Bleaching Composition

1. Field of the Invention

This invention relates to a bleaching composition comprising a hydrogen peroxide adduct and an activating agent.

2. Description of the Prior Art

Various hydrogen peroxide adducts have heretofore been used as bleaching agents, such as, for example, sodium perborate, sodium percarbonate, sodium peroxypyrophosphate, peroxyurea and the like. Especially, sodium perborate and sodium percarbonate are widely used as ingredients of detergents compositions. Activating agents are often used in combination with these bleaching agents for increasing the effects of the bleaching agents at the time of use. When combinations of a hydrogen peroxide adduct and an activating agent are used as household bleaching agents, it is desired to employ them in the form of compositions comprising both components admixed in advance, rather than as two components which are added separately. However, in these compositions, decomposition of the active ingredients is caused not only in the case of an aqueous solution, but also in the case of a powdery composition if only a minute amount of water is present, and the water formed by such decomposition further promotes and accelerates the decomposition. Therefore, it has been very difficult to store such compositions in a stable condition. As means for solving this problem of storage instability, there have heretofore been proposed various methods for reducing the contact between a hydrogen peroxide adduct and an activating agent, for example, a method comprising coating one or both of the two ingredients with a film-forming substance and a method comprising increasing the particle sizes of both ingredients. However, no completely satisfactory result has been obtained by any of these conventional methods.

One of us previously proposed a novel hydrogen peroxide adduct having the formula:

We have discovered that this hydrogen peroxide adduct can be stored stably in a powdery form in the presence of an activating agent.

More specifically, in accordance with this invention, there is provided a bleaching composition comprising a mixture of hydrogen peroxide adduct having the formula:

and an activating agent.

The hydrogen peroxide adduct of the structure 4Na.sub.2 SO.sub.4.sup.. 2H.sub.2 O.sub.2.sup.. NaCl used in this invention is an adduct synthesized by reacting sodium sulfate with hydrogen peroxide in an aqueous solution, said method being characterized in that sodium chloride is made present in the reaction system.

The synthesis of this hydrogen peroxide adduct is described in the specification of Japanese Pat. application No. 10208/74, filed Jan. 25, 1974, corresponding to U.S. Ser. No. 593,202 filed July 7, 1975 filed in the names of Ito and Mashiko, and entitled "Stable Sodium Sulfate-Hydrogen Peroxide-Sodium Chloride Adduct and Process for Preparing Same," the entire contents of which are incorporated herein by reference.

As the activating agent used in the bleaching composition according to this invention, there can be mentioned those capable of reacting with hydrogen peroxide in an aqueous solution and thus forming an organic peracid, for example, O-acylated products such as glucose pentaacetate, octa-acetylated sucrose, triacetin, acetoxybenzenesulfonates and triacetylcyanurate, N-acylated products such as tetraacetylethylenediamine and tetraacetylglycoluril, and acid anhydrides such as phthalic anhydride and succinic anhydride, and mixtures of activating agents.

The mixing ratio of the activating agent to the hydrogen peroxide adduct of formula (I), 4Na.sub.2 SO.sub.4.sup.. 2H.sub.2 O.sub.2.sup.. NaCl, is not critical in this invention, but in general, the mixing ratio of activating agent/adduct is from 99/1to 1/99, preferably from 7/3 to 1/20, parts by weight.

The bleaching composition of this invention can further contain, if necessary, a water-soluble clothes washing surfactant, water-soluble inorganic or organic builders and fillers, a pigment, a dye, a fluorescent dye, a perfume, a germicide, an antifungal agent and like conventional bleaching composition adjuncts.

In the bleaching compositions of this invention the sum of the above bleaching agent of formula (I) plus the activator, is from about 20 to about 100% by weight, preferably from 25 to 70% by weight.

The other components of the bleaching composition of this invention are chosen from the components customarily used in clothes washing detergent compositions. For example, the remaining components of the composition can be the following:

As the surfactant, there can be employed, for example conventional anionic clothes washing surfactants such as alkyl sulfates containing an alkyl group having 10 to 22 carbon atoms, soaps containing an alkyl group having 10 to 22 carbon atoms, alkylsulfonates containing 10 to 22 carbon atoms, alkylbenzenesulfonates containing an alkyl group having 10 to 22 carbon atoms, alkylphenylpolyoxyalkylene ether sulfates containing an alkyl group having 8 to 22 carbon atoms, alkylpolyoxyalkylene ether sulfates containing an alkyl group having 10 to 22 carbon atoms, isothionates of fatty acids containing a hydrocarbon chain having 10 to 22 carbon atoms and monoglyceride sulfates of fatty acids having 10 to 22 carbon atoms; conventional non-ionic clothes washing surfactants such as polyoxyalkylenealkyl ethers containing an alkyl group having 10 to 22 carbon atoms, polyoxyalkylenealkylphenyl ethers containing an alkyl group having 10 to 22 carbon atoms, alkylolamides of fatty acids containing a carbon chain having 10 to 22 carbon atoms, polyoxyethylenesorbitan esters of fatty acids having 8 to 22 carbon atoms, polyethyleneglycol-fatty acid esters having a carbon chain of 8 to 22 carbon atoms and polyoxypropylene-polyoxyethylene block copolymers; and amphoteric surfactants such as alkylbetaines containing an alkyl group having 8 to 22 carbon atoms and ethoxybetaine. These surfactants can be used singly or in the form of mixtures of two or more of them. Cationic surfactants can be used according to need.

The neutral inorganic builder or filler salt used in the bleaching composition of this invention includes neutral watersoluble inorganic salts such as sodium sulfate and sodium chloride, and the use of sodium sulfate is especially preferred.

Conventional alkaline detergent builders such as salts of condensed phosphoric acids such as tripolyphosphoric acid and pyrophosphoric acid, orthophosphoric acid salts, bicarbonates and silicates can be used. Sodium tripolyphosphate and sodium pyrophosphate are preferred.

Likewise, there can be employed in the bleaching composition, conventional organic builders such as ethylenediamine-tetraacetic acid, its salts, nitrilotriacetic acid, its salts, carboxymethyl cellulose, polyethylene glycol, tartaric acid salts and citric acid salts.

The bleaching composition of this invention is stable even if it is stored for a long time. It can be used to bleach and sterilize various clothes and it can also be used broadly as a germicide and as a oxidant.

This invention will now be described in detail by reference to the following illustrative Examples.

Glucose pentaacetate was mixed with various hydrogen peroxide adducts listed in Table 1 at a mixing weight ratio of 20/80, and the mixture was passed through a 16-mesh sieve and a 60-mesh sieve. The particles left on the 60-mesh sieve were collected. The particles were stored for 1 month at a temperature of 40.degree.C and a relative humidity of 80%, and the residual ratio of available oxygen was measured. The term "available oxygen residual ratio (%)" means ##EQU1## The results shown in Table 1 were obtained.

The above components were compounded to obtain a bleaching composition. When this composition was stored at 30.degree.C for 1 month, the available oxygen residual ratio was found to be 95%.

The above components were compounded to obtain a bleaching composition. When this composition was stored at 30.degree.C for 1 month, the available oxygen residual ratio was found to be 96%.

It was found that a bleaching composition comprising the above components is stable for a long time and valuable as a bleaching agent for household uses.

Bleaching compositions A, B, C and D indicated below were prepared.

A black tea-stained cloth was immersed for 30 minutes in an aqueous solution containing 1 wt.% of the sample composition and maintained at 40.degree.C. Then, the bleached cloth was washed with service water, air-dried and ironed. Then, the reflectivity of the cloth was measured by using an automatic-recording color-different meter, and the bleaching power was calculated according to the following formula:

Bleaching Power = (reflectivity of bleached cloth at 550 m.mu.) - (reflectivity of stained cloth at 550 m.mu.)

The reflectivity of the starting stained cloth at 550 m.mu. was adjusted at 42 .+-. 1%. Results obtained are as shown in Table 2.

In the foregoing Examples, all references to "%" mean percent by weight unless otherwise indicated.