GB990475A - Molded pulp production and process - Google Patents

Abstract

Cellulosic pulp for making moulded articles is treated with two waxes of which one melts above 212 DEG F. and is present in an amount in excess of that which will form a solid solution with the other, which melts below 165 DEG F. High-melting waxes referred to are methylene- and ethylene-bis-stearamide. Low-melting waxes referred to are hydrocarbon waxes, micro-crystalline wax and beeswax. They may be formed separately into aqueous dispersions; the high-melting wax may be dispersed in finely divided particulate form. Alternatively a dilute suspension of the low-melting wax is made first, and the high-melting wax then dispersed therein.ALSO:A moulded cellulosic pulp product has distributed throughout from 1 to 16% by weight of a mixture of two waxes. The first wax melts above 212 DEG F. and is present in an amount in excess of that which will form a solid solution with the second wax, which melts below 165 DEG F. The product may also contain finely divided particulate matter, e.g. aluminium silicate. The two waxes may be added together or separately to an aqueous slurry of the fibrous pulp, e.g. in the beater, and the slurry then formed to the desired shape and dried. The waxes may be added as dispersions which may be formed as emulsions, or by dispersing finely divided solid material. High-melting waxes referred to are ethylene-bis-stearamide and methylene-bis-stearamide, Low-melting waxes referred to are hydrocarbon waxes, micro-crystalline wax, and beeswax. The slurry may also contain resins or maleic-anhydride-modified resin which may be deposited on the fibres with the aid of alum, dyes or sodium silicate, which will react with alum to form the finely divided aluminium silicate referred to above.