Viscosity Modifiers Comprising Blends of Ethylene-Based Copolymers

Abstract

The present invention is directed to polymer blend compositions for use as viscosity modifiers comprising at least three ethylene-based copolymer components. The viscosity modifiers described herein comprise a first ethylene-based copolymer having an ethylene content of from about 35 to about 55 wt % and/or a heat of fusion of from about 0 to about 30 J/g, a second ethylene-based copolymer having an ethylene content of from about 55 to about 85 wt % and/or a heat of fusion of from about 30 to about 50 J/g, and a third ethylene-based copolymer having an ethylene content of from about 65 to about 85 wt % and/or a heat of fusion of from about 40 to about 70 J/g. The invention is also directed to lubricant compositions comprising a lubricating basestock and a polymer blend as described herein.

1 . A polymer blend composition comprising a first ethylene-based copolymer, a second ethylene-based copolymer, and a third ethylene-based copolymer, wherein:
 (a) the first copolymer has an ethylene content from about 35 to about 55 wt %;   (b) the second copolymer has an ethylene content from about 55 to about 85 wt %;   (c) the third copolymer has an ethylene content from about 65 to about 85 wt %;   (d) the ethylene content of the second copolymer is at least about 15 wt % greater than the ethylene content of the first copolymer and the ethylene content of the third copolymer is at least about 5 wt % greater than the ethylene content of the second copolymer;   (e) the first, second, and third copolymers have a weight-average molecular weight (Mw) less than or equal to about 130,000;   (f) the ratio of the melt index of the first copolymer to the melt index of the second copolymer is less than or equal to about 3.0 and the ratio of the melt index of the first copolymer to the melt index of the third copolymer is less than or equal to about 3.0; and   (g) the composition comprises from about 15 to about 85 wt % of the first copolymer, based on the total weight of the first, second, and third copolymers.   
     
     
         2 . The polymer blend composition of  claim 1 , wherein the first copolymer has an ethylene content from about 40 to about 55 wt %, the second copolymer has an ethylene content from about 55 to about 73 wt %, and the third copolymer has an ethylene content from about 70 to about 85 wt %. 
     
     
         3 . The polymer blend composition of  claim 2 , wherein the first copolymer has an ethylene content from about 45 to about 53 wt %, the second copolymer has an ethylene content from about 65 to about 73 wt %, and the third copolymer has an ethylene content from about 71 to about 85 wt %. 
     
     
         4 . The polymer blend composition of  claim 1 , wherein the first, second, and third copolymers each comprise one or more comonomers selected from the group consisting of C 3 -C 20  alpha-olefins. 
     
     
         5 . The polymer blend composition of  claim 1 , wherein the ethylene content of the second copolymer is at least about 18 wt % greater than the ethylene content of the first copolymer and the ethylene content of the third copolymer is at least about 6 wt % greater than the ethylene content of the second copolymer. 
     
     
         6 . The polymer blend composition of  claim 5 , wherein the ethylene content of the second copolymer is at least about 22 wt % greater than the ethylene content of the first copolymer and the ethylene content of the third copolymer is at least about 8 wt % greater than the ethylene content of the second copolymer. 
     
     
         7 . The polymer blend composition of  claim 1 , wherein the composition comprises from about 25 to about 75 wt % of the first copolymer, based on the total weight of the first, second, and third copolymers. 
     
     
         8 . The polymer blend composition of  claim 7 , wherein the composition comprises from about 35 to about 65 wt % of the first copolymer, based on the total weight of the first, second, and third copolymers. 
     
     
         9 . A polymer blend composition comprising a first ethylene-based copolymer, a second ethylene-based copolymer, and a third ethylene-based copolymer, wherein:
 (a) the first copolymer has a first melt heat of fusion from about 0 to about 30 J/g;   (b) the second copolymer has a first melt heat of fusion from about 30 to about 50 J/g;   (c) the third copolymer has a first melt heat of fusion from about 40 to about 85 J/g;   (d) the heat of fusion of the third copolymer is at least about 5 J/g greater than the heat of fusion of the second copolymer;   (e) the first, second, and third copolymers have a weight-average molecular weight (Mw) less than or equal to about 130,000;   (f) the ratio of the melt index of the first copolymer to the melt index of the second copolymer is less than or equal to about 3.0 and the ratio of the melt index of the first copolymer to the melt index of the third copolymer is less than or equal to about 3.0; and   (g) the composition comprises from about 15 to about 85 wt % of the first copolymer, based on the total weight of the first, second, and third copolymers.   
     
     
         10 . The polymer blend composition of  claim 9 , wherein the first copolymer has a first melt heat of fusion from about 0 to about 15 J/g, the second copolymer has a first melt heat of fusion from about 35 to about 48 J/g, and the third copolymer has a first melt heat of fusion from about 55 to about 75 J/g. 
     
     
         11 . The polymer blend composition of  claim 10 , wherein the first copolymer has a first melt heat of fusion from about 0 to about 10 J/g, the second copolymer has a first melt heat of fusion from about 40 to about 48 J/g, and the third copolymer has a first melt heat of fusion from about 65 to about 75 J/g. 
     
     
         12 . The polymer blend composition of  claim 9 , wherein the first, second, and third copolymers each comprise one or more comonomers selected from the group consisting of C 3 -C 20  alpha-olefins. 
     
     
         13 . The polymer blend composition of  claim 9 , wherein the heat of fusion of the third copolymer is at least about 8 J/g greater than the heat of fusion of the second copolymer. 
     
     
         14 . The polymer blend composition of  claim 13 , wherein the heat of fusion of the third copolymer is at least about 12 J/g greater than the heat of fusion of the second copolymer. 
     
     
         15 . The polymer blend composition of  claim 9 , wherein the composition comprises from about 25 to about 75 wt % of the first copolymer, based on the total weight of the first, second, and third copolymers. 
     
     
         16 . The polymer blend composition of  claim 15 , wherein the composition comprises from about 35 to about 65 wt % of the first copolymer, based on the total weight of the first, second, and third copolymers. 
     
     
         17 . A lubricating oil composition comprising a lubricating oil basestock, a first ethylene-based copolymer, a second ethylene-based copolymer, and a third ethylene-based copolymer wherein:
 (a) the first copolymer has an ethylene content from about 35 to about 55 wt %;   (b) the second copolymer has an ethylene content from about 55 to about 85 wt %;   (c) the third copolymer has an ethylene content from about 65 to about 85 wt %;   (d) the ethylene content of the third copolymer is at least about 5 wt % greater than the ethylene content of the second copolymer;   (e) the first, second, and third copolymers have a weight-average molecular weight (Mw) less than or equal to about 130,000;   (f) the ratio of the melt index of the first copolymer to the melt index of the second copolymer is less than or equal to about 3.0 and the ratio of the melt index of the first copolymer to the melt index of the third copolymer is less than or equal to about 3.0; and   (g) the composition comprises from about 15 to about 85 wt % of the first copolymer, based on the total weight of the first, second, and third copolymers.   
     
     
         18 . The lubricating oil composition of  claim 17 , wherein the first copolymer has an ethylene content from about 45 to about 53 wt %, the second copolymer has an ethylene content from about 65 to about 73 wt %, and the third copolymer has an ethylene content from about 71 to about 85 wt %. 
     
     
         19 . The lubricating oil composition of  claim 17 , wherein the first, second, and third copolymers each comprise one or more comonomers selected from the group consisting of C 3 -C 20  alpha-olefins. 
     
     
         20 . The lubricating oil composition of  claim 17 , wherein the ethylene content of the second copolymer is at least about 18 wt % greater than the ethylene content of the first copolymer and the ethylene content of the third copolymer is at least about 6 wt % greater than the ethylene content of the second copolymer. 
     
     
         21 . A lubricating oil composition comprising a lubricating oil basestock, a first ethylene-based copolymer, a second ethylene-based copolymer, and a third ethylene-based copolymer, wherein:
 (a) the first copolymer has a first melt heat of fusion from about 0 to about 30 J/g;   (b) the second copolymer has a first melt heat of fusion from about 30 to about 50 J/g;   (c) the third copolymer has a first melt heat of fusion from about 40 to about 85 J/g;   (d) the heat of fusion of the third copolymer is at least about 5 J/g greater than the heat of fusion of the second copolymer;   (e) the first, second, and third copolymers have a weight-average molecular weight (Mw) less than or equal to about 130,000;   (f) the ratio of the melt index of the first copolymer to the melt index of the second copolymer is less than or equal to about 3.0 and the ratio of the melt index of the first copolymer to the melt index of the third copolymer is less than or equal to about 3.0; and   (g) the composition comprises from about 15 to about 85 wt % of the first copolymer, based on the total weight of the first, second, and third copolymers.   
     
     
         22 . The lubricating oil composition of  claim 21 , wherein the first copolymer has a first melt heat of fusion from about 0 to about 10 J/g, the second copolymer has a first melt heat of fusion from about 40 to about 48 J/g, and the third copolymer has a first melt heat of fusion from about 65 to about 75 J/g. 
     
     
         23 . The lubricating oil composition of  claim 21 , wherein the first, second, and third copolymers each comprise one or more comonomers selected from the group consisting of C 3 -C 20  alpha-olefins. 
     
     
         24 . The lubricating oil composition of  claim 21 , wherein the ethylene content of the second copolymer is at least about 18 wt % greater than the ethylene content of the first copolymer and the ethylene content of the third copolymer is at least about 6 wt % greater than the ethylene content of the second copolymer.