Gypsum board is widely used for internal walls and ceilings. As part of its manufacture, Optibor® boric acid can:
- Increase strength
- Reduce weight by about 10%
- Provide better adhesion of the paper backing
- Reduce curing time
- Prevent wrinkle formation on the surface
- Create a hard gypsum edge that withstands nailing and handling
- Enhance fire retardancy
Adding Optibor to the gypsum slurry promotes the formulation of large bulky crystals (as opposed to long needle-like ones). These crystals impart a more rigid character, strengthening the board and providing a harder outer edge. They also result in faster drying times.
When also used in the starch adhesive that is used to reinforce the bond between wallboard’s paper backing and gypsum core, Optibor provides increased viscosity, quicker tack, and better fluid properties—all essential for the dependable adhesion of the paper to the core. Optibor also reacts with sodium (found in many gypsum deposits), preventing the sodium from creating wrinkles in the paper backing as the wallboard dries.
Optibor’s fire-retardant properties help prevent the paper backing from burning while in the oven and helps to protect the final product by inhibiting combustion and suppressing afterglow and smolder. And Optibor helps minimize issues that can result from the injection of foam into the slurry (as part of density and weight reduction processes).