Reduction of Retained Solvents During Lamination and Drying Operations by Spectra HE Ultra System

Heat Technologies, Inc. (HTI) specializes in manufacturing the Spectra HE™ Ultra industrial drying systems. This equipment is based on patented acoustic energy generating technology that applies ultrasonic energy via a controlled air stream. The energized air accelerates the mass-transfer of water or solvent from a nonwoven web and for the drying process during coating or print operations.

We all know the pitfalls of operations when solvent-based coatings and inks are used: high speed comes with fire hazards, complex solvent recovery systems or RTOs, and sometimes with unexpected excessive emissions of solvent vapors into the environment, which are typically followed by heavy monetary fines from local environmental authorities.

Even when the operations for drying solvent-based coating or printing processes are running safely and effectively, the lines may have difficulties meeting residual solvent levels required by various regulations. Alternatively, the process may be accepting excessive retained solvent levels as “normal” with a required tack-room hold period.

Spectra HE Ultra Lab Simulation Unit

Spectra HE Ultra Lab Simulation Unit

Lamination. Commercial Scale Testing.

Following a COVID required shut down, HTI has now reopened our demo unit. The HTI Spectra HE Ultra demo unit that allows simulation of commercial drying operations to be conducted at a line speed up to 600 fpm (200 m/min).

This was within the increased line speed requested by the customer. At proper coat-weight, increased line speed and lamination process simulation, HTI Spectra HE Ultra acoustic drying technology prepared samples that can submitted for residual solvent analysis to the third-party laboratory.

Results of the tests showed that at a line speed of 1.5x the production rate of this particular customer, the retained solvents content was at 0.25x when compared to the current line speed (300 fpm /100 m-min). The footprint of the proposed Spectra HE Ultra drying system was 50% less than the size of the standard one deployed today.

Rotogravure Printing

For a Rotogravure Press application, which was conducted on the installed equipment at a line speed of 1000 fpm, comparison showed similar results. The real advantage was also found whereby out of the 5 residual solvents present at standard conditions, trace elements of 2 of the solvents were totally eliminated. Of the 3 that were measurable, the amounts were far less when the Spectra HE Ultra system was deployed.