JPH036298A - Solid soap - Google Patents

Abstract

PURPOSE:To obtain a solid soap which does not crack during its use by adding a specified amount of a specified fatty acid alcohol ester to a soap. CONSTITUTION:A fatty acid alcohol ester of formula: R-COOR' (wherein R is 5-29C alkyl or alkenyl; R' is 1-30C alkyl or alkenyl), e.g. lauryl stearate, is added to a soap in an amount of 0.1-10wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to bar soap, particularly bar soap that does not crack during use.

[Conventional technology]

Bar soap is an important solid detergent that has been used for many years for washing the face and body. The raw materials for soap are usually a mixture of animal fats such as beef tallow and vegetable oils such as coconut oil, or their mixed fatty acids. Methods for producing soap using these raw materials include, for example, neutral oil firing. method, fatty acid neutralization method, fatty acid ester method, etc. are well known.

The neutral oil firing method is a method in which the raw material oil is saponified with an aqueous caustic alkali solution, and then glycerin is removed by salting out. The fatty acid neutralization method is a method in which raw fatty acids and a highly concentrated caustic alkali aqueous solution are continuously supplied and neutralized. In addition, the fatty acid ester method is a method in which raw material fats and oils are converted into fatty acid methyl by transesterification, and then saponified with caustic alkali to remove methanol. In any of these methods, a neat sorb with a water content of about 30% by weight is first prepared, and then dried and molded into a product.

Bar soap produced in this way remains popular due to its foaming properties, aesthetics, ease of handling, and good stability, but problems have been pointed out that include swelling, deformation, and cracking during use. In particular, the cracks become black due to dirt entering the cracks, resulting in a very unsightly appearance.

Conventionally, in order to prevent the above-mentioned cracks in bar soap, soap contains glycerin, polyethylene glycol,
Attempts have been made to include additives such as higher alcohols. Also, JP-A-48-25707 and JP-A-57-10
In publications such as No. 5500 and No. 5-167700,
Certain polymeric substances, such as polymeric substances that can dissolve in water at the pH of the soap, water-soluble polymeric substances that combine with soap to form water-insoluble substances, or cationic polymeric substances, can be used to prevent cracks in bar soap. Proposals have also been made for its use in agents.

[Problem to be solved by the invention]

However, the above-mentioned known means do not provide a sufficient crack-preventing effect, and there is a desire for an even better crack-preventing means.

An object of the present invention is to provide a bar soap in which the occurrence of cracks during use is significantly suppressed by searching for a novel anti-crack agent that can meet the above-mentioned needs.

[Means to solve the problem]

As a result of intensive studies to achieve the above object, the present inventors found that by using an alcohol ester of a fatty acid with a specific number of carbon atoms, which has a crack-preventing effect, the occurrence of cracks during use can be highly suppressed. This led to the completion of the present invention.

That is, the present invention provides general formula (A); R-COO
R'...(A) (wherein, R has 5 to 2 carbon atoms
9 alkyl group or alkenyl group, R' has 2 to 2 carbon atoms
Alcohol ester of fatty acid represented by 3o alekyl group or alkenyl accounts for 0.0% of the total soap. This relates to a bar soap characterized in that it contains 1 to 10% by weight.

[Structure and operation of the invention]

In the bar soap of the present invention, the soap base is animal fat or vegetable oil such as beef tallow, lard, coconut oil, palm oil, palm kernel oil, soybean oil, or mixed fatty acids or simple fatty acids obtained from these. It is possible to use any soap obtained using a fatty acid such as a starting material according to a known method such as the above-mentioned neutral oil firing method, fatty acid neutralization method, or fatty acid ester method.

In the present invention, specific examples of alcohol esters of fatty acids represented by the general formula (A) that are added as crack preventive agents to such soap bases include, for example, 2-ethylhexyl alcohol ester of lauric acid;
Among these esters are stearyl alcohol ester of myristic acid, butyl alcohol ester of valmitic acid, lauryl alcohol ester of stearic acid, hexyl alcohol ester of behenic acid, oleyl alcohol ester of oleic acid, and cetyl alcohol ester of capric acid. One type thereof can be used alone or two or more types can be used in combination.

The amount of alcohol ester of fatty acid used in the present invention is such that the proportion of the whole soap, which may contain a soap base and various other optional ingredients described below, is 0. 1 to 10% weight, preferably 0. It is preferable to adjust the amount to 5 to 5% by weight. If it is less than 0.1% by weight, a sufficient crack prevention effect cannot be obtained, and if it exceeds 10% by weight, problems will occur in the foamability of the soap, which is not preferable.

Alcohol esters of fatty acids can be added at any stage in the bar soap manufacturing process. For example, it may be added to neat sorb after neutralization, or to soap chips after drying.

In the present invention, in order to uniformly mix the alcohol ester of fatty acid into the soap base, an appropriate surfactant may be used as necessary. This surfactant includes, for example, the Nishi part edition: "Surfactant Handbook" (
Published by Sangyo Tosho Co., Ltd.) and ``Elucidation of the Functional Effects of New Surfactants and Development and Practical Comprehensive Technical Data on Application Products'' edited by Soft Giken Publishing Department (Management Development Center Publishing Department), etc. A wide variety of known surfactants are included.

The solid soap of the present invention includes optional components other than those mentioned above.
Conventionally known anti-crack agents such as glycerin, higher alcohols, paraffin, fatty acids, glycols, etc. may be added, and triesters of glycerin and/or polyglycerin may also be added.

Furthermore, the bar soap of the present invention may contain various additives that are added to ordinary soaps, such as chelating agents such as EDTA, humectants such as hyaluronic acid, fragrances, dyes, etc., as necessary. I can do it.

〔Effect of the invention〕

As described above, by incorporating an alcohol ester of a fatty acid having a specific number of carbon atoms into a soap base according to the present invention, it is possible to obtain a solid soap with high commercial value that does not cause problems such as cracks during use. be able to.

〔Example〕

Next, examples of the present invention will be described and explained more specifically.

Example A 28% by weight aqueous sodium hydroxide solution was added to a mixture of beef tallow fatty acid and coconut oil fatty acid in a weight ratio of 80:20, and the mixture was stirred and mixed in a 51-volume tabletop Nigu (manufactured by Irie Shokai ■). A neat sorb with a water content of about 30% by weight was prepared.

To this neat sorb, alcohol esters of fatty acids shown in Table 1 below or surfactants shown in the same table are added so that the weight percentages in the dry soap are as shown in the table. After thorough mixing, the mixture was dried until the moisture content became approximately 14% by weight.

Next, this soap composition was applied to three rolls [manufactured by Ashizawa; roll rotation speeds of 20 rpm, 48 rpm and 107 rpm.
rpm) to form flakes, and to this were added titanium dioxide, EDTA, and fragrance so that the weight percentages in the dry soap would be the proportions shown in the same table, and after stirring for 10 minutes in a kneader, the mixture was heated using a Jikken Kawa soap extruder [ After kneading three times with the screw part of Sato Iron Works ■, extrusion from the cone part,
Solid soaps of sample lights 1 to 7 were manufactured by stamping into a size of 65 mm in length, 40 ms in width, and 1 m in thickness.

In the surfactants shown in Table 1, the numbers in parentheses indicate the number of moles of ethylene oxide added.

Comparative Example Bar soaps of Samples Hikari 8 to 10 were produced in the same manner as in the example except that the conventionally known crack preventive agents shown in Table 1 were used instead of the fatty acid alcohol ester of the present invention. .

Each of the bar soaps of the above examples and comparative examples was subjected to a cracking test in the manner described below, and the results were as shown in Table 1 below.

<Crackability test> After repeating the procedure of suspending a bar of soap with a wire, immersing it in water at 10°C for 2 hours, and air-drying it for 2 hours 5 times, the surface condition of this bar of soap was visually observed, and the results were as follows: It was determined that

△: Shallow and moderate cracks are observed. ×: Deep cracks are observed on the entire surface. O: Only shallow and small cracks are observed.
As is clear from the table, the bar soaps of Samples 1 to 7 of the present invention have almost no cracks, whereas the conventional bar soaps of Samples 8 to 10 have considerable cracks. Recognize.

Claims (1)

[Claims] (1) The following general formula (A); R-COOR'...(A) (wherein, R is an alkyl group or alkenyl group having 5 to 29 carbon atoms, and R' is an alkyl group or alkenyl group having 1 to 30 carbon atoms. 1. A solid soap containing 0.1 to 10% by weight of a fatty acid alcohol ester represented by the following formula based on the total weight of the soap.