New silicones for bitumen application

01/19/2009

UV curing is especially successful when it comes to film siliconizing. This is particularly true for silicone coatings on LDPE and HDPE that are used in contact with bitumen, mastic or other sticky materials. Bitumen and the like are different from other pressure sensitive adhesives (PSA). They have a sometimes fairly low softening point at which they change to a sticky liquid and develop a high adhesion force even against a silicone coating. More and more, the market requires a good release in the vicinity of the softening point of such bitumen materials. We are proud to announce that we now have developed two new products, one for free radical and one for cationic UV curing, that fulfill this requirement and thus are much better suited for bitumen applications.
TEGO® RC 922, the product for our free radical UV curing silicones, is used as an additive from 2 to 20 % in exchange for TEGO® RC 902. A typical blend for a bitumen application would be:

RC 922/ RC 902/ RC 711/ A17 20:50:30:2

RC 922 can also be used in higher concentrations to get even better release against bitumen. In this case the cure speed and network cross linking, however, will decrease. TEGO® RC 1422, the new silicone for our cationic curing silicones, can be used alone with 2% photo initiator TEGO® Photocatalyst (PC) 1466. If need be, the anchorage additive RC 1480 may be added. Of course, RC 1422 can also be blended with TEGO® RC 1403* or RC 1401. In small amounts, RC 1422 will act as a premium release additive. Such formulations might then be used in applications with standard PSAs. Also RC 1422 has a slightly lower cure speed and cross linking density as compared to the standard cationic curing products. Both products, TEGO® RC 922 and RC 1422, are development products. Before stepping into production, we would like to have your opinion. Both RC 922 and RC 1422 are available from pilot production that we can offer for customer trials. We can run coating trials on customer substrates on our pilot lines or offer coated samples on standard substrates such as BoPP. Please ask for a sample.

*) RC 1403 is not available in the USA and Canada.