JPH036299A - Solid soap - Google Patents

Abstract

PURPOSE:To obtain a solid soap which does not crack during its use by adding a specified amount of an aliphatic dicarboxylic acid or an alkali metal salt thereof to a soap. CONSTITUTION:An aliphatic dicarboxylic acid of formula: HOOC-R-COOH (wherein R is 2-30C alkylene or alkenylene which may contain an ether bond in its carbon chain) or an alkali metal salt thereof, e.g. sodium sebacate, 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 a bar soap, and particularly to a bar soap that does not easily 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 either of these methods, a neat soap having a moisture 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, when cracks occur, dirt gets into the cracks and turns black, 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. 58-167700,
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 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 aliphatic dicarboxylic acid having a specific number of carbon atoms or a salt thereof as a crack preventive agent, the occurrence of cracks during use can be significantly reduced. After discovering that it is possible to obtain a bar soap with a reduced concentration, the present invention was completed.

That is, the present invention provides the following format (A); HOOC-
Aliphatic dicarboxylic acid or its The present invention relates to a solid soap characterized in that an alkali metal salt is contained in an amount of 0.1 to 0% by weight based on the total weight of the soap.

[Structure and operation of the invention]

In the bar soap of the present invention, the soap base includes beef tallow, pork fat, 1. Using animal fats and fats such as coconut oil, palm oil, palm kernel oil, and soybean oil, or fatty acids such as mixed fatty acids and simple fatty acids obtained from these as starting materials, the above-mentioned neutral oil firing method, fatty acid Any soap obtained according to known methods such as the Japanese method and the fatty acid ester method can be used.

In the present invention, specific examples of the aliphatic dicarboxylic acid represented by the general formula <A) added as a crack preventive agent to such a soap base include oxalic acid, malonic acid, succinic acid, and glutaric acid. , adipic acid, pimelic acid,
Speric acid, azelaic acid, sebacic acid, maleic acid,
In addition to fumaric acid, diglycolic acid containing an ether bond in the carbon chain, high dibasic acid 5LB-1 for intermediate oil production
Examples include 2°5L-20, 3B-20, and ULB-20.

In the present invention, one of the above dicarboxylic acids may be used alone or in combination of two or more, and if necessary, an alkali metal salt such as sodium salt or potassium salt of these dicarboxylic acids may be used. May be used.

The amount of aliphatic dicarboxylic acid or its alkali metal salt to be used in the present invention is determined based on the proportion of the total soap that may contain a soap base and various other optional ingredients described below.
The amount is preferably 0.1 to 10% by weight, preferably 0.5 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 such as moldability will occur, which is not preferable.

The aliphatic dicarboxylic acid or its alkali metal salt can be added at any stage in the bar soap manufacturing process. For example, it may be added to neat soap after neutralization, or to soap chips after drying.

In the present invention, in order to uniformly mix the aliphatic dicarboxylic acid or its alkali metal salt into the soap base, an appropriate surfactant may be used as necessary. This surfactant is described in, for example, "Surfactant Handbook" (published by Sangyo Tosho Co., Ltd.) edited by Nishiichi, and "Elucidation of the functional effects of new surfactants and development of applied products" edited by Soft Giken Publishing Department. A wide variety of well-known surfactants are included, such as those listed in "Practical Comprehensive Technical Data Collection" (Management Development Center Publishing Department).

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 aliphatic dicarboxylic acid having a specific number of carbon atoms or an alkali metal salt thereof into a soap base according to the present invention, it is possible to increase the commercial value without causing problems such as cracking during use. You can get high-quality solid soap.

〔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 at a weight ratio of 8:20, and the mixture was stirred and mixed in a tabletop Niguu (manufactured by Irie Shokai ■) with a capacity of 51. A neat sorb with a water content of about 30% by weight was prepared.

Add to this neat sorb an aliphatic dicarboxylic acid or an alkali metal salt thereof shown in Table 1 below, or a surfactant shown in the same table, in a proportion by weight of the dry soap shown in the table. After adding and mixing well, the mixture was dried until the water content became about 14% by weight.

Next, this soap composition was applied to three rolls [manufactured by Ashizawa ■; the number of roll rotations was 2 Orpm, 48 rpm and 10 Orpm].
107 rp to form flakes, titanium dioxide, EDTA, and fragrance were added to this so that the weight percent of the dry soap would be the proportions shown in the table, and after stirring for 10 minutes in a kneader, After kneading three times using the screw part of the Iron Works ■, extrusion from the cone part,
Solid soaps of sample sizes 1 to 7 were manufactured by stamping into a size of 65 squares in length, 40 squares in width, and 111 meters in thickness.

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

Comparative Example Sample fish 8 to 10 were prepared in the same manner as in the example except that the conventionally known crack inhibitors shown in Table 1 were used instead of the aliphatic dicarboxylic acid or alkali metal salt thereof according to the present invention. bar soap was manufactured.

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

◎: No cracks are observed or only two or three thin lines are observed. ○: Only shallow and small cracks are observed. △: Shallow and medium cracks are observed. ×: All over the surface. As is clear from Table 1 above, where deep cracks are observed, sample IIh of the present invention
It can be seen that the bar soaps Nos. 1 to 7 have almost no cracks, whereas the conventional bar soaps Nos. 8 to 10 have considerable cracks.

Claims (1)

[Claims] (1) The following general formula (A); HOOC-R-COOH...(A) (wherein, R is an alkylene group or alkenylene group having 0 to 30 carbon atoms that may contain an ether bond in the carbon chain. 1.) A solid soap containing an aliphatic dicarboxylic acid or an alkali metal salt thereof in an amount of 0.1 to 10% by weight based on the total weight of the soap.