Polymer for fuel tanks

Abstract

A fuel tank for a vehicle is disclosed, comprising at least one component which is blow-moulded multimodal poly-ethylene having a polydispersity M w /M n of at least 4, formed of at least two blocks, each having a polydispersity M w /M n of less than 4.

1 . Fuel tank for a vehicle comprising at least one component which is a blow-moulded multimodal polyethylene resin having a polydispersity M w /M n  of at least 4, formed of at least two blocks, each having a polydispersity M w /M n  of less than 4.  
     
     
         2 . Fuel tank for a vehicle comprising at least one component which is a blow-moulded multimodal polyethylene resin, wherein the polyethylene has a creep deformation at 80° C. of no more than 2.4%, and a Charpy impact at −40° C. of at least 15 kJ/m 2 .  
     
     
         3 . Fuel tank according to  claim 2 , wherein the polyethylene resin has a creep resistance at 80° C. of no more than 2.3%.  
     
     
         4 . Fuel tank according to  claim 2  or  3 , wherein the polyethylene resin has a Charpy impact at −40° C. of at least 20 kJ/m 2 .  
     
     
         5 . Fuel tank according to  claim 1 , wherein the polyethylene resin is bimodal.  
     
     
         6 . Fuel tank according to  claim 1 , wherein the polydispersity of the polyethylene resin is at least 5.  
     
     
         7 . Fuel tank according to  claim 1 , wherein an unformulated polyethylene resin, before the incorporation of any additives, has a density of from 930 to 965 kg/m 3 .  
     
     
         8 . Fuel tank according to  claim 1 , wherein a high load melt index (HLMI) of the polyethylene resin is between 2 and 7 g/10 min.  
     
     
         9 . Fuel tank according to  claim 1 , wherein μ 0  of the polyethylene resin, the viscosity at a shear rate of 1 s −1  with a conical die having a ratio of length to internal diameter of 0.3:1, is at least 2.5×10 6  dPa.s.  
     
     
         10 . Fuel tank according to  claim 1 , wherein of the polyethylene resin is bimodal and comprises 20-80% of a high molecular weight block, and 70-30% of a low molecular weight block.  
     
     
         11 . Fuel tank according to  claim 10 , wherein the low molecular weight block is a homopolymer of ethylene.  
     
     
         12 . Fuel tank according to  claim 10 , wherein the high molecular weight block is a copolymer of ethylene and one or more of butene, pentene, hexene and octene.  
     
     
         13 . Fuel tank according to any one of  claims 10  to  12 , wherein the Melt Index (MI 2 ) of the low molecular weight block is less than 500.  
     
     
         14 . Fuel tank according to  claim 10 , wherein the high load melt index (HLMI) of the high molecular weight block is between 0.001 and 2.  
     
     
         15 . Fuel tank according to  claim 10 , wherein at least the high molecular weight block of the polyethylene resin is made using a metallocene catalyst, and the polydispersity of the polyethylene resin is between 5 and 9.  
     
     
         16 . Fuel tank according to  claim 15 , wherein both blocks of the polyethylene resin are made using a metallocene catalyst.  
     
     
         17 . Fuel tank according to  claim 1 , wherein the polyethylene resin is made using a Ziegler-Natta catalyst, and the polydispersity thereof is between 10 and 18.