CZ65898A3 - Process of reducing dehydrating properties of soap and cleansing composition based on soap with weak dehydrating properties and use of talc for this purposes - Google Patents

Abstract

A method for reducing the dehydrating properties of a fatty acid salt soap is described. In use, the method includes adding to said soap, in order to produce on the skin a film replacing the natural lipid film destroyed or damaged by the soap, talc having the following combined properties: a compacted apparent density substantially lower than 0.70 g/cm<3>, and a grain size distribution such that the mean diameter D50 of the grains is substantially lower than 6 microns, and the diameter D95 is substantially lower than 20 microns.

Description

Technical field

The invention relates to a process which makes it possible to reduce the dehydration properties of soaps based on fatty acid salts. It is a further object of the present invention to provide novel cleaning compositions made using this process and the use of talc for these purposes.

BACKGROUND OF THE INVENTION

It is known from the prior art that fatty acid toilet soaps have the disadvantage of having a strong dehydrating effect on the skin. This effect results in an uncomfortable feeling of dry skin, accompanied by a feeling of tension, which occurs several minutes after use when all the water used evaporates and the freshness obtained disappears. In order to reduce the cost of the products and sometimes to increase the sensation of gentleness during washing, standard type talc was used as a soap filler; however, the refinement achieved in use (due to the layered nature of talc) is not associated with a feeling of drying after use, so that these known products also exhibit dehydration properties once the water used has evaporated.

SUMMARY OF THE INVENTION

It is an object of the present invention to reduce the dehydration properties of soaps based on fatty acid salts so as to make the soaps based on fatty acid salts so as to make them so-called &quot; 4 &quot; · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · evaporates.

The process of the invention aims to form a film on the skin during use of the soap, replacing the natural fat film which has been destroyed or damaged by the soap. Indeed, it has been shown that the drying sensation is caused by the destruction or damage of the fat film which protects the epidermis and constitutes a barrier limiting superficial dehydration of the skin. During the use of soap, the fat film is dissolved by the action of tensioactive fatty acids. In the absence of this film until it is re-formed by the epidermis, abnormal dehydration occurs on the epidermis, accompanied by the above-mentioned discomfort (dryness, tension) and the risk of skin damage. The present invention provides a method of forming a stable skin protective film during use of soap, which film replaces the natural fat film in order to limit the surface dehydration of the epidermis until the natural fat film is formed. The process according to the invention consists in adding talc having the following characteristics to the soap produced:

- a bulk density less than 0,70 g / cm,

- a particle size distribution such that the mean grain diameter ^D 50 J ^e substantially less than 6 microns, and the diameter D95 is substantially less than 20 microns.

Talc means mineral hydrated magnesium silicate, mineral chlorite (hydrated magnesium aluminum silicate) or a mixture of the two, optionally combined with other minerals (dolomite, etc.), or a talc-like substance having analogous properties.

The mean diameter D ^ q is understood to be such as 9 99. 99 99999

9 9 9 9 9 9 9 9 · diameter, where 50% by weight of the grains have a size smaller than this diameter; diameter means a value where 95% by weight of the grains have a size smaller than this value.

The bulk density of the powder is defined by AFNOR NFT30-042. In the case of talc, this value provides information on the grain form: with an equivalent particle size distribution, the type of talc having grains in lamellar very elongated form has a bulk density less than the type of talc having grains in less elongated form (more spheroid). Thus, at equivalent granulometry, this parameter can be considered for talc as a coefficient to assess the form of its particles.

The present invention is based on the following observation observed during a series of comparative experiments: a significant reduction in the drying properties of the soap was surprisingly achieved by the incorporation of talc, which had grains in a relatively spheroid, less elongated form (i.e. , within the limits where the grain size does not exceed the above values.

Preferably, a microcrystalline talc having grains of a more spheroid form is used, wherein each grain is comprised of elementary particles that are bound to each other, and these elementary particles of less than or equal to 1 micron have no preferred orientation.

It is also possible to use a talc of the lamellar type which has been subjected to crushing in order to at least partially break its layers (impact crushing, etc.).

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According to a preferred method of applying this process, a microcrystalline talc is used having the following characteristics:

and

- a bulk density in the range 0,20 to 0,60 g / cm,

particle size distribution such that the mean diameter D ^ q is in the range of 2 to 5 microns and the diameter is in the range of 6 to microns.

Better results were obtained using microcrystalline talc, which was subjected to impact crushing to achieve a bulk density in the range of 0.38 to 0.57 g / cm ³ .

The results obtained are currently difficult to explain satisfactorily. It appears that the characteristics of the talc used (bulk density corresponding to grain form, particle size distribution) lead to good grip and retention of talc on the skin surface, while grains of more lamellar form or larger are not retained by the surface and are removed by rinsing. Thus, according to the invention, a protective hydrophobic film of talc is formed on the surface of the skin which has sufficient stability to remain on the skin during rinsing and act as a barrier that limits the passage of water molecules and thus dehydration of the epidermis until the fat is restored. a film that was destroyed by soap.

In the context of the present invention, it should be noted that the known skin softening effect of using this soap is also related to the above-mentioned talc forms and this constitutes a further advantage of the invention.

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It seems that the best results were obtained when soap was added in the range of 5 to 20% by weight of talc. In addition, talc with an iron content of less than about 1.0% is preferably used in this embodiment to avoid the risk of soap degradation over time (wherein the iron content is the total amount of iron expressed as Fe ₂ O ₃ ).

The present invention encompasses cleansing compositions with poor dehydration properties, which are produced by the above process, wherein talc having the characteristics described above is added to the soap.

DETAILED DESCRIPTION OF THE INVENTION

The process for reducing the dehydration properties of soap and the soap-based cleaning composition with poor dehydration properties will be further illustrated in the following examples, which are illustrative only and are not intended to limit the scope of the present invention.

Assessment methodology used in the examples

All soap samples were evaluated by panel tests.

Prior to evaluation, soap samples were conditioned for hours at 20 ° C and 60% relative humidity. During the evaluation, the temperature of the water used was 40 ° C and the flow rate was 1 liter / minute.

The different soap samples were divided in two and subsequently each sample was independently evaluated by 8 persons (panelists) in each case in a different order of use.

Each soap sample was evaluated 24 times.

Evaluation protocol

- wash hands with comparative soap (simple soap without additive),

- dry your hands thoroughly with a towel,

- immerse hands in water for 5 seconds,

- soak the test soap and apply its defined amount (10 rotations) to the back of the left hand,

- place the palm of the right hand on the back of the left hand and rub the soap 20 times in a rotary motion,

- rinse hands under running water for 10 seconds without rubbing,

- dry your hands with a paper towel,

- after three minutes evaluate the skin touch.

The following skin parameters were evaluated:

- feeling hydrated,

- feeling dry,

- feeling soft.

The results were graded -2 to +8: the higher the value, the better the result:

Importance of individual evaluations:

- parameter hydration: -2 at all not hydrated, +8 very hydrated, - parameter drying: -2 very dry, +8 at all not dry, - parameter j emnosti: -2 at all not clear, +8 very j emná.

• · · · · · · · · · · · ·

Definition of the parameters of added talc (1) Bulk density

The method consists in subjecting a known amount of powder to shaking conditions as defined in AFNOR NF T 30-042.

The density of the product shaken off shall be calculated from the ratio of the weight used relative to the shake volume, according to the formula:

M_ ^ _o

In which:

M is the mass, in grams, of the epruvette containing the powder,

Μθ is the weight of the empty epruvette in grams,

The volume deducted after shaking in cm.

(2) Granulometry

Granulometric analysis was performed with a Sédigraph 5000 (trademark). The method is based on the measurement of the solid phase concentration (by X-ray absorption) in suspension during gravitational sedimentation. This method is applicable to powders whose grains have a diameter in the range 0,5 to 100 μπι.

The instrument directly determines the distribution curve, expressed as a percentage of the passing ratio, based on the Stockes average:

- corresponds to a diameter in which 95% by weight of the grains have a smaller diameter than this value,

- D50 corresponds to the mean diameter at which 50% by weight of the grains have a smaller diameter than this value.

Formulations used in the examples:

Formula Soap-free comparative soap Soap with talc Basic Soap: PRISAVON brand deposited ref: 9242 in Unichema International. . . 98.6% 87.3% Perfume ................... 1.0% 1.0% Titanium oxide .............. 0.4% 0.4% Talc ................... - 10.0% Added water ............. - 1,3 *

* The soap base contains water (of the order of 13%), and the water listed in the table, which has been added with talc, allows the total water content of both formulations to be kept constant.

The talc / soap premix was made in a conventional belt mixer. The final stages of soap production after premixing are commonly performed phases (crushing, refining, extrusion, cutting, pressing).

Example 1

This example illustrates a decrease in the dehydration properties of the additive soap.

This example presents a comparison of the soap containing the talc (A) of the invention and the comparison soap without talc.

Talc A parameters:

- a microcrystalline type which has been subjected to impact crushing,

- D ₉₅ = 8.5 µm

- D _5q = 3.4 μιη

- bulk density = 0,5 g / cm.

Results:

Parameters Soap-free comparative soap Soap with talc A (according to the invention) Hydration parameter 2.38 3.75 Drying parameter 3.25 4.46 Fineness parameter 4.29 5.71

The results were analyzed statistically by the Student method. It has been noted that the process of the invention provides a significantly better result than talc-free comparative soap.

Example 2

This example illustrates the effect of particle size distribution.

This example presents a comparison of two soaps containing talc (B, C) and a comparative soap without talc. Talc C did not satisfy its granulometry in the process according to the invention.

Talc parameters (lamellar origin)

talc B according to the process of the invention,

D ₉₅ = 7 pm

D _5q = 3 µπι, a

bulk density = 0.44 g / cm.

- talc C unsuitable according to the invention, ^D 95 ^{= 44} I ¹¹¹¹ '

D ₅ q = 18 µm, and bulk density = 0.74 g / cm.

Results:

Parameters Soap-free comparative soap Soap with talc B (invention) Soap with talc Hydration 3.83 4.88 3.42 Drying 5.62 6.42 5.46 Softness 5.54 6.29 5.54

It has been noted that the process of the invention (talc B) provides significantly better results with respect to the comparative soap without talc and the soap containing talc C, which is not within the scope of the process of the invention.

Claims (8)

PATENTOVÉ Claims A method for reducing the dehydration properties of a soap based on fatty acid salts, characterized in that talc having the following characteristics is added to the soap in order to form a film on the skin during use of the soap which replaces a natural fat film destroyed or damaged by soap: - a bulk density of less than 0,70 g / cm, - particle size distribution such that the mean diameter The D 3θ grain is substantially less than 6 microns and the diameter is substantially less than 20 microns. Process according to claim 1, characterized in that the soap mass is added in the range of 5 to 20% by weight of talc. Method according to either of Claims 1 and 2, characterized in that talc is added to the soap which has been subjected to crushing capable of at least partially breaking its layers. Method according to one of claims 1, 2 or 3, characterized in that talc with an iron content of less than 1.0% is added to the soap. A process according to any one of claims 1 to 4, characterized in that microcrystalline talc is added to the soap having the following characteristics: and - a bulk density in the range 0,20 to 0,60 g / cm, a particle size distribution such that the mean diameter D50 is in the range of 2 to 5 microns and the diameter D95 is in the range of 6 to 14 microns. ·· ···· ♦ · · · · A process according to claim 5, characterized in that microcrystalline talc is added which has been subjected to impact crushing to achieve a density in the range of 0.38 to 0.57 g / cm ³ . A cleaning composition with poor desiccating properties comprising a soap based on fatty acid salts added with talc according to the process of any one of claims 1 to 6, wherein the composition is capable of forming a skin film during use that replaces a natural fat film which has been damaged or destroyed by soap. 8. Use of talc having the following characteristics: and - a bulk density of less than 0,70 g / cm, - particle size distribution such that the mean diameter The D 6 grains are substantially less than 6 microns, and the diameter is substantially less than 20 microns, in order to reduce the drying properties of the fatty acid soap, by forming a film that replaces the skin's natural fat film that has been damaged or destroyed by soap.