Patents Assigned to Norma Products (US) Inc.
  • Patent number: 6230749
    Abstract: 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.
    Type: Grant
    Filed: November 29, 1999
    Date of Patent: May 15, 2001
    Assignee: Norma Products (US) Inc.
    Inventor: Janos Kertesz