The main reason for this phenomenon is that the content of base material OH Polymer is low. When the temperature is low, the reactivity of the oxime cross-linking agent is also low. At this time, the low content of OH polymer in low-grade oxime transparent sealant will lead to low reactivity of the entire sealant, causing the middle part of the sealant strip to not cure or cure very slowly. 

It is recommended to solve this problem from two aspects：

1.To improve the activity of the cross-linking agent, you can mix MOS, VOS, TOS in different proportions as needed to improve the reaction activity of the cross-linking agent.

2.Increase the content of OH Polymer