Polymer for fuel tanks

Abstract

A fuel tank for a vehicle is disclosed, comprising at least one component which is injection-moulded multimodal polyethylene resin having a polydispersity M w /M n of at least 3. Preferably the polyethylene resin is bimoldal and the injection-moulded component forms one or more of the walls of the tank.

1 . Fuel tank for a vehicle comprising at least one component which is injection-moulded, rotomoulded or thermoformed multimodal polyethylene resin having a polydispersity M w /M n  of at least 3.  
     
     
         2 . Fuel tank according to  claim 1 , wherein the multimodal polyethylene resin is injection-moulded.  
     
     
         3 . Fuel tank according to  claim 1  or  2 , wherein the polyethylene resin is bimodal.  
     
     
         4 . Fuel tank according to any preceding claim, wherein the injection-moulded, rotomoulded or thermoformed component forms one or more of the walls of the tank.  
     
     
         5 . Fuel tank according to any preceding claim, wherein the polydispersity of the polyethylene resin is at least 4.  
     
     
         6 . Fuel tank according to any preceding claim, wherein the-unformulated polyethylene resin, before the incorporation of any additives, has a density of from 930 to 965 kg/m 3 .  
     
     
         7 . Fuel tank according to any preceding claim, wherein the high load melt index (HLMI) of the polyethylene resin is between 1 and 30 g/10 min.  
     
     
         8 . Fuel tank according to any preceding claim, wherein the high load melt index (HLMI) of the polyethylene resin is between 8 and 25 g/10 min.  
     
     
         9 . Fuel tank according to any preceding claim, wherein μ 3  of the polyethylene resin, the viscosity at a shear rate of 1000 s −1  with a die having a ratio of length to internal diameter of 15:1, is less than 7000 dPa.s.  
     
     
         10 . Fuel tank according to any preceding claim, wherein the polyethylene resin is bimodal and comprises 30-70% of a low molecular weight block, and 70-30% of a high 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  or  11 , 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  11 , wherein the Melt Index (MI 2 ) of the low molecular weight block is less than 1000.  
     
     
         14 . Fuel tank according to any one of  claims 10  to  13 , wherein the HLMI of the high molecular weight block is between 0.001 and 2.  
     
     
         15 . Fuel tank according to any one of  claims 3  to  14 , wherein the polydispersity of each of the blocks is less than 4.  
     
     
         16 . Fuel tank according to any preceding claim, wherein the polyethylene resin is made using a metallocene catalyst, and the polydispersity thereof is between 5 and 12.  
     
     
         17 . Fuel tank according to any preceding claim, wherein the polyethylene resin is made using a Ziegler-Natta catalyst, and the polydispersity thereof is between 10 and 24.