Hose of impermeability and a process for manufacturing the same

Abstract

A hose of impermeability has a wall corrugated along at least a part of its length, and formed by an inner thin resin layer, a laminated layer including a metal film, or a layer formed by a metal film, and an outer thin resin layer. It has a very high fluid impermeability owing to its wall layer including or formed by a metal film, and is also very flexible, capable of absorbing vibration, light in weight and strong. A tubular inner thin resin layer is formed by extrusion as the innermost layer of a multi-layered hose wall, and a laminated tape including a metal film, or simply a metal film is spirally wound or longitudinally lapped about the inner resin layer. An outer thin resin layer is formed about a layer formed by the laminated tape, or metal film, and the whole is at least partly corrugated. Alternatively, corrugation is done before an outer thin resin layer is formed by electrostatic powder coating. A different process includes applying a laminated tape including a metal film about a mandrel to form a tubular laminated layer, and after removing the mandrel, coating the inner surface of the tubular layer with a resin powder electrostatically to form a thin resin layer thereon.

What is claimed is:  
     
         1 . A hose having a wall corrugate 6 along at least a part of its length, comprising an inner thin resin layer, a laminated layer having a metal film held between two resin films and surrounding the inner resin layer, and an outer thin resin layer surrounding the laminated layer.  
     
     
         2 . A hose as set forth in  claim 1 , wherein the laminated layer is a spirally wound or longitudinally lapped layer of a laminated tape having the metal film bonded to the resin films.  
     
     
         3 . A hose as set forth in  claim 2 , wherein at least the inner resin layer and the laminated layer, overlapping edge portions of the laminated tape, or the laminated layer and the outer resin layer are bonded with an adhesive.  
     
     
         4 . A hose as set forth in  claim 2 , wherein the laminated tape has a thickness of 200 μm at maximum.  
     
     
         5 . A hose as set forth in  claim 2 , wherein the metal film is of aluminum and has a thickness of from 7 to less than 200 μm.  
     
     
         6 . A process for manufacturing a hose of impermeability comprising the steps of: 
 extruding an inner thin resin layer about a mandrel;    applying a laminated tape having a metal film held between two resin films to an outer surface of the inner resin layer to form a laminated layer; and    forming an outer thin resin layer about the laminated layer by extrusion or electrostatic powder coating to complete a multi-layered wall, and corrugating the wall along at least a part of its length, or    corrugating a hose structure composed of the inner resin layer and the laminated layer along at least a part of its length, and forming an outer thin resin layer by electrostatic powder coating about the laminated layer to complete a multi-layered wall.    
     
     
         7 . A hose having a wall, corrugated along at least a part of its length, comprising an inner thin’ resin layer, a thin metal layer surrounding the inner resin layer, and an outer thin resin layer surrounding the metal layer.  
     
     
         8 . A hose as set forth in  claim 7 , wherein the metal layer is a spirally wound or longitudinally lapped layer formed by an aluminum film having a thickness of from 7 to less than 200 μm.  
     
     
         9 . A hose as set forth in  claim 8 , wherein at least the inner resin layer and the metal layer, overlapping edge portions of the metal layer, or the metal layer and the outer resin layer are bonded with an adhesive.  
     
     
         10 . A hose as set forth in  claim 7 , wherein at least one of the inner and outer resin layers has a thickness of 5 mm at maximum.  
     
     
         11 . A process for manufacturing a hose of impermeability comprising the steps of: 
 extruding an inner thin resin layer about a mandrel;    applying a metal film onto an outer surface of the inner resin layer to form a thin metal layer thereabout;    forming an outer thin resin layer on an outer surface of the metal layer by extrusion or electrostatic powder coating to complete a multilayered wall; and    corrugating the wall along at least a part of its length.    
     
     
         12 . A process for manufacturing a hose of impermeability comprising the steps of: 
 applying a laminated tape composed of metal and resin films about a mandrel to form a tubular laminated layer; and    after removing the mandrel, coating an inner surface of the laminated layer with a resin powder electrostatically to form a thin inner resin layer.    
     
     
         13 . A process as set forth in  claim 12 , further comprising the step of forming a protective layer surrounding the laminated layer before or after the coating step.  
     
     
         14 . A process as set forth in  claim 12 , wherein a tubular part for a hose assembly is connected to the laminated layer before the coating step, so that the tubular part may also have an inner surface coated with the resin powder.  
     
     
         15 . A process as set forth in  claim 12 , wherein the laminated tape is spirally wound or longitudinally lapped about the mandrel.  
     
     
         16 . A process as set forth in  claim 12 , wherein the laminated tape comprises a metal film and two resin films between which the metal film is held.  
     
     
         17 . A process as set forth in  claim 12 , wherein the laminated tape has a thickness of 30 to 200 μm and includes a metal film having a thickness of 7 to 50 μm.  
     
     
         18 . A process as set forth in  claim 12 , wherein the resin powder is of a thermoplastic resin and is melted under heat on the inner surface, the coating and melting being performed at least once.  
     
     
         19 . A process as set forth in  claim 12 , wherein the resin powder is selected from the group consisting of polyamide, ethylene-vinyl alcohol copolymer, polyester, modified polyolefin, and fluoro resins.  
     
     
         20 . A process as set forth in  claim 19 , wherein the modified polyolefin resin is a silane-crosslinked, acid-modified or hydroxyl-modified polyethylene resin, and the fluororesin is a chlorotrifluoroethylene-vinylidene fluoride copolymer, THV or PVDF.