Sikaflex 522 Caravan. Sikaflex 522 is a low emission 1 x component Silane Terminated Polymer sealant and adhesive. It has a high weathering and mould resistance. Sikaflex 522 meets highest EHS standards. It bonds well to a wide range of substrates with minimal pre treatment. High ageing and weathering resistant. High fungicidal resistance. Very low emission and odour. Also Sold in singles BG170. Silk is a trade mark of Sika Limited.