Investigation of optimum quality parameters for heat sensitization of natural rubber latex compounds

Abstract

Heat sensitization is used as a Abstract: method of manufacture thick wall rubber article from Natural Rubber Latex (NRL) compounds. Number of quality parameters of the NRL compound should be controlled to produce good quality thick wall rubber products. Poor quality control of NRL compound generates number of processing problems such as formation of flocks, thickening of latex compound and ultimately gelling of the whole latex compound. As a result, whole latex compound may be disposed as waste and causes number of undesirable problems. The main objective of this research was to find out the optimum ranges for the identified parameters of NRL compound for heat sensitization process to produce good quality thick wall rubber articles. Ammonium Chloride (NH4Q) was selected as a gelling agent and optimum dosage of gelling agent, temperature and pH of the gelling agent solution were investigated. In addition, optimum temperature and pH of NRL compound were investigated. It was found that 20 g of 18% NH4CI is the optimum quantity that can be incorporated to 1000 g of NRL compound. The most desirable temperature to stroe both gelling agent and NRLcompound w^as found as 21 °C. The most suitable ranges of pH for NRL compound and gelling agent were recognized as 11-11.5 and 9-11 respectively. Finally it was found that the quality problems related to the heat sensitization of NRL compound can be minimized by maintaining the above mentioned parameters in their optimum ranges.