What is Jellafin® waterproofing resin?


Jellafin®, a pressure-resistant waterproofing resin, is a two-liquid urethane resin manufactured by SEC SEAPREX Inc.
When the two liquids, "base resin" and "hardener," are mixed, they solidify to form a colorless, transparent hardened product.

Gerafin allows light and radio waves to pass through and electronic components to operate without water, even under water pressure at depths of 10,000 meters.
It also has excellent moisture-proofing, waterproofing, and electrical insulation for devices on land, enabling stable operation of IoT devices outdoors and in adverse environments.

In addition, it is expected to play a role in a wide range of fields, including deep-sea and space projects as well as infrastructure projects, by taking advantage of its feature of becoming colorless and transparent after solidification.


  • A two-component urethane resin that is clear and colorless after solidification.
  • Stable electrical properties (electrical insulation and dielectric constant) and high permeability to light, electromagnetic waves, and magnetism.
  • Ultra-high adhesion and ultra-elastic non-adhesive material with a waterproofing effect equivalent to that of an oil seal.
  • Easy to re-fuse and reseal after peeling off.
  • Direct exposure to seawater and rainwater.

Material Specifications

Coagulation time When mixed at room temperature, collapsible in 3 hours, fully cured in 24 hours
Mixing ratio 1:1 (weight)
Solution dielectric constant 2.2@2.6 to 1 kHz (no change with pressurization in air or water)
Breakdown of insulation 19kV/mm
Operating temperature -20℃~+120℃(Measured by SEC-SEAPREX Co.)
Sorting Class 4 quartz oil (fire point above 200°C)

Jellafin Benefits and Features

1 Pressure-resistant and waterproof (fresh water and seawater) Confirmation of normal operation of electronics at a water depth equivalent to 10,000m
2 Moisture and dust resistance
3 Corrosion resistance (chlorine gas, hydrogen sulfide)
4 Electrical insulation, anti-shock (anti-vibration)
5 Transparency (optical, electromagnetic, magnetic)
6 Non-woven and re-fusible

Main applications of Jellafin

Ocean sector

  • Sonar transmitter/receiver waterproofing, sonobuoy impact protection
  • Underwater camera, deep-sea LED lights (8,000 m depth), seafloor seismograph
  • Marine IoT infrastructure (cables and marine power generation systems), AUVs
  • Oceanographic sensors, support for the water industry, etc.

Social Infrastructure

  • Protection of electronic and metal components under rotting gas (mainly in sewage treatment plants)
  • Water and moisture proofing of outdoor surveillance cameras and signal lights
  • Leakage prevention and emergency reinforcement of bridge expansion systems
  • Water, moisture, and dust proofing of outdoor LED lighting

Aerospace, etc.

  • Aircraft LED wing lights, waterproofing for drones
  • Water Impact Protection for Reusable Rocket Components (Boosters)
  • Various security applications