Heat Shrinkable Sleeve

Heat Shrinkable Sleeve

Heat-shrinkable sleeve (or usually "shrink sleeve") could be a corrosion protection coating for pipelines within the kind of a wraparound or tubular sleeve that's field-applied. In recent years, several manufacturers had already developed their technologies of extruding and growth of polyolefin backing. In the past, the assembly method of backing was done by extruding, cross-linking and enlargement. However, in order to increase the production efficiency, some of the manufacturers expand the backing during extruding and then send the backing to e-beam for the cross-linking process.

The first heat-shrinkable tube/sleeves were introduced as polyethylene pipeline coatings began to replace bituminous or tape coatings within the oil and gas industry. In the processing time for polyethylene to make the sleeve backing was new technology, the adhesives used in sleeves are the same as those used on pipeline coating.

The technology used to make heat-shrinkable tube/sleeves has advanced significantly since then, with new methods of cross-linking the polyolefin backings and new-generation adhesives that are formulated to provide performance under more-demanding pipeline conditions.

Heat-shrinkable means just that, heat them up and they shrink, or more correctly, they recover in length. A heat-shrinkable sleeve starts out with a thick extruded polyolefin sheet (polyethylene or polypropylene) that is developed to be cross-linkable. It is taken to the "beam" after extruding the thick sheet. In there it is passed under a unit that subjects the sheet to electron irradiation.

The irradiation process cross-links the polyolefin. This improves the molecular structure such as the polyolefin can work as a part of a heat-shrinkable sleeve and supply the specified level of mechanical protection whereas in-service. It makes the polyolefin perform additional sort of a robust, heat-resistant, elastic material or rubber, rather than like a plastic material.

After cross-linking, the sheet is feeding into a machine that heats it up to make it as stretchable, stretches it and cools it down. Because the sheet has been cross-linked, once stretching, it'll need to recover to its original length when re-heated.