Foamed insulation coating on pipes and methods therefor

Abstract

A method of providing a foamed insulation coating on at least a portion of a pipe, including extruding a melt stream over the pipe portion. The melt stream includes a matrix polymer and expandable fillers in an unexpanded state, the melt stream being maintained at a sufficiently high temperature to maintain the matrix polymer in extrudable form and at a sufficiently high pressure to maintain the expandable fillers in the unexpanded state. Once extruded, the expandable fillers are permitted to expand into an expanded state at a lower pressure.

1 . An insulated pipe section comprising:
 a pipe section;   a foamed insulation coating at least a portion of the pipe section; and   the foamed insulation coating having been formed by extruding a melt stream comprising expandable fillers in an unexpanded state over at least the portion of the pipe section and permitting the expandable fillers in the extruded melt stream to expand into an expanded state after extruding.   
     
     
         2 . The insulated pipe section of  claim 1  wherein the melt stream includes a matrix polymer selected from the group consisting of polyimides, acrylonitrile-butadiene-styrene resins, acetals, chlorinated polyethers, fluorocarbons, polyamides (i.e., nylons), polycarbonates, polyolefins (e.g., polyethylenes, polypropylenes, chlorinated or fluorinated polyolefins, and copolymers thereof), polystyrenes and vinyls (e.g., polyvinyl chloride), thermoplastic polyurethanes and polyureas, among others, and mixtures thereof. 
     
     
         3 . The insulated pipe section of  claim 1  wherein the expandable fillers comprise expandable thermoplastic microspheres. 
     
     
         4 . The insulated pipe section of  claim 3  wherein the expandable thermoplastic microspheres are comprised of a thermoplastic material selected from the group consisting of: nitrile, acrylic or halogenated resins and their co-polymers (e.g., poly acrylonitrile-co-methacrylonitrile-co-methyl methacrylate or polyacrilonytrile-co-vinylidene chloride-co-methyl methacrylate), acrylic-modified polystyrene or styrene/methyl methacrylate and fluoro-polymers, among others, and combinations thereof. 
     
     
         5 . The insulated pipe section of  claim 1  wherein the expandable fillers in the unexpanded state are metered into the melt stream, at a controlled rate, during the extruding. 
     
     
         6 . The insulated pipe section of  claim 1  further comprising an inner anti-corrosion coating covering at least the portion of the pipe. 
     
     
         7 . The insulated pipe section of  claim 1  further comprising an outer protective coating over the foamed insulation coating. 
     
     
         8 . The insulated pipe section of  claim 1  wherein the melt stream is maintained at a temperature in the range of 150° C. to 280° C. 
     
     
         9 . The insulated pipe section of  claim 1  wherein the melt stream is maintained at a pressure in the range above 30 bars. 
     
     
         10 . A kit comprising:
 a first master batch including expandable fillers in an unexpanded state, the first master batch being in solid form; and   instructions for combining the first master batch with a matrix polymer, and melting the mixture to form a melt stream for extrusion over at least a portion of a pipe to provide at least the portion of the pipe with a foamed insulation coating.   
     
     
         11 . The kit of  claim 10  further comprising a second master batch including at least one additive, the second master batch being in solid form, wherein the instructions include instructions for combining the first master batch and the second master batch with the matrix polymer. 
     
     
         12 . The kit of  claim 10  further comprising a third master batch including the matrix polymer in solid form. 
     
     
         13 . The kit of  claim 10  wherein the instructions include instructions to combine the first master batch with the matrix polymer in a defined proportion. 
     
     
         14 . The kit of  claim 10  wherein the instructions include instructions to melt the mixture under defined temperature and pressure conditions, to inhibit expansion of the expandable fillers. 
     
     
         15 . An insulated pipe section comprising:
 a pipe section;   a first insulation layer that is closer to an outer surface of the pipe section than a second insulation layer, the first insulation layer comprising a first insulating material having a first melting point that is higher than an expected temperature at the outer surface of the pipe section; and   the second insulation layer over an outer surface of the first insulation layer, the second insulation layer comprising a second insulating material having a second melting point that is lower than the expected temperature at the outer surface of the pipe section;   the first insulation layer providing sufficient thermal insulation to achieve an expected temperature at the outer surface of the first insulation layer that is lower than the second melting point.   
     
     
         16 . The insulated pipe section of  claim 15  wherein the expected temperature at the outer surface of the pipe section is at least 135° C., and the first melting point is at least 10° C. above the temperature at the outer surface of the pipe section. 
     
     
         17 . The insulated pipe section of  claim 15  wherein the expected temperature at the outer surface of the first insulation layer is at least 10° C. below the melting point of the second insulation layer. 
     
     
         18 . The insulated pipe section of  claim 15  wherein the first insulation layer comprises a polymer resin with improved mechanical properties and temperature resistance such as for example, PPSU, PEEK, PEK, PET and PBT, ABS, fluorinated polymers, polyamides and polyimides, POM and polycarbonates. 
     
     
         19 . The insulated pipe section of  claim 15  wherein the first insulation layer has a thickness in the range of 0.5 cm-15 cm. 
     
     
         20 . The insulated pipe section of  claim 15  wherein the second insulation layer comprises a polymer selected from the group consisting of: a polyolefin, a styrene resin, a butyl rubber, a nitrile rubber, a thermoplastic polyurethane, a polyurea, and combinations thereof. 
     
     
         21 . The insulated pipe section of  claim 15  wherein the second insulation layer has a thickness in the range of 1 cm-20 cm. 
     
     
         22 . The insulated pipe section of  claim 15  wherein at least one of the first insulation layer and the second insulation layer is provided using the method of  claim 1 .