Deep blue Building Material Waterproof flame retardant PVC Foam Board
https://www.hzggpvc.com/product/pvc-foam-board/deep-blue-building-material-waterproof-flame-retardant-pvc-foam-board.html
The pvc foam board is mainly composed of pvc resin powder and calcium powder, and the raw material is extruded and shaped by the screw after heating up. It has the advantages of waterproof, insect-proof and flame retardant. The environmental protection grade is E0 grade and the flame retardant grade is B1 grade. At present, it has been widely used in construction, home decoration and advertising industry.