| Low-density polyethylene (LDPE) film | Lightweight mailers and flexible parcel bags | Flexible, water-resistant, and available in opaque or transparent formats. Film can be vulnerable to puncture or tearing depending on thickness and formulation. | Specify film thickness, dimensions, seal construction, opacity, and whether recycled content is required. Check seams and closure adhesion on filled samples. |
| Co-extruded polyethylene film | Mailers needing a combination of outer-surface and inner-layer properties | Multiple polymer layers can be designed for properties such as opacity, printability, or toughness. Performance depends on the layer structure and resin selection. | Request the layer-structure specification and verify that samples match the agreed construction. Assess puncture resistance, seal integrity, and print durability for the intended use. |
| Woven polypropylene (PP) fabric | Reusable or heavier-duty courier sacks | Interlaced PP tapes provide a woven structure. Bags may be uncoated or laminated; coatings can improve moisture resistance but affect recyclability and feel. | Confirm fabric construction, coating or lamination, seam reinforcement, handle design, and closure method. Test the finished bag under its intended payload. |
| Nonwoven polypropylene (PP) | Reusable carry-style courier bags and document or promotional bags | Made from bonded fibers rather than woven tapes. It can be lightweight and flexible, but strength and appearance depend on fabric weight and bonding method. | Specify fabric weight and construction, then check handle attachment, stitching or bonding, and resistance to abrasion during representative use. |
| Polyester fabric | Reusable courier bags designed for repeated handling | Woven polyester can provide a durable fabric surface. Water resistance depends on any coating or finish; seams and closures remain important potential failure points. | Confirm fabric specification, coating, seam design, and cleaning requirements. Evaluate wear and load-bearing areas using representative filled bags. |
| Multi-material construction | Bags combining a fabric body with film lining, stiffeners, or reinforced panels | Different components can address separate functional needs, but added layers or materials can complicate sorting and recycling. | Obtain a bill of materials and identify material combinations. Check component attachment, repairability, labeling, and end-of-life requirements in the destination market. |