Release of a cohesively strong, general purpose hot-melt pressure sensitive adhesive from a silicone liner

Abstract

Rubber based block copolymers styrene isoprene styrene (SIS) was used as rubber vehicles for the adhesive system. Wingtack ET (C5 hydrocarbon resin) in addition to rosin ester resin was the tackifier system. Naphthenic oil plasticizer was an additional processing aid of the adhesive system. Hydrophobic fumed nano-silica was used as flow hindering agent for the adhesives. The hotmelt adhesives were mixed in electrically heated sigma blender at 90°C for 1h. The adhesive system was coated with ETI Cohesio™ Machine at 177°C onto Boise facestock at 20g/m2, and then laminated with Boise liner which was coated online with UV curable acrylated poly dimethyl siloxane (silicone) at 1.6g/m2. Laminates were cut and left to cool down and condition at room temperature for 48h before testing. Thermally aged and humidity aged release forces were measured at 180° angle. Loop tack and 90° peel from corrugated card board surface were measured at room temperature. Dynamic mechanical thermal analysis was carried out from −100 to 100°C at 1Hz and 0.25% strain for formulations 5 and 6 which correspond to unacceptable and acceptable release force build up respectively.