Process for manufacturing gypsum board faced with non-woven glass fiber mat
A gypsum board comprises a set gypsum layer having a first face and a second face. A fibrous mat is affixed to at least one of the faces. The mat comprises a non-woven web bonded together with a resinous binder. The web is composed of chopped continuous glass fibers having an average fiber diameter ranging from about 9.5 to 12.5 μm. The board is exceedingly durable. It has a smooth surface that is readily finished in an aesthetically pleasing way, using paint or other wall covering systems.
1. A process for manufacturing a paintable article comprising a hydraulic set material layer having first and second faces, and first and second facers affixed thereto, at least said first facer comprising a non-woven, fibrous mat, the process comprising:
a. providing said non-woven, fibrous mat comprising a non-woven, glass fiber web having a smooth surface texture, said glass fibers consisting essentially of chopped glass fibers having an average fiber diameter ranging from about 9.5 to 12.5 μm and an average fiber length ranging from about 6 to 12 mm bound together with a resinous binder, said resinous binder comprising an acrylate copolymer latex having a glass transition temperature of about 25° C. and about 2 to 5 wt % of a crosslinker comprising melamine formaldehyde;
b. forming an aqueous slurry comprising at least one member selected from the group consisting of anhydrous calcium sulfate, calcium sulfate hemi-hydrate, and hydraulic setting cement;
c. distributing the slurry to form a layer on said first facer;
d. applying said second facer onto the top of said layer;
e. separating the resultant laminate into individual articles; and
f. drying the articles,
whereby said non-woven, fibrous mat of said first facer has a permeability of at least about 300 cfm/ft 2 measured in accordance with ASTM Standard D737 at a differential pressure of 0.5 inches of water and with a smoothness that is sufficient to permit said articles to be directly paintable.
2. A process as recited by claim 1 , wherein said hydraulic set material layer comprises gypsum.
3. A process as recited by claim 1 , wherein said chopped glass fibers are composed of at least one member selected from the group consisting of E glass, C glass, T glass, sodium borosilicate glass, and mixtures thereof.
4. A process as recited by claim 1 , wherein said chopped glass fibers are composed of E glass.
5. A process as recited by claim 1 , wherein at least about 90% by weight of said chopped glass fibers have a diameter ranging between about 9.5 and 12.5 μm.
6. A process as recited by claim 1 , wherein at least about 95% by weight of said chopped glass fibers have a diameter ranging between about 9.5 and 12.5 μm.
7. A process as recited by claim 1 , wherein at least about 97% by weight of said chopped glass fibers have a diameter ranging between about 9.5 and 12.5 μm.
8. A process as recited by claim 1 , wherein at least a majority of said chopped glass fibers have a fiber length ranging from about 6 to 18 mm.
9. A process as recited by claim 1 , wherein said resinous binder further comprises at least one water repellant agent.
10. A process as recited by claim 1 , wherein said fibrous mat has a basis weight ranging from about 0.6 to 2.2 pounds per 100 square feet.
11. A process as recited by claim 10 , wherein said fibrous mat has a basis weight ranging from about 0.9 to 2.2 pounds per 100 square feet.
12. A process as recited by claim 11 , wherein said fibrous mat has a basis weight of about 1.25±0.2 pounds per 100 square feet.
13. A process as recited by claim 1 , said second facer comprising a fibrous mat.
14. A process as recited by claim 1 , said second facer being a fibrous mat comprising a non-woven, glass fiber web, said glass fibers consisting essentially of chopped glass fibers having an average fiber diameter ranging from about 9.5 to 12.5 μm and an average fiber length ranging from about 6 to 12 mm bonded together with a resinous binder.