What primarily determines the resistance of sheet products to humidity?

The primary factor that determines the resistance of sheet products to humidity is the types of resins used in their construction. Resins play a crucial role in binding the various materials together and contribute significantly to the overall durability and moisture resistance of the product. High-quality, moisture-resistant resins can effectively mitigate the absorption of humidity, protecting the integrity of the sheet product and maintaining its structural stability over time.

While the type of particles used and the thickness of core elements can influence various physical properties, they do not have the same direct impact on humidity resistance as the resins. The face veneers, although they can contribute to the aesthetics and surface durability, also do not significantly influence the intrinsic moisture-related performance of the product compared to the resins' role. Thus, the choice of resin is critical in enhancing the performance of sheet products against humidity.