AIP Conference Proceedings [Author(s) DISRUPTIVE INNOVATION IN MECHANICAL ENGINEERING FOR INDUSTRY COMPETITIVENESS: Proceedings of the 3rd International Conference on Mechanical Engineering (ICOME 2017) - Surabaya, Indonesia (5–6 October 2017)] - The effect of filler loading on the flexural and compressive properties of untreated and treated chrome tanned leather waste (CTLW) short fibre filled unsaturated polyester composites