ABSORBENT STRUCTURES FROM AIRLAID DEFIBRATED WOOD PULP

摘要

1500053 Hydrophillic wood pulp baths PROCTER & GAMBLE CO 2 May 1975 [7 March 1975] 18526/75 Heading D1R An absorbent air-laid structure comprises bleached hydrophilic defibrated wood pulp fibres having an average fibre length of at least 2 mm and an average fibre diameter of 0.02 to 0.06 mm, the structure having a density of 0.04 to 0.18 g/c.c. Preferably the fibres are 2 to 55 mm long. Soft woods (gymnosperms) e.g. spruce are steamed to plasticise the lignin and ground. The pulp is treated with dilute sulphuric acid to destroy micro-organisms and with diethylene triamine pentaacetic acid to remove metal ions and washed with de-ionised water. The pulp is rendered hydrophilic by bleaching with a hot aqueous hydrogen peroxide or sodium peroxide in the presence of sodium silicate and magnesium sulphate, or by bleaching with a hydrosulphite and its hydrophilic character further increased by slurrying with acetone/ methanol to extract hydrophobic lipids. The hydrophilic pulp is comminuted and air laid and the web compressed in a hydraulic die or by rolling. The density of the web is measured under load of 5 g/cm2. The web may include delignified wood pulp, rayon, cotton, cellulose acetate, wool and asbestos fibres.