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.
Sikaflex®-291 meets the requirements set out by the International Maritime Organisation (IMO).
- Bonds well to a wide variety of substrates
- Good ageing and weathering resistance
- Elastic
- Low odour
- Non-corrosive
- Can be over painted
- Can be sanded
PRODUCT BENEFITS
- Bonds well to a wide variety of substrates
- Good ageing and weathering resistance
- Elastic
- Low odour
- Non-corrosive
- Can be over painted
- Can be sanded
Usage
Sikaflex®-291 is a multipurpose product for use in marine constructions. It is suitable for making 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 | 310 ml |
| Unipack | 600 ml |
Product Details
| Chemical base | 1-component polyurethane | |
| Colour (CQP001-1) | White, grey, black | |
| Cure mechanism | Moisture-curing | |
| Density (uncured) | depending on colour | 1.3 kg/l |
| Non-sag properties | Good | |
| Application temperature | ambient | 5 ─ 40 °C |
| Skin time (CQP019-1) | 60 minutes A | |
| Open time (CQP526-1) | 45 minutes A | |
| Curing speed (CQP049-1) | (see diagram) | |
| Shrinkage (CQP014-1) | 5 % | |
| Shore A hardness (CQP023-1 / ISO 48-4) | 40 | |
| Tensile strength (CQP036-1 / ISO 527) | 1.8 MPa | |
| Elongation at break (CQP036-1 / ISO 527) | 500 % | |
| Tear propagation resistance (CQP045-1 / ISO 34) | 6 N/mm | |
| Service temperature (CQP513-1) |
4 hours 1 hour | -50 ─ 90 °C 160 °C 180 °C |
| Shelf life (CQP016-1) | 12 months B |
CQP = Corporate Quality Procedure | A) 23 °C / 50 % r. h. | B) storage below 25 °C |
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: 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 for Marine Applications. Consider that these suggestions are based on experience and must be verified by tests on original substrates.
Application
Sikaflex®-291 can be processed 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.
Sikaflex®-291 can be processed with hand, pneumatic or electric driven piston guns as well as pump equipment. For advice on selecting and setting up a suitable pump system, contact the System Engineering Department of Sika Industry.
Tooling and finishing
Tooling and finishing must be carried out within the skin time of the product. It is recommended to use Sika® Tooling Agent N. 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 Sika® Cleaner-350H cleaning towels or 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.
Video
FAQs
Yes, Sikaflex®-291 can be over-painted once cured, however due to constantly varying paint formulations, it would be best to test first to ensure compatibility.
The elasticity of paints is usually lower than that of sealants. This could lead to cracking of the paint in the joint area. Enamel, Alkyd and Chlorinated rubber paints should not be used.
Sika’s Marine sealants and adhesives range accompanies you aboard the boat in various applications. Sika Marine grade sealants and adhesives are widely used in the construction of many ships, from yachts to cruise liners, from trawlers to supertankers. The Sika Marine range ensures multiple maintenance and maintenance operations throughout their working lives.
Sikaflex Marine adhesives and sealants make it possible to make flexible, perfectly waterproof and resistant assemblies between a wide variety of materials. They can be used with confidence above and below the waterline and are for the most part approved by the certifying bodies and authorised to carry the “Wheelmark”.
It is recommended to use a primer as it promotes better adhesion.
Sika® Primer 210 is a solvent-based, colourless to slightly yellow primer that reacts with moisture and forms a thin layer. This layer acts as a link between substrates and adhesives.
Sika® Primer-210 is specifically formulated for the treatment of bond faces prior to application of Sika’s 1-component Polyurethanes like Sikaflex®-291
Sikaflex®291’s Wheelmark approval symbolises conformity with the globally recognised Marine Equipment Detective.
Sikaflex®-291 bonds well to materials commonly used in marine construction, that includes but is not limited to wood, metal, metal primers and paint coatings (2-C systems), ceramic materials, plastics (GRP, etc). Read the full product data sheet for more information or contact our technical department. For detailed information please contact our Technical Service Department on [email protected] or 1300 22 33 48
Sikaflex®- 291 can be removed by using Sika Hand wipes within the first few minutes of applying the product.
However generally speaking, cured Sikaflex can only be removed mechanically, i.e. with a sharp knife, vibra saw, cheese wire or abrading it off with a sander.
Sika Remover-208 can be used to remove uncured excess material of Sikaflex adhesive or sealant from application tools or from soiled surfaces. If the product has cured, Sika Remover-208 will not get rid of the Sikaflex and you’ll have to escort to mechanical
To learn how to effectively apply Sikaflex®-291, refer to the Marine Application Guide.
Sikaflex®-291 cures at the rate of approximately 3 mm in the first 24 hours, temporary fixing aids can be removed after 24 hours, a full cure will generally be achieved after 7 days depending on the temperature, humidity and the thickness.
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. Refer to the curing speed diagram in the PDS for more information or contact Technical Service Department on [email protected] or 1300 22 33 48.
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