sealinghot

Sealinghot is a term used in packaging technology to describe a heat-activated sealing process that produces a tight, hermetic seam on flexible substrates such as multilayer plastic films and laminates. The name derives from the combination of sealing and hot, reflecting the central role of heat in forming the bond.

Process and materials: Sealinghot relies on a heat-activated adhesive or heat-softenable film, applied to one or both surfaces to be joined. During operation, the substrates pass between heated sealing bars or drums that reach temperatures above the adhesive's activation point. Pressure and dwell time determine seam strength; cooling solidifies the bond and finalizes the seal, which resists moisture, gases, and dust.

Applications: It is widely used in food packaging, medical pouches, and consumer electronics packaging, especially for barrier films requiring strong, durable seals. The technique is compatible with common polymers such as polyethylene, polypropylene, PET, and various laminates.

History: The technique developed in the late 20th century as packaging demands shifted toward higher integrity seals and faster production. Improvements in heater control, feed mechanisms, and control software have enhanced repeatability and energy efficiency.

Variants and considerations: Variants include impulse sealing and hot-bar sealing, with differing bar configurations, temperatures, and dwell times. Environmental and safety concerns center on energy use, adhesive migration, material recyclability of laminated films, and operator safety around hot equipment.

See also: Heat sealing, impulse sealing, packaging engineering.