Method of rendering chip-board or box-board liners of gypsum plasterboards resistant to accidental damage

摘要

Gypsum plaster boards are rendered resistant to damage by impregnating the liners, after manufacture of the boards, with a composition comprising an alkyl (e.g. methyl) ether of a methylol urea (obtained by reacting at least three parts of formaldehyde with one of urea in the presence of the alkyl alcohol) and an acid catalyst, e.g. phosphoric, sulphuric or hydrochloric acid, with or without a pigment or dye, e.g. an acid azo-dye, and thereafter curing by heat.