Plywood falls into two categories, three or multiple layers of thin wood plywood. The vast majority of the thin wood produced today is made of spin thin wood, often called veneer. Generally with an odd layer of veneers, the fiber direction of the adjacent layer is straight to each other, commonly three, five, seven and other odd layer. Its outer veneer is called outer ply, the front veneer is the surface, the other side is called the back.
Plywood can be divided into ordinary plywood and special plywood according to its use. Ordinary plywood is divided into class I plywood, class Ⅱ plywood, class Ⅲ plywood, class Ⅳ plywood respectively weather, water ,moisture resistant and not moisture resistant plywood plywood.
Class I plywood, with durable, boiling or steam treatment and other functions, can be used outdoors. Made from phenolic resin glue or other high-quality synthetic resin glue with comparable properties.
Class Ⅱ plywood, can be impregnated in cold water, or often hot water for a short time, but not resistant to boiling. Made with urea-formaldehyde resin or other adhesive of comparable properties
class Ⅲ plywood, can withstand short-term cold water impregnation, suitable for indoor use. Made with urea-formaldehyde resin with low resin content, blood glue or other adhesive agent of comparable performance.
class Ⅳ plywoodk, used in indoor normal conditions, has a certain bonding strength. Made with bean gum or other adhesives with comparable properties.
