Patent ID: 11884040
Assignee: UNITED STATES GYPSUM COMPANY
Field: Surface technology, coating (Chemistry)
Classification: CPC B  C  Y | IPC B  C

Claim 13:
14. A method of making a light weight gypsum board, the method comprising:
(A) preparing a gypsum slurry having foam dispersed therein;
(B) disposing the gypsum slurry between a first cover sheet and a second cover sheet to form a panel;
(C) cutting the panel into a board of predetermined dimensions; and
(D) drying the board;
such that a set gypsum core comprising a gypsum crystal matrix is formed between the cover sheets, the gypsum crystal matrix defining walls surrounding and between air voids within the gypsum crystal matrix, the majority of air voids have a diameter of about 100 microns or less, the average thickness of the walls between the air voids being about 30 microns to about 200 microns, the average wall thickness and air voids measured using three-dimensional imaging acquired by X-ray CT-scanning analysis (XMT), and the gypsum crystal matrix formed such that the set gypsum core has an average core hardness of at least about 11 pounds as determined in accordance with ASTM C-473; and the board having a density of about 35 pcf or less.