挤塑保温板的保温特性，挤塑保温板化学名叫挤塑式聚苯乙烯板(简称XPS)。XPS/挤塑式聚苯乙烯发泡硬质保温是以聚苯乙烯为原料加上其它原辅料及防火剂，通过加热混和同时注入发泡剂，然后挤压成型的硬质板发泡塑料板。

The thermal insulation property of extruded insulation board is called "extruded polystyrene board" (XPS). XPS/ extrusion polystyrene foam hard insulation is a rigid board foamed plastic board, which is made of polystyrene as raw material, adding other raw materials and fireproof agent, heating and mixing at the same time injecting foaming agent, and then extrusion molding.

挤塑聚苯乙烯的吸水率要比发泡聚苯乙烯要小10倍左右，且比泡沫玻璃还要低。试验还表明，该材料浸水之后仅在最初阶段能吸入少量水份，随后就不再吸水，这一性质使它具有极佳的保温性能且持久不变，这一特点对于倒置保温屋面至关重要。此外，挤塑聚苯乙烯的水蒸汽渗透性能要比发泡聚苯乙烯小2~4倍，因此，这种保温材料既能阻止雨水的浸入又能防止湿气渗透，从而避免了在材料内部因冷凝而积水，这是绝大多数保温材料望尘莫及的。

The water absorption rate of extruded polystyrene is about 10 times smaller than that of expanded polystyrene, and is lower than that of foam glass. The results also indicate that, after the material only in the initial stages of immersion can breathe a little water, then no water, this character make it has excellent insulation properties and enduring, the characteristics of the inverted insulating roof is very important. In addition, the water vapor permeability of extruded polystyrene foam polystyrene small than 2~4 times, therefore, in the thermal insulation material can prevent rainwater and to prevent the infiltration of moisture, which can avoid the material due to condensation of water, which is the vast majority of insulation materials beyond the hope.