Sikaflex®-291
Sikaflex®-291 is a non-sag 1-component polyurethane sealant specifically developed for the marine market, which cures on exposure to atmospheric moisture.
- Bonds well to a wide variety of substrates
- Good aging and weathering resistance
- Elastic
- Low odor
- Non-corrosive
- Can be over painted
- Can be sanded
- Listed under NSF ─ Proprietary Substances and Nonfood Compounds (black and white)
PRODUCT BENEFITS
- Bonds well to a wide variety of substrates
- Good aging and weathering resistance
- Elastic
- Low odor
- Non-corrosive
- Can be over painted
- Can be sanded
- Listed under NSF ─ Proprietary Substances and Nonfood Compounds (black and white)
Usage
Sikaflex®-291 is a multipurpose product for use in marine constructions. It is suitable to make elastic, vibration-resistant joint seals, and can also be used for a variety of interior sealing applications. Sikaflex®-291 bonds well to the materials commonly used in marine construction like wood, metals, metal primers and paint coatings (2-C systems), ceramic materials and plastics (GRP, etc.). Sikaflex®-291 must not be used to seal plastics that are prone to stress cracking (e.g. Plexiglas, Polycarbonate, etc.). Once cured, Sikaflex®-291 can easily be sanded as required. This product is suitable for experienced professional users only. Test with actual substrates and conditions have to be performed to ensure adhesion and material compatibility.Packaging
| Cartridge | 300 ml |
| Unipack | 600 ml |
| Tube | 3 oz |
Product Details
| Chemical base | 1-component polyurethane | |
| Color (CQP001-1) | White, black | |
| Cure mechanism | Moisture-curing | |
| Density (uncured) | depending on color | 1.3 kg/l (10.8 lb/gal) |
| Non-sag properties | Good | |
| Application temperature | ambient | 5 ─ 40 °C (41 ─ 104 °F) |
| Skin time (CQP019-1) | 60 minutes A | |
| Open time (CQP526-1) | 45 minutes A | |
| Curing speed (CQP049-1) | (see diagram 1) | |
| Shrinkage (CQP014-1) | 5 % | |
| Shore A hardness (CQP023-1 / ISO 48-4) | 40 | |
| Tensile strength (CQP036-1 / ISO 527) | 1.8 MPa (260 psi) | |
| Elongation at break (CQP036-1 / ISO 527) | 500 % | |
| Tear propagation resistance (CQP045-1 / ISO 34) | 6 N/mm (35 pli) | |
| Service temperature (CQP513-1) |
4 hours 1 hour | -50 ─ 90 °C (-58 ─ 194 °F) 160 °C (320 °F) 180 °C (356 °F) |
| Shelf life | 12 months B |
| CQP = Corporate Quality Procedure | A) 23 °C (73 °F) / 50 % r. h. | B) storage below 25 °C (77 °F) |
CURE MECHANISM
Sikaflex®-291 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 (see diagram 1).
Diagram 1: Curing speed Sikaflex®-291
CHEMICAL RESISTANCE
Sikaflex®-291 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.
Application
Surface Preparation
Surfaces must be clean, dry and free from grease, oil and dust.
Surface 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. Consider that these suggestions are based on experience and have in any case to be verified by tests on original substrates.
Application
Sikaflex®-291 can be processed between 5 °C and 40 °C (41 °F and 104°F), 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 (59 °F and 77 °F).
Sikaflex®-291 can be processed with manual, pneumatic or electric driven piston guns.
Tooling and finishing
Tooling and finishing must be carried out within the skin time of the product. It is recommended using Sika® Slick. Other finishing agents must be tested for suitability and compatibility prior the use.
Removal
Uncured Sikaflex®-291 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 a suitable industrial hand cleaner and water.
Do not use solvents on skin!
Overpainting
Sikaflex®-291 can be best painted after formation of a skin. Painting could be improved by treating the joint surface with Sika® Aktivator-100 or Sika® Aktivator-205 prior to paint process. If the paint requires a baking process (> 80 °C), best performance is achieved by allowing the sealant to fully cure first. All paints have to be tested by carrying preliminary trials under manufacturing conditions.
The elasticity of paints is usually lower than that of sealants. This could lead to cracking of the paint in the joint area.