Production development of a pressure sensitive adhesive from natural rubber latex

Abstract

This research aims to develop a methodology of making Pressure Sensitive Adhesive (PSAs) from natural rubber latex and to study the physical properties of PSAs. The effects of depolymerisation time, contents and types of tackifier resin on 180 ํC peel adhesion, tack and holding time have been investigated in the natural rubber, which was manufactured within Thailand. The natural rubber was depolymerized using K2S2O8 and propanols mixed with tackifier resin at various conditions. The experimental design method namely the technique of Central Composite Design (CCD) had been employed in order to minimize the number of experiments. The technique of Response Surface methodology (RSM) was used to construct the empirical model, which can explain the relationship between each variable factor and their response. The depolymerization time was found to play an important role on holding but not on 180 ํ peel adhesion and tack. The holding time decreases as the depolymerization time increases. Types and contents of tackifier resin have influence on adhesion properties. Tack and 180 ํ peel adhesion increase with content of tackifier resin for SE376A and SE790G. However the holding time decreases with increasing the content of these tackifiers. For resin ester equeous tackifier, 180 ํ peel adhesion and the holding time increase with the content of tackifier, whereas tack decrease with decrease with increasing the tackifier content.