Multi-layer tubing having electrostatic dissipation for handling hydrocarbon fluids

Abstract

An elongated multi-layer tubing having a first layer disposed radially innermost and having an inner surface capable of prolonged exposure to a fluid containing hydrocarbons and an outer surface spaced a first predetermined radial thickness from the inner surface, the first layer containing an extrudable, melt-processible thermoplastic. The tubing also includes a second layer connected to or bonded to the first layer and consists essentially of an extrudable, melt-processible thermoplastic capable of laminar adhesion with the first layer. At least one of the first and second layers can be resistant to permeation by hydrocarbons. The tubing includes a third layer connected to or bonded to the second layer and containing an extrudable, melt-processible thermoplastic.

1 - 34 . (canceled)  
     
     
         35 . An elongated multilayer tubing comprising: 
 a first layer disposed radially innermost and having an inner surface capable of prolonged exposure to a fluid containing hydrocarbons and an outer surface disposed essentially coaxial to the inner surface, the outer surface spaced a first radial thickness from the inner surface, the first layer containing an extrudable, melt-processible thermoplastic selected from the group consisting of fluoroplastics, polyamides, thermoplastic elastomers, and mixtures thereof;    a second layer having a second radial thickness, an inner surface, and an outer surface disposed essentially coaxial to the inner surface, the second layer consisting essentially of an extrudable, melt-processible thermoplastic capable of laminar adhesion with the first layer;    a third layer having a third radial thickness greater than the thickness of the first layer, the third layer connected to the second layer and consisting essentially of an extrudable, melt-processible thermoplastic.    
     
     
         36 . The elongated multilayer tube of  claim 35  wherein the second layer comprises at least one of thermoplastic polyesters, fluoropolymers, copolymers of alkenes and vinyl alcohol, copolymers of alkenes, and vinyl acetate, and blends of polyvinyl and urethane.  
     
     
         37 . The elongated multilayer tube of  claim 35  wherein the third layer has a radial thickness between 50 and 70 percent of the total tube wall thickness.  
     
     
         38 . The elongated multilayer to be of  claim 35  wherein the first, second, and third layers provide a tubing structure resistant to passive hydrocarbon permeation.  
     
     
         39 . The elongated multilayer tube of  claim 35  wherein the extrudable melt-processible thermoplastic employed in the inner layer is: 
 a polyamide selected from the group consisting of Nylon 12, Nylon 11, Nylon 6, and mixtures thereof;    a fluoropolymers selected from the group consisting of polychlorotribluoro ethylene, ethylene tetrafluoroethylene copolymers, graft copolymers of at least one of vinylidine fluoride and chlorofluoroethane with polychlorotrifluoroethylene, graft copolymers of at least one of vinylidine fluoride and chlorotrifluoroethane with ethylene tetrafluoroethane, polyvinylidine fluoride, polyvinyl fluoride and mixtures thereof.    
     
     
         40 . The elongated multilayer tube of  claim 35  wherein the thermoplastic material of the inner layer is resistant to permeation by aromatic and/or aliphatic compounds contained in automotive fuel.  
     
     
         41 . An elongated multilayer tubing comprising: 
 a first layer disposed radially innermost having a first inwardly oriented face and a second outwardly oriented face disposed essentially coaxial to the inner surface, the first layer containing an extrudable thermoplastic composition;    a second layer having an inner surface and an outer surface disposed essentially coaxial to the inner surface, the second layer consisting essentially of an extrudable, melt-processible thermoplastic capable of laminar adhesion with the first layer; and    a third layer connected to the second layer consisting essentially of a melt-processible thermoplastic containing at least one of polyamides and thermoplastic elastomers.    
     
     
         42 . The elongated multilayer tubing of  claim 41  wherein the second layer comprises at least one thermoplastic selected from the group consisting of polyvinyl fluoride, polyvinylidine fluoride, polyvinyl acetate-urethane blends, thermoplastic polyesters, polyamides, and mixtures thereof.  
     
     
         43 . The elongated multilayer tubing of  claim 42  wherein the first layer comprises at least one thermoplastic material compatible with the second layer.  
     
     
         44 . The elongated multilayer tubing of  claim 42  wherein the third layer has a thickness that comprises between 50 percent and 70 percent of a total tubing wall thickness.  
     
     
         45 . The elongated multilayer tube of  claim 42  wherein the tubing has an outer diameter below 2.5 inches.  
     
     
         46 . The elongated multilayer tube of  claim 42  wherein the tubing has a total wall thickness between 0.5 mm and 2.0 mm.