Patent ID: 6159410
Filing Date: 2000-12-12
Classification: B28B,B32B,E04C,Y10S,Y10T

Abstract:
A method for producing a gypsum-based composite article reinforced with glass fibers, wherein said article comprises:a first member made of hard gypsum;a second member made of soft gypsum having a compressive strength which is lower than that of said hard gypsum, said second member being formed on and bonded to said first member; and said second member; anda mat made of said glass fibers, said mat being embedded in said article in a manner that said first member and said second member are bonded together by means of said mat,said method comprising the sequential steps of:(a) preparing a substrate having a first shape;(b) applying a mold releasing agent to an outer surface of said substrate, thereby to form a mold releasing film on said outer surface of said substrate;(c) applying a first slurry which is a mixture of water and hard gypsum plaster, to said mold releasing film, said hard gypsum plaster being hardenable into a hard gypsum, thereby to form a first layer on said mold releasing film;(d) disposing on said first layer a mat which is made of a the glass fibers and impregnated with a second mass of said first slurry;(e) deaerating said mat disposed on said first layer;(f) applying a second slurry, which is a mixture of water and a soft gypsum plaster, to said mat, said soft gypsum plaster being hardenable into a soft gypsum having a compressive strength lower than that of said hard gypsum, such that a second lower layer is formed on said mat and thus that a precursor of said gypsum-based article is formed on said substrate, said precursor being a laminate of said first layer, said mat and said second layer;(g) curing said precursor to produce said gypsum-based article having a second shape conforming to said first shape of said substrate; and(h) removing said substrate from said gypsum-based article.