ONLINE COMPOSITION MONITORING OF MOLTEN POLY(ETHYLENE VINYL-ACETATE)

Poly(ethylene vinyl acetate) (EVA) is a very common polymer used in ho t melt adhesives. The rheological and thermal-mechanical properties of these adhesives are strongly related to the content of vinyl acetate (VA) incorporated into this random copolymer during polymerization. Re sults are presented of in-line monitoring of VA content in flowing mol ten EVA. The method used is fiber optic near infrared spectrometry. Th is method is discussed in detail and observations are made on how in-l ine fiber optic monitoring could be extended to quantitiatively measur e the composition of a flowing melt adhesive, e.g., polymer, tackifier , viscosity reducing diluent, antioxidant, etc.