Multi-purpose adhesive sealant with a wide adhesion range Sikaflex-221 is a multi-purpose 1-component polyurethane adhesive / sealant that bonds well to a wide variety of substrates like metals, metal primers and paint coatings (2-component systems), ceramic materials and plastics. It is suitable for making permanent elastic seals. - Bonds well to a wide variety of substrates
- Resistant to ageing
- Can be sanded and painted
- Passes EN45545-2 R1/R7 HL3
- Non-corrosive
- Low odour
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PRODUCT BENEFITS - Bonds well to a wide variety of substrates
- Resistant to ageing
- Can be sanded and painted
- Passes EN45545-2 R1/R7 HL3
- Non-corrosive
- Low odour
Usage Sikaflex-221 bonds well to a wide variety of substrates and is suitable for making permanent elastic seals . Suitable substrate materials are metals, metal primers and paint coatings (2-component systems), ceramic materials and plastics. It is ideally used for internal sealing and simple bonding applications. Seek manufacturer’s advice and perform tests on original substrates before using Sikaflex-221 on materials prone to stress cracking. 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 | 400 ml 600 ml | Pail | 23 l | Drum | 195 l | |
Typical Product DataChemical base | | 1-component polyurethane | Colour (CQP001-1) | | White, grey, black, brown | 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) | | 7 N/mm | Service temperature (CQP513-1) | 24 hours1 hour | -50 ─ 90 °C 120 °C 140 °C | Shelf life | | 12 months B |
CQP = Corporate Quality Procedure | A)23 °C / 50 % r.h. B)storage below 25 °C |
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Technical Information CURE MECHANISM Sikaflex-221 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 for Sikaflex-221 CHEMICAL RESISTANCE Sikaflex-221 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 Information 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-221 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-221 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 sealant. It is recommended using Sika Tooling Agent N. Other finishing agents must be tested for suitability and compatibility prior the use. Removal Uncured Sikaflex-221 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. Overpainting Sikaflex-221 can be painted after formation of a skin. If the paint requires a baking process, best performance is achieved by allowing the sealant to fully cure first. 1C-PUR and 2C-acrylic based paints are usually suitable. All paints have to be tested by carrying preliminary trials under manufacturing conditions. The elasticity of paints is usually lower than of sealants what could lead to cracking of the paint film in the joint area. |
The above design is only a sample of the options available, for reference purposes only. Our policy of continuous improvement may result in a change of specifications without notice. If any discrepencies might be between the data sheet values and standards, we reserve the rights to make technical changes. Our company will not be held responsible, as all or any of pictures, drawings, weights and dimensions details or other elements in this document are only indicative and must not be considered contractual. Contact our sales team for other specifications or custom made products.
Contact our sales team for other specifications or custom made products.