Thermal lamination, as the term suggests, is a process that uses heat to fuse a layer of protective film onto a paper or plastic substrate. It’s commonly used to protect printed surfaces – such as product labels – from damage in storage and transit, or to give product packaging moisture-resistant qualities, for example to prevent liquid or oil from leaking through.
Thermal lamination is normally done using a film coated with a temperature sensitive adhesive. The glue is often applied to the film using a process called extrusion coating, and then when it’s passed through a system of heated rollers, the adhesive melts and sticks the film firmly onto the substrate.
Conventional thermal lamination is a much faster process than ‘wet’ lamination because the drying time for the adhesive is much less. However, delamination – where the laminate and the substrate don’t properly adhere – is a fairly common drawback that can hold up production lines.
With Enviraflex, the key difference is the absence of adhesive. Using the T30 machine and our innovative EnviraflexBASE and EnviraflexLAM films, we’ve developed a completely glueless, single substrate lamination system that is fast, economical and environmentally friendly.
So how does it work?
EnviraflexBASE and EnviraflexLAM are both polyethylene films. The BASE film is printable, and compatible with all major digital technology, while the LAM film is a specially-engineered material that has been heated and pre-stretched to align its grain in one direction. This enhances the qualities of the film, conferring superior puncture and moisture resistance, better tensile strength and improved optics. It also raises the melting point of the finished film.
As a result, EnviraflexBASE and LAM can be laminated together using a precise combination of film tension, nip pressure, temperature (typically 110°C) and speed. At this temperature, the BASE layer begins to melt, and is adhered firmly to the LAM layer without the need for adhesive. A Corona treater on the T30 overcomes any potential issues caused by silicone in the inks not adhering to the laminate, using an electrical charge to increase surface tension and achieve good adhesion. The finished film is then passed through a set of chilled rollers to cool and set it.
The clear benefit of the Enviraflex system is that it’s ready to use instantly – the reel can be lifted off the T30 and placed directly on a die-cutting, slitting or packaging machine. It is thermally welded using the same principle whereby the inner BASE layer sticks to itself when heated, while the outer laminate does not melt. The result is a single-substrate pouch that is fully recyclable in kerbside facilities, that can be produced more quickly and efficiently than its conventional counterparts. Enviraflex technology is also adaptable for carton and paper label lamination. Manufacturers benefit from reduced energy costs, a lower carbon footprint, and a faster route to market, while consumers gain convenience and freshness – it truly is a win-win!
To find out more about the Enviraflex method for thermal lamination, including the T30 laminator, get in touch.