三者是密封强度的三个层级：气密拉链同时阻隔空气与液体、能承受内外压差，等级最高；水密拉链阻隔液态水、可短时浸水，但不保证长期保压；防水拉链抵挡泼溅和短时淋水。判断标准很简单——你的产品是否需要“保压”。

These are three levels of sealing: airtight zippers block both air and liquid and handle pressure differentials — the highest grade; watertight zippers block liquid water and handle short immersion but not sustained pressure; waterproof zippers resist splashes and brief rain. The simple test: does your product need to hold pressure?

三类拉链对比

Airtight vs Watertight vs Waterproof

关键区分点

Key differences

• 是否保压：气密能承受内外气压差，水密与防水不能；
• Pressure: airtight holds pressure differentials; watertight and waterproof do not.
• 浸水时长：IPX7 短时浸水 30 分钟，IPX8 可持续浸水；
• Immersion: IPX7 lasts ~30 min; IPX8 allows continuous immersion.
• 结构：气密多采用 TPU 一体成型，接缝少，失效风险低；
• Structure: airtight zippers use one-piece TPU with fewer seams and lower failure risk.
• 材料与柔韧度：等级越高材料越厚，需在柔韧与强度间权衡。
• Material & flexibility: higher grades mean thicker material — balance flexibility against strength.