| 摘要 |
The present invention relates to a multilayer tube comprising, in its radial direction from the outside inwards: an outer layer formed from a polyamide, a layer formed from a copolyamide, a layer formed from an EVOH, a layer formed from a copolyamide, an inner layer formed from a polyamide, the layers being successive and adhering to one another in their respective contact region. Advantageously, the inner layer is formed by a compound based on a polyamide and electrically conducting carbon black, producing a surface resistivity of less than 10<6 >Omega/?. The outside diameter of these tubes may range from 6 to 110 mm and the wall thickness may be from 0.5 to 5 mm. Advantageously, the petrol tube according to the invention has an outside diameter ranging from 6 to 12 mm and a total wall thickness of 0.36 mm to 1.95 mm, namely: a thickness of 50 to 700 mum for the polyamide outer layer, a thickness of 10 to 150 mum for the copolyamide layers, a thickness of 10 to 200 mum for the EVOH layer, a thickness of 100 to 500 mum for the polyamide inner layer possibly filled with electrically conducting carbon black. The tube of the present invention has a very low permeability to petrol, particularly to hydrocarbons and their additives, and in particular to alcohols, such as methanol and ethanol, or to ethers, such as MTBE or ETBE. These tubes also have good resistance to engine lubrication oils and fuels.
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