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

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
NSF-approved for incidental food contact
Potable water approved (meets AS4020 requirements)
 
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.  

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.