MICROSTRUCTURE FEATURE OF GYPSUM WALLBOARD MADE WITH HIGH STARCH AND HIGH DISPERSANT LEVEL

摘要

PROBLEM TO BE SOLVED: To provide a method for forming a gypsum wallboard having high strength and substantially lighter weight than conventional wallboards.SOLUTION: This invention relates to gypsum wallboards with a unique microstructure where the walls between voids have thickness of 20-200 μm and are enhanced in strength to substantially improve the strength and handling properties of the wallboards. A set gypsum core is made from a gypsum-containing slurry comprising: water; stucco; pregelatinized starch present in the amount of about 0.5 to about 10 wt.% based on the weight of stucco; a naphthalenesulfonate dispersant present in the amount of about 0.2 to about 2 wt.% based on the weight of stucco; sodium trimetaphosphate present in the amount of about 0.1 to about 0.4 wt.% based on the weight of stucco; and optionally glass fiber present in the amount of about 0.2 wt.% or less. A method for forming the lightweight gypsum wallboard is also provided.SELECTED DRAWING: Figure 1