Characterization of purified SKIM rubber by alkali treatment for pressure sensitive adhesive application

Due to the lack of gel phase skim rubber (SK) shows a good solubility. Consequently, this material was approached to the aspect of pressure sensitive adhesive applications. Saponification by alkali treatment was applied to remove non-rubber components in SK. The suitable reaction time and temperature for preparing highly-purified SK (HPSK) were established. The nitrogen content in SK was reduced to ca. 0.1%w/w, whereas the ester content slightly decreased. The tackiness and the adhesion properties of HPSK were evaluated by the rolling ball method and 180° peel tests, respectively. Proteins were found to be an important factor controlling tackiness property, while the adhesion property depended on both proteins and phospholipids. The pressure sensitive adhesive prepared from ribbed-smoke sheet (RSS) was also studied in comparison. The comparable in tackiness and adhesion properties of adhesive tapes prepared from RSS and HPSK suggested that the later could be used efficiently as raw material for pressure sensitive adhesives.