Patent ID: 7700505

Claim:
A gypsum board comprising at least one mat-facer and a gypsum core, wherein said at least one mat-facer comprises at least two nonwoven plies, an inner ply and an outer ply, where the inner ply is in contact with the core of said gypsum board and comprises a mixture of cellulose fibers, inorganic or mineral fibers and optionally organic fibers, and said outer piy comprises essentially cellulose fibers, wherein said mat-facer further comprises at least a binder and at least mineral filler particles, said particles being distributed at least partially into said inner ply or outer ply or both, wherein the mineral filler particles have a d 50 from about 0.1 to about 10 μm, and wherein the inner ply, the outer ply, or both the inner and outer plies further comprise a water-resistant agent.