Composition Containing A Block Copolymer And A Method Of Lubricating An Internal Combustion Engine

Abstract

The invention provides a lubricating composition containing an oil of lubricating viscosity and a block copolymer. The block copolymer may contain (a) a hydrophobic first block having C 1-30 alkyl (meth)acrylic units, wherein at least 50 wt % of the C 1-30 alkyl (meth)acrylic units are C 12-15 alkyl (meth)acrylic units, and up to 50 wt % of the C 1-30 alkyl (meth)acrylic units are C 16-20 alkyl (meth)acrylic units, with the proviso that alkyl groups of the C 1-30 alkyl (meth)acrylic units have an average total number of carbon atoms of at least 8; and (b) a second block having (meth)acrylic units further having a heteroatom-containing group providing a polar group. The invention further relates to a method of lubricating an internal combustion engine by lubricating the engine with the lubricating composition. The invention further relates to the use of the block copolymer as an emulsifier and/or pour point depressant.

What is claimed is: 
     
         1 . A method of lubricating an internal combustion engine of a vehicle fueled with a mixed gasoline/alcohol fuel, comprising supplying to the engine a lubricating composition comprising an oil of lubricating viscosity and a block copolymer having emulsifier properties, wherein the block copolymer comprises a diblock comprising:
 (a) a hydrophobic first block having C 12-18  alkyl methacrylate, with the proviso that alkyl groups of the C 12-18  alkyl methacrylate have an average total number of carbon atoms of at least 8; and   (b) a second block having C 12-18  methacrylate which further have a non-carbonyl heteroatom-containing group providing a polar group to such units, the heteroatom-containing group derived from a nitrogen-containing group, whereby said second block exhibits greater hydrophilicity than does the hydrophobic first block,   wherein the block copolymer is present in an amount from about 0.01 wt % to about 0.05 wt % of the lubricating composition and has a weight ratio of first block to second block from 6:1 to 18:1.   
     
     
         2 . The method of  claim 1 , wherein the internal combustion engine is a flexible fuel vehicle engine. 
     
     
         3 . The method of  claim 1 , wherein the hydrophobic first block comprises C 12-18  alkyl methacrylate, wherein at least 50 wt % of the C 12-18  alkyl methacrylate are C 12-15  alkyl methacrylate with the proviso that alkyl groups of the C 12-18  alkyl methacrylate have an average total number of carbon atoms of at least 8. 
     
     
         4 . The method of  claim 1 , wherein the hydrophobic first block comprises C 12-18  alkyl methacrylate, wherein at least 70 wt % of the C 12-18  alkyl methacrylate are C 12-15  alkyl methacrylate with the proviso that alkyl groups of the C 1-30  alkyl (meth)acrylic units have an average total number of carbon atoms of at least 8. 
     
     
         5 . The method of  claim 1 , wherein the hydrophobic first block comprises C 12-18  alkyl methacrylate, wherein at least 80 wt % of the C 12-18  alkyl methacrylate are C 12-15  alkyl methacrylate, with the proviso that alkyl groups of the C 1-30  alkyl (meth)acrylic units have an average total number of carbon atoms of at least 8. 
     
     
         6 . The method of  claim 1 , wherein the nitrogen containing group contains a monomer selected from the group consisting of dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, dimethylaminopropyl acrylate, dimethylaminopropylacrylamide, dimethylaminopropylmethacrylamide, and mixtures thereof. 
     
     
         7 . The method of  claim 1 , wherein the block copolymer is a methacrylate polymer. 
     
     
         8 . The method of  claim 1 , wherein the block copolymer is a linear diblock copolymer. 
     
     
         9 . The method of  claim 1 , wherein the block copolymer is obtained from a controlled radical polymerisation process or other living polymerisation process. 
     
     
         10 . The method of  claim 9 , wherein the controlled radical or other living polymerisation process is one of RAFT (Reversible Addition Fragmentation Transfer), ATRP (Atom Transfer Radical Polymerisation), nitroxide-mediated or anionic polymerisation. 
     
     
         11 . The method of  claim 10 , wherein the controlled radical polymerisation process is a RAFT process. 
     
     
         12 . A lubricating composition comprising an oil of lubricating viscosity and a block copolymer comprising a diblock having emulsifier properties comprising:
 (a) a hydrophobic first block having C 12-18  alkyl methacrylate, wherein at least 50 wt % of the C 12-18  alkyl methacrylate are Cu-15 alkyl (meth)acrylic units, with the proviso that alkyl groups of the C 12-18  alkyl methacrylate have an average total number of carbon atoms of at least 8; and   (b) a second block having (meth)acrylic units which further have a non-carbonyl heteroatom-containing group providing a polar group to such units, the heteroatom-containing group derived from a nitrogen-containing group, whereby said second block exhibits greater hydrophilicity than does the hydrophobic first block, and has a weight ratio of first block to second block from 6:1 to 18:1.   
     
     
         13 . The lubricating composition of  claim 12 , wherein the hydrophobic first block comprises C 12-18  alkyl methacrylate, wherein at least 70 wt % of the C 12-18  alkyl methacrylate are C 12-15  alkyl (meth)acrylic units, with the proviso that alkyl groups of the C 12-18  alkyl methacrylate have an average total number of carbon atoms of at least 8. 
     
     
         14 . The lubricating composition of  claim 12 , wherein the hydrophobic first block comprises C 12-18  alkyl methacrylate, wherein at least 80 wt % of the C 12-18  alkyl methacrylate are C 12-15  alkyl methacrylate with the proviso that alkyl groups of the C 12-18  alkyl methacrylate have an average total number of carbon atoms of at least 8. 
     
     
         15 . The lubricating composition of  claim 12 , wherein the nitrogen containing monomer is selected from the group consisting of dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, dimethylaminopropyl acrylate, dimethylaminopropylacrylamide, dimethylaminopropylmethacrylamide, and mixtures thereof. 
     
     
         16 . The lubricating composition of  claim 12 , wherein the block copolymer is a methacrylate polymer. 
     
     
         17 . The lubricating composition of  claim 12 , wherein the block copolymer is a linear diblock copolymer. 
     
     
         18 . The lubricating composition of  claim 12 , wherein the block copolymer is obtained from a controlled radical polymerisation process or other living polymerisation process. 
     
     
         19 . The lubricating composition of  claim 18 , wherein the controlled radical or other living polymerisation process is one of RAFT (Reversible Addition Fragmentation Transfer), ATRP (Atom Transfer Radical Polymerisation), nitroxide-mediated or anionic. 
     
     
         20 . The lubricating composition of  claim 18 , wherein the controlled radical polymerisation process is a RAFT process. 
     
     
         21 . The method of  claim 1 , wherein the alcohol of the mixed gasoline/alcohol fuel is ethanol. 
     
     
         22 . The method of  claim 1 , wherein the mixed gasoline/alcohol fuel contains from 5 wt % to 85 wt % alcohol. 
     
     
         23 . The method of  claim 1 , wherein the mixed gasoline/alcohol fuel contains from 10 wt % to 85 wt % alcohol. 
     
     
         24 . The method of  claim 1 , wherein the mixed gasoline/alcohol fuel contains from 15 wt % to 85 wt % alcohol. 
     
     
         25 . The method of  claim 1 , wherein the block copolymer has pour point depressant properties. 
     
     
         26 . The method of  claim 6 , wherein the nitrogen-containing monomer is dimethylaminoethyl methacrylate. 
     
     
         27 . The method of  claim 1 , wherein the hydrophobic first block contains at least 70 wt % of C 12-15  alkyl (meth)acrylic units and up to 30 wt % of C 16-30  alkyl (meth)acrylic units. 
     
     
         28 . The method of  claim 1 , wherein the wherein the hydrophobic first block contains at least 50 wt % of C 12-15  alkyl (meth)acrylic units.