A well-considered chemical composition of the rubber compound is that the cornerstone to a high-quality fender and favourable admixture behaviour. In avoidance of inconsistencies in the product’s final properties, the choice of raw rubber is especially necessary.
The initial condition of Natural Rubber (NR) as a natural product will vary in seriousness because of varied molecular weight and uneven molecular distribution. NR is sourced in the sort of latex from a tree referred to as flowering tree. High consumption and the geographical limitations of this raw material in the 18 century cause the event of synthetic rubber (SR). The foremost of times used artificial rubber in fender compounds is styrene-butadiene rubber (SBR). Today, it's become normal to mix NR with SR which, because of the varied complementary properties of different rubber varieties, has an enhancing impact on the fender’s physical properties like aging stability, tensile strength and process-ability. counting on the composition of the rubber mix, the opposite combination ingredients ought to be balanced exactly so as to get the optimum options of the ultimate rubber fender.
Natural rubber in its original type possesses an awfully high molecular weight (which equals a high viscosity) and uneven molecular structure – a condition that complicates homogeneous mixing with caoutchouc also as uniform dispersion with alternative ingredients. For this reason, mechanical chew is conducted previous to the particular intermixture method so as to get a fabric surface that's receptive to dispersion of compound mix and compounding ingredients.
During the mechanical chewing method, the cut forces of the rotors in an indoor mixer breaks down the rubber’s molecular structure, shorten the long molecular chains and manufacture a parallel alignment of the molecules. The results a coffee consistency rubber with uniform malleability and flowability – and therefore being a material with ideal mixing properties and process ability. Rubber makers can favour to acquire masticated rubber or to perform in-house chew (as done at SFT), that provides additional opportunities for quality management and in-batch also as batch-to-batch uniformity. Chew is usually finished internal mixers (for additional info on mixers, see following section concerning intermixture equipment). When victimisation an indoor mixer, the natural rubber enters the mixing chamber through the hopper door in block type and is processed by the two serious steel rotor paddles off the mixer. The masticated rubber is discharged and directly dropped onto a steelworks, wherever it's sheeted for additional process ability. All steps from masticating to finalisation are monitored and documented exactly.