We offer two UV curable silicone release systems. Both are solventless and produce release coatings without the use of heat. They differ in their underlying chemistries. The first is based on silicone acrylates and cures via a free radical mechanism. The second release system uses epoxy silicones and cures in the presence of a cationic photo catalyst.
TEGO® RC Silicones are functional silicone polymers. The functional groups are firmly linked to the silicone backbone.
UV curing requires the addition of a photoinitiator (PI).
In order to complement our well established TEGO® RC silicone acrylates, we also offer epoxy silicones. They are represent by the TEGO® RC 1400 Series and a suitable photo catalyst.
Generally, cationic photo catalysts are sensitive to impurities in the substrate and to humidity. Careful selection of a suitable substrate is necessary i.e. substrates which contain no ingredients that may poison the catalyst. The curing is initiated by UV radiation and exhibits some post-cure until the reaction is complete. Cationic curing takes place in a normal atmosphere, therefore nitrogen inerting is not required. They can be cured with standard UV equipments as used in the printing industry. This is the cationic system’s main advantage over free radical curing silicones. Therefore, cationic UV siliconizing is often the first choice when standard release values are required on suitable substrates.
BENEFITS OF CATIONIC CURING
- No nitrogen inerting required
- Very simple UV curing units
- Low extractables
TEGO® RC Silicones are a perfect fit for release liners for all applications. Typical fields of application are industrial release liners, self-adhesive labels, graphic arts, tapes and hygienic products.
The term RC Silicones stands for Radiation Curing Silicones. Release liners made with UV curable silicones are growing in popularity. For the last 25 years, Evonik has been an expert in UV curable silicone release systems for the PSA (pressure sensitive adhesive) market.
Through cooperations with equipment manufacturers for converting and coating as well as material suppliers Evonik's TEGO® RC team strives for continuous improvement of processes, making us the partner of choice for in-line siliconizing. TEGO® RC Silicones guarantee successful in-line converting of entire labels.