A modifier is a substance that is added to plywood glue to change its properties and performance. A modifier can have different functions, such as:
- Improving the curing speed and bonding strength of the glue
- Reducing the formaldehyde emission and toxicity of the glue
- Increasing the water resistance and durability of the glue
- Enhancing the viscosity and stability of the glue
Some common types of modifiers used in plywood manufacturing are:
Formaldehyde scavenger: This is a modifier that can react with the free formaldehyde in the glue and reduce its emission and odor. Formaldehyde scavenger can also improve the water resistance and hydrolytic stability of the glue. Some examples of formaldehyde scavengers are urea, melamine, and sodium bisulfite.
Toughener: This is a modifier that can reduce the brittleness and cracking of the glue line and increase its toughness and flexibility. Toughener can also improve the impact resistance and aging resistance of the glue. Some examples of tougheners are polyvinyl acetate, polyvinyl alcohol, and rubber.
Water repellent: This is a modifier that can increase the water resistance and weather resistance of the glue. Water repellent can also prevent the swelling and shrinking of the plywood. Some examples of water repellents are phenol, resorcinol, melamine, and paraffin wax.