NETWORK STRUCTURE AND PROPERTIES OF PLATINUM-CATALYZED ADDITION CURE RELEASE COATINGS

Silicone-release coatings are used by the pressure-sensitive adhesive industry for labeling applications. Typical release coatings are prepared by the platinum-catalyzed addition reaction of a silicone hydride fluid with a silicone vinyl polymer. Methodology has been developed to determine the network structure of cured release coatings, which involves degradation of the network with trifluoromethane sulfonic acid in excess hexamethyldisiloxane. Gas chromatography-mass spectrometry (GC-MS) and gas chromatography (GC) were employed to identify and quantify residual functionality and cross-links. Residual hydride functionality was also determined by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The observation of network structure by solid-state Si-29-NMR using cross polarization (CP) and magic angle spinning (MAS) is also discussed. The networks underwent a postcure as evidenced by a decrease in residual hydride functionality and an increase in silane content and/or cross-links.