Investigation of the effect of some additives on the mechanical properties of NR/SBR elastomer based sole materials

Various materials have been used in production of shoe sole. The most of the material groups are shoe soles with elastomer based. In this field, in elastomer based sole materials, different fitting materials were used instead of traditional filling materials.In this study, alternative filling materials beside carbon black (such as glass balls, glass fiber, powder of mica and wollastonit) are used. Its mechanical properties and cost analysis were investigated. As the result, Classical Formula, types of A and B were compared with other alternative filling samples. Test study occurred into two steps. In widespread used material of the industry, Classic Formula, the rate of natural rubber (NR) was reduced while styrene butadiene synthetic rubber (SBR) was increased. The rate of additional filling material was 8,9 %. Then, by adding alternative filling material 8,15 % into material type A, five different samples were produced. The mechanical properties of these composites were investigated. Test results showed that Wollastonit, mica powder and glass ball are used with carbon black and this caused an improvement into mechanical features. As powder of leather bold was not uniformly distributed in the mixture due to agglomeration and making a weak bonding with it, rubber material exhibited lower performance in terms of psychical properties. In this step, due to weakness of resistance on breaking and corrosion, the second Formula study was applied. In the second phase of this study, the total ratio of NR/SBR is 44,6 % and SBR increased. Additional filling rates are 5,15- 9,4- 13,4 and 17,2 %. Almost all the mechanical properties of type B material were improved by the addition of filling materials, except for glass fiber and powder of leather board. It was observed that the density of type B material was decreased, also hardness ratio was increased. Subjecting to Bennewart elasticity test, all materials exhibit acceptable results. Mechanical values were generally improved, elastic values of 5,15 % of filling materials were exhibited. According to the cost analysis for elastomered sole materials, glass ball samples (B1, CK1 and B2 CK2) and wollastonit filled samples (B1 W1 and B2 W2) are the most common effective materials with the best properties.Keywords: NR, SBR, Wollastonit, Glass Spheres, Glass fiber, Mica powder, Elastomers, Rubber sole.