A surface active agent, also known as a surfactant, is a substance that can reduce the surface tension of a liquid or increase its spreading and wetting properties. Surface active agents are used in plywood manufacturing to improve the properties and performance of the glue. They can have different functions, such as:
Emulsifying: This is the ability to form stable mixtures of two or more immiscible liquids, such as oil and water. Emulsifying agents can help to disperse the glue evenly on the wood surface and prevent separation or settling of the glue components. Some examples of emulsifying agents are sodium lauryl sulfate, lecithin, and polyethylene glycol.
Wetting: This is the ability to lower the contact angle between a liquid and a solid surface, making the liquid spread more easily and uniformly. Wetting agents can help to increase the adhesion and penetration of the glue into the wood pores and fibers, enhancing the bonding strength and durability of the plywood. Some examples of wetting agents are sodium dodecylbenzene sulfonate, sodium lignosulfonate, and sodium silicate.
Dispersing: This is the ability to prevent the aggregation or sedimentation of solid particles in a liquid medium, such as pigments, fillers, or modifiers. Dispersing agents can help to maintain the homogeneity and stability of the glue, preventing the formation of lumps or clumps that could affect the quality and appearance of the plywood. Some examples of dispersing agents are sodium polyacrylate, sodium carboxymethyl cellulose, and sodium hexametaphosphate.