JP2541265B2 - How to stabilize soap - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stabilizing method for preventing the deterioration of odor and color of soap due to deterioration with time or heat.

[Conventional technology]

It is generally considered that the factors that inhibit the stability of soap such as aging stability and thermal stability are the same as the factors that inhibit the stability of the fatty acid as a raw material.

A factor that inhibits the stability of fatty acids is the formation of peroxides, which are primary oxides, by the autoxidation of fatty acids, and free radicals are formed from these, which then undergo chain transfer reactions one after another to secondary oxides. And a carbonyl compound, an aldehyde compound or a polymer, which causes deterioration of odor and color. In addition, the oxidation of this fatty acid accelerates the deterioration of the fatty acid in the presence of metals such as Cu and Fe, which accelerates because it acts as a catalyst.

Therefore, for stabilizing fatty acids, conventionally, an antioxidant that functions as a scavenger of free radicals and a chelating agent that seals the action of metals are added to the fatty acid base oil. Is said to be effective, and a method similar to this has been adopted for stabilizing soap.

[Problems to be Solved by the Invention] When stabilizing a soap using a stabilizer comprising such an antioxidant or a chelating agent, it is possible to use two or more stabilizers having different action mechanisms in combination. It is considered desirable for increasing the stabilizing effect. However, finding a combination of two or more such stabilizers is
It's not always easy.

The reason for this is that even if two or more stabilizers having different mechanisms of action are used in combination, it cannot always be said that a synergistic effect can be obtained, and rather, the action functions of each other may be lost rather. Moreover, even if this is not achieved, in many cases, the effect is not so different from that when used alone.

For this reason, there have been few reports to date that a large stabilizing effect was obtained by combining two or more kinds of stabilizers. For example, JP-B-57-43598 discloses ethylenediaminetetraacetic acid or its alkali metal salt. To 1-hydroxyethane-1. 1-diphosphonic acid or its alkali metal salt is used in combination.

In view of the above circumstances, the present invention seeks a new combination of two or more stabilizers that can be expected to have a synergistic effect, thereby further improving the daily stability and thermal stability of soap. The aim is to obtain soap with higher practical value.

[Means for solving the problem]

In order to achieve the above-mentioned object, the present inventors repeated extensive experimentation in which various known stabilizers known as antioxidants and chelating agents were variously combined, and as a result, one specific antioxidant was identified. It was found that a remarkable synergistic effect is exhibited when three components, namely, and two specific chelating agents are used in combination, and that the daily stability and heat stability of soap can be significantly improved. The invention was completed.

That is, the present invention, in a soap base, ethylenediaminetetraacetic acid (hereinafter, abbreviated as EDTA) or an alkali metal salt thereof, 1-hydroxyethane-1.1-diphosphonic acid (hereinafter, abbreviated as HEDP) or its alkali The present invention relates to a method for stabilizing soap, which comprises adding three components of a metal salt and 2,6-di-tert-butyl-4-hydroxytoluene (hereinafter abbreviated as BHT).

Thus, in the present invention, as the chelating agent, the same E as disclosed in the above Japanese Patent Publication No. 57-43598 is used.
While using DTA or its alkali metal salt and HEDP or its alkali metal salt, it was also used in combination with BHT as an antioxidant. It was found that a high-quality soap in which the odor and the color are significantly suppressed from being significantly deteriorated due to daytime or heat can be obtained. Such action and effect are based on the synergistic effect of the above three components, and one or two of the above three components are used.
As is clear from the comparative examples described below, the high-level stabilizing effect of the present invention cannot be expected with only the seeds.

[Structure and operation of the invention]

Examples of the soap base to which the stabilizer in the present invention is added include beef tallow fatty acid sodium soap, coconut oil fatty acid sodium soap, hydrogenated castor oil fatty acid sodium soap, and other various animal and plant substances conventionally known as soap bases. Sodium fatty acid soap or the like may be used alone or in combination of two or more kinds, and if necessary, a part thereof may be potassium soap or lower amine soap.

In the present invention, as a stabilizer to the above soap base, EDTA or an alkali metal salt such as sodium salt or potassium salt, HEDP or an alkali metal salt such as sodium salt or potassium salt, and BHT The components are added, and the addition amount is set within an appropriate range depending on the type of soap base and the purpose of use of the soap.

In general, the total amount of the above-mentioned three-component stabilizer is usually in the range of 0.05 to 0.5% by weight in the total soap composition including the optional ingredients described below and the soap base and optionally blended. , Of which EDTA or an alkali metal salt thereof as a chelating agent and HEDP or an alkali metal salt thereof are each 0.01 to 0.2% by weight in the total soap composition, preferably 0.0
3 to 0.1% by weight, and BHT is 0.001 to 0.05% by weight, preferably 0.005 to 0.03% by weight in the total soap composition.

If any one of the three components is added in an excessively small amount, the synergistic effect of using the three components together cannot be expected. Further, if the addition amount of EDTA or its alkali metal salt is excessive among the three components, the stability may be deteriorated. Even if the amount of HEDP or its alkali metal salt or BHT added is excessive, the above-mentioned fear is small, but even if it is used in excess of a certain value, the effect cannot be expected to increase, which is economically disadvantageous.

The timing of adding these three component stabilizers is not particularly limited. Generally, neat soap having a relatively high water content is prepared, then added and uniformly mixed, and then dried until a predetermined water content of usually 15% by weight or less is obtained. If desired, known optional ingredients such as moisturizers, fragrances, dyes and the like can be appropriately added to the dry soap.

〔The invention's effect〕

In the present invention, by using the three components of EDTA or its alkali metal salt, HEDP or its alkali metal salt and BHT in combination as a stabilizer, it is extremely excellent in daily stability and thermal stability, and It is possible to obtain soap with high practical value in which thermal odor and deterioration of color do not easily occur.

〔Example〕

Hereinafter, examples of the present invention will be specifically described in comparison with comparative examples.

Examples 1 to 4 To a mixture of beef tallow fatty acid and coconut oil fatty acid in a weight ratio of 80:20, an aqueous sodium hydroxide solution having a concentration of 28% by weight was added, and the mixture was placed in a tabletop kneader having a capacity of 5 (manufactured by Irie Shokai Co., Ltd.). Stir-mix to make a neat soap with a water content of 30% by weight, and add EDTA or its alkali metal salt as a stabilizer and HE
A predetermined amount of three components of DP or its alkali metal salt and BHT was added and dried to obtain a dry soap composition having a water content of about 13 to 14% by weight.

Next, this soap composition was formed into flakes by applying three rolls (manufactured by Ashizawa Co., Ltd .; roll speed 20 rpm, 48 rpm, 107 rpm) to titanium dioxide and fragrance [Shiono Koryo Co., Ltd.'s trade name ROSE BLANCHE]. Was added in an appropriate amount and stirred in a kneader for 10 minutes, and this was further kneaded 3 times in the screw section of a laboratory soap extruder (manufactured by Sato Iron Works Co., Ltd.), then extruded from the cone section and stamped into solid soap. And molded.

The thus-obtained four kinds of solid soaps had the contents of the above-mentioned three-component stabilizer contained therein as shown in Table 1 below. The titanium oxide content was 0.2% by weight and the fragrance content was 1% by weight.

Comparative Examples 1 to 3 EDTA or its alkali metal salt as a stabilizer, HEDP
Alternatively, three kinds were prepared in the same manner as in Examples 1 to 4 except that two components of the alkali metal salt and BHT were used so that the content in the final bar soap was the ratio shown in Table 1 below. Of solid soap was obtained.

Comparative Example 4 The content of citric acid as a stabilizer in the final bar soap is
Solid soap was obtained in the same manner as in Examples 1 to 4 except that the soap was used in an amount of 0.3% by weight.

Each of the solid soaps obtained in the above Examples and Comparative Examples was treated at 25 ° C.
Stability test at 50 ℃ for 150 days
Was subjected to a thermostability test in which it was left in a thermostatic chamber for 60 days, the changes in hue and odor were examined in the daily stability test, and the changes in hue were examined in the thermostability test. The results are as shown in Table 1 below. The changes in hue and odor were examined by the following method.

Using SM Color competent user coater Model4 of <hue change> Suga Test Instruments Co., measured L _ab values of Hunter manner as (whiteness) b value (yellowness), for these initial values before standing , 25 ℃, 1
It was examined how much the values changed after being left for 50 days (after the stability test over time) and at 50 ° C. for 60 days (after the heat stability test).

It should be noted that the larger the L _ab value, the higher the whiteness, and the larger the b value, the higher the degree of yellowness.

<Change in odor> After being left at 25 ° C for 150 days (after the stability test over time), the odor was examined by comparing it with a one left in a separately prepared refrigerator at 5 ° C for 150 days. Those that did not have a scent of fragrance were evaluated as Δ, and those that started to smell of oil were evaluated as x.

As is clear from Table 1 above, according to the present invention, as a stabilizer, EDTA or an alkali metal salt thereof,
With the combination of HEDP or its three components of alkali metal salt and BHT, both the color and the odor are small, and the stability over time and the thermal stability are good, but in the case of using a stabilizer other than the above, It can be seen that these are inferior in stability.

Claims (1)

(57) [Claims] 1. A soap base containing ethylenediaminetetraacetic acid or an alkali metal salt thereof, 1-hydroxyethane-1,1-diphosphonic acid or an alkali metal salt thereof, and 2.6-di-tert-butyl-4. -A method for stabilizing soaps, characterized in that three components with hydroxytoluene are added.