This invention relates to a hair oil formulation with a conditioning agent and a method for preparing a conditioned hair oil.

Hair oil treatments provide nourishment and conditioning to hair, but leave a residual greasy feel and are difficult to remove without depleting moisture in the hair. Glycerol Quat (2,3-dihydroxypropyl trimethylammonium chloride) has been used as a moisturizing agent in skin creams, as disclosed in US7282471. However, the prior art does not address the problem of improving hair oil formulations.

The problem addressed by the present invention is to provide an improved hair oil formulation.

STATEMENT OF INVENTION

The present invention provides a composition comprising: (a) vegetable oil; (b) an aliphatic quaternary ammonium salt having from five to twenty carbon atoms and from two to six hydroxyl groups; and (c) a surfactant package.

The present invention is further directed to a method for preparing a conditioned hair oil. The method comprises combining with a hair oil: (a) an aliphatic quaternary ammonium salt having from five to twenty carbon atoms and from two to six hydroxyl groups; and (b) a surfactant package.

DETAILED DESCRIPTION

Percentages are weight percentages (wt ), temperatures are in °C and results were obtained at room temperature (20-25°C), unless specified otherwise. Percentages listed with formulated ingredients are the percent solids of the aqueous solution or dispersion.

Percentages in the composition are based on the entire composition including water and oil.

HLB value (hydrophile-lipophile balance) is a measure of the degree to which a nonionic surfactant is hydrophilic or lipophilic. It is expressed as percentage by weight of the hydrophilic portion of the surfactant molecule:

HLB molecular weight of hydrophilic portion

5 total molecular weight

The HLB values of all nonionic surfactants are typically verified by experimental techniques by the manufacturer. The HLB numbers used in the example are from the data reported by

ICI Americas Inc (Ref: "The HLB SYSTEM a time-saving guide to emulsifier selection, ICI

Americas Inc. Wilmington, Delaware) For purposes of this invention, aliphatic compounds are compounds containing no aromatic rings, i.e., they may include both straight or branched chains and non-aromatic rings. Alkyl groups are straight or branched chain hydrocarbon groups.

The composition of this invention may contain more than one vegetable oil. Preferred vegetable oils may include, e.g., coconut oil, sesame oil, mustard oil, argan oil, olive oil, almond oil, safflower oil and avocado oil; preferably coconut oil. Preferably the vegetable oil is present in the composition in an amount from 60 to 85 wt , preferably at least 65 wt , preferably at least 67 wt , preferably at least 69 wt ; preferably no more than 80 wt , preferably no more than 78 wt , preferably no more than 76 wt , preferably no more than 74 wt .

Preferably, the aliphatic quaternary ammonium salt has no more than eighteen carbon atoms, preferably no more than sixteen, preferably no more than fourteen, preferably no more than twelve, preferably no more than ten, preferably no more than nine, preferably no more than eight; preferably at least six. Preferably, the aliphatic quaternary ammonium salt has no more than five hydroxyl groups, preferably no more than four, preferably no more than three. Preferably, the ratio of the number of carbon atoms in the salt to the number of hydroxyl groups is from 1.5:1 to 6: 1, preferably from 1.7: 1 to 4.5:1, preferably from 2:1 to 4:1, preferably from 2.5: 1 to 3.5:1. Preferably, no carbon atom in the aliphatic quaternary ammonium salt is attached to more than one hydroxyl group. Preferably, at least one methyl group is attached to the quaternary nitrogen atom, preferably at least two, preferably three. Preferably, the aliphatic quaternary ammonium salt has only one nitrogen atom. Preferably, the aliphatic quaternary ammonium salt is an acyclic compound. Preferably, the aliphatic quaternary ammonium salt is a saturated aliphatic compound. Preferably, the aliphatic quaternary ammonium salt has no non-hydrocarbon substituents other than the quaternary nitrogen and the hydroxyl groups. Preferably, the aliphatic quaternary ammonium salt has at least one 2,3-dihydroxypropyl group attached to the quaternary nitrogen atom. The anion of the aliphatic quaternary ammonium salt preferably is halide, preferably chloride. Aliphatic quaternary ammonium salts and their methods of preparation are disclosed, e.g., in

WO2012050769.

Preferred aliphatic quaternary ammonium salts include, e.g.,

2,3-dihydroxylpropyl trimethylammonium chloride (Glycerol Quat)

2-(2,3-dihydroxypropyldimethylammonium)- 1-butanol chloride

-(2,3-dihydroxypropyldimethylammonium)-2-hydroxymethyl-l, 3-propanediol chloride

2,3 dihydroxypropyl(di)hydroxyethylbutylammonium chloride

2,3 dihydroxypropyldimethylcyclohexanemethanolammonium chloride

In some cases, quaternary salts like those shown above are obtained as a mixture of quaternary salts, including byproducts which usually are structurally related and which may have similar properties. In this event, the amount of the quaternary salt in the composition is the total weight of the salt as obtained including byproducts, but excluding any water.

Preferably, the aliphatic quaternary ammonium salt is present in the composition in an amount from 0.5 wt to 6 wt , preferably at least 0.8 wt , preferably at least 1 wt , preferably from at least 1.2 wt , preferably at least 1.4 wt , preferably at least 1.6 wt , preferably at least 1.8 wt ; preferably no more than 5 wt , preferably no more than 4 wt , preferably no more than 3.5 wt , preferably no more than 3 wt . Percentages are on a solids basis, i.e., the salt itself, exclusive of any water it contains.

The surfactant package is one or more surfactants added to the composition.

Preferably, the surfactant package comprises more than one surfactant. Preferably, the surfactant package has a mixture HLB value from 5 to 10, preferably at least 5.5, preferably at least 6, preferably at least 6.5, preferably at least 6.7; preferably no greater than 9, preferably no greater than 8, preferably no greater than 7.5, preferably no greater than 7.3.

Mixture HLB value is calculated as the weighted average of the individual HLB values of the surfactants based on their weight percentages in the surfactant package. Preferably, the surfactant package comprises a first surfactant (or combination of surfactants) having an HLB value from 3 to 6, preferably at least 3.5, preferably at least 3.8; preferably no greater than 5.5, preferably no greater than 5, preferably no greater than 4.8. Preferably, the first surfactant is present in the surfactant package in an amount from 50 to 85 wt , preferably from 55 to 76 wt , preferably from 62 to 74 wt . Preferably, the first surfactant is a mono- ester of a fatty acid and a tetrahydrofuran compound having 3-4 hydroxyl groups and 5-6 carbon atoms, preferably sorbitan. Preferably, the fatty acid has at least sixteen carbon atoms, preferably eighteen carbon atoms. Preferably, the first surfactant is combined with one or more additional surfactants having higher HLB values to achieve the desired average. Preferably, the surfactant package comprises a second surfactant (or combination of surfactants) having an HLB value from 14 to 19, preferably from 15 to 18. Preferably, the second surfactant is present in the surfactant package in an amount from 10 to 25 wt , preferably from 12 to 20 wt , preferably from 14 to 19 wt . Preferably, the second surfactant is monosaccharide ester of a fatty acid in which the monosaccharide also is substituted with from 12 to 30 polymerized ethylene oxide units (preferably from 15 to 25); preferably the fatty acid has from eight to sixteen carbon atoms, preferably from ten to fourteen. Preferably, the surfactant package comprises a third surfactant (or combination of surfactants) having an HLB value from 5 to 12, preferably from 6 to 11, preferably from 7 to 10. Preferably, the third surfactant is present in the surfactant package in an amount from 10 to 25 wt , preferably from 12 to 20 wt , preferably from 13 to 17 wt . Preferably, the third surfactant is monosaccharide ester of a fatty acid, preferably a fatty acid having from eight to sixteen carbon atoms, preferably from ten to fourteen.

Preferably, the surfactant package is present in the composition in an amount from 15 to 30 wt , preferably at least 17 wt , preferably at least 19 wt , preferably at least 20 wt , preferably at least 21 wt ; preferably no greater than 28 wt , preferably no greater than 27 wt , preferably no greater than 26 wt , preferably no greater than 25.5 wt .

Preferably, the composition comprises water in an amount from 1 to 10 wt , preferably at least 2 wt , preferably at least 2.5 wt , preferably at least 3 wt , preferably at least 3.5 wt ; preferably no greater than 8 wt , preferably no greater than 7 wt , preferably no greater than 6 wt , preferably no greater than 5 wt .

Preferably, the ingredients of the composition are blended in the form of a microemulsion, preferably a water-in-oil (w/o) microemulsion, preferably at a temperature from 15°C to 35°C. Microemulsions are isotropic, thermodynamically stable transparent (or translucent) systems of oil, water and surfactant, frequently in combination with a co- surfactant and with a droplet size usually in the range of 10 to 200 nm, preferably from 20 to 100 nm, preferably from 30 to 60 nm. They are formed spontaneously or with a little input of energy and therefore are simple to prepare. Formation of microemulsions is not process dependent, i.e., the order of addition of starting materials or speed/type of mixing is not critical to the preparation of the microemulsions, which is highly advantageous for large- scale production.

Preferably, the composition is substantially free of silicones, i.e., it has no more than 5 wt silicones, preferably no more than 2 wt , preferably no more than 1 wt , preferably no more than 0.5 wt , preferably no more than 0.2 wt , preferably no more than 0.1 wt , preferably no more than 0.05 wt .

Preferably, the composition has three main phases :- a. Aqueous phase consisting of water + aliphatic quaternary ammonium salt b. Oil phase consisting of dehydrated vegetable oil

c. The surfactant package

EXAMPLES

The surfactant system consists of polyoxy ethylene sorbitan monolaurate (TWEEN20), sorbitan monolaurate (SPAN20) and sorbitan monooleate (SPAN 80). TWEEN 20 is hydrophilic whereas SPAN 20 and SPAN 80 are hydrophobic. The ternary surfactant system was based on the proportion shown in the table below and has a mixture HLB value of 7.

Virgin Coconut Oil (VCO) is filtered using filter paper in the presence of anhydrous sodium sulfate to obtain dehydrated VCO and was used as the continuous phase.

In theory, the micro-emulsion system has three main phases:

a. Aqueous phase consisting of Water + hydrophilic active, which in this case is a 50% Glycerol Quat solution

b. Oil phase consisting of dehydrated VCO

c. The ternary surfactant system

The surfactant to aqueous phase ratio (weight basis) is fixed at 4.5:1 and the VCO to Aqueous phase + Surfactant ratio (weight basis) is fixed at 2.3:1.

Shown in the Table below is a representative formulation for preparing a 1% active Glycerol Quat based micro-emulsion.

The final product (micro-emulsion) is prepared by following the procedure below:

1. All the ingredients were measured to required quantities.

2. The ternary surfactant system is mixed with DI water and Glycerol Quat (50% solution) on a hot plate stirrer

3. Stir at a medium speed for 10 minutes while maintain the temperature to 38-40 °C

4. The resulting mixture was cooled to around 30-31 °C while continuing to stir

5. Dehydrated VCO is added dropwise while stirring at high speed and maintaining the temperature to ~30°C.

6. The presence of transparent micro-emulsion mixture indicates the optimum ratio of water/surfactant/oil.

Coconut oil based water-in-oil (w/o) micro-emulsions were prepared with a Glycerol Quat loading of 2.75% and 5% - using the procedure described above. The samples were then compared for conditioning improvement against virgin coconut hair oil (VCO) and a blank micro-emulsion (i.e. a water-in-oil microemulsion with no Glycerol Quat). Wet combing

The test is performed on a DIASTRON MTT 175 Hair Combing Machine. This machine uses a tensile tester to measure the force required to pull a comb through a hair tress before and after treatment with a product.

Virgin hair tresses were obtained from International Hair importers and Products Inc. (NY, USA). The following procedure was performed to measure wet combing resistance on DAISTRON MTT 175 Hair Combing machine:

The hair tress was washed and dried using the standard procedure

The hair tress measuring 200mm in length was applied with 0.5gm of the product and was gently massaged for 1 minute.

The treated tress is then clamped to the load cell of the MTT 175 and a hard rubber comb is attached to the moving bridge of the tensile tester. The tress is combed at the rate of 500 mm/min speed setting available in the machine.

The resistance to combing is measured as the variation of gm-force experienced by the hair tress with respect to the length of the tress. Table 1. Wet Combing Resistance

As shown in Table 1, the water- in-oil microemulsion containing 5% Glycerol Quat provides the least combing resistance amongst all samples tested and reduces the peak combing force by about 70% as compared to control (Virgin Coconut Oil). The blank microemulsion also provides a conditioning effect and as expected lowers combing resistance significantly (about 58% as compared to control).

Dry Combing

The hair samples from wet combing study were washed for 1 minute under flowing tap water without any soap or shampoo. The resulting samples were completely oil-free and without any tackiness or grease - whereas on the other hand the control sample still had oil on the hair fibers and was greasy to touch. The control swatch was then washed with a commercial 2-in-l shampoo (containing conditioner) to remove the oil. All the test samples were then dried for 4 hours before conducting the dry combing test.

The dry combing test was performed on the same set of four hair samples obtained from wet combing:

blank microemulsion,

microemulsion with 2.75% Glycerol Quat (50%),

microemulsion with 5% Glycerol Quat (50%)

virgin coconut hair oil applied swatch washed with a 2-in-l shampoo

Table 2. Dry Combing Resistance

The blank microemulsion does not provide any conditioning on dry hair mainly because of the absence of the conditioning active i.e. Glycerol Quat. The hair samples applied with Glycerol Quat containing microemulsion provide improved conditioning with increasing concentration mainly due to the deposition of the cationic polyhydric salt on the hair shaft as demonstrated by the drop in peak load in Table 2. The treatment of a hair sample with 5% Glycerol Quat microemulsion formulation achieves almost equivalent dry conditioning imparted on the control (Virgin coconut Oil) hair sample after washing with a commercial silicone containing 2-in-l shampoo.