| 主权项 |
1. A composite building board comprising:
a mat including a first portion having a thickness, the first portion comprised of a latex based cementitious pre-coating and a polymeric additive and a foaming agent, the mat further including a second portion comprised of a series of non-woven, randomly aligned glass fibers, the glass fibers having upper and lower extents, with the upper extents embedded within the pre-coating, a plurality of pores formed within an upper surface of the pre-coating, the pores created by the foaming agent and having a depth ranging from approximately 0.05 mm to 1.0 mm, the depth of the pores being less than the thickness of the first portion; a dense layer of set gypsum penetrating the lower extents of the glass fibers by approximately 90% to 100%, whereby the lower extents of the glass fibers are substantially encased by the dense layer, the dense layer including a polymeric additive; a core layer of set gypsum that is bonded to the dense layer, the core layer having a density that is less than the density of the dense layer, the core layer including a polymeric additive that is bonded to the polymeric additive in the dense slurry layer; a coating, the majority of which comprises a hot melt thermoplastic with a melting point of between 100° F. to 500° F. adhered to the upper surface of the pre-coating, the coating applied in a molten state such that it substantially fills the pores within the upper surface of the pre-coating to form a mechanical bond between the coating and the mat, the coating bonding to the polymer additive in the pre-coating. |
