Development of TPU foaming technology for incorporation in EHC's escalator handrails

扶手是自动扶梯的重要组成部分，它允许使用者在移动时提供支撑和抓握。这对用户的安全很重要，特别是那些身体虚弱或平衡困难的人。扶手的主要部件之一是内骨架，它为扶手提供了灵活性和结构。加拿大依合斯是世界上最大的自动扶梯扶手制造商之一，目前使用固体热塑性聚氨酯（TPU）制造骨架层。TPU是一类具有高耐磨性、高强度和弹性的聚氨酯塑料。然而，自动扶梯扶手的当前设计使用需要大量树脂的固体TPU。通过使主体发泡，可以减少胎体中的树脂量，同时保持所需的机械性能。除了积极的环境影响外，减少扶手中使用的材料量将大大节省生产成本。反过来，这不仅从财务角度来看是有益的，而且还减少了材料浪费，从而减少了负面的环境足迹。建议项目的目标是将扶手骨架的重量降至最低 同时保持所需的机械性能水平。减少结构重量的一种有效方法是通过将气泡引入聚合物基质中使材料发泡，从而在材料内产生微孔结构。这将产生功能上等同于或优于扶手中使用的常规固体TPU的材料，同时保持机械性能。通过将多伦多大学发泡领域的学术专业知识与世界领先的自动扶梯扶手制造商之一相结合，可以预见自动扶梯扶手制造的新型泡沫和工艺创新。目前，依合斯每年生产100万公斤的扶手，仅节省15%的材料使用量，依合斯每年就可节省至少100万美元的生产成本。此外，这将为改善目前的制造系统创造机会，从而在加拿大创造更多的就业机会。

Handrails are essential components of an escalator that allow the users a means of support and grip while moving. This is important for the safety of the users, especially those who have weakness or trouble balancing. One of the main components of handrails is the inner carcass, which gives flexibility and structure to the handrails. EHC Canada, one of the largest escalator handrail manufacturers in the world, currently utilizes solid Thermoplastic Polyurethane (TPU) for making the carcass layers. TPU is a class of polyurethane plastics that has high abrasion resistance, high strength and elasticity. However, the current design of escalator handrail utilizes solid TPU which requires large mass of the resin. It is possible to reduce the amount of resin in the carcass while maintaining the required mechanical properties through foaming the main body. Besides the positive environmental effects, reducing the amount of material used in the handrails will significantly save on the production cost. This in turn, will not only be beneficial in a financial point of view, but also reduce material waste, thereby reducing the negative environmental footprint. The goal of the proposed project is to reduce the weight of the handrail carcass to a minimal amount while maintaining the required level of mechanical performance. One effective method of reducing the weight of a structure is by foaming the material by introducing bubbles into the polymer matrix thereby creating a micro porous structure within the material. This would create a material functionally equivalent or better than the conventional solid TPU used in handrails while maintaining mechanical properties. Through the combination of academic expertise in the foaming field at the University of Toronto together with one of the Leading escalator handrail manufacturers in the world, novel foam and process innovations are envisioned for the manufacturing of escalator handrails. Currenltly, EHC manufactures 1 million kilograms of handrails annually and by saving just 15% of materials usage would save EHC atleast $1 Million in production costs anually. Additionally, this would open opportunities for improvement of the current manufacturing systems which would in turn create more jobs in Canada.