GB485504A - Improvements in or relating to insulating materials and apparatus for the manufacture thereof - Google Patents

Abstract

485,504. Moulding plastic compositions containing vermiculite. BRITISH ZONOLITE PRODUCTS, Ltd. (Schundler & Co., Inc., F. E.) March 17, 1937, No. 7848. [Classes 22, 70, and 87 (ii)] Insulating slabs are produced by mixing a cementitions slurry containing granules and laminae of vermiculite and a small percentage of fibre, placing the slurry into a mould having at least one perforated face, separating liquid from the slurry by passing it through the perforations, and finally removing the slab. The fibre constituent is preferably asbestos and the cement may be Portland cement or magnesium oxy-sulphate cement. One example of a suitable mixture comprises 100 parts of vermiculite, 45 parts of Portland cement, and 18 parts of asbestos fibre, all by weight. Another mixture comprises 25 lb. of vermiculite 2 lb. of long fibre asbestos, 4 to 8 1b. of active magnesium oxide and sufficient magnesium sulphate solution to produce a sloppy consistency. The mould 13 has a perforated bottom 14 covered by a screen cloth' 15. The mould is dipped into the slurry and suction is applied through pipe 17 to draw material into the mould and remove liquid. The formed slab is discharged by air pressure through the pipe 18. Trunnions 20 are provided on the mould so that it may be inverted if necessary. In a modification, Fig. 4, the mould 23 stands on a suction box 26 on a gasket 28. After the liquid has been removed the mould 23 is inverted to deliver the slab. Instead of suction, air or mechanical pressure may be applied to dewater the slab. When making pipe coverings the mould is of semi-cylindrical shape. The slab may be finally dried at a temperature of 400 to 600‹ F. preferably after being air cured for 24 to 48 hours. Specification 485,505 is referred to.