Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – With oxygen or halogen containing chemical bleach or oxidant...
Patent
1997-03-21
1998-10-27
Einsmann, Margaret
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
With oxygen or halogen containing chemical bleach or oxidant...
510375, 8111, 25218643, 25218625, 25218627, C11D 339, C01B 1510
Patent
active
058278117
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to particles comprising a peroxy compound and a dicarboxylic acid having from 5 to 10 carbon atoms or a salt thereof. The invention also relates to use of the particles and a composition containing such particles.
Powder detergent compositions often contain peroxy compounds as bleaching agents which release hydrogen peroxide or peroxy acids in aqueous solutions. However, many peroxy compounds are not storaae stable. Their decomposition is supposed to be catalysed by metal cations moving comparatively freely through the water normally being present in detergents, but is also facilitated by the alkaline pH (normally from about 8 to about 12) and by other components commonly present in detergents, for example zeolites or bleaching activators such as TAED (tetraacetylethylene diamine), TAGU (tetraacetylglucoluril) or PAG (penta acetyl glucose)
In order to make environmental friendly detergents, it is desirable to use alkali metal carbonate peroxy hydrate, commonly known as percarbonate, as a bleaching agent. However, the activity of percarbonate in a detergent decreases rapidly through decomposition if the detergent is stored at normal room temperature and humidity.
Many attempts to stabilize percarbonate have been done, for example by mixing or coating with stabilizing substances such as sulfates, carbonates, borates, silicates or organic substances. Such stabilizing methods are described in the patent literature, for example in GB 1466799, GB 1538893, GE 1575792, EP 459625, U.S. Pat. No.3,975,280 and EP 573731.
U.S. Pat. No.4,075,116 describes preparation of percarbonate from sodium carbonate, hydrogen peroxide and different additives.
CH patent 659082 describes mixing bleaching agents with high amounts of inorganic carbonates and water soluble acids and thereby increasing the dissolution rate.
Japanese laid open patent application (Kokai) Sho 58-74508 describes a mixing percarbonate with silicate and phosphate, borate, citrate, tartrate or succinate of sodium and thereby increasing the dissolution rate.
U.S. Pat. No. 5,340,496 describes stabilization of percarbonate with certain combinations of inorganic salts and carboxylic acids, particularly long chained acids such as oleic acid.
The object of the present invention is to provide particles comprising a peroxy compound, particularly alkali metal percarbonate, with improved storage stability, particularly in detergent compositions. It is another object of the invention to provide particles comprising a peroxy compound only containing environmental friendly constituents.
Through the present invention, these objects has been fulfilled by providing particles comprising a peroxy compound with capability of releasing hydrogen peroxide or peroxy acids in aqueous solutions, the particles further comprising up to 15% by weight, preferably up to about 10% by weight, most preferably up to about 5% by weight of a preferably water soluble dicarboxylic acid having from 5 to 10 carbon atoms or a salt thereof. The particles preferably comprise more than about 0.01% by weight, most preferably more than about 0.05% by weight of such a dicarboxylic acid or a salt thereof. The amount of the peroxy compound in the particles is suitably from about 10 to about 99% by weight, preferably more than 50% by weight and most preferably up to about 95% by weight. The dicarboxylic acid in the particles may be mixed with the peroxy compound and/or be included in a coating.
It is assumed that the dicarboxylic acid acts as a chelating agent, but it has surprisingly been found that the dicarboxylic acids according to the invention gives superior storage stability compared to conventional chelating agents such as EDTA. Too high a concentration of dicarboxylic acids or salts thereof will however decrease the thermal stability, particularly at high concentrations of the peroxy compounds.
It is preferred to use an alkali metal or an alkaline earth metal salt of the dicarboxylic acid. Alkali metals are preferably selected from sodium, potassium or mixtures thereof, a
REFERENCES:
patent: 3975280 (1976-08-01), Hachmann et al.
patent: 3977988 (1976-08-01), Tokiwa et al.
patent: 4075116 (1978-02-01), Mesaros
patent: 4231890 (1980-11-01), Yagi et al.
patent: 5340496 (1994-08-01), Sato et al.
Jigstam Monica
Lagnemo Hans
Oddstig Cecilia
Einsmann Margaret
Eka Chemicals AB
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