Is nylon water resistant?

Contents

1. What is Nylon?

1.1 Basic Information

1.2 Nylon Types and Typical Applications

2. Waterproof and Water Resistant Difference

2.1 What is Waterproof and Water Resistant?

2.2 Waterproof and Water Resistant Examples

2.3 Waterproof and Water Resistant Standards

3. Is Nylon Waterproof or Water Resistant?

4. How to Test the Water Resistant of Nylon?

5. Factors Affecting Nylon’s Water Resistant and Methods to Enhance Nylon’s Water Resistance

6. Nylon Manufacturing Process

7. Conclusion

8. People Also Ask

I. Which is more waterproof, nylon or polyester?

II. Is nylon waterproof and breathable?

III. Does Nylon being hydroscopic mean that the 3D printed result will also be hydroscopic, or would it have enough water-resistance for such a project? What other filaments have these properties?

1. What is Nylon?

1.1 Basic Information

● Nylon, also known as polyamide,abbreviated as PA

● Invented by the American chemist Wallace Carothers on Feb 28, 1935

● First synthetic fiber and one of the most widely used synthetic materials in the world

● Its name is determined by the number of carbon atoms in the monomers used to synthesize them

● Properties

1.2 Nylon Types and Typical Applications

● Nylon can be classified based on its main chain structure into aliphatic, semi-aromatic, and fully aromatic types

● Aliphatic nylon:

– has many varieties, large output and wide application

– named according to the number of carbon atoms contained in the monomer: PA6, PA12, etc

● Aromatic nylon:

– mostly are high-temperature nylon

– high temperature resistance, radiation resistance and corrosion resistance

2. Waterproof and Water Resistant Difference

2.1 What is Waterproof and Water Resistant?

● Waterproof:

– Water cannot penetrate for extended periods

– Main features:

*  Can withstand water pressure of more than 1 meter (IP67 and above)

*  No penetration after continuous immersion for 24 hours

*  Stay sealed even after high-pressure washing (10MPa)

● Water Resistant

– Can withstand some water exposure but is not fully waterproof

– Main features:

** Resistant to low-pressure water splashes (such as IP54 rating)

** Short-term (<30 minutes) rain protection

** Cannot withstand continuous immersion or high-pressure water impact

2.2 Waterproof and Water Resistance Examples

2.3 Waterproof and Water Resistant Standards

ISO:

● ISO 811: Textiles – Determination of resistance to water penetration – Hydrostatic pressure test

● ISO 1420: Rubber – or plastics-coated fabrics – Determination of resistance to penetration by water

● ISO 4920: Textile fabrics – Determination of resistance to surface wetting (spray test)

ASTM:

● ASTM D7017: Standard Performance Specification for Water-Resistant Rainwear and All-Purpose, Water-Repellent Coat Fabrics

● ASTM E96: Standard Test Methods for Water Vapor Transmission of Materials

Industry-specific Standards:

● MIL-STD-810G: US military standard to test equipment can withstand various environmental conditions, including water exposure

● AATCC 22: Test Method for Water Repellency: Spray Test

● JIS L 1092: Testing methods for water resistance of textiles by Japanese Industrial Standard

● EN 343: Protective clothing – Protection against rain

Ingress Protection:

– Water resistant: typically IP54 to IP65

– Waterproof: typically IP67 and above

** First numeral: solid particle protection, 0-6 or X (X means no data is available to specify a protection rating concerning these criteria)

** Second numeral: liquid ingress protection, 0-9 or (X means no data is available to specify a protection rating concerning these criteria)

3. Is Nylon Waterproof or Water Resistant?

Material properties:

Limitations of basic nylon:

● Standard nylon 6 water absorption rate 2.5-3.5% (saturated state)

● Dimensional change after water absorption 0.8-1.5% (flow direction)

● Wet state is generally 10-20% lower than dry state in mechanical strength

Advantages for industrial applications:

● Sufficient mechanical properties after water absorption

● No rust, ideal for a humid environment

● Dimensional changes can be compensated for by design and process

Water resistant performance:

Unmodified nylon:

● Injection molded parts: IP54-IP55 (water resistant)

● Machining parts: IP55-IP56 (depending on surface finish)

Modified nylon:

● Nylon 12 injection molded parts: up to IP66

● 30% glass fiber reinforced nylon: water absorption reduced by 40%

● Carbon fiber added: dimensional stability increased by 50%

Surface finish:

● Fluorine coating treatment: up to IP67

● Plasma treatment: improve surface hydrophobicity

● Laser microstructuring: super hydrophobic surface

Textile materials:

● The inherent characteristics of nylon itself determine that it is not a naturally waterproof material

● Untreated pure nylon materials usually exhibit the following water-based properties:

– Short-term water resistance: Since the surface of nylon fibers is smooth and has a certain degree of hydrophobicity, it can resist short-term slight water exposure, such as rain splashing or brief contact, and exhibits water resistant properties

– Long-term permeability: When soaked for a long time or facing continuous water pressure, water molecules will gradually penetrate the microstructure of nylon materials. This is because:

** Nylon molecular chains contain polar amide groups (-CONH-), which can form hydrogen bonds with water molecules

** Nylon has a high moisture absorption rate (up to about 3% under standard conditions)

** Textile nylon has interfiber pores, providing channels for water penetration

● Applications: Nylon products on the market that are advertised as “waterproof” are usually specially treated:

– High-density woven nylon (such as ballistic nylon) can improve water resistance

– Surface waterproof coatings (such as polyurethane, polyvinyl chloride, silicone resin, etc.) can impart waterproofness

– Laminated waterproof films (such as Gore-Tex, eVent) can achieve breathable waterproofness

● to Conclude

– Nylon itself is water resistant rather than waterproof

– But it can be made waterproof through an appropriate process treatment

– When purchasing, consumers should pay attention to the specific waterproof indicators of the product (such as hydrostatic pressure value) rather than simply relying on material claims

4. How to Test the Water Resistant of Nylon?

Test method for water resistance of industrial nylon parts

1) Static immersion test (industrial standard)

Points:

● Distilled water immersion (23±2℃)

● Measure the size and weight changes regularly

● Time duration: 24h to 1000h

● Standard reference:

– ISO 62: Plastics – Determination of water absorption

– ASTM D570: Standard Test Method for Water Absorption of Plastics

2) Pressure jet test (simulating industrial environment)

Test parameters:

● Water pressure: 0.5-10MPa (depending on application requirements)

● Water temperature: 20-80℃ (simulating different working conditions)

● Spray angle: 0-90°all-round test

● Time duration: 5-30 minutes of continuous spraying

Equipment example:

● High pressure steam cleaning jet simulation machine

● Multi-function environmental test chamber

3) Hot and cold cycle test (accelerated aging)

Test procedure:

● High temperature and high humidity (85℃/85%RH, 8h)

● Low temperature immersion (-20℃ water, 4h)

● Room temperature recovery (4h)

● Repeated cycle (5-20 times)

Evaluation:

● Appearance changes (cracks, deformation)

● Dimensional stability

● Mechanical property retention rate

5. Factors Affecting Nylon’s Water Resistant and Methods to Enhance Nylon’s Water Resistant

1) Material selection

● Nylon substrate selection:

– PA12: water absorption 0.7-1.2%

– PA612: water absorption 0.6-1.3%

– PA66: water absorption 2.5-3.5% (needs modification)

● Reinforcement:

– 30% glass fiber reinforcement: water absorption reduced by 40%

– Mineral added: improve dimensional stability

– Carbon fiber reinforcement: also improves conductivity

● Additive selection:

– Waterproof masterbatch (fluorine-containing compound)

– Nanocomposite materials (clay/ Silica)

– Elastomer toughening agent (improves low temperature performance)

2) Injection molding process optimization

● Drying:

– 80-100℃ hot air drying for 4-8h

– Dehumidification drying with dew point ≤-40℃

– Residual moisture ≤0.1%

● Injection molding parameters:

– Melt temperature: 240-290℃ (depending on the material)

– Mold temperature: 60-120℃ (high mold temperature improves crystallization)

– Pressing pressure: 60-100MPa

– Cooling time: sufficient cooling to reduce internal stress

● Post-treatment:

– Heat treatment (120℃×4h to reduce internal stress )

– Moisture conditioning (balanced moisture content)

3) Machining process control

● Tool selection:

– Carbide tool (wear-resistant)

– Sharp cutting edge (reduce material tearing)

– Appropriate back angle (15-20°)

● Cutting parameters:

– Cutting speed: 200-400m/min

– Feed rate: 0.1-0.3mm/rev

– Cutting depth: finishing 0.1-0.5mm

● Cooling:

– Compressed air cooling (preferred)

– Minimal lubrication (avoid water-based coolant)

– Dry cutting (simple shape)

● Surface finish:

– Precision grinding (Ra0.4-0.8)

– Polishing (reduce surface pores)

– Ultrasonic cleaning (remove cutting residues)

4) Optimization

● Wall thickness design:

– Uniform wall thickness (avoid shrinkage marks)

– Reinforcement rib (improve rigidity)

– Minimum wall thickness ≥1mm (injection molded parts)

● Sealing structure:

– Double sealing groove

– Dynamic sealing takes into account wear compensation

– Static sealing uses elastomer gaskets

● Connection:

– Ultrasonic welding (high-strength sealing)

– Laser welding (precision connection)

– Structural adhesive (3M DP series)

6. Nylon Manufacturing Process

7. Conclusion

Based on more than 20 years of experience, Xiamen Eternal Precision would recommend:

1) Material selection:

● When selecting nylon materials for long-term humid environments, priority is given to materials with low moisture absorption and good waterproof properties, such as PA12 and PA610

● At the same time, treated PA66 or glass fiber reinforced PA66 can be selected according to the strength and stiffness requirements of specific applications

● It is key to ensure that the material can maintain stable performance and dimensions in a specific environment

● Or you could just send us the information, our dedicated engineering team will recommend right materials for your products/applications

2) Process:

● Injection molding: complex shapes, large order quantity

● Machining: small batches, high precision

● Extrusion: tubular, long strip

● Blow molding: hollow products

● Injection molding + machining: special requirements

3) Waterproof design:

● Injection molded parts: uniform wall thickness + glass fiber reinforcement + surface coating

● Machining parts: precision matching + special sealing + surface finish

● Blowing molding parts: seam treatment + uniform wall thickness+ Drainage design + material with good waterproof

● Extruded parts: sealing structure + surface finish + appropriate wall thickness + Connection

● General principles: avoid water accumulation structure + design drainage channel

4) Economic balance:

● Non-critical waterproof parts can adopt the “nylon 6 + local waterproof treatment” solution, which is 30-40% lower in cost than full waterproof materials and meets most industrial needs

5) Quality verification system:

● It is recommended to establish a three-level testing system:

– Incoming material inspection (basic material properties)

– Process inspection (key dimensions and appearance)

– Finished product verification (waterproof performance and functional testing)

8. People Also Ask

I. Which is more waterproof, nylon(PA) or polyester (PET)?

1) Water absorption(24h)

● PA6: 2.5-3.5%

● PET: 0.4-0.8%

2) Key indicators of waterproof performance

● Initial water resistance

– Polyester has lower surface energy and hygroscopicity, so its natural water resistance is better than nylon

● Long-term waterproofness

– Nylon has a greater dimensional change after absorbing water (0.8-2%), which affects the sealing performance

– Polyester has a higher wet strength retention rate

3) Suggestion

● Polyester

– Long-term humid environment (such as outdoor tent fabric)

– Basic water repellency without coating (outer layer of umbrella)

– Parts with high dimensional stability requirements (precision instrument packaging)

● Nylon

– Waterproof parts that need to be combined with abrasion resistance (waterproof backpacks)

– Dynamic bending applications (inflatable boat materials)

– Low temperature environments (nylon 12 is more cold-resistant than polyester)

4) Industrial waterproof materials

● Polyester: geotextile, waterproof membrane base fabric

● Nylon: waterproof seals, flexible containers

5) Conclusion:

● In its untreated state, polyester is naturally more water-resistant

● After professional waterproofing treatment, both can reach the highest protection level, but polyester is more durable and cost-effective

● Mechanical properties, ambient temperature and cost factors should be taken into consideration

II. Is nylon waterproof and breathable?

● Waterproof

– Nylon itself is not a completely waterproof material

– It has a certain degree of hygroscopicity and can absorb water, which may affect its waterproof performance

– Can be coated or otherwise treated (such as polyurethane coating) to enhance its waterproofness

– Applications: raincoats, outdoor gear, etc.

● Breathable

– Nylon has relatively good breathability, especially when it is not waterproofed

– It allows water vapor to pass through, thereby providing a certain degree of breathability

– Can remain comfortable in some applications and avoid excessive moisture when worn

● Comprehensive considerations

– After waterproofing treatment, the breathability of nylon may be affected

– Many waterproof materials are designed with breathability in mind to ensure that while waterproofing, they can still allow sweat and water vapor to escape, thereby improving wearing comfort

● Conclusion:

– Nylon materials have certain advantages in terms of waterproofness and breathability, but the specific performance depends on how the material is treated and the applications

– When selecting nylon materials for waterproof and breathable applications, it is recommended to consider whether an additional waterproof coating is required and the breathability design of the material

III. Does Nylon being hydroscopic mean that the 3D printed result will also be hydroscopic, or would it have enough water-resistance for such a project? What other filaments have these properties?

1) Material hygroscopicity of nylon 3D printed products

● Material hygroscopicity

– All nylons (including PA6/PA11/PA12) absorb moisture

– Water absorption difference

2) Special effects of 3D printing

● Interlayer pore structure intensifies moisture absorption, faster than injection molded parts

● 24-hour water absorption: around1.2% for PA12 3D prints

● Changes in mechanical properties: tensile strength decreases by 15-25%

3) Solutions

Nylon easily absorbs moisture, which may cause bubbles or reduced strength in printing, below are some ways to tackle water absorption:

Before printing:

● Choose modified nylon materials to reduce hygroscopicity and improve dimensional stability

● Store in a dry place (such as a sealed box + desiccant)

● Preheat the material before printing

After printing:

● Dry after printing

● Use moisture-proof packaging to reduce moisture absorption

● Surface coating: spray or dip silane, fluorocarbon coating or nano-hydrophobic coating to block water penetration

4) Alternative Filaments

5) Practice Recommendation:

● Short-term waterproofing needs (<1 year):PA12 + surface treatment

● Long-term underwater applications: PVDF or PEEK materials

● Dynamic sealing parts :flexible materials such as TPU/TPE

● High-precision parts :the amount of water absorption and expansion should be calculated in advance (PA12 is recommended with a 0.3% dimensional allowance)