Pembuatan sol karet lembaran untuk sandal

The purpose of the research was to find best formulation for rubber sole sheeting for sandal. The formulation of the compounds were made by variation ratio of natural rubber and sintetic rubber SBR as follow : 100/0, 75/25, 50/50, 25/75 and 0/100, where as the variation ratio of carbon black N330 and aluminium silicate filler 100/0, 60/40 and 20/80 respectively. Compounding process was carried out on two roll mill. The rubber compounds were vulcanized at temperature 150oC and pressure of 150 kg/cm2 with curing time as indicated by curometer. Vulcanized rubber were tested based on SNI. 06-0899-1989 : Rubber sheeting for sole. The best formulation was consist of natural rubber 75 phr, sintetic rubber SBR 25 phr, stearic acid 3 phr, zinc oxide 5 phr, Minarex B oil 5 phr, car bon black 100 phr, MBTS 1 phr, PBN 1 phr and sulfur 2 phr. The physical properties of the best compound were : tensile strength 185,42 kg/cm2, elongation at break 276,64%, tear resistance 158,90 kg/cm2, hardness 74 shore A, density 1,21 g/cm3, Grasselli abrasion resistance 0,326 mm3/kgm, permanent set 7,78% and no crack on the flex cracking test. The best compound could meet the requirements of SNI. 06-0899-1989.