| 摘要 |
The present invention provides a multilayer tube comprising (a) a first outer thermoplastic layer and (b) a second inner thermoplastic diffusion barrier layer which is directly bonded or fused to the first layer by a material-to-material bond. The second layer has a thickness of from about 0.1 to about 0.6 mm. At least one layer of the multilayer tube has an elongation value at break of at least about 130%. Also, at least one layer of the multilayer tube includes a heat stabilizer. The multilayer tube of the present invention is able to withstand 1,000 hours or more of contact with fuels without the layers delaminating. Furthermore, the multilayer tube is able to withstand 1,000 hours or more in an antifreeze mixture of 5 to 50 percent by volume of methanol in water at from about -20 to about 80° C. without the layers delaminating. The multilayer tube of the present invention does not require an intermediate bonding or primer layer to join the thermoplastic layers. Additionally, the multilayer tube does not delaminate after prolonged contact with fuel, oil, and antifreeze or heating and cooling. The multilayer tube may be used in motor vehicles as a fuel line or a vapor return or recovery line.
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