Characterisation and quantification of lubricants in a cross-linkable varnish by Fourier transform infrared absorption spectroscopy (FT-IR) and differential scanning calorimetry

The lids of beverage cans are coated with varnish before stamping. In light of the considerable stress undergone by the metal during stamping, the coefficient of friction of the cross-linked coating must be optimised. To this end, the compounder can add lubricants to the varnish matrix. After heat treatment of the varnish, they contribute to the success of the stamping process. The present work describes the use of Fourier transform infrared spectroscopy and differential scanning calorimetry to characterise these mixtures of lubricants and to assay them in situ in the varnish.