Firstly, the quality of the inferior insulating strip is unstable and cannot guarantee the "three sex" requirement of the insulating aluminium curtain wall. Poor quality insulation strips due to low cost of raw materials, complex ingredients, backward extrusion process, extensive production, mold design level, and other factors, resulting in low dimensional precision, if after wearing the insulation doors and windows, the doors and windows borders by rainwater infiltration, the effect of the heat insulation greatly reduced, and the border walls damp mildew, affecting the appearance of the building. Second, poor aging resistance. Tensile strength and anti-aging properties are directly related to the safety of insulating aluminium doors and windows curtain wall, and the ageing of PVC is the worst in the plastic family and is poisonous. Thirdly, the mechanical properties are low. Fourth, with the aluminum profile line expansion coefficient mismatch. Fifth, not safe and environmentally friendly. The counterfeit PVC heat insulation strips will release the poisonous gases slowly during the long term use. Because PVC insulation in the production of Plasticizer (Dibutyl terephthalate), anti-aging Agent (PB-stearate), such as some toxic additives to enhance its heat resistance, toughness, if the temperature reaches 70 ℃ above PVC will decompose the production of chlorine, hydrogen chloride, such as excitant gases, toxic.