COMPOSITION AND PROCESS FOR PRODUCING BIODEGRADABLE FOAM PACKAGES

摘要

The invention relates to a polymeric composition that can be processed by melt techniques to be converted into biodegradable polymeric foam packages for friable products and to a process for preparing the same. According to the invention, the composition comprises 10...90% starch, 90...10% polyvinyl alcohol, 0.01...3% maleinized polyethylene, 5...30% glycerol, 40...50% diethylene glycol, 5...50% water, 0.01...2% calcium stearate, 0.01...3% Irganox B215, 0.01...3% antistatic agent, 0.01...3% surface-active agent, 1...5% treated silicate laminate, 1...50% expanding agent, the additive amounts being expressed as ratios of 100% mixture of starch and polyvinyl alcohol. The process, as claimed by the invention, consists, in a first stage in thermally-mechanically treating the silicate in a plasticizer conveniently selected for the polymers within the mixture, after which, in a second stage, the solid components are mixed with the liquid ones under preset conditions and, in the third stage, the so obtained mixture is subjected to extrusion and granulation under preset conditions, the resulting granules being processed by injection and converted into packages.