JP2002069494A - Bleaching agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide bleaching agent which is highly effective in bleach and capable of obtaining good stability by suppressing decomposition of an alkali metal hypochlorite being a base when stored in distribution process or at home. SOLUTION: The bleaching agent contains 0.1-10 wt.% of an alkali metal hypochlorite, 0.01-15 wt.% of an inorganic buffer consisting of an inorganic acid and/or its alkali metal salt pKa=9 or more, and is that content of the alkali metal hydroxide is less than 0.05 wt.%, and to be at pH 9-11.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fast-acting hypochlorite bleach, and more particularly, to an excellent bleaching performance.
The present invention relates to a bleaching agent having good aging stability of a product even in a weakly alkaline region.

[0002]

2. Description of the Related Art In recent years,
Increased women's social advancement, aging, and increased awareness of lifestyles have led to a change in consumers' awareness of cleaning, making it easier to clean and shortening cleaning times. Is desired.

[0003] In order to meet such demands, dirt caused by mold in places where water is frequently used such as tiles, joints, plastics, pottery, drain pipes and the like in bathrooms, bathtubs, kitchens, etc., especially around houses. There is a demand for the development of a cleaning agent that can remove ash in a short time.

However, when the purpose is to remove stubborn dirt such as mold, it cannot be easily removed with a normal cleaning agent containing a surfactant as a main component.
For this reason, in order to remove these stains, highly alkaline bleaching agents based on alkali metal hypochlorite are often used, but in order to further easily and effectively wash them, There has been a demand for further performance of a bleaching detergent based on alkali metal hypochlorite as a main base, that is, development of a bleaching agent having improved bleaching speed. On the other hand, when a bleaching agent is used as a product, not only the bleaching performance but also its storage stability become a problem.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bleaching agent having excellent bleaching performance and good stability over time.

[0006]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, as shown in Examples described later, the pH was adjusted to a normal liquid bleaching agent. It was found that the bleaching ability was improved by lowering the pH from around pH 13 to a lower pH. Further, as a result of intensive studies, it was found that bleaching containing a specific amount of an alkali metal hypochlorite and a specific buffering agent was performed. When the content of the alkali metal hydroxide of the agent is less than 0.05% by mass, a bleaching agent having excellent aging stability and improved bleaching speed even in a pH range lower than that of a normal liquid bleaching agent can be obtained. It was found that it could be obtained. Further, it has been found that a surfactant having a specific molecular structure can be used as a bleaching agent without impairing the stability of the alkali metal hypochlorite.

That is, adding a buffer to a liquid bleach containing an alkali metal hypochlorite is disclosed in WO 88/054.
No. 61, WO88 / 054622, EP-A6224
No. 51, EP-A 654 482, Tokuyohei 9-5109
No. 97, EP-A-668345, Tokuyohei 11-505
No. 284, No. 11-505286, No. 11
No. 501361 and JP-A-10-251687. However, there is no mention of lowering the pH from around pH 13 of conventional liquid bleaches to a lower pH, or no specific composition for lowering the pH is disclosed, and in fact, at low pH, It did not ensure sufficient stability of the alkali metal hypochlorite. Therefore, the present inventors have proposed that the bleaching agent has a low pH.
As a result of intensive studies on the stabilization of alkali metal hypochlorite, the pH of the bleach was measured using a specific buffer.
Together with controlling the alkali metal hydroxide content in the bleach, more preferably controlling the content of alkali metal chloride contained in the bleach, alkali metal hypochlorite The present inventors have found that the pH can be adjusted to a lower level from around pH 13 of a normal liquid bleaching agent while maintaining sufficient salt stability, and that the bleaching performance can be improved by lowering the pH, thereby completing the present invention. .

Further, a study was conducted on surfactants which can be blended with such a bleaching agent having a reduced pH. Usually, a surfactant is added to a liquid bleaching agent. And a pH lower than usual bleaching composition, although many surfactants impair the stability of the alkali metal hypochlorite, include the addition of a buffer. No. 510945, Tokiohei 10-50
No. 2121 and JP-T-11-501078 do not disclose the addition of a surfactant or the type thereof.

In Japanese Patent Application Laid-Open No. 50-70411, a buffer having a lowered pH and an alkyl sulfonate having a carbon chain length of 8 to 18 or a water-soluble betaine are added as a specific surfactant. Although disclosed as a thickening-type polishing detergent composition containing an abrasive, this also did not ensure sufficient stability of the alkali metal hypochlorite.

The present inventors have conducted various studies on surfactants which can be incorporated into the bleaching agent of the present invention without impairing the stability of the alkali metal hypochlorite salt. In the pH range of the present invention, alkali hypochlorite such as a surfactant having no structure or functional group such as a hydroxyl group, a double bond or betaine, or a surfactant having a perfluoroalkyl group or a siloxane bond in a molecular structure. It has been found that it is more preferable to mix a specific amount of a surfactant that does not promote the decomposition of the metal salt.

Accordingly, the present invention provides an inorganic buffer comprising (1) 0.1 to 10% by mass of an alkali metal hypochlorite, and (2) an inorganic acid having _a pKa of 9 or more and / or an alkali metal salt thereof. Containing 0.01 to 15% by mass of an agent, and (3)
A bleaching agent characterized in that the content of the alkali metal hydroxide is less than 0.05% by mass and the pH is 9 to 11.5.

Here, the bleaching agent further comprises (4) an alkali metal chloride having a molar concentration of 0.005 to 1.2 times the molar concentration of the alkali metal hypochlorite. Or (5) a surfactant that does not promote the decomposition of the alkali metal hypochlorite, preferably a surfactant having a perfluoroalkyl group or a siloxane bond in the molecular structure. It is more preferable that the surfactant contains at least one or more selected surfactants in an amount of 0.01 to 5% by mass, or that it becomes a liquid or foam and adheres to the surface of the bleaching object.

Hereinafter, the present invention will be described in more detail. The bleaching agent of the present invention comprises an inorganic buffer comprising (1) an alkali metal hypochlorite salt and (2) an inorganic salt having _a specific pKa value. And (3) controlling the content of alkali metal hydroxide in the bleach containing a specific amount of
The pH value was adjusted to a specific range.

Here, the kind of the alkali metal hypochlorite, which is the component (1) of the present invention, is not particularly limited, and examples thereof include sodium hypochlorite and potassium hypochlorite. These can be used alone or in an appropriate combination of two or more. In the case of the present invention, among these, sodium hypochlorite and the like are particularly preferable.

The content of the alkali metal hypochlorite in the bleaching agent of the present invention is 0.1 to 1 with respect to the whole preparation.
0 mass%, preferably 1 to 5 mass%. When the content of the alkali metal hypochlorite is less than 0.1% by mass, the bleaching power becomes insufficient. On the other hand, when the content exceeds 10% by mass, the improvement of the bleaching power cannot be expected by further blending.

The pK _a for use in the present invention is 9 or more inorganic acids and / or inorganic buffers consisting of alkali metal salts are those which can maintain the pH of the bleaching agent of the present invention to 9 to 11.5 . Such pK inorganic acids and alkali metal salts thereof having _a, for example, "Chemical Handbook Fundamentals II
4th Edition ”(edited by The Chemical Society of Japan, September 3, 1993
On page 317 of Mar. 0, published by Maruzen Co., Ltd., these can be used alone or in combination of two or more. In the present invention, pKa is _a value at 25 ° C.

In the present invention, among these, for example, one selected from carbonic acid, hypoiodic acid, phosphoric acid, diphosphoric acid, tripolyphosphoric acid, silicic acid and alkali metal salts thereof.
It is more preferable to mix the species or two or more species in an appropriate combination. Note that these alkali metal salts do not need to replace all of the hydrogen ions of the oxo acid with alkali metal ions.For example, in the case of a sodium salt of phosphoric acid, monosodium phosphate, disodium phosphate, Any of the trisodium phosphates can be used.

The content of the inorganic buffer in the bleaching agent of the present invention is from 0.01 to 15% by mass, preferably from 0.1 to 10% by mass, more preferably from 0.5 to 10% by mass, based on the whole preparation. 8% by mass. If the content of the buffer is too small, not only the pH of the bleaching agent cannot be adjusted to the specific pH range of the present invention, but also the effect of maintaining the pH during storage is small, and the object of the present invention cannot be achieved. On the other hand, if the content is too large, not only is it not possible to expect an increase in the effect of further blending, but also problems such as precipitation and turbidity are likely to occur when the bleach is stored.

The kind of the alkali metal hydroxide which is the component (3) of the bleaching agent of the present invention is not particularly limited. Normally, industrially available alkali metal hypochlorite stabilizes alkali metal hypochlorite by making it strongly alkaline at about pH 13, and therefore, a small amount of alkali metal hydroxide is used. Is supplied in the form of an aqueous solution containing, and the bleaching agent using the same necessarily contains an alkali metal hydroxide. Therefore, in the present invention, it is desirable to control the content of the alkali metal hydroxide mixed in the alkali metal hypochlorite. Examples of the alkali metal hydroxide include sodium hydroxide and potassium hydroxide.

The bleaching agent of the present invention obtains good stability during storage of the alkali metal hypochlorite in the bleaching agent by adjusting the content of the alkali metal hydroxide to a specific concentration. It is. That is, as described above, usually, the bleach using an industrially available alkali metal hypochlorite necessarily includes the alkali metal hydroxide, but in the bleach of the present invention. It is necessary that the content of the alkali metal hydroxide be less than 0.05% by mass. The reason for this is that the presence of the alkali metal hydroxide more than this not only lowers the bleaching speed but also makes the pH of the bleaching agent of the present invention within the range of the present invention. A large amount of a buffer consisting of a metal salt is required, resulting in high cost and problems such as precipitation during storage.

In order to make the concentration of the alkali metal hydroxide contained together with the alkali metal hypochlorite less than 0.05% by mass, for example, the aqueous solution of the alkali metal hypochlorite to be used is used. It is preferable to neutralize the alkali metal hydroxide contained in the compound to convert it into a salt. The acid used for neutralization, of the above inorganic buffers, the use of inorganic acids having 9 or more pK _a, further preferably.

The bleaching agent of the present invention can contain a predetermined amount of an alkali metal chloride as the component (4), and the kind of such an alkali metal chloride is not particularly limited, but is blended. Examples thereof include alkali metal chlorides contained in alkali metal hypochlorite. For example, if the alkali metal hypochlorite of the component (1) is sodium hypochlorite, industrially available hypochlorous acid may be used. Since the aqueous solution of sodium acid usually contains sodium chloride,
Examples of the alkali metal chloride as the component (4) include sodium chloride.

The content of the alkali metal chloride in the bleaching agent of the present invention is such that the molar concentration thereof is 0.005 to 1.2 times the molar concentration of the alkali metal hypochlorite. , Preferably 0.01 to 0.8 times.
When the content of the alkali metal chloride is within this range,
Further, the stability of the alkali metal hypochlorite is improved. In addition, if the content is less than the above range, the production cost increases, which is not practical.

The means for adjusting the content of the alkali metal chloride to the above range is not particularly limited. For example, as described above, in the case of sodium chloride contained in sodium hypochlorite, After producing a high-concentration aqueous solution of sodium hypochlorite, it is preferable to obtain a bleaching agent having the above-mentioned alkali metal chloride content by using a low-salt product or the like subjected to desalting treatment such as cooling to precipitate sodium chloride. .

It is more preferable that the bleaching agent of the present invention further contains a surfactant which does not promote the decomposition of the alkali metal hypochlorite at pH 9 to 11.5 as the component (5). Here, in the present invention, "does not promote decomposition of alkali metal hypochlorite at pH 9 to 11.5"
Means that after adding a surfactant to an aqueous solution of an alkali metal hypochlorite at the relevant pH, the solution is stored at 50 ° C. for 2 weeks, and compared with a case where no surfactant is added, Means that the remaining amount is the same.

Examples of such surfactants include those having no structure or functional group such as amine oxide, hydroxyl group, double bond or betaine in the molecule. Preferred are alkali metal salts of alkyl sulfonic acids, alkali metal salts of alkyl benzene sulfonic acids, alkali metal salts of phosphoric acid esters, alkali metal salts of saturated fatty acids, and alkali metal salts of polyoxyethylene alkyl ether sulfate.

Further, a surfactant having a perfluoroalkyl group or a siloxane bond in the molecular structure is also preferable. Examples of the surfactant having a perfluoroalkyl group in the molecular structure include alkali metal salts of perfluoroalkylsulfonic acid, alkali metal salts of perfluoroalkyl acid, and N-carboxymethyl (N-alkyl) -perfluoroalkylsulfonamide. And the like. Examples of the surfactant having a siloxane bond include, for example, a silicone surfactant and the like, more preferably a silicone surfactant having an anionic group, still more preferably phosphate, sulfonate and / or the like. Alternatively, a silicone surfactant having a carboxylate group can be used.

In the present invention, the above surfactants can be used alone or in an appropriate combination of two or more. In the case of the present invention, it is more preferable not to contain a surfactant other than the surfactant of the component (5).

The bleaching agent of the present invention may contain the above surfactant in the range of 0.01 to 5% by mass based on the whole preparation. More than this does not necessarily increase the effect of adding the surfactant. Preferably it is in the range of 0.01 to 3% by mass, more preferably 0.05 to 2% by mass.

Further, the bleaching agent of the present invention may contain a normal amount of a washing builder, a chelating agent, an enzyme, a fragrance, etc., if necessary, as long as the effects of the present invention are not impaired.

Specifically, examples of the washing builder include inorganic builders such as aluminosilicates and layered silicates such as zeolites, and polycarboxylic acids such as nitrilotriacetic acid, lactic acid, citric acid, glycolic acid, succinic acid, and polyacrylic acid. Organic builders such as acid salts can be mentioned. Also,
Hydrotropes such as aromatic sulfonates such as toluenesulfonate and xylenesulfonate can be included. These components are present in the bleach of the present invention in an amount of from 0 to 40.
It is preferred that the content be contained by mass%.

As the chelating agent, for example, sodium ethylenediaminetetraacetate, 1-hydroxyethylidene-
Examples of the enzyme include 1,1-diphosphonic acid and the like, and examples thereof include alcalase and lipase. Furthermore, in addition to the above components, a fluorescent agent, a dye, a foam inhibitor such as silicone, a stabilizer such as a hypohalous acid compound, and the like can be included.

The bleaching agent of the present invention has a pH of 9 to 11.5, preferably 10 to 11.4, more preferably 1 to 11.4.
0.5 to 11.3. If the pH is lower than this range, the stability of the alkali metal hypochlorite decreases even if other additives are contained in the range of the present invention. Conversely, if the pH is higher than this, the improvement of the bleaching ability due to the lowering of the pH, which is the object of the present invention, is not achieved, and the effect on the skin and the mucous membrane of the eye is increased by the strong alkaline action.

The means for adjusting the pH of the bleaching agent of the present invention to the above-mentioned pH range is not particularly limited. However, in order to maintain the pH of the bleaching agent of the present invention during storage or use, the above-mentioned means may be used. It is desirable to adjust the pH by adding a buffer.

The bleaching agent of the present invention is not particularly limited in its dosage form and method of use, but it is prepared as a liquid bleaching agent or a liquid bleaching detergent, and becomes a liquid or foam to be applied to the surface of the bleaching body. It is more preferable to use it as a dosage form that adheres. In addition, the state that the liquid bleach adheres to the surface of the bleaching body includes not only a state in which the liquid bleach is spread but also a state in which the liquid bleach adheres in a mist state or a water droplet state.

In order to prepare such a dosage form, for example, a bleaching agent prepared as a liquid composition may be used directly from a container or may be applied using a brush or the like. It is preferable in terms of simplicity to use a discharge container provided with such a discharge container, and such a discharge container is provided with a discharge device for discharging a bleach having the above composition, and the discharge device has a piston / cylinder. It can be used without any particular limitation as long as it has a sliding part such as the above or a fitting part for the passage of liquid into the pump housing.

The bleaching agent of the present invention can bleach a bleaching body with good bleaching performance by using it in a bleaching body in the same dosage and usage manner as ordinary bleaching agents or bleaching detergents.

[0038]

The bleaching agent of the present invention has high bleaching power,
In addition, when the bleach is stored in the distribution process or at home, the decomposition of the alkali metal hypochlorite, which is the bleaching base, can be suppressed, and the composition has good stability. Furthermore, it is possible to reduce the adverse effects of a high pH on the skin and mucous membranes of the eye.

[0039]

Next, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Examples 1 to 12 and Comparative Examples 1 to 3 Table 1
Various bleaching detergents (bleach compositions) having the compositions shown in Tables 1 to 3 were prepared according to a conventional method, and the bleaching rate and the storage stability (residual rate of alkali metal hypochlorite and pH) were measured. The results are shown in Tables 1 to 3. In addition, each physical property value was calculated | required by the following method. Here, phosphoric acid (orthophosphoric acid) dissociates three stages, pK _a (25 ° C.) of the third stage 12.35, likewise carbonate pK _a (25 ° C.) of the second stage in two stages 10. 33
It is. In Comparative Example 2, the pH was adjusted using hydrochloric acid.

<Sodium hypochlorite content> The effective chlorine concentration determined by the iodometry method was defined as the sodium hypochlorite content.

<Buffer Concentration> The salt formed by neutralization was included in the concentration.

<Sodium hydroxide (NaOH) content>
A neutral aqueous solution of hydrogen peroxide is added to the aqueous sodium hypochlorite solution used as a raw material to decompose sodium hypochlorite, and titrated with hydrochloric acid using phenolphthalein as an indicator to determine total N.
The a ion molar concentration was determined. Next, the effective chlorine concentration in the aqueous sodium hypochlorite solution, which was also used as a raw material, was determined by an iodometry method, and this was converted to a NaClO molar concentration. From the former total Na ion molarity, the latter NaClO
By subtracting the molarity, the NaOH concentration in the aqueous sodium hypochlorite solution used as the raw material was calculated. The NaOH concentration in the liquid bleach composition is calculated by calculating the amount of NaOH brought in from the raw material based on the amount of the raw material used.
Was added, and when NaOH was neutralized by the added substance, the amount was subtracted to calculate.

<Alkali Metal Chloride Content> The chloride ion content in the composition was analyzed by the Mohr method, and the value in terms of sodium chloride was shown.

<Evaluation Method of Storage Stability> 5
After storage at 0 ° C. for 2 weeks, the pH is measured, and the concentration of the alkali metal hypochlorite in each of the bleach compositions is determined by a fully automatic titrator (Hiranuma Sangyo Co., Ltd .: TS
-980), the sample reacted with potassium iodide and acetic acid was titrated with a sodium thiosulfate solution. This concentration was defined as the residual ratio of the alkali metal hypochlorite to the initial concentration, and was determined according to the following evaluation criteria.

Evaluation criteria: A: Residual rate of alkali metal hypochlorite 70 to 100% O: Residual rate of alkali metal hypochlorite 60 to 70%
Less than ×: Residual rate of alkali metal hypochlorite 0 to 60%
Less than

<Method of measuring bleaching power> Black mold (Clados)
porium cladosporioides was cultured and applied to unglazed tiles (SPAX made by INAX)
-1060) was used as a model plate. This model mold plate was placed horizontally and various bleaching compositions 0.5
g was dropped on the plate. After leaving for 2 minutes, washing with water and air-drying, a colorimeter (manufactured by MINOLTA; CR-200)
The lightness (L value) is measured by using the following formula, and the L value of the unglazed tile before applying the mold is Ls, the L value of the model mold plate before bleaching is L0, and the L value after bleaching is L1. The bleaching rate was determined.

Bleaching rate (%) = ｛(L1-L0) / (Ls
−L0)｝ × 100

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

[Table 3]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C11D 7/10 C11D 7/10 D06L 3/08 D06L 3/08 (72) Inventor Takayasu Kuboen Sumida-ku, Tokyo 1-3-7 Honjo, in Lyon Co., Ltd. (72) Inventor Yasuo Nomura 1-3-7, Honjo, Sumida-ku, Tokyo (72) Inventor Minoru Kishi Minoru, Sumida-ku, Tokyo 1-3-7 F-term in Lion Corporation (reference) 4H003 AA02 AB03 AB14 AB19 AB31 AB34 AB38 AB44 AC15 BA12 DA05 EA04 EA08 EA16 EA19 EA21 ED02 EE08 FA02 FA28 FA29 FA44

Claims (5)

[Claims] (1) 0.1% of an alkali metal hypochlorite is used.
1 to 10% by mass, (2) an inorganic acid having _a pKa of 9 or more and / or
Or 0.01% of an inorganic buffer comprising an alkali metal salt thereof.
(3) A bleaching agent characterized in that the content of alkali metal hydroxide is less than 0.05% by mass and the pH is 9 to 11.5. 2. The composition according to claim 1, further comprising (4) an alkali metal chloride having a molar concentration of 0.005 to 1.2 times the molar concentration of the alkali metal hypochlorite. Bleach as described. 3. The bleaching composition according to claim 1, further comprising (5) a surfactant which does not promote the decomposition of the alkali metal hypochlorite at a pH of 9 to 11.5, in an amount of 0.01 to 5% by mass. Agent. 4. The bleaching agent according to claim 3, wherein the surfactant is at least one selected from surfactants having a perfluoroalkyl group or a siloxane bond in a molecular structure. 5. The bleaching agent according to claim 1, wherein the bleaching agent adheres to the surface of the bleaching substance in a liquid or foam form.