Poly bag seal type is the most underrated detail in garment packaging design. The closure determines reusability, dust and moisture protection and the unboxing experience — and it directly affects unit price and packing efficiency. Choosing the right seal keeps your garments clean and presentable through shipping, warehousing and retail display.
This guide compares six common seal types by features and best use, with category-based selection advice and sampling checks.
1. Why the Seal Type Matters
- Protection — a loose closure lets in dust, moisture and odors; light-colored garments are especially sensitive
- Customer experience — resealable bags let shoppers store garments again; a big plus for e-commerce
- Cost and efficiency — the more complex the closure, the higher the unit cost and packing time; balance experience against budget
2. Six Common Seal Types Compared
| Seal Type | Features | Best For | Notes |
|---|---|---|---|
| Flat bag (heat-sealed) | Lowest cost; needs heat sealing | High-volume export, transit protection | Not resealable; opened by tearing |
| Self-seal bag | Resealable, good dust protection | E-commerce shipping, retail | The seal strip needs extra edge space |
| Tacky / ziplock bag | Tight seal, reusable | Premium garments, accessories | Test zipper strength; can stiffen in cold |
| Zipper bag | Smooth open-close, durable seal | Premium brands, boutique packaging | Higher cost; confirm zipper color |
| Hanger bag (with hole) | Built-in hanger hole, shelf-ready | Retail hanging display | Hole position must match hangers |
| Antistatic bag | Static shielding, dust and moisture protection | Functional wear, electronics | Composite film; harder to recycle |
3. Choosing a Seal by Garment Category
- E-commerce shipping — self-seal or ziplock bags first; shoppers can re-store garments and returns stay easy
- Retail hanging — hanger bags go straight to the rail, saving unbagging and re-hanging labor
- Premium brands — zipper bags with branded printing create an unboxing moment and protect garments in long-term storage
- Sea freight export — heat-sealed flat bags with thicker film and desiccants offer the best cost-to-protection ratio
4. Printing, Punching & Moisture Notes
Once the seal type is set, confirm three details with your supplier:
- Surface vs reverse printing — surface inks are vivid but scratch-prone; reverse printing sits between film layers, more durable, but check the position against the seal strip
- Hanger holes and tear notches — keep holes clear of print and the seal area; notch position affects unboxing, so test on samples
- Sea freight moisture — for long voyages use thicker film, add desiccants and line cartons with moisture barriers
💡 Tip: Seal durability must be tested: self-seal strips should stay tight after 20+ open-close cycles, and zippers must not crack in cold conditions. Tell us the seal type, thickness (gauge or micron) and size when sampling — we can send free samples for you to test.
Related Articles
- Trims FAQ: all articles
- Garment Bag Types: OPP, PE, CPE, Resealable & Antistatic
- OPP vs PE Bags: Clarity, Feel & How to Choose
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