold additive as claimed in  claim 1 . 
     
     
         13 . The fuel oil as claimed in  claim 12 , in which the middle distillate has a content of constituents having an n-alkyl chain having 16 or more carbon atoms of more than 4% by weight. 
     
     
         14 . The fuel oil as claimed in  claim 12 , in which the middle distillate has a proportion of long-chain n-paraffins having 28 or more carbon atoms of less than 1% by weight.