Arian Baft Partow 
Is a Jumbo Bag Waterproof? Coating vs. Lamination vs. Liner Bags
Coating and lamination make a jumbo bag highly moisture-resistant, but neither one makes it fully waterproof — here is what actually seals out moisture, and when you need it.
A standard woven polypropylene jumbo bag, with no additional treatment, is not moisture-resistant: the fabric is made of interlaced tape yarns, so it inherently has tiny gaps between the warp and weft threads. Two common treatments close these gaps and improve moisture resistance — coating and lamination — but the result of either is "moisture-resistant," not "fully waterproof."
The difference between the two: with coating, a thin layer of molten polypropylene is extruded and spread directly onto the fabric surface, with no separate film. With lamination, a pre-made polypropylene film (usually BOPP) is bonded to the fabric using heat and pressure. Visually and functionally the results are similar — both close the weave gaps — but lamination typically gives a more uniform and slightly higher level of moisture resistance, which is why it is more common for moisture-sensitive products.
A point that is often overlooked: even a fully laminated or coated jumbo bag is not 100% waterproof, because the stitched seams (bottom, top, and panel joints) are perforated by the sewing needle, and those small needle holes remain a possible entry point for moisture unless something extra is done. For products that genuinely need to be sealed from water — not just resistant to it — the standard solution is an inner liner bag, usually made of polyethylene, placed independently inside the outer fabric bag as a fully closed layer with no stitched seams.
Choosing between plain fabric, coating, lamination, or an inner liner depends on how sensitive the product is and how it will be stored and transported. Hygroscopic chemical products or sensitive food products usually need a liner, while cement or many mineral products are usually fine with lamination or simple coating. Arian Baft Partow manufactures all three levels — uncoated, laminated, and with an inner liner — based on the product and the customer's requirements.
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