Location
Paper & Pulp
ICL condensed phosphates are used in paper coating and filling to promote the dispersion of kaolin clay, lithopone, titanium dioxide, iron oxide, calcium carbonate and other ingredients in aqueous suspensions. Phosphates like STPP, TSPP and SHMP act to disperse particles by adsorbing on the surface of particles and giving them a negative charge. The particles repel each other, limiting flocculation and lowering the viscosity of suspensions. This results in slurries that are easier to handle and transport. The reduced flocculation also allows for better packing on the sheet and superior gloss development, opacity and brightness.
In pulping applications, STPP or TSPP are effective in deflocculating and dispersing pitch even under conditions of hard water. The phosphates sequester the hard water ions of calcium and magnesium as well as ions from iron. The sequestration of hard water ions allows for superior surfactant action, while the sequestration of iron increases the effectiveness of the bleach system resulting in improved brightness. In kraft or semi-chemical pulping, the use of STPP along with surfactants reduces black liquor loss, decreases digestion time, increases screen yield, improves washer effectiveness and produces freer stock.
In rayon pulps, the same STPP/surfactant system will reduce the level of residual resin content. In stocks containing precipitated calcium carbonate fillers, the addition of phosphoric acid converts the precipitate into calcium phosphate, resulting in better brightness of the bleached papers.
Phosphates like STPP, TSPP and SHMP act to disperse particles by adsorbing on the surface of particles and giving them a negative charge. The particles repel each other, limiting flocculation and lowering the viscosity of suspensions. This results in slurries that are easier to handle and transport. The reduced flocculation also allows for better packing on the sheet and superior gloss development, opacity and brightness.
In pulping applications, STPP or TSPP are effective in deflocculating and dispersing pitch even under conditions of hard water. The phosphates sequester the hard water ions of calcium and magnesium as well as ions from iron. The sequestration of hard water ions allows for superior surfactant action, while the sequestration of iron increases the effectiveness of the bleach system resulting in improved brightness. In kraft or semi-chemical pulping, the use of STPP along with surfactants reduces black liquor loss, decreases digestion time, increases screen yield, improves washer effectiveness and produces freer stock.
In rayon pulps, the same STPP/surfactant system will reduce the level of residual resin content. In stocks containing precipitated calcium carbonate fillers, the addition of phosphoric acid converts the precipitate into calcium phosphate, resulting in better brightness of the bleached papers.