Heat sealing technology is applied to packaging using thermoplastic materials, since heat seal technology can easily create bags from thermoplastic films, seal the bags, or fabricate bottles after heating and cooling them.
Heat seal properties are influenced by a polymer’s thermal and rheological properties as well as factor such as the following:
*Seal-bar temperature
*Seal-bar pressure
*Dwell time
*Sealing bar configuration
*Package design
When heated, thermoplastic polymers change from solid to a liquid and then return to the solid stated after cooling.
Thermoset polymers, the other main type of polymer, exhibit a low viscosity when heated. They then begin cross-linking and cannot subsequently be melted.
Heat seal technology is used for packaging pre-heated and sterilized foods, baby and family care products, injectable and oral medicines, snacks, toiletries and components of electronics and precision machines.
Most polymers used for heat-seal layers belong to polyolefin family such as low-density polyethylene (LDPE), ethylene copolymer, acid copolymer, ionomer and PP.
Hence, these polymers have a number of desirable characteristics such as low cost, high moisture resistance, high flexibility, low heat seal temperature, and ease of processing.
Heat sealing
