GERMICIDAL COMPOSITION Technical Field The present invention relates to germicidal com¬ positions which can be used for a wide variety of ap¬ plications ranging from applications to foods, paper and fibers to domestic applications. Specifically, the present invention relates to germicidal compositions which can be used typically for the sterilization and disinfection of city water for purification, the sterilization and disinfection of general foods led by meat and fishery products, the antisepsis of wood, antisepsis in paper manufacturing processes, and the sterilization and disinfection of toilet, bath rooms and kitchen at home and which are excellent in sterilizing effects and storage stability. Background Art

It is known that an inorganic peroxide such as sodium perborate, sodium percarbonate or sodium persul- fate generates both hydrogen peroxide and nascent oxygen when dissolved in water and owing to these hydrogen peroxide and nascent oxygen, the peroxide ex¬ hibits cleaning, bleaching, sterilizing and disinfect- ing effects.

Use of such an inorganic peroxide alone however results in release of oxygen at once in a short time so that oxygen will escape in the form of large bubbles to the outside of a system to which the inorganic peroxide is applied. Nascent oxygen will therefore be lost quickly, leading to the drawback that no sufficient sterilizing effects will be provided.

With a view toward overcoming such a drawback of inorganic peroxides, compositions have been developed in which an inorganic peroxide is mixed with, as an ac¬ tivator for the inorganic peroxide, an organic acid ester such as an acetate ester or a propionate ester (Japanese Patent Laid-Open Nos. 14886/1973, 25011/1977, 139500/1970 and 63504/1987) . These compositions each forms an organic peracid when reacted with water at a place to be sterilized. The resultant organic peracid reacts further with water and generates oxygen, thereby exhibiting sterilizing effects.

These compositions however undergo such reactions in the presence of even a slightest amount of water so that when stored for a long time, they will give off an irritating organic acid odor. Among these composi¬ tions, those containing an inorganic peroxide and an ester of a polyhydric alcohol and an organic acid in combination are relatively stable against water (Japa-

nese Patent Laid-Open No. 25011/1977) . They are, on the other hand, accompanied by the drawback that due to their low solubility in water, an organic peracid is not produced sufficiently, hence oxygen is formed only at a low rate and their sterilizing power is low.

Incidentally, compositions with an organic peracid incorporated therein as is are accompanied with the drawback that they have an irritating odor and are hence low- in commercial value. Further, those composed of an organic peracid alone will involve the drawback that they decompose when stored for a long time.

Accordingly, an object of the present invention is to provide a germicidal composition which stably generates an organic peracid, has sustained sterilizing power and has excellent storage stability.

Disclosure of the Invention

The present invention provides a germicidal com¬ position comprising the following components (A) , (B) and (C) :

(A) an inorganic peroxide,

(B) an incomplete ester of a polyhydric alcohol with an organic acid, and

(C) an alkali earth metal salt. By the combination of these three components, the

resulting germicidal composition according to the pres¬ ent invention has good storage stability, good water solubility and high and long-lasting sterilizing ef¬ fects so that it can be used for a wide variety of ap- plications ranging from applications to foods, paper and fibers to domestic applications.

Best Modes for Carrying Out the Invention

Examples of the component (A) , that is, the in- organic peroxide used in the present invention include sodium percarbonate, sodium perborate, sodium peroxytripolyphosphate, sodium peroxypyrophosphate and sodium peroxysilicate. Among them, sodium percarbonate and sodium perborate are particularly preferred. The component (B) which is the incomplete ester of the polyhydric alcohol with the organic acid serves as an activator for the inorganic peroxide as the com¬ ponent (A) . It reacts with the component (A) to form an organic peracid. One of characteristic features of the present in¬ vention resides in the incorporation of the incomplete ester of the polyhydric alcohol with the organic acid as an activator for the inorganic peroxide. The com¬ position with this incomplete ester incorporated there- in has excellent water-solubility and dramatically im-

proved sterilizing effects compared with conventional compositions containing the complete ester of a polyhydric alcohol with an organic acid. The term "in¬ complete ester" as used herein means an ester in which the degree of esterification of a polyhydric alcohol is less than 100%. The esterification degree can preferably be 5-95%, with 60-95% being particularly preferred. Incidentally, the esterification degree can be measured from the degree of absorption at 3500 cm ^-1 in an infrared absorption spectrum.

Illustrative examples of the polyhydric alcohol can include glycerins such as glycerin, diglycerin, triglycerin and polyglycerin; alkali-modified sucroses such as sorbitol, glutitol, pentaerythritol, alkyl- polyglycosides and alkylfuranosides; alkylene-oxide ad- ducts of these glycerins and sucroses. Preferred exam¬ ples of the organic acid can include saturated or un- saturated C ₁ _ ₈ fatty acids. Specific examples include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, octanoic acid, acrylic acid, methacrylic acid, crotonic acid, al- lylacetic acid, dimethylacrylic acid and monocarboxylic acids. Dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, maleic acid and fumaric acid can also be employed.

Examples of the alkali earth metal salt as the component (C) can include alkali earth metal salts of inorganic acids and halides of alkali earth metal salts. Illustrative alkali earth metals can include calcium and magnesium, illustrative inorganic acids can include sulfuric acid, nitric acid, phosphoric acid and carbonic acid, and illustrative halogens can include chlorine and bromine. Specific examples of the com¬ ponent (C) include magnesium sulfate, calcium sulfate, magnesium phosphate, calcium phosphate, magnesium nitrate, calcium nitrate, magnesium chloride, calcium chloride, basic magnesium carbonate and calcium car¬ bonate, and anhydrous salts thereof.

The component (C) has stabilizing effects for the organic peracid to be formed through the reaction be¬ tween the component (A) and the component (B) , and the addition of the component (C) has improved the long- lasting ability of sterilizing effects.

In the germicidal composition according to the present invention, the components (A) to (C) can be mixed properly depending on its application purpose. In view of sterilizing effects, storage stability, economy and the like, it is preferred to mix 0.01-10 parts by weight of the component (B) and 0.01-90 parts by weight of the component (C) with 1 part by weight of

the component (A) . Particularly preferred is to add the component (C) 0.01-100 times, particularly 0.1-20 times in weight relative to the component (B) .

In addition to the above three components, the germicidal composition of the present invention can contain various additives such as surfactants, in¬ organic or organic alkali metal salts, builders, flavorants, pigments, dyes, pH regulators and metallic chelating agents. Illustrative surfactants can include nonionic, anionic and ampholytic ones. Specific exam¬ ples can include nonionic surfactants such as polyoxy- ethylene (hereinafter abbreviated as "POE") C ₆ _ ₂₂ alkyl ethers, POE C ₄ _ ₁₈ alkylphenol ethers, block or random polyoxypropylene-polyoxyethylene alkyl ethers, POE phenylphenol ether, POE styrenated phenol ether and POE tribenzylphenol ether; anionic surfactants such as lig- nin sulfonate salts, alkylbenzene sulfonate salts, alkyl sulfonate salts, POE alkyl sulfonate salts, POE alkylphenylether sulfonate salts, POE alkylphenylether- phosphate ester salts, POE phenylphenolether sulfonate salts, POE phenylphenolether phosphate ester salts, naphthalene sulfonate salts, naphthalenesulfonic acid- formaldehyde condensates, POE tribenzylphenolethersul- fonate salts and POE tribenzylphenylphenolether phosphate esters; and ampholytic surfactants such as

alkylaminotrimethylglycines, alkyldimethyla ine oxides and alkyldia inoethylglycine hydrochlorides. They may be used either singly or in combination. The content of the surfactant in the germicidal composition can be 0-20 wt.%, preferably 1-10 wt.%.

Preferred examples of the alkali metal salts in¬ clude alkali metal salts of organic acids and those of inorganic acids. Specific examples of the former ones can include alkali metal salts of carboxylic acids such as succinic acid, malonic acid, citric acid and gluconic acid, glutaric acid; and those of the latter on can include alkali metal salts of phosphoric acid compou such as tripolyphosphoric acid, hexametaphosphoric acid phosphoric acid, and alkali metal salts of mineral acids such as Na ₂ S0 ₄ , K S0 ₄ and NaHS0 ₄ . The addition of such a salt makes it possible to provide improved storage stability and also to prevent the generation of an organic peracid odor. These salts may be used ei¬ ther singly or in combination. These alkali metal salt can be added preferably in an amount of 0.1-10 wt.%, with 0.5-5 wt.% being particularly preferred.

Illustrative examples of the pH regulator include organic acids such as citric acid, malonic acid, suc¬ cinic acid and gluconic acid. They may be used either singly or in combination. It is preferred to add such

a regulator in such an amount as providing an aqueous solution of the composition of this invention with pH 5-10, for example in an amount of 0.5-5 wt.%.

Examples of the metal chelating agent can include ethylenedia inetetraacetic acid, nitrilotriacetic acid, tripolyphosphoric acid and polyhydroxyacrylic acid, and salts thereof.

The germicidal composition according to the pres¬ ent invention can be produced in a solid form such as powder, granules or tablets by a method known per se in the art. Upon use, it is diluted with water and is then applied. The concentration of the composition differs with the item, place or the like to be treated. In general, however, 25-1,000 ppm is desired in terms of πhe concentration of the inorganic peroxide.

Alternatively, the components (A) , (B) and (C) can be furnished in separate packages and upon use, they are diluted together with water and are then ap¬ plied together. Examples

The present invention will hereinafter be de¬ scribed more specifically by various examples. It should however be borne in mind that this invention is by no means limited to or by the examples.

Example 1

Various germicidal compositions were prepared as shown in Tables 1-3 to meet the requirements of various fields. After they were hydrated, the amounts of organic peracids released, that is, the concentrations of the organic peracids upon elapsed times of 15, 30 and 60 minutes after the hydration were measured, respectively. The results are shown in Tables 1-3.

Table 1

Table 2

Table 3

As is apprent From Tables 1-3, it should be un¬ derstood that each invention composition comprising the components (A) , (B) and (C) generates a corresponding organic peracid in a large amount and furthermore, the organic peracid remains at a high concentration for a long time. Example 2 Storage Stability Test

In accordance with the compositions shown in Table 4, germicidal compositions were prepared by pro- portioning the components. They were hermetically stored at 40°C and 75% humidity for a month. Each com¬ position was then checked for any organic acid odor.

As is shown in Table 4, it has been found that, although each composition comprising the components (A) , (B) and (C) has good storage stability, its storage stability can be improved further by the addi¬ tion of an alkali metal salt.

Table 4

Example 3

The sterilizing power of the composition accord¬ ing to the present invention was studied against Escherichia Coli IFO 3796 by modifying the Tanaka's meth- od [Tokumitsu Tanaka, "Method for Measuring Sensitivity to Chemicals" edited by Susumu Mitsuhashi, Kodansha, Tokyo Japan (1980)].

Described specifically, about 100 μl (±5%) of precultured cells (about 10 ⁸ cells/m£) were taken. They were inoculated to a test tube containing 10 m_ of a solution of an invention germicidal composition which solution had been prepared 15 minutes ago by diluting the composition a predetermined number of times in distilled sterile water, and the solution was allowed to act on them at room temperature. At fixed intervals after the inoculation, the contents of the test tube were sampled out by a platinum loop and in¬ oculated to a 96-well Petri dish (product of Corning Glass Works.; 370 μl per well) whose wells each con- tained 300 μl of a postculture medium. After the cells were incubated at 37°C for 2 days, the growth of the cells was determined. Incidentally, all the composi¬ tions shown in Tables 5 to 7 contained, in addition to the components (A) , (B) and (C) , 1% of citric acid, the balance being anhydrous sodium sulfate.

As is presented in Tables 5 to 7, it should be understood that each composition according to the pres¬ ent invention has excellent sterilizing effects.

Table 5

Table 6

Table 7

Industrial Applicability

The germicidal compositions according to the present invention have strong and long-lasting sterilizing effects and also excellent storage stability, so that they can be employed at a wide vari- ety of places ranging from various factories to home.