Supex 7221 PU adhesive is a solvent-free as well as a moisture curing adhesive . At room temperature and the required humidity in the joint sufficient strength will be obtained after approximately 10 to 15 minutes. It is cured in a heated press for faster curing. Maximum temperature must not exceed 70°C.
Application Areas of Supex 7221
Used for the manufacture of sandwich elements with porous surfaces (e.g. wood) which contain humidity. The surfaces can be bonded to one another or to metals, laminated panels, various plastics, rigid foams made of polystyrene, polyurethane as well as others.
PROPERTIES SUPEX 7221
- APPEARANCE Light viscous liquid
- COLOUR Straw to Brown
- ODOUR Slight odour Characteristic Musty (moulds).
- SOLUBILITY Insoluble in water reacts with water, Soluble in aromatic solvents
- S.G 1.1
- BOILING POINT (°C) >300
- VISCOSITY 7000-10000 cps 25°C
- FLASH POINT (°C) >200 (Closed cup)
- STORAGE STABILITY 8months
Supex 7221 Adhesive application procedureApplication Temperature : 10 to 35 °C. Supex 7221, one part PU adhesive is applied to the surface by spatula or doctor blade. One can also apply by spraying or rolls. In case of bonding surfaces without sufficient humidity or which are not moisture permeable the required amount of moisture is provided by other methods. Moreover, a proven procedure is the combined spraying of the adhesive at the same time with water in a fine mist. Water is never sprayed onto the bare metal in the case of separate adhesive and water mist application. However, it is sprayed on the other substrate or ideally on the adhesive. Bonding surfaces should be brought together immediately after adhesive application. This assures sufficient contact pressure while curing although preferably in a press. Since Supex 7221 cures by reaction with humidity, open containers must always be properly sealed and protected against moisture immediately after taking out the quantity needed. For the same reason we recommend to use up opened containers as soon as possible. APPLICATION :
- Material/ substrates to be bonded should be grease, dust and dirt free.
- Press the panel in the press at the minimum load 0.6 N/square mm for 30 min for 70°C .
- period of between 1 to 4 hours will be required for good bonding dependent on the temperature and the nature of the materials to be bonded. Post curing it is ready for any kind of coating.
- should not be applied to wet surfaces (i.e. surfaces where there are visible signs of moisture such as obviously damp patches). This product requires water misting which results in a faster full cure.
What is PUR Adhesive Technology?
Liquid PUR (Polyurethane) adhesives , Eg: Supex 7221, are reactive moisture curing adhesives known for Strong Bonds and Exceptional Heat, Cold and Moisture-Resistance; this makes liquid PUR adhesive an excellent choice for most difficult to bond, low energy substrates and they perform very well in extreme weather environments.
PUR adhesive forms very strong permanent bonds to most materials including: Solid Woods, MDF/Particle Board, Metal, Paper, Glass, Wooden Veneer, Clear Plastic Boxes, Plastics, PVC, Foils.
The primary advantages of using PUR adhesive include:
- reduced cost of the adhesives, on a /Kg. basis.
- NO HAP’s or VOC’s, 100% Solvent Free.
- The elimination of a plant explosion risk; lower insurance costs.
- No more need for air pollution control devices.
- The removal of dryers in the production line