Rotomoulding release agent preparation for auto part fabrications. (2022) - Yeetsorn, Rungsima
Abstract: As it produces parts with intricate details and finishes, minimal waste, few stress points, and excellent wall thickness uniformity, rotational moulding is one of the commercial shaping processes for manufacturing polymeric automotive parts. Use of a mould release agent is critical for a demoulding approach in rotational moulding, and the main requirement for typical use of a mould release agent is suitability in work environments at very high temperatures (>200 °C). Surprisingly, Thailand has approximately 2000 mould manufacturers, which can be attributed to the high demand for mould release agents; however, a vast majority of release agents are imported from abroad. This research aims to formulate the semi-permanent water-based release agents for shaping engineering plastics via a rotational moulding process. The main functions of the produced release agent include allowing the resin to become attached to the mould wall during the initial heating phase of the moulding cycle, ensuring that the fully molten skin of the rotomoulded part remains in close contact with the mould wall throughout the heating cycle. The rotomoulded part must remain in close contact with the mould wall during the initial part of the cooling cycle until the part has enough cohesion within its structure to resist collapse when the release process begins. The release agent used to aid in the quick release of rotomoulded parts while minimizing surface abrasion damage. First, chemical characterizations were performed using Fourier-transform infrared spectroscopy. Next, processability, surface characteristic, thermal stability, adhesion performance, and rheological characteristic were observed via Fourier-transform infrared spectroscopy, contact angle, thermogravimetric analysis, differential scanning calorimetry, adhesion tester, and rheometer, respectively, to inspect the possibility of using the produced release agents for a rotational moulding process. Experimental results confirm successful formulated rotomoulding release agent, however; the repetition of using a release agent needs further improvements for cost reduction.