Why do some window and door sealants crack after curing?

There are several reasons: 1. The poor adhesion to the substrate causes the delamination phenomenon, which usually occurs at the edges of the joint. 2. During the initial curing process of the sealant, the joint deforms excessively, resulting in cracks in the middle of the joint. 3. The thickness and width of the applied sealant do not meet the specification requirements. If the thickness is too thin or the contact width is too narrow, it will lead to damage or bond failure during use. If the thickness is too thin, it usually results in cracking in the middle. If the contact width is too narrow, it usually causes cracking on the sides. 4. Poor quality sealant (oiled sealant) was used. After a period of time, the sealant loses elasticity and cracks, and the cracks have no pattern.