In the RADS technology, also known as FIPFG technology (Formed In Place Foam Gaskets), the two components – resin and hardener – are conveyed with gear-pumps to the dosing head, intimately mixed together with a dynamic stirrer, then applied to the part. As soon as resin and hardener come in contact, polymerization and foaming reactions start, ending up ultimately as a fully expanded cross-linked foam gasket. Depending on system reactivity, foams are fully expanded and tack-free within seconds or minutes, and fully cross-linked, ready-to-assemble within hours.
For polyurethane (PU) formulations, as currently used in RADS, the hardener consists of a liquid isocyanate MDI and the resin of a more or less viscous polyol mixture. For two-dimensional parts where the gasket is applied in a groove, the resins used are only slightly viscous – honey like – resulting in a seamless gasket with smooth surface. For three-dimensional parts or parts without groove, viscous – thixotropic – resins are used and the resulting gasket have a height/width ratio around 1:2 (see design guidelines below).
PU-Foams are highly elastic, with very low residual deformation over the years, ensuring a long lasting sealing performance.
Our standard formulations have Shore hardness 00 ranging from 40 to 70. On demand, we can make softer or harder foams. Final foam density is typically between 0.25 and 0.40 g/cm3.
Our PU foams can be used for temperatures between -40°C and + 100°C, and up to +160°C for short time.
Other properties like special colour, UL-94 HF1 flame retardancy, food-approval, antimicrobial-treatment, IP68 protection class, UV-stabilisation, low fogging or UL-50 Listing are available on request.
Optimal sealing properties are reached at 20-60% compression. For an extended lifetime, the foam should be protected from UV radiation; permanent contact with water, for instance through rain water accumulation should be avoided as well.
For application of the foam in a groove, optimal parameters are as follows:
For application of the foam without a groove, optimal parameters are as follows: