Nylon is a synthetic polymer, and the question of whether it is waterproof or water resistant is nuanced because it is used in many different forms. Nylon fabric is not inherently waterproof, but its molecular structure allows it to repel water on the surface. To understand how nylon products interact with moisture, it is necessary to clarify the difference between water resistance and waterproofing and examine how the material is modified during manufacturing.
Defining the Terminology
The terms “water resistant” and “waterproof” describe distinct levels of protection against moisture penetration. A water resistant material repels light exposure to water, such as mist or drizzle, for a limited time. This resistance often comes from a tight weave or a light chemical treatment that causes water to bead and run off, but moisture will eventually soak through under sustained contact. Waterproof materials, in contrast, are fundamentally impermeable to water penetration, regardless of the time or pressure applied. This standard requires a complete barrier, often quantified using a hydrostatic head rating, which measures the height of a column of water the fabric can withstand before leaking.
Nylon’s Inherent Properties
Nylon fibers are polyamides and possess a dual nature regarding moisture interaction. The fiber surface is hydrophobic, naturally pushing water away and causing droplets to bead up. However, the nylon polymer is also hygroscopic on a molecular level, allowing it to absorb moisture from the air or through direct contact.
When woven into a fabric, the material’s construction dictates its performance. Standard, untreated nylon fabric has microscopic gaps between the woven threads, allowing water to pass through under pressure or prolonged exposure. The density of the weave, often indicated by the denier, influences the fabric’s natural resistance. For example, a higher denier nylon is more tightly constructed, offering greater inherent resistance. Despite this, standard nylon fabric is considered water permeable and not genuinely water resistant.
Manufacturing for Water Protection
Coatings and Treatments
To transform nylon into a protective shell, manufacturers use specialized coating and treatment processes. One common method involves applying a coating of polyurethane (PU) or polyvinyl chloride (PVC) to the interior side of the fabric. This substance forms an impenetrable, non-porous film that acts as a physical barrier, providing the product with a true waterproof rating. A different approach uses Durable Water Repellent (DWR), an invisible chemical finish applied to the exterior face. DWR lowers the fabric’s surface tension, forcing water droplets to roll off; this treatment enhances water resistance but is often used only as a first line of defense.
Seam Sealing
Achieving a fully waterproof final product requires more than just coated fabric, as sewing compromises the barrier. Stitching creates tiny needle holes that allow water to seep through, making the seams the weakest point. To solve this, manufacturers apply seam sealing or taping, where waterproof tape is heat-applied over the stitched areas on the interior. This crucial final step ensures a continuous, impermeable barrier, allowing the finished item to perform as truly waterproof gear.