Polyethylene modified asphalt compositions

Abstract

A polymer modified bituminous composition for roofing applications that comprises polyethylene as the primary modifier.

1 . A modified bitumen composition for roofing application comprising: 
 a polymer modifier consisting essentially of polyethylene; and    asphalt,    wherein the polyethylene consists of a mixture of high density polyethylene and low density polyethylene in a ratio ranging from about 4:1 to 1:4 LDPE to HDPE by weight.    
     
     
         2 . The composition of  claim 1 , wherein the polyethylene is linear.  
     
     
         3 . The composition of  claim 1 , wherein the polyethylene has a molecular weight between about 1,000 and 25,000.  
     
     
         4 . The composition of  claim 1 , wherein the polyethylene has a melt flow index value between about 5 and 50.  
     
     
         5 . The composition of  claim 1 , wherein the low density polyethylene has a density less than 0.95 g/cm 3 .  
     
     
         6 . The composition of  claim 1 , wherein the low density polyethylene has a density less than 0.93 g/cm 3 .  
     
     
         7 . The composition of  claim 1 , wherein the low density polyethylene has a density ranging less than about about 0.915 g/cm 3  and the high density polyethylene has a melt flow index ranging from 2 to 20.  
     
     
         8 . The composition of  claim 1 , further comprising at least one plastification agent.  
     
     
         9 . The composition of  claim 8 , comprising: 
 a. about 1 to 20 percent by weight of polyethylene,    b. about 1 to 10 percent by weight of a plastification agent,    c. about 5 to 50 percent by weight of filler, and    d. remaining portion of asphalt.    
     
     
         10 . The composition of  claim 9 , comprising: 
 a. between about 5 to 15 percent by weight of polyethylene,    b. between about 3 to 6 percent by weight of plastification agents,    c. between 5 and 50 percent by weight of filler, and    d. between 40 and 70 percent by weight of asphalt.    
     
     
         11 . The composition of  claim 10 , comprising: 
 a. about 5 to 10 percent by weight of polyethylene,    b. about 20 to 35 percent by weight of filler,    c. about 4 to 5 percent by weight of plastification agent, and    d. about 50 to 65 percent by weight of asphalt.    
     
     
         12 . The composition of  claim 11 , comprising: 
 a. about 10 percent by weight of polyethylene,    b. about 4 percent by weight of plastification agent.    
     
     
         13 . The composition of  claim 1 , comprising: 
 a. about 5 percent by weight of low density polyethylene;    b. about 5 percent by weight of high density polyethylene.    
     
     
         14 . The composition of  claim 8 , comprising: 
 a. about 6 percent by weight of low density polyethylene;    b. about 1.5 percent by weight of high density polyethylene;    c. about 2.5 percent by weight of plastification agent.    
     
     
         15 . A modified bitumen composition for roofing application comprising: 
 a polymer modifier consisting essentially of polyethylene;    one or more plastification agents;    and asphalt.    
     
     
         16 . The composition of  claim 15 , wherein the polyethylene consists of a mixture of high density polyethylene and low density polyethylene in a ratio ranging from 1:4 to 4:1 LDPE to HDPE by weight.  
     
     
         17 . The composition of  claim 15 , wherein the polyethylene is linear.  
     
     
         18 . The composition of  claim 15 , wherein the polyethylene has a molecular weight between 1,000 and 25,000.  
     
     
         19 . The composition of  claim 15 , wherein the polyethylene has a melt flow index value between 5 and 50.  
     
     
         20 . The composition of  claim 15 , wherein the low density polyethylene has a density less than 0.95 g/cm 3 .  
     
     
         21 . The composition of  claim 15 , wherein the low density polyethylene has a density less than 0.93 g/cm 3 .  
     
     
         22 . The composition of  claim 15 , wherein the low density polyethylene has a density ranging less than about about 0.915 g/cm 3  and the high density polyethylene has a melt flow index ranging from 2 to 20.  
     
     
         23 . The composition of  claim 15 , wherein the low density polyethylene has a density ranging less than 0.91 and the high density polyethylene has a melt flow index ranging from 2 to 20.  
     
     
         24 . The composition of  claim 15 , comprising: 
 a. about 7.5 percent by weight of polyethylene, and    b. about 2.5 percent by weight of plastification agent.