Blocked isocyanates

Aqueous booster systems for waterproofing and cross-linking

RUCO-GUARD®, ®RUCO-COAT
Blocked or Non-blocked Boosters/Cross-linking Agents - NMP-free

Isocyanate cross-linking agents are, above all, suitable for the formaldehyde-free cross-linking of polymer emulsions. Out of the core competence of fluorocarbon chemistry a whole series of boosters and cross-linking products based on blocked/non-blocked isocyanate cross-linking agents has been developed in the past few years. The non-blocked types are highly reactive. However, they have to be worked in relatively quickly, particularly into aqueous systems (limited pot life). Therefore, most of the booster systems are blocked, i. e. the highly reactive isocyanate groups are temporarily closed with a protective group. They have long-term stability and can be used in aqueous product systems (long-term storage tests are recommended). When applied, boosters are unblocked by means of temperature and develop their effect-strengthening activity.

Aliphatic or Aromatic Boosters

The unblocking temperature depends first of all on two parameters. The most important factor is the selection of a suitable blocking agent. Decisive is the type of the isocyanate raw material used. Here one distinguishes between aliphatic and aromatic isocyanates.

Aliphatic isocyanates

have a relatively high unblocking temperature but, as a rule, they have a much higher resistance to yellowing at higher curing temperatures and in subsequent exposure to UV-light, ozone or nitrogen oxide.

Aromatic isocyanates

have a relatively low unblocking temperature, but as a rule, they have a much lower resistance to yellowing at higher curing temperatures and in subsequent exposure to UV-light, ozone and nitrogen oxide. Therefore, depending on the process and the field of application, different booster systems are used.