GB456434A - Improvements in or relating to the sizing of paper or paper pulp - Google Patents

Abstract

456,434. Sizing paper-pulp. DU PONT DE NEMOURS & CO., E. I., Wilmington, Delaware, U.S.A. Feb. 1, 1935, No. 3400. Void [Abridged as open to inspection under Sect. 91 of the Acts, Aug. 2, 1935]. [Class 96] Paper pulp, e.g. cotton rag, soda, sulphite, or kraft is sized with a fatty acid soap or a wax, e.g. sodium, ammonium or other stearate, laurate, oleate, palmitate, melissate, or Japan wax, paraffin wax, carnauba wax, beeswax, or synthetic waxes, together with a protein, e.g. casein, gelatine, glue, albumin, soya bean meal extract, or cotton seed meal the soap or wax which is applied as an aqueous solution, dispersion or emulsion, may comprise between 5 and 40 per cent of the total, a strong, waterproof paper which does not discolour with age being thus produced. The size which comprises 0À5-10 per cent of the weight of the fibre may be precipitated by adding aluminium sulphate, e.g. at the beater before or after adding the size, e.g. to make the pH value = 4À5, or by alum, sulphuric acid, or calcium chloride. In an example to 100 parts of high alpha-cellulose chemical wood pulp hydrated in a beater are added 11À1 parts of a 3 per cent solution of sodium stearate and 22À2 of a 3 per cent solution of casein dispersed with sodium hydroxide. Sheets are formed in a hand mould, pressed, and dried at 100- 110‹ C. In other examples are used blood albumin peptized with ammonia, or Japan wax emulsified with sodium stearate.