Some of the new inks don’t smell, so is ventilation and a fresh air supply still important?

Strong solvent inks usually require solvent control systems to meet OSHA and EPA requirements. Manufacturers of solvent printers have a duty to honestly present the hazards created by their systems. Designing safe inks that perform well has been a challenge for printer manufacturers and their ink manufacturing partners.

Solvent inks are used on uncoated vinyls. All vinyls are made of polyvinyl chloride polymer filled with organic plasticizers to make them flexible. These plasticizers account for up to half the weight of the vinyl. For ink to bond to this vinyl, the ink has to soften the vinyl and dissolve some of the plasticizer molecules near the surface to the vinyl to enable the pigment and its binders to adhere. If the surface is not softened, the plasticizer is not partially dissolved by the solvents and the adhesion and durability of the printed image may be poor. Solvents that give this performance may not be very friendly to people and may have a low flash point, making them hazardous to ship, handle, store, and use.

Material Safety Data Sheets (MSDS) must be provided by law with all ink purchases. To learn the truth about the solvents in an ink, you must look at each ink’s MSDS. Different colors may have different solvent systems. Major solvents are listed by their chemical names on the MSDS. Solvent inks will cause eye irritation and many cause skin irritation if spilled. Some improved inks now include more aggressive solvents that may be harmful to people if they spend a lot of time running the printers with improper ventilation.

—Fabric Graphics Association Board of Directors