Evonik Degussa Gmbh

Degussa Gmbh

Klaus Zimmermann

Harald Jakob

Ulrike Kottke

Michael Fender

Ralph Overdick

Silke Stoschek

Coated sodium percarbonate particles, having an inner shell layer which comprises at least one inorganic, hydrate-forming salt as the main constituent, and an outer shell layer which comprises an alkali metal thiosulfate, an alkaline earth metal thiosulfate and/or an ammonium thiosulfate, are stable to storage and have an improved storage stability in detergents and cleaning agents. Detergents and cleaning agents which comprise such sodium percarbonate particles show a reduced oxidative attack on oxidation-sensitive constituents of the composition during storage. Machine dishwashing agents in the form of tablets which comprise such sodium percarbonate particles and a corrosion protection agent for silver show a reduced yellowing of the tablets during storage.

Sodium percarbonate particles having a shell layer comprising thiosulfate

The invention concerns coated sodium percarbonate granules comprising a core produced by fluidized bed spray granulation, containing sodium percarbonate as its main component, an inner coating layer containing an organic, hydrate-forming salt as its main component, and an outer coating layer containing as its main component at least one surfactant containing in the molecule one or more sulfate or sulfonate groups in the form of an alkali metal, alkaline-earth metal or ammonium salt. The invention also concerns a process for the production of the granules, the use of the granules in bleaching and cleaning agents, and bleaching and cleaning agents containing the granules. The sodium percarbonate granules according to the invention display improved storage stability combined with high internal stability and a high active oxygen content.

Coated sodium percarbonate granules with improved storage stability

The invention relates to liquid detergent and cleaning agent compositions of high storage stability. They comprise a liquid medium with a water content of up to 15 wt. % and particulate coating bleaching agents suspended therein. The bleaching agent has a dissolving time of at least 5 minutes and a coating of at least two layers: The innermost layer comprises one or more hydrate-forming inorganic salts as the main component(s), and an outer layer, which makes up 0.2 to 5 wt. % of the coated bleaching agent, comprises alkali metal silicate(s) with a modulus of SiO2 to M2O (M=alkali metal) of greater than 2.5 as the main component(s). Preferred compositions comprise sodium percarbonate with an innermost layer of substantially sodium sulfate and an outermost layer of substantially 0.5 to 1.5 wt. % sodium silicate (modulus 3.2 to 4.2) as the bleaching agent.

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Rodenbach, Germany

Klaus Zimmermann