Is nylon water resistant? In this article, we are going to discuss nylon’s chemical structure and waterproof capabilities.
Introduction
Nylon is a tough, stretchy, human-made plastic derived from oil. Unlike natural fibers like cotton, nylon can be melted and molded into various shapes, making it useful for everything from clothes and backpacks to car parts. In this article, we will briefly introduce the waterproof properties of nylon.
What is Water Resistance
Water resistance shields materials from light moisture like splashes or light rain, unlike waterproof barriers that completely block water. This makes them valuable for everyday items, protecting them from minor spills and keeping them functional in damp conditions.
| Material | Water Exposure | Durability | Breathability | Seams |
|---|---|---|---|---|
| Water-resistant | Light splashes | Some protection | Good | Standard |
| Waterproof | Full submersion | Complete protection | Limited | Sealed/Taped |
TL;DR: Water-resistant for brief splashes and breathability, waterproof for complete water protection.
Chemistry and Structure of Nylon
Nylon’s Hydrophobic Effect
Nylon’s water resistance hinges on its structure. Strong amide groups make it durable, but also create tiny gaps between chains where water can eventually seep in. Hydrogen bonds, though strengthening the material, can also act as water channels.
So, while nylon repels water initially, prolonged exposure allows water to find its way through these gaps and pathways.
Nylon’s Structure: A Balancing Act for Water Resistance
Nylon repels light rain because it has microscopic water-hating islands (hydrophobic) in its structure. Strong ties form a fence-like network around them.
However, there are certain weak locations, such as gaps and water-loving patches (hydrophilic). These ultimately let water in, therefore nylon is best suited for gentle showers rather than severe downpours.
Factors Affecting Nylon’s Water Resistance
While nylon offers decent water resistance, several factors can influence its performance:
- Climate: Hot and humid environments can accelerate water penetration through nylon. The water molecules are more energetic and can exploit the gaps in the structure more easily.
- Fabric Treatment: Water-repellent (DWR) coatings add an extra layer of defense, but they wear off over time and require reapplication. Some treatments can also impact breathability.
- Weave and Thickness: Denserly woven or thicker nylon fabrics have fewer gaps for water to sneak through, offering superior water resistance compared to thin or loosely woven types.
| Factor | Effect |
|---|---|
| Temperature & Humidity | Downward trend |
| Fabric Treatment | Boosts initially, fades over time |
| Thickness & Weave | Tighter = better |
Diverse Applications of Nylon
SLS 3D Printed Nylon Applications
Prototypes: Due to its affordability and good dimensional stability, SLS nylon is commonly used for creating functional prototypes with complex geometries. These prototypes can be used for testing form, fit, and functionality before investing in mass production.
End-use parts: SLS nylon can be quite strong and durable, making it suitable for some end-use parts, particularly those with complex designs that might be difficult or expensive to produce with traditional methods. Examples include:
Snap-fit enclosures: Nylon’s stiffness and snap-fit functionality make it ideal for housing electronic components.
Lightweight machine parts: Certain SLS nylons offer a good balance of strength and weight, making them suitable for components in machines that require some structural integrity but also need to be lightweight.
Functional ducts and vents: SLS nylon can be 3D printed with intricate channels and airflow paths, making it useful for creating lightweight air ducts or ventilation components.
CNC Machined Applications
Gears and sprockets: Nylon’s low friction coefficient and wear resistance make it a good choice for gears and sprockets, particularly in low-torque applications.
Bushings and bearings: Similar to gears, nylon’s self-lubricating properties make it suitable for bushings and bearings, especially in applications where lubrication might be impractical or messy.
Fasteners and clips: CNC machining allows for precise creation of threads and complex shapes, making nylon a good material for custom fasteners and clips.
Jigs and fixtures: Nylon’s affordability and machinability make it ideal for creating jigs and fixtures used in manufacturing processes. These tools often require specific shapes and features that can be precisely produced with CNC machining
Nylon’s Applications with Enhanced Water Resistance
Drone Components:
- Battery Compartments: A water-repellent nylon compartment, 3D printed with SLS, can house drone batteries. While not submersible, it offers some protection from splashes and light rain during flight, especially when combined with sealing features in the design.
- Aerodynamic Housings: Water-repellent nylon can be SLS printed for housings around propellers or other drone components. The water-repellent properties can help minimize water spray from affecting the functionality of these parts.
Plumbing Components (Non-Pressure):
- Drainage Spouts: CNC machined nylon can be used for drainage spouts due to its durability and water-repellent properties. While not designed for high water pressure, it can effectively channel rainwater away from buildings.
- Inspection Covers: Covers for access points in plumbing systems can be CNC machined from water-repellent nylon. This offers some protection from accidental spills or leaks within the system.
Optimize water-resistant nylon products
Design for Water Resistance
In both SLS and CNC machined parts, water resistance can be enhanced by incorporating design features that promote water resistance, such as angled surfaces or channels.
Design Considerations:
- Angled Surfaces and Channels: When designing the nylon part, incorporate features that promote water shedding. For example, angled surfaces or integrated channels can help direct water flow away from critical areas, minimizing water accumulation and maximizing the effectiveness of the DWR coating.
- Sealing Techniques: In situations where a higher degree of water resistance is desired, consider incorporating sealing techniques during the design phase. This could involve designing interlocking parts or incorporating gaskets or O-rings for a tighter fit, reducing water ingress points.
Post-processing for Enhanced Water Resistance
After SLS or CNC machining, the nylon parts can be treated with a DWR coating to further improve their water resistance. This additional step significantly enhances their ability to repel water.
Please note: For applications requiring complete waterproofing or submersion, other materials or techniques might be more suitable. Wax, polyester (PET), and thermoplastic polyolefin (TPO) can all waterproof and potentially substitute for nylon.
Testing Nylon’s Water Resistance
Standardized methods, established by organizations like ASTM (American Society for Testing and Materials) and ISO (International Organization for Standardization), provide a reliable means of evaluation. These tests mimic real-world conditions (water pressure, spray, humidity) and assess performance based on key metrics:
- Hydrostatic Pressure Resistance: It measures water pressure a nylon fabric withstands before leaking (higher mm = better).
- Water Repellency Rating: This rating (often based on spray tests) determines how well water beads up and rolls off (higher rating = better rain protection).
- Water Vapor Transmission Rate (WVTR): This metric measures breathability (g/m²/day). Lower WVTR indicates better moisture barrier properties for raincoats (blocking rain but allowing sweat vapor to escape).
Conclusion
Nylon offers basic water resistance, but water will eventually soak through it. A Durable Water Repellent (DWR) coating can further improve nylon’s water resistance. Sloped surfaces and channels in the nylon design can also help improve water resistance.
For applications requiring greater water resistance, you may want to consider using alternative materials instead of nylon.
Unionfab: Broad Nylon Selection for Manufacturing
Unionfab empowers your 3D printing projects with high-performance nylons like SLS Nylon 11, SLS Nylon 12 white, and glass-filled Nylon 12 off-white for designs demanding rigidity, allowing you to select the perfect material for each stage of your project.
Whether you opt for 3D printing or traditional manufacturing techniques like CNC machining or vacuum casting, Unionfab seamlessly integrates your chosen material into the production process.
