If you unwind something that is wrapped around an object, you unfasten it, and if it unwinds, it becomes unfastened.

解开，打开，松开(卷绕之物)

to unwind a ball of string

解开一团绳

He unwound his scarf from his neck.

他从脖子上解下围巾。

The bandage gradually unwound and fell off.

绷带逐渐松开脱落了。