Rock wool sandwich panel Rockwool sandwich panels manufactured by Zhongjie company are made of a high quality Rockwool. Turning 90 degrees after cutting, assure the fiber direction perpendicular to the sheet to increase the strength. Spraying the high-intensity fire-proof adhesive to the surface of the core and the sheet, ensure that it won't be cracking after a long time. On the other hand, we use the polyurethane side sealing technology which greatly improves the insulation waterproof performance and general quality.