ABSTRAKManufaktur produk karet diawali oleh pembuatan kompon karet dengan cara mencampurkan karet dengan bahan kimia. Salah satu bahan kimia utama karet adalah bahan bantu olah yang berfungsi untuk mempermudah pencampuran dan distribusi bahan kimia terutama bahan pengisi dalam matriks karet. Faktis cokelat yang dihasilkan dari vulkanisasi minyak nabati dengan sulfur merupakan bahan bantu olah karet yang banyak digunakan dalam industri hilir karet. Dalam reaksi vulkanisasi terjadi pembentukan ikatan silang antar trigliserida dalam minyak nabati yang dijembatani oleh sulfur. Penelitian ini bertujuan untuk menen-tukan kondisi optimum pembentukan faktis cokelat pada skala laboratorium berkapasitas 200 ml/batch dari minyak jarak kepyar sebagai sumber trigliserida yang direaksikan dengan sulfur (23 dan 24 bsm) pada berbagai suhu
ABSTRACTManufacture of rubber goods is began with rubber compounding by mixing the rubber with its chemicals including processing aids. The function of processing aids is to facilitate the compounding process. Brown factice from vulcanization of vegetable oil with sulphur, is the most processing aid being used in downstream rubber industry. During vulcanization, the triglyceride content on vegetable oil form crosslink which is bridged by sulphur. The research was aimed to determine the optimum condition of brown factice formation at laboratory scale (200 ml/batch) from castor oil which was reacted with various sulphur concentration (23 and 24 pho) and themperature of reaction ( C and sulphur concentration of 24 pho. By those condition, the brown factice had 52.43% extract acetone content, 1.20% free sulphur content, 0.11% ash content and pH 6.45 and crosslink density as 3.2 x 10 -4 mol/ml. The brown factice also had good brown color and elastic texture. Based on its properties, the brown factice achieved was feasible to be developed at higher scale.