Patent ID: 6475313
Filing Date: 2002-11-05
Classification: B28B

Abstract:
A process for making gypsum board having at least one face comprising a high density gypsum layer overlaying a lower density, foamed gypsum core comprising the following steps:(1) feeding a first paper sheet material to a gypsum board manufacturing line; (2) feeding a scrim material to the gypsum board manufacturing line; (3) placing said paper sheet material and scrim material in alignment but separated whereby they form a trough; (4) depositing a high density calcium sulfate hemihydrate slurry in the trough between said paper sheet material and said scrim material and into contact with said paper and scrim; (5) compressing said paper sheet material, said scrim material and said high density hemihydrate slurry whereby said scrim material is encapsulated in said high density calcium sulfate hemihydrate slurry to form a laminated paper/scrim/hemihydrate slurry; (6) passing the laminated paper/scrim/hemihydrate slurry to a gypsum board forming station; (7) bringing said laminated paper/scrim/hemihydrate slurry into contact with a foamed, lower density calcium sulfate hemihydrate slurry at said board forming station, said foamed, lower density slurry being carried on a second paper sheet material; and (8) passing the paper sheet materials with the scrim and both high density and lower density slurries there between along the manufacturing line until they are sufficiently cured to the point where they can be cut to length and passed to a kiln for final curing.