New polyethylene

Abstract

The present invention relates to a low density polyethylene having a molecular weight distribution Mw/Mn which is greater than 15, a storage modulus G′ (5 kPa) which is above 3000 and a vinylidene content which is at least 15/100k C, compositions, a process for production of the low density polyethylene, a continuous ethylene polymerization method for introducing vinylidene in a low density polyethylene, a method for an extrusion coating process, an article, e.g. an extrusion article, and use in extrusion coating.

1 . A process for the production of a low density polyethylene in a tubular reactor by radical initiated polymerization under high pressure, wherein the polymerization is performed by:
 reacting an ethylene monomer under the action of one or more radical initiators,   wherein the amount of used radical initiators measured by the amount of used active oxygen is at least 3 times the conventionally used amount, and   wherein the low density polyethylene has:
 a molecular weight distribution Mw/Mn which is greater than 15, 
 a storage modulus G′ (5 kPa) which is above 3000, and 
 a vinylidene content which is at least 15/100 k C. 
   
     
     
         2 . A process according to  claim 1 , wherein the amount of used radical initiators measured by the amount of used active oxygen is at least 0.125 kg AO/ton PE. 
     
     
         3 . The process according to  claim 1 , wherein said high pressure is from 1000 to 3000 bar. 
     
     
         4 . The process according to  claim 2 , wherein the polymerization is performed by reacting the ethylene monomer under the action of one or more low temperature decomposition peroxides. 
     
     
         5 . The process according to  claim 3  where the polymerization is performed under the action of one or more peroxides having a 0.1 hour half-life temperature which is below 100° C. 
     
     
         6 . The process according to  claim 1 , wherein a radical initiator cocktail is used, wherein the radical initiator cocktail comprises the following radical initiators:
 Initiator A, T½ 0.1 h at 75-90° C. in chlorobenzene,   Initiator B, T½ 0.1 h at 80-95° C. in chlorobenzene,   Initiator C, T½ 0.1 h at 105-125° C. in chlorobenzene,   Initiator D, T½ 0.1 h at 125-140° C. in chlorobenzene, and   Initiator E, T½ 0.1 h at 155-175° C. in chlorobenzene,   wherein T½ is the 0.1 hours half life temperature (T½).   
     
     
         7 . The process according to  claim 1 , wherein the one or more radical initiators are selected from the group consisting of peroxides, oxygen, and combinations thereof. 
     
     
         8 . A process according to  claim 1 , wherein the amount of used radical initiators measured by the amount of used active oxygen is at least 0.127 kg AO/ton PE. 
     
     
         9 . The process according to  claim 1 , wherein said high pressure is from 1500 to 2500 bar.