Gas Chromatography Screening for Acrylate Monomer Byproducts in Varnishes
Quantifying residual acrylate monomers by gas chromatography requires solvent extraction and headspace screening to verify compliance with food migration limits.
Acrylate Monomer
Molecular Block
Reactive organic molecule that serves as the primary component in ultraviolet and electron beam curable inks and coatings. An acrylate monomer contains a functional group that undergoes rapid polymerization when exposed to high energy radiation. This reaction converts a liquid coating into a solid film in a fraction of a second on the printing line.
Viscosity Control
Liquid properties of the formulation are determined by the molecular weight and the number of functional groups present in the monomer. Adding a monofunctional acrylate monomer reduces the viscosity of the ink to allow for smooth application via flexographic or offset processes. This thinning effect happens without the use of volatile organic solvents that would evaporate into the atmosphere.
Different monomers provide varied levels of flexibility, adhesion, gloss and chemical resistance to the final printed surface.
Safety Profile
Occupational health considerations and food safety requirements dictate the selection of specific molecules for packaging applications. Use of an acrylate monomer with low skin irritation and low volatility protects press operators from exposure during the wash up process. In the context of food packaging, the degree of conversion from monomer to polymer must be nearly total to prevent the migration of small molecules into the food.
Residual unreacted material is monitored using gas chromatography mass spectrometry to ensure compliance with health standards. Migration limits are strictly enforced.