Paper cup fans are not simply paper, but are composed of multiple layers of composite materials:

• Raw paper layer: The main body provides structural strength and rigidity. Usually made of food grade wood pulp, kraft paper or white cardboard with temperature resistance.
• Coating layer: A thin layer of polyethylene plastic film applied to surfaces (typically inner surface, high-end products have both inner and outer surfaces).
• Function: Waterproof, leak proof, oil proof. Without this layer, the paper cup would quickly become soft and soaked.
• Printing layer: Patterns or logos printed before laminating using environmentally friendly food grade ink.

A paper cup fan is a multi-layer structural thin sheet that combines printing, waterproofing, and other functions.