Technical field

The invention concerns the area of manufacturing of means of hygiene, namely, toilet soaps with antimicrobic properties which can be used both for medical and household purposes.

Toilet soaps containing antimicrobic additives giving disinfectant properties to them, are at present widely spread.

State of the art

Compositions of toilet soap with antimicrobic properties, containing a soap fatty basis and functional additives, including antimicrobic ones on the basis of Tryclozan (3,4,4'-trichlor-2'-hydroxydiphenyl ether) are known [Russian patents RU N. 2147607, pub. 2000, and RU N. 2163255, pub. 2001].

In particular the toilet antibacterial soap described in the patent N. 2163255 contains soap shavings, an antioxidant, titan dioxide, perfumery odorant, dye and also Tryclozan and oil extracts of medicinal grasses.

The given soap possesses foam properties and provides disinfectant and deodorant effects.

However it is established by modern researches that Tryclozan suppresses both pathogenic microflora and protective resident microflora, what can lead to negative effects at application of soap. The presence of phenolic and aromatic haloid-forming groups in Tryclozan exerts irritating and allergenic influence on the skin.

At present, in the field of cosmetology and hygiene, significant attention is given to finding of preparations, including for washing of the body, with composite structure based on the use of natural components of inorganic origin and biologically compatible with the skin of a human being.

The following materials are widely used for said purposes in compositions developped for hygiene and cosmetics:

- metals or metal compounds of silver, copper, zinc, lead, chromium, etc. which show antimicrobic properties in respect to a wide spectrum of gram-positive and gram- negative bacteria (A.P.Krasilnikov "Guide on antiseptics" - Minsk: the High school, 1995, 91, 109; "Guide on medical products applied in medical practice in the USSR" under M.A.Kluev.- M.: Medicine, 1989); - components on the basis of layered minerals, such as bentonite, whose presence in the structure of a soap leads to improvement of cleaning and degreasing influence on the skin.

A toilet soap containing a soap basis (64 - 80% by weight), a powder of bentonite with the size of particles from 8 up to 15 μ, in amount of at least 16% b.w. and functional additives including humidifying, for example, glycerin, lanolin, etc. is described in the patent US N. 7285521, pub. 2007.

Absorbent activity of a bentonite powder in the given structure of a soap, improves cleaning and degreasing of the skin. However, in the given technical description, antimicrobic action of the soap on the skin is not demonstrated.

The composition of soap containing a soap basis, an antibacterial agent on the basis of a powder of zinc oxide, foam component as salt of lauric acid and also smectite clay, is disclosed in the application US 2009/0286706, pub. 19.11.2009.

Antimicrobic action of soap on the skin is provided due to the presence of zinc oxide in its composition. However the expediency of using said antibacterial agent is limited by costs for its obtaining and by the negative influence on the skin, i.e. increase in dryness.

In the technical description of application WO2006/097238, pub. 21.09.2006, which is chosen as the closest prior art of the present invention, a toilet soap with antimicrobic properties containing a soap basis, antimicrobic agents, an antioxidant, functional additives and water is described.

A powder of montmorillonite (bentonite in Na ⁺ form) in amount from 5 up to 30% b.w. is used in the composition of the soap, what gives to soap adsorbing properties. A mix of 3,4,4'-trichlorcarbanilide (TCC) and 3,4,4'-trichlor-2'-hydroxydiphenyl ether (TCN), in amount not higher than 2% b.w. is used as antimicrobic agent in the indicated application.

It is described to use odorant, humidifiers (for example, glycerin or lanolin) or other additives as additional functional additives according to the invention. The basis of toilet soap is traditionally obtained by saponification of fats, such as food fats, palm oil, coconut oil, sunflower oil, etc.

Risks of inflammatory processes are reduced when using the soap.

However the use of antibacterial agents on the basis of the specified organic compounds containing phenolic and aromatic haloid-forming groups, is inexpedient, as it was already marked above, due to their irritating and allergenic influence on the skin. The presence of a mineral (bentonite in Na ⁺ form) containing cations of alkaline metals (Na ⁺ , K ⁺ ) in the structure of the soap leads to increase in pH (alkalinity of soap), what adversely influences the skin.

For improvement of cosmetic properties of soap its compounding contains a significant amount of humidifying, softening additives and antioxidants, what increases the price of soap.

At the same time antimicrobic agents on the basis of inorganic components (see patent RU N 2330673, pub. 2008) are widely known in the technical field. The antimicrobic agent on the basis of nanoparticles of a bentonite powder intercalated by ions of Ag ⁺ or/and by ions of Cu ²⁺ , which are obtained at modification of bentonite with solutions of inorganic salts of silver nitrate or copper sulfate, after preliminary enrichment of bentonite with cations of Na ⁺ , by its processing with a water solution of an inorganic salt of sodium and subsequent cleaning, is described in the above named patent.

The antimicrobic agent is obtained from mineral, ecologically safe components and can be used as additive to various preparations, including for medical and cosmetic purposes.

However development of a composition of soap with antimicrobic properties is not described in the given patent.

Disclosure of the invention

The problem of the present invention consisted in the creation of a soap with antimicrobic properties, providing the technical result of obtaining an antimicrobic effect of prolonged action, while decreasing the risk of occurrence of negative by-effects.

The task of the invention consisted in the creation of a soap with antimicrobic properties, providing the technical result of antimicrobic protection of the skin, due to the use of components biologically compatible with the skin of a human being and lowering at the same time the risk of occurrence of negative dermatological effects present in the structure of soap.

The toilet soap containing a soap basis, an antimicrobic agent, an antioxidant, functional additives and water is described for the solution of the put technical task. According to the present invention the soap in addition contains polyvinylpyrrolidone and nanoparticles of a bentonite powder intercalated by ions of Ag ⁺ or/and by ions of Cu ²⁺ as the antimicrobic agent. The bentonite powder is obtained by modification of a bentonite with water solutions of silver nitrate or copper sulfate, after preliminary enrichment with cations of Na ⁺ by means of processing with a water solution of an inorganic salt of sodium and subsequent cleaning. The composition of soap has the following ratio of components, expressed in % by weight.

soap basis 70,0-80,0 bentonite powder intercalated by ions of

Ag ⁺ or Cu ²⁺ or a mix of mentioned powders

at the ratio 1: (0,5÷4) 1,0-10,0 Polyvinylpyrrolidone 0,1-1,0 Antioxidant 0,2-0,5 functional additives 2,5- 5,0 water the rest, the size of the particles of the bentonite powder is no more than 150 nm.

According to the invention, the quantitative content of metals in the composition of soap is of 0,02-0, 8% b.w..

According to the invention titan dioxide, glycerin, citric acid and other additives are used as functional additives, at the following ratio in the composition of the soap, expressed in % by weight:

titan dioxide 0,1-0,5 glycerin 2,0- 2,5 citric acid 0,1-0,5 other additives 0,3- 1 ,5.

According to the invention "Antal P-2" is used as an antioxidant.

According to the invention a perfumery composition or/and a cosmetic cream is preferably used as other additives.

According to the invention soap shavings are used as a basis.

According to the invention polyvinylpyrrolidone with molecular weight 12 TO ³ - 40· 10 ³ is used.

The soap described in the present invention provides a prolonged antimicrobic protection of the skin while decreasing any negative influence on it, due to the presence of an antimicrobic agent and a biopolymer, biologically compatible with the skin. At manufacturing of the soap composition, cations of silver and copper intercalated into nanoparticles of bentonite are released as a result of cation exchange processes. They are connected with functional groups (— C=0) of polyvinylpyrrolidone with formation of nanoclusters of silver and copper stabilized by polyvinylpyrrolidone so rendering antimicrobic prolonged action on the skin at application of the soap.

Other components included in the soap according to the invention are traditionally used components for maintening uniformity of washing and cosmetic properties of soap.

Analysis of prior art did not reveal technical solution with a set of properties corresponding to the present technical solution and realizing the above described result.

The analysis of the known level of technics testifies the conformity of the present technical solution to criteria of "novelty" and «degree of inventiveness*.

The declared technical solution can be industrially realized for manufacturing soap with antimicrobic properties while decreasing the risks of occurrence of negative dermatological effects.

Detailed description of the invention.

The essence of the invention is explained by a choice of raw components for realization of the invention, examples of its realization and the results of tests.

For realization of the invention the following products are used:

- soap shavings obtained preferably from sodium salts of natural or/and synthetic fatty acids, which are traditionally used for manufacturing various toilet soaps;

- polyvinylpyrrolidone (PVP) with molecular weight 12T0 ³ - 40Ί0 ³ , water soluble biopolymer used in medicine and cosmetics included as a modifier of viscosity of water solutions and a stabilizer of foam in washing products. It is preferable to use polyvinylpyrrolidone VFS 42-1791-88, molecular weight 20T0 ³ -30' 10 ³ ;

- titan dioxide as pigment-filler used in manufacturing soaps. It is a barrier from UV-radiation;

- glycerin used in cosmetics, including in manufacturing of soaps, as a functional additive softening the skin and protecting it from dryness;

- the antioxidant «Antal Ρ-2», traditionally used in production of soap as a stabilizer for prevention of oxidation and as a plasticizer for improvement of rheological properties of soap masses; - citric acid traditionally used in production of soap for regulation of pH and as an intensifier of antioxidizing properties;

- other functional additives traditionally used in compositions of soap: odorants (perfumery compositions), a cosmetic cream for improvement of operational properties of soap, including organoleptic ones;

- an antimicrobic product on the basis of inorganic components (see patent RU N. 2330673).

The antimicrobic product is obtained with a two-stage technological process. At the first stage montmorillonite (bentonite in Na ⁺ form) is processed with a water solution of sodium chloride (NaCl), with retention intervals of bentonite in the given solution within 10-24 hours. Then it is repeatedly decanted at washing with deionized water up to pH=7, with removing of chlorine and subsequent drying.

At the second stage, the obtained semifinished product (bentonite enriched with ions of sodium) is processed with a water solution of silver nitrate (AgNC^) or copper sulfate (CuS0 ₄ ). Cations (Na ⁺ ) are replaced by cations of the metal-assistant (Ag ⁺ or Cu ²⁺ ) as a result of reactions of ionic replacement. Then cleaning of the intercalated product from salts of sodium, filtration, drying and grinding are carried out.

The following procedure was applied for manufacturing 100 g of bentonite intercalated by ions of Ag ⁺ and Cu ²⁺ (according to the present invention):

- initial raw component, i.e. bentonite in Na ⁺ form (montmorillonite) in amount of 110 g; 10% water solution of sodium chloride and 15% water solutions of the inorganic salts, namely, silver nitrate (AgN03) and copper sulfate (CuS04).

Activation (enrichment) of bentonite with ions of sodium and intercalation of the obtained semi-finished product of bentonite (after its enrichment with ions of sodium) with ions of silver and copper was carried out at the ratio bentonite : solution, as 1: 10 (weight parts).

The obtained antimicrobic agents were estimated in respect to the size of the particles and analyzed for definition of the quantitative contents of silver and copper.

The control of the size of the particles of the obtained bentonite powders, intercalated by ions of silver or copper, was made by using an electronic microscope. In result it was established that nanoparticles of a bentonite powder have a size of no more than 150 nanometers. Determination of the quantitative contents of silver and copper in the obtained products was carried out by means of titrimetric analysis by using indicators fixing a point of equivalence of titration. From 2 up to 8% by weight of metals (silver, copper) is contained in the modified powder of bentonite, depending on the initial raw product, as well as on the amount of activating and intercalating (modifying) reagents.

The specified amount of the named metals in bentonite powders is the optimum. The increase in amount of metals leads to increase in costs for obtaining the antimicrobic agent while their decrease in an intercalated bentonite powder leads to decrease of antimicrobic activity.

For manufacturing the soap according to the invention, a traditional process is used:

- the components specified in the above description are injected in soap shavings; the obtained soap masses are mixed up to a homogeneous condition;

- soap masses are subjected to additional machining (milling) with the subsequent formation, cutting of the obtained pieces, stamping of soap, packing.

For developping a composition of soap the quantity of the components was determined experimentally, taking into account the conditions of maintenance of effective antimicrobic protection of the skin and balance of washing and cosmetic properties of soap.

The combination of components specified in the invention and their amount is the optimum for obtaining a firm soap with antimicrobic properties and corresponding to dermatological requirements.

The use of polyvinylpyrrolidone (PVP), at the specified amount and molecular weight, in the structure of the soap, is optimum for formation of stable nanoclusters of antimicrobic action and for obtaining the optimum viscosity for homogenization of soap masses in a composition of soap.

Viscosity of soap masses sharply increases when using a PVP with molecular weight higher than 40-10 ³ or/and in an amount higher than 1,0% b.w. for manufacturing of soap, what worsens the process of homogenization.

Use of PVP with molecular weight lower than 12- 10 ³ worsens stabilizing influences of the given compound on foaming, with decrease in formation of active nanoclusters of antimicrobic action in the solution. Decreasing the amount of PVP to less than 0,1% b.w. in the composition of soap worsens its stabilizing influence and antimicrobic property of soap.

The antibacterial agent on the basis of nanoparticles of a bentonite powder intercalated by ions of silver and/or copper when used in the invention provides the disclosed antimicrobic action, without side dermatological influence, at the amount specified in the invention, in a composition of soap. Decrease of the amount of this agent in the soap worsens its antimicrobic action while increase in the amount leads to increase in cost/price.

The ratio of a mix of used bentonite powders intercalated by ions of silver (Ag ⁺ ) and ions of copper (Cu ²⁺ ) specified in the invention, is most expedient economically and optimum for antimicrobic properties of soap.

The specified size of particles of a bentonite powder is most expedient on conditions of process, of its injection in soap masses and on maintenance of prolonged action of antimicrobic effect at application of the soap.

The qualitative and quantitative structure of other components included in a composition of the soap according to the invention, providing its washing and cosmetic properties, is optimized on the basis of traditional developments applied for manufacturing of solid soap (see, for example, soap "Safeguard" manufactured by «Procter and Gamble» and also patent RU N. 2147607, whose developper is OSC «Cosmetic association "Freedom" »). Compositions of the given soaps contain also an antibacterial agent on the basis of Tryclozan, whose application worsens dermatological properties of soap, as it was already underlined.

Examples of realization of the invention, according to which the samples of the soap have been obtained on the labware, are given below.

The quantitative content of components in each given example is calculated for obtaining g 500 of soap.

Example 1.

Soap shavings - 74%; the antimicrobic agent on the basis of a bentonite powder intercalated by ions of Ag ⁺ - 2,5%; polyvinylpyrrolidone with molecular weight 20Ί0 ³ - 30· 10 ³ - 0,3%; the antioxidant (Antal P-2)- 0,3%; glycerin - 2%; citric acid - 0,1%; titan dioxide - 0,1%; perfumery composition (arbitrary type with a flower smell) - 0,5%; water - the rest. Example 2 is the same as example 1, but a bentonite powder intercalated by ions of Cu ²⁺ in amount of 2,5% b.w. is used as the antimicrobic agent.

Example 3 is the same as example 1, but a bentonite powder intercalated by ions of Cu ²⁺ in amount of 5,0% b.w. is used as the antimicrobic agent.

Example 4 is the same as example 1, but a mix of bentonite powders intercalated by ions of Ag ⁺ and Cu ²⁺ , at a ratio in the mix as 1:1, and in amount of 2,5% b.w. is used as the antimicrobic agent.

Example 5 is the same as example 1, but a mix of bentonite powders intercalated by ions of Ag ⁺ and Cu ²⁺ in a ratio in the mix as 1:5, and in amount of 2,5% b.w., is used as the antimicrobic agent.

Example 6 is the same as example 1, but in the presence of low-molecular medical- grade polyvinylpyrrolidone with molecular weight 8 10 ³ -10'10 ³ in the amount of 1,0% b.w. (PVP is used in medical-grade preparations for detoxication and improvement of rheological properties of blood).

Example 7 (control) is the same as example 1, but Tryclozan in the amount of 3% b.w. is used as the antimicrobic agent.

The samples of soap, with weight 110 g, are obtained by the examples 1-7. 4 samples of the soap of each example were manufactured in view of losses during manufacturing.

Estimation of antimicrobic properties of the soap was performed by means of microbiological tests in relation to gram-negative (Escherichia coli) and gram-positive (Staphilococcus aureus) bacteria, by dissolving the soap of examples 1-7 in liquid nutrient mediums.

Microbial activity was 107 COE/ml.

The antimicrobic effect was determined by subsequent inoculation of each solution in a solid nutrient medium.

As a result of the tests it was established that antimicrobic effect takes place as summarized hereinafter:

- gram-positive bacteria (S. aureus): for the soap of the examples 1, 3 and 7, within 24 hours; for the example 4 - within 20 hours; for the example 2, 5 and 6 within 15 hours;

- gram-negative bacteria (E. coli): for the soap of the examples 1 and 4 - within 20 hours; for the example 3 - within 24 hours; for the examples 2, 5 and 7 - within 18 hours. It follows from the microbiological tests that the compositions of soap according to the examples 1, 3, 4 and 7 are the most effective for antimicrobic properties, in relation to the specified microorganisms.

Decrease in efficiency of antimicrobic activity of the soap of the example 2, concerning bacteria S. aureus, testifies the expediency of increasing concentration of the antibacterial agent on the basis of a bentonite powder intercalated by ions of copper, in the composition of the soap. This is demonstrated by the microbiological tests of the sample of soap of the example 3.

Decrease in antimicrobic activity of the soap of the example 5 testifies the inexpediency of changing the weight ratio of the mix of the antimicrobic agents specified in the application.

Decrease in antimicrobic activity of the sample of soap of the example 6 testifies the inexpediency of using PVP with molecular weight lower than 12T0 ³ in the composition of soap. The use of PVP with molecular weight lower than 12· 10 ³ worsens stabilizing influence of the given preparation on foaming, with decrease in formation of active nanoclusters of antimicrobic action in the solution.

The estimation of properties of the samples of soap during use (examples 1-7) was performed basing on their dermatological influence on the skin of hands of tested persons, with frequent use within 8 days. 14 persons have been invited for testing (each two persons used the same sample of soap obtained from the examples 1-7).

It was established, as a result of the tests, that:

- the soap of the examples 1-5 does not show irritating and allergic influence on the skin during all term of tests;

- the soap of the example 7 had irritating action on the skin of the test person after 5 days of its application;

- the soap of the example 6 does not show irritating and allergic influence on the skin, but the given soap has an increased speed of dissolution. Term of test of the soap grew short till 4 days.

Thus, it is established, on the basis of the collected data, that the soap according to the examples 1-4 of the invention is the most effective in antimicrobic protection of the skin and has not negative dermatological influence on it. What testifies an optimum choice of components and of their amount, for the composition of the soap according to the invention.

The soap obtained from examples 1-4 corresponds to standard requirements for organoleptic, physical and chemical characteristics.