GETA QUOTE
Modified nylon (glass fiber/carbon fiber reinforced, seawater-resistant, weather-resistant and flame-retardant grades) features light weight, salt spray & seawater resistance, low maintenance, low noise and superior corrosion resistance. It is widely used to replace carbon steel, stainless steel, aluminum alloy and copper alloys in marine and ship sectors. Below is a full introduction covering environmental challenges, mainstream modification solutions, typical applications, recommended grades and selection guidelines.
1.1 High salt spray (NaCl) & extreme humidity (over 90%): Conventional PA6 is prone to hydrolysis and sharp strength decline.
1.2 Long-term seawater immersion: Materials require low water absorption, excellent dimensional stability and hydrolysis resistance.
1.3 Intense ultraviolet radiation (1.5–2 times that on land): Easily causes chalking, discoloration and cracking.
1.4 Cyclic temperature variation (-40℃ ~ +120℃): Thermal expansion and contraction may lead to warpage and sealing failure.
1.5 Persistent vibration, impact and abrasion: Caused by wind, waves and propeller operation under long-term load.
1.6 Fire resistance (SOLAS standard): Low-smoke halogen-free and flame-retardant performance is mandatory for ship interior parts.
2. Mainstream Modified Nylon Grades for Marine Use
2.1 Resin Matrix Selection (Ranked by seawater resistance & low water absorption)
- PA12: Water absorption ≈ 1.3% (only 1/4 of PA6), dimensional change < 0.1%. First choice for deep-sea and outdoor exposed components.
- PA612: Low water absorption, outstanding hydrolysis and salt spray resistance. Ideal for sealing and high-pressure parts.
- PA66: Excellent strength and heat resistance, commonly used for indoor non-immersed components.
- PA6: Cost-effective. Must be modified with reinforcement, weather resistance and flame retardancy; only applicable to dry indoor areas on ships.
2.2 Key Modification Technologies for Marine Service
- Glass fiber reinforcement (GF15–40%): Improves rigidity, mechanical strength and heat resistance, and reduces creep. Typical grades: PA6-GF40, PA12-GF15.
- Carbon fiber reinforcement (CF20–30%): Delivers higher strength and modulus, better lightweight effect, creep resistance and fatigue resistance. Used for high-end structural and sealing parts.
- Seawater & hydrolysis resistance: Formulated with hydrolysis stabilizers. Strength retention rate exceeds 90% after 1000 hours of seawater immersion.
- Weather & UV resistance: Compounded with carbon black and UV stabilizers. Strength retention rate above 90% after 1500 hours of salt spray testing.
- Flame retardancy (V-0 / Low-smoke halogen-free): Complies with SOLAS regulations, required for cabin interior materials.
- Toughening modification: Enhances low-temperature impact resistance (no brittle fracture at -40℃), suitable for handrails, brackets and housings.
3. Typical Application Scenarios (By Component Location)
3.1 Exposed Hull & Deck Components (Salt spray + UV + Rain)
Vent grilles, window frames, handrails, bollard guards: PA6-GF30 weather-resistant grade. Replaces aluminum alloy; no painting required, service life extended from 2 years to 5 years, maintenance cost reduced by 60%.
Propellers for yachts and lifeboats: Long glass fiber reinforced PA6-GF40. Only 1/5 the weight of copper propellers, higher thrust and excellent seawater resistance, with much lower cost.
Deck brackets and railing bases: PA66-GF40 weather-resistant grade. High rigidity and resistance to vibration caused by sea wind.
Water pump impellers, valve seals and pipe connectors: PA612-GF30 / PA12-GF20. Volume change < 1% and hardness retention over 90% after 1000 hours of seawater immersion.
Deep-sea seals and pressure vessel gaskets: PA612-CF30. Under 30 MPa pressure at 3000 meters deep sea, sealing performance remains 99.7% after 5000 working cycles, and abrasion loss is only 1/5 of traditional PU materials.
Submarine cable sheaths and buoys: PA12 flame-retardant & weather-resistant grade. Low water absorption and anti-marine organism adhesion property.
3.3 Cabin Interior & Structural Parts (High humidity + Salt spray + Fire hazard)
Cabin partitions, ceiling panels and equipment bulkheads: PA6-GF15 flame-retardant grade. Low smoke, halogen-free, dimensionally stable and vibration-resistant.
Electrical control box housings, terminal blocks and switch enclosures: PA66-GF30 flame-retardant V-0 grade. Good electrical insulation, prevents short circuit caused by salt spray corrosion.
Seat frames, storage compartment frames and interior panels: Toughened & weather-resistant PA6-GF20. Lightweight, impact-resistant and easy to clean.
Gears, bearing seats, pulleys and piston rings: Wear-modified PA6-GF40 (added with PTFE/silicone oil). Self-lubricating, maintenance-free, low noise, resistant to seawater and lubricants.
Engine peripheral brackets and radiator parts: PA66-GF40 heat-stabilized grade. Continuous service temperature up to 150℃ and above, resistant to coolant.
4. Recommended Commercial Grades & Application Guidance
4.1 PA B3WG8 (PA6-GF40, long glass fiber reinforced & heat-stabilized)
Application: High-rigidity indoor brackets, engine peripheral parts and non-submerged structural components. Features excellent heat resistance, low creep and good dimensional stability. Not recommended for long-term seawater immersion due to relatively high water absorption of PA6 matrix.
4.2 PA 73G40T BK416 (PA6-GF40, short glass fiber reinforced, heat-stabilized & toughened)
Application: Outdoor exposed parts, deck brackets, handrails and equipment housings. High impact resistance, good salt spray and weather resistance with cost advantages, an ideal alternative to aluminum alloy.
4.3 PA12 L-GF15 (PA12-GF15, flame-retardant & weather-resistant)
Application: Deep-sea components, window frames, cabin partitions and ceiling panels. Low water absorption, superior hydrolysis and salt spray resistance, flame retardant. Top choice for long-term immersed and outdoor marine parts.
4.4 Carbon Fiber Reinforced PA612-CF30
Application: Deep-sea seals, high-pressure components and high-end structural parts. Ultra-high strength and modulus, low creep and outstanding seawater resistance. Specially developed for high-end deep-sea equipment.
5. Material Selection Guidelines & Notes
5.1 For long-term seawater immersion: Prioritize PA12 / PA612. Ordinary PA6 is not applicable due to high hydrolysis risk.
5.2 For outdoor components under strong UV radiation: Must adopt weather-resistant grade with carbon black addition, otherwise cracking will occur within 1–2 years.
5.3 For cabin interior materials: V-0 flame retardant + low-smoke halogen-free formulation is required to meet SOLAS standards.
5.4 For heavy-load & long-term stressed parts: Select long glass fiber (LGF) or carbon fiber (CF) reinforced grades for better creep resistance.
5.5 Cost optimization: Use PA6-GF30/40 for indoor parts, weather-resistant PA66-GF40 for outdoor deck parts, and PA12-GF20 for underwater components.
