Plaster-bound moulding contg. lignocellulose fibre reinforcement - obtd. from fibre slurry from cellulose@ mfr. and opt. lime slurry and waste contg. set plaster from moulding e.g. plasterboard mfr.

摘要

Plaster-bound fibre mouldings, esp. plasterboard, contains a set binder (I) contg. plaster and, as fibrous reinforcement, lignocellulose fibres (II) obtd. from the fibre slurry from cellulose mfg. Also claimed is a method of mfg. the above mouldings. The moulding also contains (III) and other usual additives. It contains 65-85, pref. 75-80 (wt.)% (I), 10.8-17.1, pref. 11.1-13.4% (II), 3.6-11.4, pref. 5-4.9.8% (III) and 0.7-3% finely ground (IV). The moulding is produced by mixing wet fluffed (II) with CaSO4.1/2H20 powder and opt. usual additives, moulding to a fibre mat and compressing until the binder sets. (II) contains 60-125% moisture. On a dry basis, the finely-divided (III) powder or CaCO3 content is adjusted to 0.5-2.0% by pptn. on (II); and the ratios of components are (II):CaSO4.1/2H20=0.15-0.30, pref. 0.17-0.20; (III) or CaCO3:CaSO4.1/2H20=0.05-0.2, pref. 0.0-0.15; powdered and crystalline ammonium sulphate:CaSO4.1/2H20=0.01-0.03, pref. 0.02; and (IV):CaSO4.1/2H20=0.01-0.05, pref. 0.02. USE/ADVANTAGE - The prods. are used in the building industry. The mouldings utilise waste materials, including fibre slurry and opt. also lime slurry (III) from cellulose mfr., e.g. from straw by the sulphate process, and set (I)-(II) mixts. (IV) from moulding mfr. 50 kg fibre sludge (125% moisture) were loosened in a laboratory refiner, mixed with 200 g powdered (III) and fluffed, when (III) was deposited on the surface of the fibres and prevented aggregation on mixing with CaSO4.1/2H20. Plasterboard was made from (A, B) 889.1, (C) 835.4 g CaSO4.1/2H20, 220.3 g dry fibre sludge, (A, B) O, (C) 64.8 g dry (III), (A) 0, (B) 17.78, (C) 16.71 g (NH4)2SO4 and (A) O, (B) 17.78, (C) 16.71 g (IV). These boards had a bulk density of (A) 1180, (B) 1190, (C) 1209 kg/cu.m; and flexural strength of (A) 5.3, (B) 5.7, (C) 6.1 MPa.