Multilayer Pipe

Abstract

A multilayer pipe having an inner layer of a thermoplastic polymer and a contoured, metallic barrier layer deposited thereon.

1 - 72 . (canceled)  
   
   
       73 . A multilayer pipe having an inner layer of a thermoplastic polymer and a contoured, metallic barrier layer deposited thereon.  
   
   
       74 . A multilayer pipe having a stabilised inner layer of a thermoplastic polymer and a contoured, metallic barrier layer deposited thereon, wherein the inner layer comprises an extruded thermoplastic polymer comprising at least one polar stabilizer, wherein the thermoplastic polymer is selected from the group consisting of: 
 (i) a thermoplastic polymer provided with pendant polar functional groups,    (ii) a thermoplastic polymer comprising an effective amount of at least one filler provided with pendant polar functional groups, and    (iii) a thermoplastic polymer comprises a blend of a non-polar thermoplastic polymer and a thermoplastic polymer provided with pendant polar functional groups.    
   
   
       75 . A multilayer pipe according to  claim 73 , wherein the contoured metallic barrier layer is disposed between the thermoplastic polymer inner layer and at least one additional outer layer.  
   
   
       76 . A multilayer pipe according to  claim 73 , wherein the thermoplastic polymer of the inner layer comprises a polyolefin.  
   
   
       77 . A multilayer pipe according to  claim 76 , wherein the polyolefin is selected from the group consisting of polyethylene, cross-linked polyethylene and polypropylene.  
   
   
       78 . A multilayer pipe according to  claim 73 , wherein the thermoplastic polymer of the inner layer comprises a polar functional polyolefin.  
   
   
       79 . A multilayer pipe according to  claim 78 , wherein the thermoplastic polymer of the inner layer comprises a polar functional polyolefin produced by grafting of a moiety selected from polar functional groups and monomers onto a polyolefin backbone.  
   
   
       80 . A multilayer pipe according to  claim 79 , wherein the polar functional polyolefin polymer is a polar functional polyethylene.  
   
   
       81 . A multilayer pipe according to  claim 80 , wherein the polar functional polyethylene is ethylene/glycidyl methacrylate graft copolymer.  
   
   
       82 . A multilayer pipe according to  claim 73 , wherein the thermoplastic polymer of the inner layer comprises a blend of a non-polar semi-crystalline polyolefin polymer and a polar functional polyolefin polymer.  
   
   
       83 . A multilayer pipe according to  claim 82 , wherein the thermoplastic polymer comprises a blend of a polyethylene polymer and a polar functional polyethylene polymer.  
   
   
       84 . A multilayer pipe according to  claim 83 , wherein the blend of polyethylene polymers is cross-linked.  
   
   
       85 . A multilayer pipe according to  claim 73 , wherein the outer metallic barrier layer comprises a metal selected from the group consisting of aluminium, stainless steel and copper.  
   
   
       86 . A multilayer pipe according to  claim 85 , wherein the metallic layer is formed by a method selected from the group consisting of sputtering, spraying, plasma coating, galvanically-coating and electro-deposition.  
   
   
       87 . A multilayer pipe according to  claim 86 , wherein the outer barrier layer is directly bonded to the inner thermoplastic polymer layer.  
   
   
       88 . A multilayer pipe according to  claim 73 , wherein the thickness of the deposited metallic barrier is such that the metallic layer acts as a barrier to limit oxygen and water vapour diffusion into the inner thermoplastic polymer layer and also impedes diffusion of stabilisers and other additives out from the inner thermoplastic polymer layer.  
   
   
       89 . A multilayer pipe according to  claim 73 , wherein the metallic layer is at least 0.01 μm, in thickness.  
   
   
       90 . A multilayer pipe according to  claim 89 , wherein the metallic layer is from 0.05 μm to 5 μm in thickness.  
   
   
       91 . A multilayer pipe according to  claim 73 , wherein the shape of the deposited metallic barrier layer and the outer surface of the inner layer is selected from the group consisting of helically convoluted, circumferentially convoluted, corrugated, ribbed, and patterned such that their surfaces vary in cross-section along the length of the pipe in a regular fashion.  
   
   
       92 . A multilayer pipe according to  claim 91 , wherein the contoured surfaces of the deposited metallic barrier layer and the outer surface of the inner layer are formed with sinusoidal corrugations.  
   
   
       93 . A multilayer pipe according to  claim 73 , wherein the inner thermoplastic polymer layer comprises a polymeric matrix provided with functional groups that also increase the wetting of the deposited metallic barrier layer by the polymeric matrix.  
   
   
       94 . A multilayer pipe according to  claim 73 , wherein the surface of the metallic barrier layer is modified to improve its wetting behaviour.  
   
   
       95 . A multilayer pipe according to  claim 74  wherein the polar stabiliser is selected from the group consisting of a phenolic antioxidant, a phosphite, a phosphonite, a benzotriazole and a sterically-hindered amine.  
   
   
       96 . A multilayer pipe according to  claim 74  wherein the stabiliser is present in the inner polymeric layer in an amount of from 0.01 to 5 weight percent, based on the weight of the inner polymeric layer.  
   
   
       97 . A multilayer pipe according to  claim 74  wherein the filler is inorganic-based filler.  
   
   
       98 . A multilayer pipe according to  claim 74  wherein the inorganic-based filler is selected from the group consisting of talc, mica, calcium carbonate, kaolin, clay, magnesium hydroxide, calcium silicate, carbon black, graphite, iron powder, silica, diatomite, titanium oxide, iron oxide, pumice, antimony oxide, dolomite, dawsonite, zeolitic filler, vermiculite, montmorillonite and hydrated alumina.  
   
   
       99 . A multilayer pipe according to  claim 74  wherein the inorganic-based filler has a mean particle diameter of up to 10 μm.  
   
   
       100 . A multilayer pipe according to  claim 74  wherein the inorganic-based filler(s) content of the inner polymeric layer is from 0.5 to 25 weight percent, based on the weight of the polymeric matrix.  
   
   
       101 . A multilayer pipe according to  claim 74  wherein the filler is selected from the group consisting of filler having pendant functional polar groups on its surface and filler that has been treated to produce such surface functional groups.  
   
   
       102 . A multilayer pipe according to  claim 74  wherein the filler comprises a component selected from the group consisting of talc, mica, calcium carbonate, hydrated alumina and titanium dioxide.  
   
   
       103 . A multilayer pipe according to  claim 74  wherein the filler is a nanofiller.  
   
   
       104 . A multilayer pipe according to  claim 103 , wherein the nanofiller is present in an amount of from 1% to 5% by volume, based on the volume of the inner polymeric layer.  
   
   
       105 . A multilayer pipe according to  claim 104 , wherein the particles of the nanofiller are substantially uniformly dispersed in the inner polymeric layer.  
   
   
       106 . A multilayer pipe according to  claim 74  wherein an adhesive layer is disposed between the inner polymeric layer and the contoured deposited metallic barrier layer.  
   
   
       107 . A multilayer pipe according to  claim 106 , wherein the adhesive layer comprises a polymer comprising one or more functional groups selected from the group consisting of carboxyl, carboxylic, anhydride, epoxy, hydroxyl, isocyanate, aldehyde ester, acid amide, amino, hydrolysable silyl and cyano.  
   
   
       108 . A multilayer pipe according to  claim 75 , wherein the additional outer polymeric layer comprises cross-linked polyethylene.  
   
   
       109 . A method of producing a multilayer pipe comprising an inner layer of a thermoplastic polymer and a metallic barrier layer, which comprises extruding a polymeric composition comprising a thermoplastic polymer to form an inner layer having a contoured outer surface and depositing a metallic barrier layer onto the contoured surface.  
   
   
       110 . A method according to  claim 109 , wherein the thermoplastic polymer comprises at least one polar stabilizer, and wherein the thermoplastic polymer is selected from the group consisting of: 
 (i) a thermoplastic polymer provided with pendant polar functional groups,    (ii) a thermoplastic polymer comprises an effective amount of at least one filler provided with pendant polar functional groups, and    (iii) a thermoplastic polymer comprises a blend of a non-polar thermoplastic polymer and a thermoplastic polymer provided with pendant polar functional groups.    
   
   
       111 . A method according to  claim 109 , wherein the inner layer is separately extruded in a first step.  
   
   
       112 . A method according to  claim 109 , wherein the inner layer is extruded using an apparatus selected from the group consisting of (i) a corrugator and (ii) an extruder provided with a rotating die to provide a pipe having a smooth inner wall and a helically corrugated outer wall.  
   
   
       113 . A method according to  claim 109 , wherein an internal mandrel is used to provide increased pressure on the corrugated outer wall and thereby obtain a smooth contoured outer surface on the inner layer for deposition of the metallic barrier layer.  
   
   
       114 . A method according to  claim 109 , wherein the metallic barrier layer is deposited on the outer contoured surface of the inner layer to a thickness suitable to obtain the desired barrier properties against moisture, oxygen and organic contaminants.  
   
   
       115 . A method according to  claim 109 , wherein the metallic barrier layer is deposited by a sputtering technique.  
   
   
       116 . A method according to  claim 109 , wherein the metallic barrier layer is deposited by a method selected from the group consisting of arc spraying, flame spraying, plasma spraying and HVOF.  
   
   
       117 . A method according to  claim 109 , wherein the surface of the metallic barrier layer is modified to improve its wetting behaviour.  
   
   
       118 . A method according to  claim 117 , wherein the metallic barrier layer is treated by physical surface modification.  
   
   
       119 . A method according to  claim 118 , wherein the metallic barrier layer is treated by a method selected from the group consisting of plasma treatment, abrasion, ablation, and cleaning.  
   
   
       120 . A method according to  claim 117 , wherein the metallic barrier layer is treated by chemical surface modification.  
   
   
       121 . A method according to  claim 120 , wherein the metallic barrier layer is treated by a method selected from the group consisting of solvent cleaning, chemical cleaning, treatment with chemical modifying agents to introduce surface functional groups, deposition of surface layers by plasma deposition of a polymeric layer containing functional groups, deposition of a glassy layer, and other surface coating techniques.  
   
   
       122 . A method according to  claim 109 , wherein an additional outer polymeric layer is extrusion coated onto the contoured metallic barrier layer.  
   
   
       123 . A method according to  claim 122 , wherein the extruded additional outer layer provides a smooth outer surface for the pipe.  
   
   
       124 . A multilayer pipe according to  claim 73  further comprising an outer layer, wherein the compressive E-modulus of the inner layer is lower than the compressive E-modulus of the outer layer.  
   
   
       125 . Use of a multilayer pipe according to  claim 73  in a hot water transport system.  
   
   
       126 . A multilayer plastics pipe comprising a plastics inner layer, a metallic barrier layer and a plastics outer layer, wherein the pipe is capable of axial deformation and the compressive E-modulus of the inner layer is lower than the compressive E-modulus of the outer layer.