A major manufacturer of paper products was having difficulty with white spots appearing on their product.
Stereomicroscope examination indicated white particles/inclusions on or in the paper. The particles/inclusions were analyzed by Fourier transform infrared spectroscopy (FTIR) and/or scanning electron microscopy (SEM) combined with energy dispersive x-ray spectrometry (EDS).
White/translucent flakes lightly adhering to the paper’s surface were composed of carbon, oxygen, nitrogen, sulfur, and chlorine and the infrared absorption spectrum suggested a protein-based material, a finding consistent with skin flakes.
White spots included in the paper were comprised of titanium and probably came from paper pigments. Clear/translucent flakes lightly adhering to the surface of the paper were consistent with polyester.
With the contaminants identified, the manufacturer was able to target the cleanup of their processes.