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，在用户移动时提供支撑和抓地力。这对使用者的安全很重要，尤其是那些有弱点或平衡困难的人。扶手的主要组成部分之一是内胎，它使扶手具有灵活性和结构。EHC加拿大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）制造胴体层。TPU是一类具有高耐磨性、高强度和高弹性的聚氨酯塑料。然而，目前的自动扶梯扶手设计使用固体TPU，这需要大量的树脂。通过对主体进行发泡，可以在保持所需机械性能的同时，减少胴体中的树脂含量。除了对环境的积极影响外，减少扶手材料的使用量将大大节省生产成本。反过来，这不仅有利于经济效益，而且还减少了材料浪费，从而减少了负面的环境足迹。拟议项目的目标是将扶手胴体的重量降至最低

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.