Marine Epoxy System (Osmosis-Resistant, Infusion/Laminating)

CAS 25068-38-6In StockSample available

Key Features

  • Low water absorption (<2%) — osmosis-resistant for long-term marine immersion
  • Anti-blush formulation — no amine bloom on uncured surfaces in humid conditions
  • BPA/BPF blend for optimal balance of properties and low viscosity
  • Multiple pot life grades for different marine processes
  • Excellent adhesion to GRP, wood, foam core, and metal

Marine Epoxy System is a two-part epoxy resin/hardener combination specifically formulated for marine composite construction including boat hull lamination, deck structures, mast fabrication, and osmosis-resistant hull barrier coatings. The system provides the combination of low water absorption, excellent adhesion to glass and carbon fiber, and long-term hydrolytic stability required for continuous immersion service in fresh and salt water environments.

The resin component is based on BPA/BPF blend epoxy with low-ionic-content formulation and controlled molecular weight to minimize water uptake. The hardener is a cycloaliphatic or aromatic amine system with anti-blush/anti-moisture-uptake additives. Water absorption after full cure is <2% (28-day ASTM D570), compared to 5-8% for equivalent polyester-based marine systems. This significantly reduces osmotic blister formation in fiberglass boat hulls during prolonged water immersion.

Applications include new-build boat hull lamination using wet lay-up, infusion, or vacuum bagging processes; repair and re-lamination of GRP hulls; barrier coating application over existing polyester GRP to prevent osmosis; wooden boat encapsulation; and carbon fiber mast and appendage construction for performance sailing. Gel time and pot life options cover hand lay-up (60-120 min pot life), infusion (180-480 min), and fast-cure repair grades (20-40 min).

Specifications

ParameterValue
Pot Life (25°C)20-480 min (grade dependent)
Hydrolyzable Chloride≤200 ppm
Mix Ratio (by weight)100:30-50
Adhesion (GRP surface)>12 MPa (pull-off)
Mixed Viscosity (25°C)300-800 mPa·s (grade dependent)
Tg (post-cure 60°C/4h)60-80°C
Water Absorption (28-day, ASTM D570)<2%

Applications

New-build GRP boat hull wet lay-up and infusionCarbon fiber performance boat structures (masts, daggerboards)Osmosis barrier coating over polyester GRPWooden boat encapsulation and structural repairMarine composite repair and re-lamination

FAQ

Osmotic blistering in GRP hulls results from water permeating through the gelcoat and resin matrix, then accumulating at hydrophilic sites (catalyst residues, resin-fiber interfaces, voids) to form osmotic concentration gradients that draw more water in. Polyester resins have water absorption of 5-8% due to ester hydrolysis sites and higher void content; epoxy resins absorb <2% and are resistant to hydrolysis. An epoxy barrier coat (minimum 300 µm, typically 500-600 µm, of pure epoxy applied directly over bare GRP) eliminates the osmotic gradient driving force by creating a nearly impermeable barrier. ISO 2812-2 immersion testing confirms <0.5% weight gain for epoxy barrier-coated panels versus 3-5% for uncoated GRP.

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