Shaw Industries, Inc.

Shawcor Ltd.

Robert Edward Steele

Dilip K Tailor

Peter Jackson

Marcus P Heydrich

Michael A Romano

Amarjit Tathgur

Alfredo Andrenacci

John H Oliver

James L Smythe

Rajni R Lakhani

Chunglee Hank Yih

Jeffery A D State

Dennis T H Wong

Michael Verge

Real R Dezainde

Sean A Haberer

Peter Singh

Donald C Warren

Method of coating pipe having a raised weld bead. Curable resin polymer is applied to the pipe and allowed to bond to form a cured or partially cured polymer layer on the pipe. Powder form adhesive composition is applied on the polymer layer while hot, with fusion into a film bonding to the polymer. Powder form polyolefin is applied to the adhesive while hot with fusion into a film bonding to the adhesive to form a powder-based coating. Following forming of the powder-based coating, the pipe is cooled from the inside. An outer polyolefin covering is bonded to the powder-based coating and the pipe cooled to ambient temperature. This procedure can avoid voids, cavities or pinholes forming in the coating adjacent the weld bead.

Coating method for pipe having weld bead

A crosslinked, predominantly polypropylene-based article comprises a silane-modified ethylene-based polyolefin, at least 50 percent by weight of a non silane-modified polypropylene, and a silane condensation catalyst. The article is moisture crosslinked to a sufficient degree that it possesses thermoset properties such that, when the article is heated to a temperature above the crystalline melting point of the non silane-modified polypropylene, it is softened but does not become liquid. The article preferably comprises a heat-shrinkable sleeve for a high-temperature transmission pipeline.

Crosslinked, predominantly polypropylene-based compositions

A moisture-crosslinkable polyolefin material, comprising a silane-grafted polyolefin blend, and coatings or insulations, including heat-shrinkable coatings and insulations, prepared therefrom. The coating material is formed by a process comprising: (a) reacting a pre-blended mixture of polyolefin and polypropylene, or higher polyolefin, resins and optional compatibilizing agent, with an appropriate silane and silane-grafting initiator to produce a silane-modified polyolefin blend composition; (b) forming the coating or insulating material by melt processing the composition produced in step (a) with a silanol condensation catalyst; and (c) crosslinking the formed coating or insulating material by exposing it to moisture, preferably at an elevated temperature.

Crosslinked compositions containing silane-modified polypropylene blends

A moisture-crosslinkable polypropylene material, comprising silane-grafted polyolefin or olefin-silane copolymer and non silane-modified polypropylene homopolymer or copolymer; and coatings or insulations, including heat-shrinkable coatings and insulations, prepared therefrom. The coating material is formed by a process comprising: (a) reacting polyolefin with a silane in the presence of a free-radical initiator to form a silane-grafted polyolefin, or copolymerizing a polyolefin with silane; (b) preparing a mixture of the silane-modified polyolefin prepared in (a) with polypropylene homopolymer or copolymer, and a silanol condensation catalyst; (c) forming the coating or insulating material by melt processing the mixture formed in step (b); and (d) crosslinking the coating or insulating material by exposing it to moisture, preferably at an elevated temperature.

Crosslinked compositions containing silane-modified polyolefins and polypropylenes

A casing member for forming a connection between tubular sections. The member has heat shrinkable end portions, for connecting on respective adjacent end surfaces of the tubular sections adjacent the joint, and a middle portion for spanning between the end surfaces of the tubular sections. The end portions are formed integrally with at least a portion of the middle portion and have a zone that has a relatively small wall thickness while the middle portion having a relatively large wall thickness. This member may be made by heat shrinking a sleeve on an inner core on a mandrel or by uniting opposed ends of a heat shrink sheet having one or more auxiliary layers bonded to it. The properties of the core or auxiliary layer or layers may be tailored to provide desired properties or capabilities.

Heat shrinkable member

A pipeline is covered with a continuous wrapping sheet having heat-activatable adhesive on its inner side. The wrapping may be helically applied or may be heat shrunk to impart a circumferential stress conforming the wrapping tightly to the surface of the pipe. High frequency induction heating is applied to cause the adhesive to wet and bond to the pipe surface. The wrapping can be applied progressively and continuously along a pipeline excavated from the ground while the pipeline is in service. The product conveyed within the pipe assists in rapidly cooling the adhesive and wrapping sheet so that the pipe can be promptly relaid in the ground.

Method for covering a pipeline by wrapping

Heat-shrinkable cap comprising a heat-shrinkable tube sealed at one end by heat recovering that end of tube over a dimensionally stable, solid plug. The tube and plug are mutually weldable under heat, or are bonded together, thereby providing an air and water-tight seal at the sealed end. The open end of the cap may be internally coated with adhesive to provide an air and water-tight seal over an object such as a cable-end when the cap is heat recovered over said object.

Heat shrinkable end caps

A heat shrinkable wrap-around sleeve comprises a heat shrinkable sheet with a heat stable strip welded on one end. The free end of the heat stable strip is overlapped on the outer side of the opposite end of the sheet and welded thereto by heating applied directly on the outer side. This allows the material of the strip to differ in its properties from the material of the sheet, so that the nature of welded closure can be tailored to particular applications. It also allows manufacture of sleeves having hold-down adhesives applied on them to be conducted with greater ease and economy. The sleeve can be manufactured using continuous welding, for example by heated wedge welding.

Heat shrinkable protective sheets

A multiple layer wraparound sleeve having a heat shrinkable backing layer and at least one functional layer has the functional layer as a discrete sheet which is connected to one end of the backing layer, and is of at least sufficient length that, when the sleeve is wrapped around the pipe or other substrate at least twice, the functional layer sheet wraps around the substrate first with its ends overlapping and the backing layer wraps around the functional layer sheet with its ends overlapping. This allows wrappings of reduced thickness to be employed without problems of voids occurring between the functional layer and the substrate.

Multi-layer wraparound heat shrink sleeve

A longitudinally heat shrinkable closure sheet has a hold-down adhesive portion adjacent each longitudinal end for application on the exposed end portions a heat shrinkable wrap-around sleeve applied around a pipe or other article to be covered. Heat is applied to the closure sheet in order to weld the adhesive free portion of the underside of the closure sheet to the end portions of wrap-around sleeve. The initial shrinkage of the closure sheet between the hold-down adhesive portions draws it tightly into contact with the upper side of the end portions. Shearing forces are applied between the closure sheet and the end portions firstly as the closure sheet contracts relative to the end portions, and secondly, as the sleeve shrinks, develops hoop stress and stretches the closure sheet, and a high strength fusion bond is achieved between the closure sheet and sleeve.

Heat shrinkable closure sheets and sleeve structures and methods

A heat shrinkable covering in the form of a sheet which is heat shrinkable in a longitudinal direction, and a stiffening member connected at each of two longitudinally spaced transversely extending superimposable zones of the sheet. One stiffening member has holes and the other studs in the form of arm portions which are insertable through the holes to secure the stiffening members together. The arm portions can be flattened down onto the outside of the covering to retain the stiffening members together while reducing risk of the studs interfering with items such as cables adjacent the covered article. Preferably the studs have a resiliently compressible head portion which snap fits into holes formed through the sheet adjacent the holes in the stiffening member to facilitate locating the overlapped zones of the sheet relative to one another. In use, the sheet is wrapped around an article, the stiffening members are engaged together, and the sheet is then heat shrunk. The stiffening members support the juxtaposed edges of the sheet at points intermediate the coupling points, thus resisting the tendency for the edges of the sheet to separate as a result of the hoop stresses generated in the sheet on shrinking.

Heat shrinkable covering

A heat shrinkable covering for an article, such as a pipe, comprises a heat shrinkable material in the form of a flexible sheet which is wrapped around the article so that its ends overlap. The overlapping end portions are bonded together by means of a hold-down adhesive, preferably a shear-resistant adhesive, leaving an adhesive-free region at the interface. Heat is applied externally to the overlapping end portions so as to effect a fusion bond at the adhesive-free region of the interface, and the sheet is heat-shrunk onto the article in known manner. The covering offers the advantages and convenience of application common to conventional wrap-around sleeves, while having the intrinsic strength properties of a seamless tubular sleeve.

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Richmond Hill, Canada

Robert Edward Steele