Solvay Interox Gmbh

Solvay (societe Anonyme)

Solvay Interox (societe Anonyme)

Solvay Interox Sa

Manfred Mathes

Werner Doetsch

Alun P James

Graham R Horne

Richard Roesler

Helmut Honig

Gerd Hecken

Soraya Parvaneh

Romano Pardini

Lido Signorini

Stefano Bigini

Robert Owen

Pier-Luigi Deli

Uwe Droste

Klaus-Guenter Gerling

Juan-Teva Carlier

Gabriele Wasem

Tom Candy

Harald Beck

Paul-Wilhem Fuchs, Deceased

Richard R&ouml;sler

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.

Process for preparing coated alkali metal percarbonate, coated alkali metal percarbonate obtainable by this process, its use in detergent compositions, and detergent compositions containing it

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.

Coated sodium percarbonate particles, process for their preparation, their use in detergent compositions and detergent compositions containing them

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. In some embodiments at least a fraction of the mother liquor introduced into the dissolution tank is obtained by extraction from the reaction vessel and in other embodiments a fraction of the sodium percarbonate is introduced in solution in the mother liquor and a fraction is introduced in particulate form directly into the reaction vessel. Large particle sodium percarbonate is provided which has a 7 day aged heat emission at 40C. of not more than 3 &mgr;W/g measured in a microcalorimeter over 16 hours that is lower than the heat emission from conventionally produced sodium percarbonate employing a chloride salting-out agent.

Sodium percarbonate and process for producing sodium percarbonate

A method for the &ldquo;dry&rdquo; 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. The invention also relates to the sodium percarbonate products obtained and to detergent compositions containing such sodium percarbonate products.

Method for producing sodium percarbonate

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 35&deg; 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. In some embodiments at least a fraction of the mother liquor introduced into the dissolution tank (,) is obtained by extraction from the reaction vessel (,) and in other embodiments a fraction of the sodium percarbonate (,) is introduced in solution in the mother liquor (,) and a fraction is introduced in particulate form (,) directly into the reaction vessel (,). Large particle sodium percarbonate is provided which has a 7 day aged heat emission at 40&deg; C. of not more than 3 &mgr;W/g measured in a microcalorimeter over 16 hours that is lower than the heat emission from conventionally produced sodium percarbonate employing a chloride salting-out agent.

Process for producing sodium percarbonate

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.

Process for the production of sodium percarbonate

Solid peroxo compounds and peroxy compounds stabilized by coating

Process for preparing a sodium percarbonate product

Coated alkali metal peroxy salts and process for their preparation

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.

Detergent composition containing alkali metal peroxysalt stabilized with

Growing community of inventors

Bad Hoenningen, Germany

Manfred Mathes