A self-seal envelope or plastic bag can be closed by pressing two sides of it together.

The cupboard is full of boxes of paper and self-seal envelopes. 储物柜里装满了一盒盒的白纸和自封信封。

Put the used test strip in the self-seal bag provided and throw it away. 将用过的试纸放入随附的自封袋中并扔掉。

(of a pipe, tyre, container, etc.) to automatically seal (= close) small holes in its surface

The armour would self-seal in the unlikely event of something smashing a hole in it. 万一有什么东西在上面砸了一个洞，盔甲会自动密封。

The inner tube self-seals small punctures without the rider noticing. 内胎可以自行修补小的穿孔，而骑手不会察觉到这一点

(of a substance) to form a cover or structure that prevents air, water, etc. from entering or leaving it

The inside of the tyre is coated with a soft sticky layer that self-seals when punctured. 轮胎内部涂有一层柔软的粘性层，在被刺破时会自动密封。