Burgess, Ryan and Wayne
Method of preparing novel bitumen compositions
 A method of preparing novel bitumen compositions which comprises a first step wherein an olefinic unsaturated organic compound having a molecular weight varying between 300 and 30,000 is added to a bitumen having a penetration value varying between 30 and 220, and a second step wherein a polymer having a molecular weight varying between 100,000 and 2,000,000 is added to the product obtained from said first step. 
Elf Union
C
C08L
inventional
Paul Robert
Maldonado Leger