Improvement On Tear Resistance Of Rubber Moulded Mat By Varying Filler And Accelerator Contents

• Main Author: Soh, Tiak Chuan
• Format: Thesis
• Language: English; English
• Published: UTeM 2016
• Subjects: T Technology (General); TA Engineering (General). Civil engineering (General)
• Online Access: http://eprints.utem.edu.my/id/eprint/18554/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=100386; HF5351.M34 2016

An industrial baby product, rubber moulded mat, produced in Rubber Leisure Products Sendirian Berhad has encountered with tear problem at the complicated shape of suction cups when it is manually stripped after moulding process. Its tear resistance has been improved in this work to reduce the high rejection and reworking rates in production by focusing on the two parameters of fillers and accelerators. The effect of fillers was focused on the content of precipitated silica and calcined clay whereas the effect of accelerators was studied by using mercaptobenzothiazole disulphide (MBTS), Zn-2-mercaptobenzo thiazole (ZMBT) and diphenyl guanidine (DPG). Phase 1 of this research involved the analyses of different ratios and combinations of fillers and accelerators. Phase 2 involved the analyses of tensile strength and tear strength of vulcanizates with 5 levels of fillers and 4 levels of accelerators by using statistical factorial design of experiment. Phase 3 focused on the test mechanism of hot-tear-strength, mass production validation and benefit-cost analysis. A scorch-safe filled masterbatch added with silane coupling agent was formulated. Multiple-stage melt mixing method can disperse effectively the fillers into the smaller aggregated structure. The combination of accelerators MBTS:DPG:ZMBT enhanced better the rubber tear resistance than the conventional MBTS:DPG system. An optimum formulation was produced with the levels of fillers:accelerators at 0.65phr:1.77phr and reduced the content of calcium carbonate from 40 phr to 20 phr which have imparted better tear resistance. The finely dispersed and uniformly distributed fillers, optimum crosslink density and predominantly polysulphidic crosslink type improved primarily the rubber tear resistance especially on hot-tear-strength. The new formulation did not deteriorate the end-use function and colour aesthetic of the finished product as well as did not increase the product manufacturing cost.