WO2012016578A1

WO2012016578A1 - Thickening agents for cosmetic oil phases

Info

Publication number: WO2012016578A1
Application number: PCT/EP2010/004824
Authority: WO
Inventors: Wolfgang Denuell; Cindy Muenzenberg; Oliver Pietsch
Original assignee: Cognis IP Management GmbH
Current assignee: Cognis IP Management GmbH
Priority date: 2010-08-06
Filing date: 2010-08-06
Publication date: 2012-02-09
Anticipated expiration: 2013-02-06

Abstract

The use of certain polymers, derived from fumaric acid and fumaric acid esters is disclosed for the thickening of oil-phases of cosmetic compositions.

Description

Thickening agents for cosmetic oil phases

The present invention is related to the area of cosmetic compositions and covers oil- based compositions comprising certain polymers suitable for increasing the viscosity.

Cosmetic hair and skin-care emulsions are expected by the consumer to satisfy a number of requirements. Apart from the cleansing and caring effects which determine the particular application, importance is attributed to such diverse parameters as highest possible dermatological compatibility, good lipid-layer-enhancing properties, elegant appearance, optimal sensory impression and shelf life. Besides a number of surfactants, cosmetic hair- and skin-care preparations generally contain, above all, oil components and water. The oil component (emollients) used include, for example, hydrocarbons, ester oils and vegetable and animal oils/fats/waxes.

Many cosmetic compositions, irrespectively if present as homogenous solution, dispersion or aqueous emulsion contain certain compounds to increase their viscosity. In order to thicken the aqueous phase of cosmetic composition it is known to use water-soluble vegetable gums, such as alginates and tragacanth, water-soluble cellulose derivatives, such as carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, water-soluble starch derivatives and synthetic polymers, such as polyvinylalcohol, polyethylene oxides or polyacrylic acids. If an oil phase needs to be thickened clearly less polymeric thickeners are known, e.g. often copolymers of styrol are used. Otherwise non polymeric molecules could be used, e.g. metal soaps like Zinc stearate.

Due to the limited amount of suitable polymers for oil thickening, there is a constant need to find new or improved thickening agents accordingly. Besides an improvement of thickening power, different properties are also of interest, e.g. the compatibility of the thickener with different matrices, and/or the compatibility with human skin and hair and/or the use of raw materials from renewable sources.

The object of the present invention has been to find new rheology modifiers able to provide the appropriate rheological behavior to oil-based cosmetic compositions.

CONFIRMATION COPY The present invention refers to the use of polymers comprising monomers according to the general formula (I) ROOC-CH=CH-COOR', in which R and R' independently from each other represents either hydrogen or methyl or stand for a linear or branched alkyl or alkenyl radical having 2 to 22 carbon atoms with the proviso, that at least one moiety R or R' is not a hydrogen atom as thickening agent for cosmetic acceptable oil phases.

Cosmetic acceptable oil phase

Basically, the phrase "oil phase" encompass all kinds of oil bodies or oil components, in particular vegetable oils, fatty acid alkyl esters based on said C6-C22 fatty acids, mineral oils, silicone oils and their mixtures. The term "cosmetic acceptable" refers to those kinds of organic oils or blends of oils which can be used in such compositions which came into intense and/or direct contact to the human skin, scalp, hair or nails, without harming them.

Examples illustrating the nature of suitable hydrophobic carriers without limiting the invention to these examples are: C6-C22-Fatty alcohols, Guerbet alcohols based on fatty alcohols having 6 to 18, preferably 8 to 10, carbon atoms, esters of linear C6- C22-fatty acids with linear or branched C6-C22-fatty alcohols or esters of branched C6-C13-carboxylic acids with linear or branched C6-C22-fatty alcohols, such as, for example, myristyl myristate, myristyl palmitate, myristyl stearate, myristyl isostearate, myristyl oleate, myristyl behenate, myristyl erucate, cetyl myristate, cetyl palmitate, cetyl stearate, cetyl isostearate, cetyl oleate, cetyl behenate, cetyl erucate, stearyl myristate, stearyl palmitate, stearyl stearate, stearyl isostearate, stearyl oleate, stearyl behenate, stearyl erucate, isostearyl myristate, isostearyl palmitate, isostearyl stearate, isostearyl isostearate, isostearyl oleate, isostearyl behenate, isostearyl oleate, oleyl myristate, oleyl palmitate, oleyl stearate, oleyl isostearate, oleyl oleate, oleyl behenate, oleyl erucate, behenyl myristate, behenyl palmitate, behenyl stearate, behenyl isostearate, behenyl oleate, behenyl behenate, behenyl erucate, erucyl myristate, erucyl palmitate, erucyl stearate, erucyl isostearate, erucyl oleate, erucyl behenate and erucyl erucate. Also suitable are esters of linear C6-C22-fatty acids with branched alcohols, in particular 2-ethylhexanol, esters of C18-C38- alkylhydroxy carboxylic acids with linear or branched C6-C22-fatty alcohols, in particular dioctylmalate, esters of linear and/or branched fatty acids with polyhydric alcohols (such as, for example, propylene glycol, dimerdiol or trimertriol) and/or Guerbet alcohols, triglycerides based on C6-C10-fatty acids, liquid mono-/di-/triglyceride mixtures based on C6-C18-fatty acids, esters of C6-C22-fatty alcohols and/or Guerbet alcohols with aromatic carboxylic acids, in particular benzoic acid, esters of C2- CI 2- dicarboxylic acids with linear or branched alcohols having 1 to 22 carbon atoms or polyols having 2 to 10 carbon atoms and 2 to 6 hydroxyl groups, branched primary alcohols, substituted cyclohexanes, linear and branched C6-C22-fatty alcohol carbonates, such as, for example, Dicaprylyl Carbonate (Cetiol® CC), Guerbet carbonates, based on fatty alcohols having 6 to 18, preferably 8 to 10, carbon atoms, esters of benzoic acid with linear and/or branched C6-C22-alcohols (e.g. Finsolv® TN), linear or branched, symmetrical or asymmetrical dialkyl ethers having 6 to 22 carbon atoms per alkyl group, such as, for example, dicaprylyl ether (Cetiol® OE), ring-opening products of epoxidized fatty acid esters with polyols and/or silicone oils (cyclomethicones, silicone methicone grades, etc.). A further preferred oil phase is selected from silicone oils, especially hydrophobically modified silicone oils (e.g. Dow Corning® 2502 by Dow Corning).

Suitable as cosmetic acceptable oil phases, or part of this oil phases, are also vegetable oils, but with the proviso that rape seed oil, and derivates thereto, including rape seed oil methyl esters are excluded, because those oils are potentially irritating the human skin. Also excluded are oils, which are based on non-renewable sources, like mineral oils, paraffin oils and preferably commercial white oil.

Especially preferred cosmetic acceptable oil phase are selected from

i) Fatty alcohols and Guerbet alcohols,

ii) Esters of Guerbet alcohols with linear or branched fatty acids,

iii) Fatty acid esters of linear or branched fatty alcohols,

iv) Fatty acid esters of glycerol

v) Dialkylcarbonates,

vi) Dialkylethers,

any mixtures of the compounds i) to vi). Especially preferred oil phases according to the present teaching are selected from groups iii), iv), v) and/or vi) as well as any mixture thereof.

Polymers

The polymers according to the present invention represent polymers containing monomers according to the following formula (I)

ROOC-CH=CH-COOR' (I) in which R and R' independently from each other represents either hydrogen or methyl or stand for a linear or branched alkyl or alkenyl radical having 1 to 22 carbon atoms with the proviso, that at least one moiety R or R' is not a hydrogen atom.

Polymers according to this invention are such compounds which contain at least 5 and preferably at least 8 monomers. The polymers according to this invention may comprise only one monomer (then homopolymers are present) or may contain two or more monomers according to formula (I) (then co- or terpolymers are present). In one preferred embodiment the polymers will only consist of monomers according to formula (I) above.

Preferably such monomers according to formula (I) are selected where both groups R and R' are selected from linear or branched, saturated or unsaturated alkyl or alkenyl radical having 1 to 22 carbon atoms. More preferred are monomers where R and/or R' are selected from saturated alkyl groups with contain 6 to 22, and more advantageous from 12 to 22, and preferred from 16 to 22 C-atoms.

A certain preferred embodiment pertains to the use of polymers, containing monomers according to formula (I), whereby the groups R and/or R' are selected from blends of linear saturated C16/C18 alkyl chains, or of blends of C18/C22 alkyl chains, or both. Linear groups R and/ or R' might be preferred over branched ones. The most preferred moiety R and/or R' is the behenyl-group, comprising of a linear saturated alkyl group with 22 C-atoms. In a further preferred embodiment R and R' both represent such a behenyl group in the monomers according to formula (I). The polymers are based preferably on fumaric acid mono- or diesters accordingly, and can be described as polyfumarates. The polymers may consist of the monomers according to formula (I), but also suitable in the sense of the present invention are co- polymers, containing together with the monomers according to formula (I) different monomers too. A preferred different monomer is fumaric acid. But in the sense of the present invention homo-polymers consisting of fumaric acid monomers only are excluded. But it is preferred to use polymers which contains fumaric acid together with other monomers according to formula (I) wherein in these other monomers at least one moiety R or R' will not be a hydrogen atom. Again, preferred monomers are those where R and/or R' is selected from a behenyl group.

Typical examples for R and/or R' are methyl, ethyl, propyl or butyl groups, or these groups are derived from C6-C22 fatty alcohols, as for example capryl alcohol, 2- ethylhexyl alcohol, C8-C10 fatty alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, elaidyl alcohol, linolyl alcohol, conjugated linolyl alcohol, linoleyl alcohol, ricinolyl alcohol, 12- hydroxystearyl alcohol, gadoleayl alcohol, arachidonyl alcohol, behenyl alcohol, eruciyl alcohol, Guerbet alcohols based on fatty alcohols having 6 to 18 carbon atoms, and their mixtures.

Particularly preferred are such polymers, based on monomers which comprising short (C6-C14) and/or long chain (C16-C22) fatty alcohols, for example esters obtained from 2-ethylhexyl alcohol and behenyl alcohol as moieties R and/or R'. Behenyl alcohol could be used in a commercial available technical grade, which means that it is not a pure linear C22-alcohol, but a blend of CI 8-, C20- and C22-alcohols, with the majority (by weight) of C22-alcohol.

Different monomers according to formula (I) could be present in the inventive polymers. Preferred are those co-polymers comprising of a first monomer according to formula (I), and a second monomer which is structural different to said first monomer, preferably fumaric acid. The term "structural different" in this regard mean that the second monomer will not fall within the definition of Markush formula (I). Preferred are polymers, where 40 to 100 mol %, and more advantageous of 70 to 100 mol % of all monomers are selected from those monomers according to formula (I), and it is then preferred to select those monomers according to formula (I) where R and/or R' represent a C-22 alkyl group, preferably a linear one. The monomers up to 100 mol % then are selected from different compounds comprising unsaturated moieties, whereby unsaturated dibasic carboxylic acids, like fumaric acid could be preferred monomers.

The polymers used as thickener according to the present invention can be obtained according to the standards method known in organic chemistry. Esterification of the fumaric acid with the corresponding alcohol can be done by known methods in the art for example, by using / oluene sulfonic acids. Typically, the polymerization is initiated by a radical starter, for example a persulfate. It is possible, to prepare the esters in a first step followed by polymerization or vice versa, that means first preparing the polymeric backbone and than esterifying the polymer thus obtained.

The polymers according to the present invention show a preferred weight average molecular weight in the range of about 3,000 - 300,000 Da and preferably between 25,000 - 200,000 Da and most preferred between 60,000 - 100,000 Da.

A further embodiment of the invention is therefore directed to the use of the polymers as described above as thickening agent for the preparation of or for the use in cosmetic compositions. "Thickening" in the sense of the present technical teaching encompasses any increasing of the viscosity of a given oil-phase after the polymer has been added, compared to the viscosity, measured without this additive, according to the same methods, and with the same equipment at the same physical conditions (temperature, air pressure, humidity etc.).

The polymers in the sense of this invention could be used as thickening agent for incorporation in all kind of cosmetic preparations, whereby oils as well as any kind of emulsions with water and oil are possible products. The inventive polymers could also be used in aqueous dispersions. Preferred oily products are for example body care and cleansing preparations, in particular body oils, baby oil, body milk, massage oils, shower oils, antiperspirants and deodorants, sun protection oils, creams, or lotions. Preferred emulsions are water-in-oil emulsions. Furthermore the polymers in the sense of this invention could be used in decorative cosmetic products like lip sticks, lip gloss and the like.

The ready made compositions, containing the polymers according to the present invention may be applied as a care component to tissues, papers, wipes, nonwovens, sponges, puffs, plasters and bandages which are used in the field of hygiene and care (wet wipes for baby hygiene and baby care, cleaning wipes, facial wipes, skin care wipes, care wipes containing active ingredients against ageing of the skin, wipes containing sun protection formulations and insect repellents and wipes for decorative cosmetics or for after-sun treatment, toilet wipes, antiperspirant wipes, diapers, handkerchiefs, wet wipes, hygiene products, self-tanning wipes). They may also be used inter alia in hair-care, hair-cleaning or hair-colouring compositions.

They may furthermore also be used in decorative cosmetics, such as lipsticks, lipglosses, foundations, make-up, pressed and loose powders, eye-shadow, mascaras and the like.

One embodiment of the present invention is therefore directed to the use of the polymers as defined above in cosmetic compositions comprising any cosmetic acceptable oil phase, in amounts from 0.1 to 10 % by weight, and preferably from 0.5 to 8.0 % by weight or 1.0 to 6.0 % by weight and particularly preferred in the range between 1.5 and 3.0 % by weight (calculated on the total weight of the cosmetic composition).

Those preferred cosmetic composition may be present as oils or as water containing emulsions, and most preferred as W/O emulsions. Furthermore, as far as emulsions are concerned the amount of the polymer is in a preferred embodiment selected from 0.1 to 6.0 % by weight, and more advantageously from 0.5 to 3.0 % by weight, calculated on the total weight of the emulsion.

Depending on the application envisaged, the cosmetic compositions contain besides the above describes polymers as thickeners a number of other auxiliaries and additives such as, for example, consistency factors, superfatting agents, stabilizers, polymers, pH-adjusting agents, phospholipids, biogenic agents, antioxidants, deodorants, antiperspirants, antidandruff agents, film formers, swelling agents, insect repellents, self-tanning agents, tyrosinase inhibitors (depigmenting agents), fillers, hydrotropes, solubilizers, preservatives, perfume oils, dyes, UV-filters etc. The compositions where the polymeric thickening agents of the present invention are used are preferably free of any biocides.

A further advantage in using the above mentioned polymers is an enhanced ability of the thickened oils containing them to stabilize any kind of particles against separation or settlement. In this regard particles could mean capsules, microcapsules, pigments, sensory modifiers, air bubbles, dispersed polymer particles and the like. These stabilizing properties are therefore also a subject matter of the present application.

Examples

Preparation of polymer samples

Fumarate dibehenyl ester is polymerized by radical polymerization at 80°C using sodium persulfate as initiator. The resulting polymer has a weight average molecular weight of approx. 120.000 Da and has been tested in different application examples which are listed below. Additionally other Polyfumarates have been prepared accordingly, starting with Fumarate diesters with different chain lengths of the ester groups. Finally also mixtures of different fumarate diesters or of a fumarate diesters with fumaric acid have been polymerized to copolymers in the same way.

Application tests

A polymer of fumarate dibehenyl ester has been added to various cosmetic acceptable oil phases, stirred at 80°C for 60 minutes, stored at 23°C for at least 12 hours and the viscosity was measured (if not mentioned at 23 °C ± 2°C). For all compositions the viscosity data directly after addition of the polymer is shown, and after 2 minutes shearing. The data show that the polymers are able to thicken the various oils. Furthermore, the shear data indicate that a composition containing the polymers according to the present invention show a shear-thinning behavior, nevertheless a high viscosity is kept even under shear conditions.

The compositions and the results of the viscosity measurement are shown in the following tables (all amounts are expressed as %-by weight). Comparison compositions are marked as CI, C2 etc. The cosmetic oils and other ingredients used in the tests are as follows:

The polymers in the following tables are named e.g. like "Poly-C 18/22-Fumarate". That means a homopolymer of a fumaric acid diester with two C 18/C20/C22-fatty alcohol (= behenyl alcohol) ester groups.

Example 1 : Thickening of Palm Oil

Example 2: Thickening of different Oils or Mixtures thereof

Example 3 : Thickening of a Body Massage Oil

Example 4: Thickening of different Oils with Polyfumarates with varying C-chain Length of Ester Groups

Oil / Polymer 26 27 28 29 30 C6

Cetiol® LC

Cetiol® CC

Myritol® 331 97% 97% 97% 97% 97% 97%

Poly-C12/C14-

3%

Furmarate

Poly-C16/C18-

3%

Fumarate

Co-Polymer of 95%

C18/C22-Fumarate 3%

and 5% Fumaric Acid

Poly-C18/C22-

3%

Fumarate

Copolymer of 95%

C18/C22-Fumarate 3%

and 5% Fumaric Acid

C18/C22-Fumarate

3% (No Polymer)

Brookfield VT Sp.3, 20 Sp.3, 20 Sp.6, Sp.6, 20 Sp.5, 20 Sp.3,

Spindle, Speed rpm rpm 20 rpm rpm rpm 20 rpm at start of

< 50 1,550 36,000 11,000 6,100 750 measurement [mPas]

after 2 min. of

< 50 1,550 24,000 4,300 4,800 750 measurement fmPas]

Example 5: Temperature dependent Viscosity Measurements with Plate-Plate

Rheometer

Preparation of Samples (Polymer in Oil): The Polymer was added to the oil and stirred at 80°C for 60 minutes. Afterwards the sample was cooled and stored at 23°C for at least 12 hours. These are the recipes of the Body Massage Oil containing two different amounts of polymer:

Measurement procedure: Shear-rate controlled measurements are performed using a commercial rheometer (Malvern/Bohlin CVOR-120) with a 40 mm plate-plate geometry and a gap height of 1 mm, temperature is controlled by a Peltier system in the lower plate. Measurement temperatures are 14 °C, 21 °C, and 28 °C. After reaching thermal equilibrium, the sample is allowed to rest for 1200 s, and after that a shear rate ramp test (up-down) is conducted between 5 s^_1 and 100 s^_1, 22 data points are collected in a measurement time of 30 s. A total of 2-3 individual measurements are conducted per sample and temperature. The viscosity values reported are averages of the data points collected at a shear rate of 100 s^-1.

The results are shown in the following table:

Behenylfumarate

(Monomer)

The samples (oil plus polymer) show an enormously high viscosity in the Newton area. That is a sign for the ability of these mixtures to stabilize particles etc. Additionally the viscosity of the samples decreases intensively when shear stress is applied. This shear-thinning behavior could be an advantage in many cosmetic applications. Example 6: Flow Curves of Selected Thickened Oil Samples

Preparation of Samples (Polymer in Oil): The Polymer was added to the oil and stirred at 80°C for 60 minutes. Afterwards the sample was cooled and stored at 23°C for at least 12 hours. Measurement procedure for flow curves: Flow curves were determined using a commercially available rheometer Bohlin^® CVO-R 120 (Malvern Instruments, Herrenberg/Germany) with the Bohlin^® software version 6.50.5.7. Experiments were performed at 20°C using cone-plate geometries 4°/40mm and l°/40mm, depending on the viscosity range of the samples.

After filling, a shear rate controlled pre-shear of 1 s^"1 was applied for 15s to standardize the shear-history of the samples. This was followed by 75s of rest. The actual measurement was a stress controlled ramp, ranging from shear stresses of 0.06 Pa to the maximum of 7162 Pa obtainable with the available instrument. For the complete ramp, a total of 150 data points were programmed to be recorded in logarithmic progression within 300s of total measurement time.

For the flow curves given here the instantaneous viscosity is plotted as a function of the shear stress applied. The curves are shown in Figure 1. Viscosity of pure Oils (without Polymer): Pure Cetiol^® CC shows newtonian behavior with a viscosity of approx. 5 mPa s, pure Myritol^® 318 with approx. 20 mPa s.

Example 7: Preparation of W/O-emulsions

Certain w/o-emulsions containing the fumarat-polymers according to the present invention have been prepared:

* Biocide; ** Preservative

Claims

1. The use of polymers comprising monomers according to the general formula (I) ROOC-CH=CH-COOR\ in which R and R' independently from each other represents either hydrogen or methyl or stand for a linear or branched alkyl or alkenyl radical having 2 to 22 carbon atoms with the proviso, that at least one moiety R or R' is not a hydrogen atom as thickening agent for cosmetic acceptable oil phases.

2. The use according to claim 1 , characterized in that the groups R and R' in the monomers according to general formula (I) are both selected from linear or branched alkyl or alkenyl radical having 1 to 22 carbon atoms.

3. The use according to claims 1 or 2, characterized in that the groups R and R' are both selected from linear saturated alkyl groups with 22 C-atoms.

4. The use according to any of the preceding claims 1 to 3, characterized in that the monomer according to formula (I) is a fumaric acid ester.

5. The use according to any of the preceding claims 1 to 4, characterized in that said polymers show a molecular average molecular weight of 3,000 - 300,000 Da and preferably between 25,000 - 200,000 Da and most preferred between 60,000 - 100,000 Da.

6. The use according to any of the preceding claims 1 to 5, characterized in that said polymer is a copolymer of a first monomer according to formula (I) and a second monomer which is structural different to the first monomer.

7. The use according to any of the preceding claims 1 to 6, characterized in that said polymer is a copolymer of a first monomer according to formula (I) and a second monomer which is fumaric acid.

8. The use according to any of the preceding claims 1 to 7, characterized in that the cosmetic acceptable oil phase is selected from C6-C22-fatty alcohols, C6- C18 Guerbet alcohols, esters of Guerbet alcohols with fatty acids, fatty acid esters of linear or branched C6-C22-fatty alcohols, fatty acid esters of glycerol, dialkylethers, and dialkylcarbonates, or any mixtures thereof.

9. The use according to any of the preceding claims 1 to 8, characterized in that rape seed oil, rape seed oil methyl ester, and commercial white oil is disclaimed as cosmetic acceptable oil phase.

10. The use according to any of the preceding claims 1 to 9, characterized in that 0.1 till 10.0 wt.-% of the polymer is used, calculated on the total weight of the cosmetic acceptable oil phase, and preferably 1.0 till 6.0 wt.-%.

11. The use according to any of the preceding claims 1 to 10, characterized in that the cosmetic acceptable oil phase is part of an aqueous emulsion, preferably an W/O emulsion.

12. The use of polymers according to claim 1 to stabilize particles in the oil phase of a cosmetic composition.

13. Cosmetic oil composition, containing a cosmetic acceptable oil-phase and from 0.1 to 10 % by weight of a polymer, according to claim 1.

14. Cosmetic emulsion composition, containing at least a cosmetic acceptable oil- phase, water, and from 0.1 to 10 % by weight of a polymer, according to claim 1.