Process for Preparing Polymers and Compositions Thereof

Abstract

The present invention provides a process for preparing a polymer, employing the steps of: (1) contacting a free radical initiator; a chain transfer agent containing a thiocarbonyl thio group and a free radical leaving group; and a radically polymerisable monomer, to form a polymer chain; and (2) contacting the polymer chain of step (1) with at least one of a polyvalent coupling agent, a polymerisation inhibitor, a grafting acylating agent, an amine and an oil of lubricating viscosity. The invention further provides compositions and uses for the polymer.

What is claimed is: 
     
         1 . A composition comprising an oil of lubricating viscosity and a star polymer derived from at least two monomers comprising:
 (a) at least 50 wt % of a mixture of C12 to C15 alkyl substituted (meth)acrylate monomers; and   (b) less than 50 wt % of an alkyl (meth)acrylate monomer containing 1 to 30 carbon atoms in the alkyl group, other than the C12 to C15 alkyl substituted (meth)acrylate monomer;   (c) optionally containing less than 20 wt % styrene; and   (d) optionally containing less than 10 wt % alkyl methacrylamide, wherein the star-polymer has about 7 to about 50 arms present on the star polymer, and wherein the star polymer is prepared by a reversible addition-fragmentation chain transfer controlled radical polymerisation process.   
     
     
         2 . The composition of  claim 1 , wherein the star polymer is derived from at least two monomers consisting essentially of:
 (a) at least 50 wt % of a mixture of C12 to C15 alkyl substituted (meth)acrylate monomers; and   (b) less than 50 wt % of an alkyl (meth)acrylate monomer containing 1 to 30 carbon atoms in the alkyl group, other than the C12 to C15 alkyl substituted (meth)acrylate monomer.   
     
     
         3 . The composition of  claim 1 , wherein the star polymer is derived from at least two monomers comprising:
 (a) at least 50 wt % of a mixture of C12 to C15 alkyl substituted (meth)acrylate monomers; and   (b) less than 50 wt % of an alkyl (meth)acrylate monomer containing 1 to 30 carbon atoms in the alkyl group, other than the C12 to C15 alkyl substituted (meth)acrylate monomer;   (c) containing less than 20 wt % styrene; and   (d) optionally containing less than 10 wt % alkyl methacrylamide.   
     
     
         4 . The composition of  claim 1 , wherein the star polymer is derived from at least two monomers comprising:
 (a) at least 50 wt % of a mixture of C12 to C15 alkyl substituted (meth)acrylate monomers; and   (b) less than 50 wt % of an alkyl (meth)acrylate monomer containing 1 to 30 carbon atoms in the alkyl group, other than the C12 to C15 alkyl substituted (meth)acrylate monomer;   (c) containing less than 20 wt % styrene; and   (d) containing less than 10 wt % alkyl methacrylamide.   
     
     
         5 . The composition of  claim 1 , wherein the star polymer is present from 0.1 wt % to 60 wt % of the composition. 
     
     
         6 . The composition of  claim 1 , wherein the star polymer is present from 1 wt % to 50 wt % of the composition. 
     
     
         7 . The composition of  claim 1 , wherein the star polymer is present from 2 wt % to 45 wt % of the composition. 
     
     
         8 . The composition of  claim 1 , wherein the star polymer is present from 5 wt % to 40 wt % of the composition. 
     
     
         9 . The composition of  claim 1 , wherein the star-polymer has about 10 to about 50 arms present on the star polymer. 
     
     
         10 . The composition of  claim 1 , wherein the star-polymer has about 12 to about 40 arms present on the star polymer. 
     
     
         11 . The composition of  claim 1 , wherein the oil of lubricating viscosity is present from 15 wt % to 99.9 wt % of the composition. 
     
     
         12 . The composition of  claim 1 , wherein the oil of lubricating viscosity is present from 30 wt % to 98.9 wt % of the composition. 
     
     
         13 . The composition of  claim 1 , wherein the oil of lubricating viscosity is present from 40 wt % to 97.9 wt % of the composition. 
     
     
         14 . The composition of  claim 1 , wherein the oil of lubricating viscosity is present from 50 wt % to 94.5 wt % of the composition. 
     
     
         15 . The composition of  claim 1 , wherein the composition further comprises 0.01 wt % to 20 wt % of other performance additives, and wherein the other performance additives include metal deactivators, detergents, dispersants, viscosity modifiers, friction modifiers, dispersant viscosity modifiers, extreme pressure agents, antiwear agents, antioxidant, corrosion inhibitors, foam inhibitors, demulsifiers, pour point depressants, seal swelling agents and mixtures thereof. 
     
     
         16 . The composition of  claim 1 , wherein the composition further comprises 0.1 wt % to 15 wt % of other performance additives, and wherein the other performance additives include metal deactivators, detergents, dispersants, viscosity modifiers, friction modifiers, dispersant viscosity modifiers, extreme pressure agents, antiwear agents, antioxidant, corrosion inhibitors, foam inhibitors, demulsifiers, pour point depressants, seal swelling agents and mixtures thereof. 
     
     
         17 . The composition of  claim 1 , wherein the composition further comprises 0.5 wt % to 10 wt % of other performance additives, and wherein the other performance additives include metal deactivators, detergents, dispersants, viscosity modifiers, friction modifiers, dispersant viscosity modifiers, extreme pressure agents, antiwear agents, antioxidant, corrosion inhibitors, foam inhibitors, demulsifiers, pour point depressants, seal swelling agents and mixtures thereof. 
     
     
         18 . A process for preparing a polymer and a lubricating composition thereof, comprising the steps of:
 (1) contacting:
 (i) a free radical initiator; 
 (ii) a chain transfer agent containing a thiocarbonyl thio group and a free radical leaving group; and 
 (iii) a radically polymerisable monomer, to form a polymer chain; 
   wherein the process of step (1) is a controlled radical polymerisation process with living characteristics; and at least about 50% of the polymer chains from step (1) contain a reactive end group capable of reacting with a polyvalent coupling agent;   (2) contacting the polymer prepared by step (1) with a polyvalent coupling agent to form a star-polymer, wherein the star polymer is derived from at least two monomers comprising:
 (a) at least 50 wt % of a mixture of C12 to C15 alkyl substituted (meth) acrylate monomers; and 
 (b) less than 50 wt % of an alkyl (meth) acrylate monomer containing 1 to 30 carbon atoms other than the C12 to C15 alkyl (meth) acrylate monomer; 
 (c) optionally containing less than 20 wt % styrene; and 
 (d) optionally containing less than 10 wt % alkyl (meth)acrylamide, 
   (3) optionally contacting the polymer prepared by step (1) or step (2) with a polymerisation inhibitor; and   (4) mixing the polymer prepared by step (2) or step (3) with an oil of lubricating viscosity to form a lubricating composition.