Abstract: Coated sodium percarbonate particles, process for their preparation, their use and detergent compositions containing them Coated sodium percarbonate particles containing a sodium percarbonate core at least partially surrounded by at least one coating layer containing a hygroscopic compound, said hygroscopic compound being present in an amount such that the coated sodium percarbonate particles are capable of absorbing an amount of water (measured at an initial water content of less than 0.5% wt and after storage during 24 h at 32° C. and 50% RH) which is increased, compared to the uncoated sodium percarbonate core particles, with at least 0.1% of water per kg of coated sodium percarbonate particles.

Abstract: A process for preparing coated particulate alkali metal percarbonate in which coating is carried out by mixing percarbonate with a solid particulate coating and agent and optionally with an aqueous liquid, so that the amount of water present during mixing does not exceed 12% of the total weight of the mixture. Coated alkali metal percarbonate obtainable by this process and its use as active bleach in detergent compositions is also disclosed.

Abstract: A process for preparing coated particulate alkali metal percarbonate in which coating is carried out by mixing percarbonate with a solid particulate coating agent and optionally with an aqueous liquid, so that the amount of water present during mixing does not exceed 12% of the total weight of the mixture. Coated alkali metal percarbonate obtainable by this process and its use as active bleach in detergent compositions.

Abstract: Coated sodium percarbonate particles are provided which contain a sodium percarbonate core, and a coating layer substantially free from sulate, borate and magnesium compounds, having at least 30 and at most 75% w/w of an alkali metal carbonate and at least 25 and at most 70% w/w of an alkali metal silicate. The alkali metal carbonate and silicate being uniformly dispersed in the coating layer. Also provided is a process for the preparation of the coated sodium percarbonate particles and their use in detergent compositions.

Abstract: Sodium percarbonate is traditionally made in a crystallization process from aqueous hydrogen peroxide and sodium carbonate with recycle of mother liquor in the presence of a substantial concentration of a salting out agent, conventionally sodium chloride. The invention provides a process intended to be conducted without addition of chloride salting-out agent in which the dissolution step is controlled to restrict the sodium carbonate concentration to below 95%, preferably 60 to 90% of its saturated concentration at a temperature preferably controlled to at most 35C. and the mole ratio of hydrogen peroxide:sodium carbonate in the reaction vessel is controlled to between 0.7 to 1.2:1, and preferably about 1:1.

Abstract: Sodium percarbonate is traditionally made in a crystallization process from aqueous hydrogen peroxide and sodium carbonate with recycle of mother liquor in the presence of a substantial concentration of a salting out agent, conventionally sodium chloride.

Abstract: A method for the “dry” production of sodium percarbonate (dry process), in which monohydrate crystals of sodium carbonate are reacted with a quasi-stoichiometric quantity of concentrated aqueous hydrogen peroxide solution, relative to the quantity of active oxygen required in the sodium percarbonate to be produced. This method can be combined to great advantage with subsequent compaction of the sodium percarbonate obtained. Sodium percarbonate products containing varying concentrations of active oxygen of at least 10 weight percent, particularly high active oxygen concentrations of above 14.5 weight percent, can be produced. The resulting sodium percarbonate products are distinguished in that they have remarkably advantageous dissolution rates, stabilities and compatibility with detergent bases, and are superior to conventional sodium percarbonates obtained, for example, by a crystallization process.

Abstract: Sodium percarbonate is traditionally made in a crystallization process from aqueous hydrogen peroxide and sodium carbonate with recycle of mother liquor in the presence of a substantial concentration of a salting-out agent, conventionally sodium chloride. The invention provides a process intended to be conducted without addition of chloride salting-out agent in which the dissolution step (1) is controlled to restrict the sodium carbonate concentration to below 95%; preferably 60 to 90% of its saturated concentration at a temperature preferably controlled to at most 35° C. and the mole ratio of hydrogen peroxide: sodium carbonate in the reaction vessel is controlled to between 0.7 to 1.2:1, and preferably about 1:1.

Abstract: A flexible process for production of homogeneous sodium precarbonate particles or granules according to which a reaction slurry with an average to high solids content is prepared initially from an aqueous hydrogen peroxide solution of up to maximum 50% by weight and solid soda, this reaction slurry, which optionally may be finely ground by wet comminution, being subsequently subjected immediately to short-term drying, preferably spray drying, and, optionally, granulation. The process enables production, in an efficient manner, of essentially homogeneous sodium percarbonate particles or granules with variable active oxygen contents of 10 to 14.5% by weight and grain sizes and bulk densities which are variable within wide ranges.

Abstract: The stabilization of solid peroxo and peroxy compounds, in particular of sodium percarbonate and acetyl peroxyborate compounds is described, which can be achieved by coating the peroxo and peroxy compounds with a coating material which is a mixture of essentially a) a fatty acid or preferably an alkali metal or alkaline earth metal salt thereof and b) an anionic surfactant from the group of longer chain substituted sulphonates and sulphates.

Abstract: A process is disclosed for preparing a novel sodium percarbonate product useful in pH-regulated washing and cleaning systems. The disclosed sodium percarbonate product substantially is a mixed sodium percarbonate/sodium bicarbonate compound obtained by reacting, for example, sodium bicarbonate with an aqueous hydrogen peroxide solution.

Abstract: The use of lactobionic acid, lactobionic acid salts and/or lactobionic acid derivatives as covering material is disclosed for coating alkali metal peroxy salts, in particular for coating sodium percarbonate. In an advantageous alternative of the invention, alkali metal peroxy salts are provided with a covering layer that contains as covering materials lactobionic acid and/or lactobionic acid salt mixed with boric acid and/or a boric acid salt as additional covering material. This coating stabilizes the alkali metal peroxy salts and protects them against humidity and decomposition. In another advantageous alternative, lactobionic acid, lactobionic acid salts and/or lactobionic acid derivatives are used in combination with or in particular mixed with an inorganic mineral salt mixture of alkali metal sulphate and alkali metal chloride as additional covering material for coating alkali metal peroxy salts, in particular for coating sodium percarbonate.

Abstract: Particulate alkali metal peroxy salts are stabilized by coating with a crystallized mineral salt mixture of alkali metal sulfate and alkali metal chloride which optionally may additionally contain alkali metal silicate. Particularly suitable alkali metal peroxy salts include peroxypyrophosphate, peroxytripolyphosphate, peroxymonosulfate and peroxycarbonate. The coated peroxy salts are incorporated in bleaching and detergent compositions.