ZEMSIL® في قطاع البحرية والبحر العميق

Silicone Materials in Marine and Shipbuilding

The marine environment combines salt spray, UV radiation, wide temperature swings, immersion, and mechanical vibration — conditions that degrade most polymer systems within a few seasons. Silicone materials are uniquely suited to this environment: they resist hydrolysis, retain elasticity from -60 °C to +200 °C, and do not support mold or microbial growth without dedicated biocide treatment. Key application areas in marine and shipbuilding include structural sealing, antifouling release coatings, cable and electrical system insulation, and fuel/hydraulic system seals requiring chemical resistance.

Sealants for Vessel Construction and Maintenance

Silicone sealants are the dominant choice for above-waterline sealing in marine construction. Porthole glazing, deck hardware installation, hull-superstructure joints, and hatch seals all rely on one-component RTV or two-component RTV-2 silicone formulations. Critical performance requirements:

Adhesion to mixed substrates: GRP (glass-reinforced polyester), aluminum, teak, and painted steel are common bonding surfaces. Silane coupling agents — particularly CS-550 (KH-550, aminosilane) and CS-560 (KH-560, epoxysilane) — are used in the sealant primer system to ensure adhesion to both inorganic and organic substrates without primer failure from water immersion.

Movement accommodation: vessels flex continuously. A silicone sealant with elongation >400% and Shore A hardness of 15–35 handles joint movement without cohesive failure. ZEMSIL SB-RTV2 two-component systems allow controlled pot-life and hardness adjustment, which professional shipyard applicators prefer over one-component products.

Below-waterline and wet-area sealing: neutral-cure silicone is preferred in areas with prolonged contact with metal hardware (to avoid acetic acid from acetoxy-cure variants corroding brass or aluminum fittings). ZEMSIL SS-N (neutral cure) and SS-WS (waterproofing sealant) are appropriate grades for these zones.

Antifouling Release Coatings

Silicone-based fouling-release coatings operate on a fundamentally different principle from biocidal antifouling paints: instead of toxins, they present a low-surface-energy surface (surface energy typically 20–24 mN/m) to which barnacles, tubeworms, and biofilm cannot bond effectively. When the vessel moves at >7–10 knots, hydrodynamic shear removes attached organisms.

The coating matrix is a cross-linked PDMS network. Key silicone inputs:

• DM-series PDMS base polymer (DM-100 to DM-5000 range): the elastic matrix; lower viscosity grades produce softer, more fouling-release-active coatings but require careful cure management
• MH (hydrogen-terminated silicone oil): used as crosslinker in platinum-catalyzed hydrosilylation systems
• CS-171 (vinyltrimethoxysilane) and CS-151 (methyltrimethoxysilane): provide adhesion to the primer layer and control network density

Fouling-release coatings do not replace biocidal antifouling in tropical or slow-speed vessel applications. For high-speed commercial vessels (ferries, naval vessels, offshore service), they offer fuel savings of 3–8% vs conventional antifouling by reducing hull drag.

Cable Insulation and Electrical Systems

Marine electrical cable must pass IEC 60092 fire-resistance tests (IEC 60331, IEC 60332-3) and function after salt-fog exposure per IEC 60068-2-11. Silicone rubber insulation and jacketing, based on HTV silicone (SB-HTV) or peroxide-cured PDMS compounds, meets these requirements where PVC cannot sustain temperature or fire performance.

Typical marine silicone cable applications:

• Engine room cable (continuous 180 °C, short-term to 200 °C)
• Fire survival cable in accommodation and control spaces (rated per IEC 60331-21)
• Shore power connectors and exposed deck wiring

Fumed silica (FS-200, FS-300) is the primary reinforcing filler in silicone cable compounds, contributing to tensile strength (>8 MPa typical) and tear resistance, while the silicone matrix provides inherent flame resistance (limiting oxygen index >28%).

Fluorosilicone for Fuel and Hydraulic Systems

Standard PDMS silicone swells in aliphatic and aromatic fuels, rendering it unsuitable for fuel line seals, injector O-rings, or bilge pump diaphragms. ZEMSIL FL (fluorosilicone, FVMQ) solves this: the trifluoropropyl side chains provide fuel and oil resistance (volume swell <10% in ASTM fuel C) while retaining silicone's wide service temperature range (-55 °C to +175 °C).

Key marine applications for FL fluorosilicone:

• Fuel system O-rings and gaskets (diesel, gasoline, and marine biofuel blends)
• Hydraulic system seals on steering and stabilizer systems
• Vent tube seals in diesel engine exhaust systems
• Fuel hose inner layer compound

Product Selection Guide

Related Reading

Sealing applications, High-temperature resistance, Fluorosilicone FL series, Silicone sealant SS-N, RTV-2 silicone rubber, Fumed silica FS-200, CS-550 silane coupling agent, Defense industry guide.