JPS6367520B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a cleaning composition containing a monosalt of O-substituted malic acid, and its purpose is to exhibit weak acidity or neutrality during use and exhibit excellent foaming and cleaning power. Moreover, it is an object of the present invention to provide a chemically stable detergent composition that is mild to the skin. In recent years, there has been a strong demand for cleaning agents that come into direct contact with the skin during use, such as shampoos, facial soaps, and kitchen detergents, to have so-called skin-mild properties that do not alter the stratum corneum of the skin. In response to this, various cleansing agents using surfactants that are mild to the skin have been proposed. Mild surfactants that cause less skin irritation are generally nonionic surfactants such as glycerin fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkyl ethers, and polyoxyethylene alkyl phenyl ethers. Are known. but,
Nonionic surfactants generally have poor foaming properties, and these surfactants alone cannot satisfy the foaming properties required for general household cleaning products. Recently, N-acylamino acid salts have attracted attention as ionic surfactants that are mild to the skin and have good foaming properties, and have been put into practical use. However, N
- N-acyl amino acid salts such as acyl sarcosine salt, N-acyl-N-methyl-β-alanine salt, and N-acyl glutamate have insufficient solubility in water and tend to form white precipitates under weakly acidic conditions. Therefore, it is difficult to obtain a practically satisfactory cleaning agent using this type of surfactant. The present inventors have developed a cleaning method that exhibits weak acidity to neutrality close to the pH of the skin surface when used, is mild to the skin, has excellent cleaning power and foaming properties, and does not produce insoluble matter. As a result of intensive research to develop a cleaning agent, it was discovered that a cleaning composition containing a certain type of O-substituted malic acid monosalt has the above-mentioned performance. That is, the present invention is based on the general formula

[Formula] or

[Formula] (wherein R is a saturated or unsaturated hydrocarbon group having 12 to 16 carbon atoms, and M is an alkali metal, ammonium, alkanol ammonium or lower alkylammonium) A cleaning composition containing an acid monosalt is provided. In the cleaning composition of the present invention, the monosalt of O-substituted malic acid used as the main active ingredient can be produced by reacting monochlorosuccinic acid with a long-chain alcohol to etherify it or by using an alkali catalyst. O-substituted malic acid can be produced by a method such as reacting maleic diester or fumaric diester with alcohol in the presence of O-substituted malic acid, and then neutralizing the acid. O
The substituent of the monosalt of -substituted malic acid is a saturated or unsaturated hydrocarbon group, and the hydrocarbon chain may be linear or branched. However, the number of carbons greatly affects the performance of cleaning agents, and if the number of carbons is less than 10, the cleaning power and foaming will decrease, and 18
If it is larger, foaming and water solubility will deteriorate. Therefore, the number of carbon atoms in the hydrocarbon group is particularly preferably in the range of 12 to 16. The positive component constituting the O-substituted malic acid monosalt is an alkali metal,
Although selected from ammonium, alkanol ammonium, and lower alkylammonium, preferred O-substituted malic acid monosalts are salts of alkali metals such as lithium, sodium, and potassium, and monoethanolamine, diethanolamine, triethanolamine, tripropanol. Alkanolamine salts such as amines. O-substituted malic acid and its salts can each be used as main active ingredients in cleaning compositions, but
When obtaining a cleansing composition that is mild to the skin,
The main active ingredient is preferably one that exhibits weak acidity with a pH of about 4 to 7 when used as a detergent. Therefore, in the present invention O-substituted malic acids are used in the form of monosalts. Incidentally, the pH of a typical 15% aqueous solution of O-substituted sodium malate is as follows. O-laurylmalate monosodium salt PH=5.45 Same di-Na salt PH=7.20 O-palmitylmalate monosodium salt PH=6.15 Same di-Na salt PH=8.95 The following O-substituted malic acids can be used in the present invention. Specific examples of monosalts include O-lauryl malic acid, O-myristyl malic acid, O-palmityl malic acid, O-oleyl malic acid, O-coco alkyl malic acid, O-tallow alkyl malic acid, and oxo. Examples include monosalts such as O-alkylmalic acids derived from synthetic alcohols having 11 to 15 carbon atoms or 12 to 13 carbon atoms obtained by synthetic methods such as reactions. The amount of O-substituted malic acid monosalt to be incorporated into the cleaning composition of the present invention varies depending on the form of the cleaning composition. Generally speaking for liquid and powder compositions 1-40% by weight, preferably 5-30% by weight
ranges from 1 to 95% by weight, preferably from 3 to 90% by weight for solid compositions, and from 1 to 60% by weight, preferably from 3 to 50% by weight for gel-like compositions. are appropriate. The cleaning composition of the present invention can be used as a facial soap, shampoo, body shampoo, and kitchen light detergent (food washing detergent), but the O-substituted malic acid monosalt does not undergo hydrolysis in an aqueous solution and is Since it is chemically stable, it is particularly preferable to use it in a liquid or gel form. Any component can be added to the cleaning composition of the present invention as long as it does not impede the performance of the O-substituted malic acid monosalt. Such optional ingredients include
Comparatively skin-friendly substances such as O-substituted malates, nonionic surfactants, cationic surfactants, amphoteric surfactants, soaps, and alcohol ethoxy sulfates with a small or large number of carbon atoms in the hydrocarbon chain of the substituent. In addition to mild anionic surfactants, antioxidants, ultraviolet absorbers, sequestering agents, bactericides, bacteriostatic agents, water-soluble polymer compounds, water-soluble inorganic compounds, colorants, fragrances, and hydrotropes. , monohydric or polyhydric lower alcohols, and the like. Next, the present invention will be described in more detail with reference to examples. Note that various performance evaluations described in the Examples were performed by the following methods. (1) Skin irritation The hands of 10 testers were immersed in a 1% aqueous solution (at 35°C) of a liquid detergent composition for 1 minute, and then dried for 1 minute, which was repeated 15 times. After 24 hours, the skin The degree of skin roughness was determined by visual observation. 〇: Almost no skin roughness △: Partial dry exfoliation change on the stratum corneum surface layer of the skin ×: Dry exfoliation change over 30% (2) Static friction coefficient A hair bundle (5 g, 20 cm) was mixed with 1 g of the stock solution of the liquid cleansing composition. After rubbing for 1 minute and rinsing, leave the hair in a constant temperature room at 25℃ and 65% RH for 24 hours to dry.After that, measure the static friction coefficient of the hair using a friction coefficient meter (manufactured by Nippon Rheology Co., Ltd.). was measured. In addition, from a comparison with the smoothness of hair according to a sensory test, it has been recognized that when the coefficient of static friction is 0.17 or less, the smoothness of hair is excellent. (3) Hair smoothness (sensory test) Sodium dodecyl sulfate (SDS) was used as a control sample, and hair strands (5
g, 20cm) was evaluated using the paired comparison method by 20 testers. +: Better than SDS ±: Slightly better than SDS -: Equivalent to SDS (4) Foaming power 20 ml of 6% aqueous solution of liquid cleaning composition (25°C)
was placed in a 100 ml cylinder, 0.2 g of liquid lanolin was added as an artificial stain, the mixture was shaken 20 times for 10 seconds, the mixture was allowed to stand for 1 minute, and the foam volume (ml) was measured. ×: 0 to 5 ml (almost no foaming) △: 5 to 30 ml (slightly foaming) ○: 30 to 60 ml (quite foaming) ◎: 60 ml or more (very foaming) Example 1 Using surfactant, sulfuric acid, and purified water A liquid detergent with a surfactant concentration of 15% and a pH of 6 was prepared, and the performance of each liquid detergent was evaluated. The results are shown in Table 1.

[Table] As is clear from Table 1, O-lauryl malate monosalt has less skin irritation than LAS-Na, AS-Na, and LES-Na, and also has conditioning properties (static friction coefficient and hair smoothness) is N-
It can be seen that it is almost equivalent to the acylamino acid salt and superior to the N-acylamino acid salt in terms of foaming power. Example 2 Using a surfactant, sulfuric acid, sodium hydroxide and purified water, the surfactant concentration was 15% and the PH
We prepared liquid detergents with different values and evaluated the performance of each liquid detergent. The results are shown in Table 2. Note that all malate salts in the table were used in the form of monosalts.

[Table] As shown in Table 2, O-alkyl malates whose alkyl group has 8 or less carbon atoms foam poorly.
Further, even in O-alkyl malate salts in which the number of carbon atoms in the alkyl group falls within the range specified in the present invention, foaming and skin irritation deteriorate at the alkaline side (PH=9). Examples of formulations of shampoo compositions and soap compositions containing the O-substituted malic acid monosalt of the present invention are illustrated below. Shampoo formulation example Parts by weight Monosodium Coco alkylmalate 15 Coconut fatty acid diethanolamide 3 Cationized cellulose 1.5 Sodium benzoate 1 EDTA-2Na 0.1 Flavor 0.5 Purified water 78.9 (Adjust the pH of the composition by 4 with malic acid) ) A liquid shampoo was obtained with the above composition. Soap formulation example Parts by weight O-monosodium tallow alkylmalate 90 Malic acid 1 Flavor 1.3 Water 7.7 The above composition was kneaded and molded by machine to obtain a soap.

Claims (1)

[Claims] 1 General formula: [Formula] or [Formula] (wherein R is a saturated or unsaturated hydrocarbon group having 12 to 16 carbon atoms, and M is an alkali metal, ammonium, alkanol ammonium or lower 1. A weakly acidic skin cleansing composition comprising an O-substituted malic acid monosalt represented by (alkyl ammonium).