Method of manufacturing shrinkable tubing with integral tear strip

A method of continuously forming a packaging sleeve of heat-shrinkable thermoplastic with an integral tear strip, comprising the steps of

• (a) supplying heat shrinkable tubing in the form of a sleeve comprising a flattened tube having a first wall and second wall connected along parallel first and second lines of connection;
• (b) forming lines of weakness in said first and second walls proximate to one of said lines of connection whereby said lines of weakness and the line of connection define tear strip zones therebetween;
• (c) forming a reinforcing-levering band in said zones formed by welding superimposed portions of said first and second walls;
• (d) said reinforcing levering band being disposed parallel to said lines of weakness and in combination with said zones and lines of weakness establishing a tear strip for opening the sleeve;
• and
• (e) said reinforcing levering band being adapted when said sleeve is applied over an article and subjected to heat to assume a generally arcuate cross-section and to project outwardly from the surface of the article.