PLASTERBOARD MANUFACTURE

摘要

TITLE: IMPROVEMENTS IN PLASTERROARD MANUFACTURE Satisfactory or enhanced dry bond between the gypsum core of plasterboard and paper facing sheets is achieved by treatment of at least the inner faces of the paper sheets with a water soluble zirconium salt before contacting the sheets with a core slurry containing gypsum plaster and starch as a dry bond assistant. The preferred zirconium salt is zirconium acetate although other salts such as oxychloride, nitrate and sulphate can also be used. The preferred level of zirconium is from 1 to 2 g. per square metre of paper, expressed as zirconium dioxide, and excellent dry bonds are formed with as little as 0.2% starch by weight of core solids, which represents an important economy in the use of starch.