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Sikaflex®-591: Multifunctional sealant for marine application


Sikaflex®-591 is a multipurpose sealant based on Sika’s Silane Terminated Polymer (STP) technology. With its excellent resistance against the harsh maritime weathering conditions, it can be used for a wide range of marine applications.

The product exceeds common environmental and safety standards and sets a new benchmark from an ecological point of view; it meets the low spread flame requirements (FTP Code Part 5) set out by the International Maritime Organization (IMO).

  • IMO approved
  • Exceeds EH&S standards
  • Free of isocyanate, solvents, PVC, phthalates and tin catalysts
  • Highly elastic
  • Excellent weathering stability
  • Very good processing and tooling characteristics
  • Bonds well to a wide variety of marine substrates


Sikaflex®-591 is suitable for elastic, vibration-resistant joint seals and for a wide variety of interior and exterior sealing applications, while it is not suitable for applications with teak wood and plastics that are prone to stress cracking (e.g. PMMA, PC, etc.). It bonds well to substrates commonly used in the marine industry.

This product can be used only by experienced professional users only. Test with actual substrates and conditions have to be performed to ensure adhesion and material compatibility.


Sikaflex®-591 cures by reaction with atmospheric moisture. At low temperatures the water content of the air is generally lower and the curing reaction proceeds somewhat slower. The product is:

  • generally resistant to fresh water, seawater, diluted acids and diluted caustic solutions;
  • temporarily resistant to fuels, mineral oils, vegetable and animal fats and oils;
  • not resistant to organic acids, glycolic alcohol, concentrated mineral acids and caustic solutions or solvents.
  1. Surface Preparation

Surfaces must be clean, dry and free from grease, oil and dust. The treatment depends on the specific nature of the substrates and is crucial for a long lasting bond; suggestions for surface preparation may be found on the current edition of the appropriate Sika® Pre-treatment Chart.

  1. Application

Sikaflex®-591 can be processed (with hand, pneumatic or electric driven piston guns) between 5 °C and 40 °C, but changes in reactivity and application properties have to be considered. The optimum temperature for substrate and sealant is between 15 °C and 25 °C.
In case Sikaflex®-591 could get in contact with polyurethane, ensure that those products are cured or wait at least 24 hours prior to seal.

3. Tooling and finishing

Tooling and finishing must be carried out within the skin time of the product. It is recommended using Sika® Tooling Agent N, other finishing agents must be tested for suitability and compatibility prior the use.

  1. Removal

Uncured Sikaflex®-591 can be removed from tools and equipment with Sika® Remover-208 or another suitable solvent. Once cured, the material can only be removed mechanically.
Hands and exposed skin have to be washed immediately using hand wipes such as Sika® Cleaner-350H or a suitable industrial hand cleaner and water. Do not use solvents on skin!


SAIM: Mini Controller

The Mini Controller designed by the Swedish Zipwake and distributed in Italy