FR2694189A1 - A process for raising viscosity of cosmetic - by incorporating polyglyceryl methacrylate gel and soln. of polyacrylic-methacrylic acid, with synergistic effect - Google Patents

Abstract

The viscosity of cosmetic compsn. is raised by incorporation of a polyglyceryl methacrylate gel and a soln. of polyacrylic/methacrylic acid such that neutralisation of this soln. to pH above 6 gives a greater viscosity than is obtd. with the additives separately. Pref. the compsn. contains 1-50% of the polyglyceryl methacrylate gel, pref. "Lubrajel" (RTM), and 0.1-10% of polyacrylic/methacrylic acid, pref. "Thixotrate" (RTM). The compsn. is an emulsion, cream, shampoo, lotion, milk, mask, liq. soap, gel, toothpaste, deodorant, rinse, combing compsn. or shaving foam. ADVANTAGE - The two additives give a simple, economical and lasting stability to the cosmetics, without affecting the lightness of a cream, or producing tackiness. The gels are transparent.

Description

A large number of cosmetic preparations are characterized by a certain viscous appearance: creamy creams, gels, milks more or less fluid, shampoos and liquid soaps, or toothpastes and shaving foams.

The viscosity of a preparation depends on many factors; some ingredients have such a specific viscosity that their concentration in the finished product defines the viscosity obtained. In most cases, however, the formulator must use thickening agents to thicken the emulsion, gel, shampoo. These thickening agents are of a very diverse nature, ranging from NaCl salt for certain shampoos and liquid soaps to polysaccharides, gums and cellulose derivatives, as well as soluble silicates, carbomers, and other polymers.

According to the formula to be thickened, the most appropriate thickening agent is chosen, but the choice is often difficult, the compromises between efficiency, price, ease of use, cosmetic touch, stability over time, compatibility with other ingredients and or the pH are usually unsatisfactory.

Two areas are particularly concerned by this problem: emulsions and shampoos.

Cosmetic emulsions (creams, milks, lotions) are characterized by the dispersion of an aqueous phase in an oily phase (W / O emulsion) or an oily phase in an aqueous phase (O / W emulsion). It is important to note that this simplification does not describe, but includes globally, complex, multiple emulsions, vesicular dispersions such as liposomes, micelles, liquid crystals and other structural arrangements between lipid molecules and hydrophilic and aqueous molecules. .

These emulsions are, from the energy point of view, metastable. The cosmetic formulator has at its disposal a number of chemical, mechanical and technical means for stabilizing the emulsion over time, and over a wide range of temperatures.

The type and precise characteristics (touch, density, color, fineness, stability) of an emulsion depend firstly on the type of emulsifier (surfactant) used to obtain a homogeneous emulsion.

But the right choice of the surfactant system is often not enough. Other ingredients are needed.

One of the most commonly used means is to increase the viscosity of the external phase of the emulsion to reduce the mobility of the droplets of the internal phase and thus reduce the chance of collision and coalescence between these droplets.

The gelling substances usually used (cellulose derivatives, gum arabic, vinyl polymers, silicate gels) often have various disadvantages: sticky touch or incompatibility with electrolytes, laborious preparation of the gel beforehand, high sensitivity to pH, especially acidic pH etc.

In the case of shampoos, it is especially the search for viscosity agents for formulas based on nonionic surfactants which proves difficult. Salts, alkanolamides and other viscosifiers are often not active without the presence of anionic or cationic charged groups.

The object of this patent is the discovery of a synergy between two substances which makes it possible to stabilize cosmetic preparations, emulsions of all kinds as well as various shampoos in a simple, economical, durable and cosmetically advantageous manner.

The patented method consists of the combined use of a prefabricated ready-to-use gel of the polyglyceryl methacrylate type (for example LUBRAJELR from United
Guardian Inc.) and a solution of polyacrylmethacrylic acid (eg
THIXOTRATER of United Guardian, Inc.). In fact, the polyglyceryl methacrylate gels, which can be obtained inter alia by reaction of a sodium glycerate with a methacrylic acid and acrylic acid polymer, followed by controlled hydration, have found many uses in the cosmetic formulation (lubricant, moisturizer, humectant). But an emulsion can not be stabilized by a few percent of this gel. At 5% of gel, for example, the viscosity is far too low. It is always necessary and still an agent of the families listed above, which often complicates the process of manufacturing, increases tackiness ("tackiness") or makes granular emulsions, not pleasant to the touch.

In tests of thickeners in different types of emulsions, using among other solutions methacrylic and acrylic polymers in acid form which have the property of gelling during the neutralization between pH 6.5 and 7.5, it was observed unexpectedly that emulsions containing a few percent of LUBRAJELR became much more viscous than those without LUBRAJELR.

The following example illustrates this effect:
AF creams were prepared, their viscosity and their feel were evaluated in comparison.

A B C D E F
Polysorbate 60 3.35 3.35 3.35 3.35 3.35 3.35
Sorbitan stearate 1.65 1.65 1.65 1.65 1.65 1.65
Octyl palmitate 8.00 8.00 8.00 8.00 8.00 8.00
Cyclomethicone 1.00 1.00 1.00 1.00 1.00 1.00
Mineral oil (and) lanolin alcohol 1.00 1.00 1.00 1.00 1.00 1.00
PPG-15 Stearyl ether 2.00 2.00 2.00 2.00 2.00 2.00
Beeswax 1.00 1.00 1.00 1.00 1.00 1.00
Cetyl alcohol 1.00 1.00 1.00 1.00 1.00 1.00
Preservatives 0.30 0.30 0.30 0.30 0.30 0.30
Water qsp100 qsp100 asp100 qsp100 qsp100 qsp100
Carbomer 0.20 - - - - 0.20
Triethanolamine 0.2 - - - - 0.20
THIXOTRATE - - 1.00 2.00 1.00
LUBRAJEL - 5.00 - 5.00 5.00 (pH of neutralization: 6.5 using NaOH)
Viscosity (cps) - BROOKFIELD:
A: 150,000 - B: 500 B: 500-C: 80,000 - D 300,000 - E: E: 1,000,000 - F: 250,000
Touch (averages of dimensions) A: 2.5 - B: too fluid - C: 2.7 - D: 2.0 - E: 3.5 - F: 3.0
Results:
The listed viscosities clearly show the described effect: 1 and 2% thickener (THIXOTRATER in this case) give, after neutralization, average viscosities, similar to those obtained with the conventional carbomer; the cream with 5% gel polyglyceryl methacrylate and THIXOTRATER has a viscosity significantly higher than that of the cream of reference. The
LUBRAJELR alone does not increase the viscosity significantly.

The touch, evaluated by 5 experts in the profession and rated on a scale of 0 to 4 (not pleasant / tacky to very pleasant / soft) shows a clear advantage for creams containing the poly lyceryl / methacrylate / polyacrylmethacrylate combination). A significant advantage of this formula lies in the ease of manufacture: carbomer gels or cellulosic derivatives must be prepared long before, often requiring pre-heating.

The combination of the substances subject of the patent does not require any particular precaution. The ready-to-use gel (LUBRAJELR or equivalent) is dissolved and homogenized easily in the aqueous phase, the solution of the acryl-methacrylic polymer is added after formation of the emulsion and finally neutralized to pH and / or desired viscosity.

As regards the shampoos, the following formulas illustrate the advantage of mixing the polyglyceryl methacrylate and polyacryl methacrylate gels which are the subject of this patent.

A B C D E
Decyl glucoside 14.00 14.00 14.00 14.00 14.00
Caprylyl / capryl glucoside 8.00 8.00 8.00 8.00 8.00
Cocamidopropyl-amine oxide 2.00 2.00 2.00 2.00 2.00
Cocamidopropyl betaine 7.50 - - - -
Water qsp100 asp100 qsplOO qsplOO qsplOO
THIXOTRATE - 2.00 2.00 -
LUBRAJEL - 5.00 - - 5.00
A: non-ionic + betaine
B: nonionic + THIXOTRATER + LUBRAJELR
C: nonionic + THIXOTRATER
D: nonionic only
E: non-ionic + LUBRAJELR
Results: it is thus demonstrated that the combination LUBRAJELR (or equivalent) + THIXOTRATER (or equivalent) makes it possible to thicken completely non-ionic shampoos, and this in a simple, fast and inexpensive way.

The advantages of the combined use of the substances described are therefore multiple: the formulator of cosmetic products enjoys a great deal of flexibility.

 He can adjust the viscosity of the formula of the finished product by modifying the respective proportions of the polymers, by playing on the pH of the neutralization, and this at the end of the process (even late rectifications on the produced products are thus possible), he can obtain high viscosities without modifying the light touch of the cream, without "tackiness"; it enjoys the advantages of polyglycerylmethacrylates gels without problem of incompatibility with other thickening agents. The manufacture of viscous products is facilitated by the omission of the preparatory phase of cellulosic gel, carbomer or silicate.

Another advantage is that the gels obtained are transparent, the thickening effect does not opacify the medium.

 It is obvious that all possible applications of the subject method of the invention can not be envisaged and listed here. The formulator skilled in the art of preparing finished products will be able to make use of the advantage of the invention in various fields other than those described above: toothpastes, lotions, masks, deodorants, gels of any kind, products rinsing agents, demellants, shaving foams.

The exact nature of the two synergistic gels is not essential: one must be part of the gels of the polyglyceryl methacrylate type, that is to say be a clathrate of glycerine, water, polyester of acrylic and methacrylic acid. and sodium glycerate; The other an acid solution of copolymer of acrylic and methacrylic acid. The respective concentrations to be used to obtain the thickening effect described can vary in large proportions: between 1 and 50% of polyglyceryl methacrylate gel and between 0.02 and 10% of polyacrylmethacrylic acid (dry weight), diluted before
the use at a suitable concentration, - between 0.1 to 20% of a solution of polyacrylmethacrylic acid ready
for use with between 10 and 50% dry matter content.

Claims (5)

1. A method for increasing the viscosity of the compositions  cosmetics which consists of using together in the formula a gel  polyglyceryl methacrylate and a solution of polyacrylmethacrylic acid  such as the neutralization of the latter solution at a pH> 6 conducts  at a higher viscosity than using each of the components  isolated. 2. Cosmetic compositions thickened according to the method of  claim 1.  between 0.1 and 10% of poyacrylmethacrylic acid.  they contain between 1 and 50% of polyglyceryl methacrylate gel and Cosmetic compositions according to claim 2, characterized in that 4. Cosmetic compositions according to claims 2 and 3 characterized  in that the polyglyceryl methacrylate gel is a LUBRAJELR and that  polyacrylmethacrylic acid is THIXOTRATER. 5. Cosmetic compositions according to claims 2 to 4 characterized  in that they are emulsions, creams, shampoos,  lotions, milks, masks, liquid soaps, gels, pasta  toothpastes, deodorants, rinses, detanglers or  shaving foams.