| 摘要 |
<p>A method for the formation of a tube from thermoplastic packaging film on a tube-forming apparatus is disclosed. The method comprises feeding the thermoplastic film to tube-forming apparatus and heat sealing the thermoplastic film into the form of a tube using a longitudinal heat seal. The film used in the method is formed by extrusion of molten synthetic thermoplastic polymer through an annular die to form a tube of said molten polymer, expanding the molten tubular film so-formed and then cooling said film, subsequently heating the film under tension to a temperature of 50-100 °C and then cooling to a temperature of less than 40 °C. The amount of tension applied to the film is such that the thickness of the film remains substantially unchanged. The formation of the film and the film are also disclosed. The method results in improvements in the runnability of the film, especially on form, fill and seal apparatus in the packaging of liquids, as shown by the number of leaking pouches.</p> |
