PVC foam board, also known as PVC foam sheet, refers to a lightweight and versatile plastic material composed of two rigid sheets enclosing an inner foam core made primarily of polyvinyl chloride (PVC) resin combined with foaming agents.

The basic composition of PVC foam boards includes:

• PVC resin powder - Forms the main component, making up over 70% of the foam board by weight. PVC resin imparts rigidity, weather resistance, and fire retardant properties.
• Activated light calcium carbonate - Added between 10-20% by weight. This mineral filler enhances the foam density and improves dimensional stability.
• Foaming aids - Around 2-5% by weight. The foaming aids aid in the expansion of the resin into a uniform closed-cell foam structure. Common foaming aids include azodicarbonamide and zinc compounds.

• Additional additives - Minute quantities of heat stabilizers, lubricants, and pigments may be included to optimize performance.