(4) Elongation: Elongation is the elastic performance of the sealant after it is completely cured. It also belongs to one of the mechanical properties. It refers to the percentage of the total elongation of the material when stretched to the original length. The elastic sealant will have a larger elongation. As the minimum requirement for elongation, the sealant must meet the requirements for fixed elongation in national standards.

(5) Tensile modulus and displacement capacity. Tensile modulus and displacement capacity are the comprehensive performance of the above-mentioned mechanical properties. The tensile modulus characterizes the strength produced when the sealant is stretched to a certain elongation. Therefore, the measurement method of the amount is simultaneously with the elongation. For example, when the elongation is 25%, the amount of stretch is 0.46Mpa. The displacement capacity is the displacement capacity that the sealant can withstand when the joint is displaced due to the thermal expansion and contraction of the substrate. For example, we say that the sealant has a displacement capacity of ± 25%, which indicates that the glue seam using this product can withstand the stretching and compression of the original width of 25%. For example, the original glue seam width is 12mm, which can be compressed to 9mm at maximum To 15mm. Displacement capacity can be measured by tensile compression cycle or cold-drawn hot-pressing cycle method.