GB585319A - Bituminous emulsion - Google Patents

Abstract

Bitumen in water emulsions are made from hard, brittle, bitumens which can be ground to a powder at 77 DEG F. without sticking to the grinding surfaces. Asphalts and pitches, e.g., coal tar pitches de-oiled by steam distillation in vacuo, may be used. The bitumen is preferably melted and emulsified in a colloid mill, which may be steam jacketed, under sufficient pressure to prevent boiling of the aqueous phase. High melting non-sticky emulsifying agents are preferably employed, e.g., alkali soaps of resins such as "Vinsol" (Registered Trade Mark) though clay, protein, e.g., soya bean meal, defibrinized blood, or casein, soap or hot dilute caustic alkali may be used. The emulsions on desiccation at 77 DEG F. yield a dry residue which readily re-emulsifies on stirring with water. Examples describe the use of asphalt having a 190-200 DEG F. softening point and a penetration (A.S.T.M. D5-25 method) of 0-5. Specifications 254,021, [Class 2 (iii)], and 288,821, [Class 1 (i)], are referred to.ALSO:Adhesives suitable for paper and plywood comprise a water-soluble urea-formaldehyde resin, a resin-setting agent, e.g. ammonium chloride, an aqueous paste of starch, and a bitumen in water emulsion made from a hard, brittle, bitumen, asphalt or pitch which can be ground to a powder at 77 DEG F. without sticking to the grinding surfaces (see Group III). The emulsions may also be used as resin extenders. Specifications 254,021, [Class 2 (iii)], and 288,821, [Class 1 (i)], are referred to.ALSO:Bitumen in water emulsions made from hard, brittle bitumens which can be ground to a powder at 77 DEG F. without sticking to the grinding surfaces (see Group III) are used as sizing and waterproofing agents for fibrous pulp, paper, board and felted fibrous articles. Asphalts and pitches may be used. Alum or sodium silicate with or without acid may be used to flocculate the emulsions during sizing. Examples describe the impregnation of unformed pulp and of multiple ply papers which are formed into multiple ply boards. Specifications 254,021, [Class 2 (iii)], and 288,821, [Class 1 (i)], are referred to.