十年前,美国就着手研究在铁道车辆上采用聚氨酯泡沫塑料作隔热材料,经过四年试验证明,用这种发泡塑料,可使保溫车的隔热系数大大降低,因而决定试用这种发泡塑料和塑料板制造车顶及车门(图1)。 Ten years ago, the United States started to study the use of polyurethane foam as a heat insulation material on railway vehicles. After four years of tests, it was proved that using such foamed plastic can greatly reduce the thermal insulation coefficient of the insulation car and decided to try this Styrofoam and plastic panels for roofs and doors (Figure 1).