阅读说明：本技术 包含月桂油的透明纳米乳液 (Clear nanoemulsion containing bay oil ) 是由 权聪玲 于 2019-01-21 设计创作，主要内容包括：本发明涉及水包油型乳液,其中在油相中使用特定的油(例如月桂油)而同时出人意料地保持了优异的透明度。在一个方面,所述乳液在油相中包含脂肪酸。在单独的共同待决申请中,本发明包含一种用于制备所述含脂肪酸透明纳米乳液的高能效方法。(The present invention relates to oil-in-water emulsions in which a specific oil (e.g. bay oil) is used in the oil phase while unexpectedly maintaining excellent clarity. In one aspect, the emulsion comprises a fatty acid in the oil phase. In a separate co-pending application, the present invention comprises an energy efficient process for preparing the fatty acid containing transparent nanoemulsion.)

1. An oil-in-water nanoemulsion comprising:

1) internal oilA phase comprising 3.5 to 40 wt% of a lauric oil of the nanoemulsion composition, wherein the lauric oil is one or more oils, wherein C is saturated₁₂Length fatty acids (12:0) comprise 30% to 85% of the fatty acid composition of the one or more oils, wherein at least 5% total lauric and non-lauric triglyceride oils are present; and

2) an external aqueous phase comprising:

i. from 55 to 90% by weight of the nanoemulsion of water and glycerol, wherein the ratio of the glycerol to the water is 2.5:1 or higher, preferably from 2.8:1 to 10:1 or from 3.0:1 to 5: 1; and

ii.3 to 12% of a surfactant system comprising a water soluble surfactant selected from anionic surfactants, amphoteric surfactants and mixtures thereof, wherein the anionic surfactant comprises 15% or more, preferably 40% or more (up to 100%, preferably 95%, although preferably 40% to 85%, or 50% to 85%) of the total surfactant system,

wherein the turbidity of the composition is less than 100NTU, preferably less than 80NTU, more preferably from 60 to 1 or from 50 to 5,

wherein the nanoemulsion is prepared by mixing the ingredients forming the nanoemulsion and passing through a homogenizer one or more times at a pressure of 7000psi or less (482.6 bar or less), preferably 1500 to 5500psi (103.4 to 379.2 bar).

2. The nanoemulsion of claim 1, wherein the average particle diameter D [4,3] of the oil droplets formed in the nanoemulsion is 100nm or less, preferably 20 to 95.

3. The nanoemulsion of claim 1 or 2, wherein the anionic surfactant is selected from the group consisting of alkyl sulfates, alkyl ether sulfates, N-acyl derivatives of amino acids, and mixtures thereof.

4. The nanoemulsion of any of claims 1-3, wherein the internal oil phase further comprises from 0.1 to 7% by weight of the nanoemulsion of a fatty acid or fatty acid mixture, and wherein the melting temperature of the fatty acid or mixture is from-10 ℃ to 30 ℃, preferably from 0 ℃ to 25 ℃.

5. The nanoemulsion of any of claims 1-4, wherein the lauric oil is selected from the group consisting of coconut oil, palm kernel oil, babassu oil, tukum oil, murumuru oil, corolla minutissima oil, petiolus lupulus oil, cuphea oil, laurel oil, and mixtures thereof.

6. The nanoemulsion of any of claims 1-5, wherein lauric oil comprises from 30% to 85%, preferably from 40% to 55%, of lauric acid esters attached to glycerol moieties.

7. The composition according to any one of claims 1 to 6, wherein the highly unsaturated non-lauric triglyceride oil having an iodine value of greater than 50 partially replaces lauric oil at a level of 0 to 30% of lauric oil, but wherein lauric oil is present at a level of at least 3.5%.

8. The composition according to claim 7, wherein the non-lauric high IV oil is selected from the group consisting of sunflower oil, grape seed oil, argan, and mixtures thereof.

Technical Field

The present invention relates to novel oil-in-water nanoemulsions. The inner phase comprises lauric oils, such as coconut oil, palm kernel oil, and mixtures thereof. Highly saturated oils such as these are used for skin moisturization, but are not considered suitable for use in oil-continuous clear cleansing compositions because such oils are generally opaque and semi-solid (due to high saturation) at ambient temperatures. Surprisingly, when bay oil is used, excellent transparency is obtained, particularly in systems comprising anionic cleansing surfactant in the aqueous phase and high levels of glycerin. Furthermore, nanoemulsions (preferably with at least a minimum level of amphoteric surfactant in the aqueous phase) allow good foaming.

Background

Generally, clear oil-clear compositions that are oil-continuous are desired, e.g.Nourishing Care shower oil because this composition is attractive (a clear composition desired by the consumer) while providing excellent cleaning and moisturization (e.g., the oil is a moisturizer).

Such clear oil compositions are typically delivered in the form of oil soluble surfactants dissolved in liquid vegetable oils, such as sunflower oil, soybean oil, and the like. These vegetable oils are typically high oleic (18:1) and linoleic (18:2) oils. The high degree of unsaturation makes the composition susceptible to oxidation. Oil soluble surfactants used in these systems also generally provide much poorer foam performance (foam is another desirable attribute) than typical anionic and amphoteric cleansing surfactants.

Coconut and palm kernel oils contain high levels of medium and long chain saturated fatty acids. Both oils are rich in lauric acid. For the purposes of the present invention, high levels of lauric acid (12:0) (saturated C) are included₁₂Long length fatty acids) (30% or more of the fatty acid composition of the oil or oils) are referred to as lauric oils. The high saturation level stabilizes the bay oil against oxidation. However, such highly saturated oils have a higher melting point than other liquid vegetable oils. They are considered to be unsuitable because they become semi-solid at ambient temperature (due to the high melting point)Suitable for use in clear oil continuous cleaning liquid compositions.

Therefore, there is a need to develop a cleaning composition rich in lauric oils (which do not oxidize as readily as less unsaturated oils), which can maintain excellent transparency and can further provide satisfactory foam.

Transparent nanoemulsions are known in the prior art. U.S. patent No. 8,834,903 to simonet et al discloses a nanoemulsion purportedly transparent comprising an oil phase which may contain an oil selected from oils of animal or vegetable origin (column 4, lines 25-26) and further comprising a nonionic surfactant, a sugar fatty ester (sugar fat ester) or a glycolipid ether, wherein the transparency is measured by Nephelometric Turbidity units (Nephelometric Turbidity units) or NTUs and has a value in the range of 60 to 600 NTUs. It also discloses emulsions comprising glycols (e.g. glycerol) to help improve the clarity of the formulation.

U.S. patent No. 7,393,548 to Friedman discloses cosmetic or pharmaceutical compositions in the form of oil-in-glycerin (oil-in-glycerin) emulsions to promote stratum corneum penetration and dermal penetration of bioactive compounds. The oil may be coconut oil, although no one oil has a recognized advantage over another oil in terms of clarity. The reference is silent about transparency. Nor do they disclose a surfactant system comprising an anionic surfactant.

Nanoemulsion compositions comprising triglyceride oils in the inner phase and anionic surfactants in the outer aqueous phase are also not new. Applicants have filed a process directed to (1) an internal phase comprising triglyceride oil and/or petrolatum (and fatty acids); and (2) an outer phase with a specific surfactant (e.g., an amino acid-based surfactant) (e.g., european patent application No. 16166487). There is no disclosure in this application of such compositions that are transparent or that such transparency is achievable in the presence of a particular type of oil. It is not disclosed that the melting point of the fatty acid or fatty acid mixture is also critical to obtain transparency if a fatty acid is used. No process criticality is recognized nor is the formation of transparent nanoemulsions comprising fatty acids disclosed, in particular, as an energy efficient process for making particularly high transparency compositions, as disclosed in the applicant's co-pending application.

None of the above references describe a nanoemulsion comprising a highly saturated lauric oil (i.e. which is not easily oxidized), which maintains good transparency; while providing satisfactory lather and desirable moisturization. Furthermore, none of the references disclose a method for preparing a transparent lauric oil nanoemulsion in an efficient manner.

Disclosure of Invention

Surprisingly, the applicant has now found a lauric oil nanoemulsion which retains excellent clarity and comprises highly water-soluble anionic and/or amphoteric cleansing surfactants. The composition is efficiently prepared by passing through a homogenizer at least once at a pressure of 7,000psi or less (482.6 bar or less; to convert from psi to bar, we divide the pressure value by 14.504) and the resulting composition provides at the same time the consumer desired moisturization (from the oil and humectant present), satisfactory foam, and a highly transparent (value less than 100, preferably less than 60 as measured by nephelometric turbidity units or NTU).

More specifically, in one aspect, the compositions of the present invention comprise an oil-in-water nanoemulsion, wherein the nanoemulsion comprises:

1) an internal oil phase comprising from 3.5% to 40%, preferably from 5% to 40% or from 10% to 40% by weight of the nanoemulsion composition of bay oil, defined as one or more oils, wherein C is saturated₁₂The length fatty acids (12:0) constitute 30% or more, preferably 30 to 85% of the fatty acid composition of the one or more oils. Preferably, the oil is an oil selected from coconut oil, palm kernel oil, various other bay oils described below, and mixtures thereof; and

2) an external aqueous phase comprising:

i. from 55 to 90% by weight of the nanoemulsion of water and glycerol, wherein the ratio of the glycerol to the water is 2.5:1 or higher, preferably from 2.8:1 to 10:1 or from 3:1 to 5: 1; and

ii.3-12% of a surfactant system comprising a water soluble surfactant selected from anionic surfactants, amphoteric surfactants and mixtures thereof, wherein the anionic surfactant comprises 15% or more, preferably 40% or more (up to 100%, preferably 95%, although preferably from 40% to 85%, or from 50% to 85% of the total surfactant system, i.e. at least some amphoteric surfactant is present) of the total surfactant system;

wherein the turbidity of the composition is less than 100NTU, preferably less than 90NTU, more preferably 80 to 1NTU or 70 to 2NTU, most preferably 60 to 5 NTU.

The nanoemulsions of the present invention are typically prepared by combining an oil phase comprising bay oil and an aqueous phase comprising surfactant, glycerol and water in a conventional mixer and passing the mixture through a homogenizer 1 or 2 times (or more times, if desired) at a homogenization pressure of 7000psi (pounds per square inch) or less (482.6 bar or less), preferably 1500psi to 5500psi (103.4 to 379.2 bar). The higher the number of passes, the lower the NTU value (see example 7 and example 8). Alternatively, the nanoemulsion may be prepared by pumping the oil phase and the aqueous phase simultaneously into a homogenizer without mixing in a conventional mixer.

The temperature used to prepare the nanoemulsion ranges from ambient temperature to 60 ℃.

Preferably, the volume mean diameter D4, 3 of the oil droplets is 100nm or less, more preferably 20 to 95 or 30 to 85 or 40 to 75.

Surprisingly, nanoemulsions can be obtained that provide excellent moisturizing oils, humectants (e.g., glycerin), and good foaming characteristics while maintaining excellent transparency.

In another aspect, the internal oil phase further comprises from 0.1 to 7 wt% of a fatty acid or fatty acid mixture of the nanoemulsion composition, wherein the melting temperature of the fatty acid or fatty acid mixture is from-10 ℃ to 30 ℃, preferably from 0 ℃ to 25 ℃, or from 5 ℃ to 20 ℃. Fatty acids or fatty acid mixtures with melting temperatures above 30 ℃ tend to cause turbidity and gelation in the nanoemulsion, resulting in opaque nanoemulsions at ambient temperature (comparative examples F and G). Of course, if heated, for example above 40 ℃, the composition is fluid and transparent.

In another aspect of the present invention, the efficiency of preparing transparent nanoemulsions comprising fatty acids can be further improved as subject of the related co-pending application. In particular, the present invention relates to a less energy consuming process (e.g., a single pass using only a high pressure homogenizer) to obtain a nanoemulsion composition having free fatty acids in the oil phase and a turbidity of 45NTU or less, preferably 40NTU or less or 35NTU or less or 30NTU or less. The process comprises first preparing a concentrated emulsion comprising an oil phase additionally comprising a fatty acid or fatty acid mixture having a melting point of 30 ℃ or less, wherein the oil phase is typically present at a level of greater than 50 to 85% of the concentrated emulsion; and an aqueous phase comprising glycerol and water in a ratio of 1:2 to 2: 1. Concentrated emulsions were prepared by passing through a low pressure homogenizer at a rotor speed of 3000 to about 7000rpm or at a pressure of 200 to 500psi (13.8 to 34.5 bar) in a conventional mixer equipped with a rotor/stator high shear device; the concentrate is then diluted to the desired oil range (5 to 40%, preferably 10 to 38% by weight of the nanoemulsion oil; as discussed below, the theoretical lower limit of 5% may comprise up to 1.5% non-lauric triglyceride oil and 3.5% lauric triglyceride oil) and to the desired ratio of glycerol to water (2.5:1 or higher, preferably 2.8:1 to 10:1 or 3:1 to 5: 1); and passing the diluted emulsion once through a high pressure homogenizer. This alternative method is superior to the method normally used in this application in that it allows passage using only a single high pressure homogenizer (much lower energy consumption) while providing better transparency (as measured by turbidity of 45NTU or less, 40NTU or less, or 35NTU or less) than the method currently used (see example 7, comparative example used as the method, compared to example 12 c).

Brief description of the drawings

FIG. 1 is a schematic of a typical process without the use of a concentrate followed by dilution.

Fig. 2 is a schematic of a process in which a concentrate is formed and then diluted.

Detailed Description

Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". All amounts are by weight of the final composition, unless otherwise specified.

It should be noted that any particular upper concentration may be combined with any particular lower concentration or amount when any range of concentrations or amounts is specified.

For the avoidance of doubt, the word "comprising" is intended to mean "including", but not necessarily meaning "consisting of … …" or "consisting of … …". In other words, the listed steps, options or alternatives need not be exhaustive.

The disclosure of the invention found herein is considered to cover all embodiments found in the claims as if they were multiply dependent upon each other, regardless of the fact that the claims are found to be possibly present in a form without multiple dependency or redundancy.

The nanoemulsions of the present invention are capable of delivering excellent moisturizing bay oils, highly saturated oils, which have high melting points and are generally expected to result in opaque oil-continuous cleaning compositions (because the high melting points make them appear solid and they are opaque). Surprisingly, the use of these bay oils as internal phase, the use of glycerol and water in defined ratios, mixing during relatively low energy consumption (using at least 1 pass of the homogenizer at a pressure of 7000psi or less) and the use of highly water soluble anionic and/or amphoteric surfactants in the aqueous phase of the nanoemulsion makes it possible to obtain compositions which maintain excellent transparency and further provide good foam. The composition further provides moisturization via an oil (bay oil) and a humectant (e.g., glycerin).

In another aspect, the present invention provides a nanoemulsion further comprising a fatty acid or a mixture of fatty acids in the oil phase, such fatty acid or mixture having a defined melting temperature (-10 ℃ to 30 ℃). In a co-pending application, the present invention provides an even less energy intensive process for the preparation of nanoemulsions comprising the oil phase further comprising a fatty acid or a mixture of fatty acids, while at the same time obtaining excellent transparency values.

The present invention is defined in more detail below.

Oil phase

Vegetable oils are often used as moisturizing agents in cosmetic compositions. The main component of vegetable oils is a triglyceride or triacylglycerol, an ester derived from glycerol and three fatty acids. The composition of the fatty acid esters attached to the glycerol moiety defines the physical and chemical properties of the triglyceride oil, respectively. Vegetable oils, such as sunflower oil and soybean oil, which are frequently used in cosmetic compositions, are liquid at ambient temperature and are susceptible to oxidation due to the high content of unsaturated components (e.g., oleic acid (18:1) and linoleic acid (18:2)) in their fatty acid composition. Their iodine value (a measure of the amount of unsaturation in the oil, expressed as the mass of iodine in grams consumed by 100 grams of oil) is therefore typically in the range of 80 to 140.

The oil in the internal phase of the oil-in-water nanoemulsion (of both the co-pending application and the present invention) is bay oil, a group of high lauric (12:0) oils, present in amounts between 30 and 85%, unlike most vegetable oils. The bay oil of our invention also typically contains 5 to 20% of medium chain C₈And C₁₀A saturated fatty acid. The laurel oil includes coconut oil, palm kernel oil, babassu (babassu) oil, tukum oil, murumuru oil, ouricur (ouricui) oil, palm petiolus lupulus (cohune) oil, some perilla oil, and laurel oil. Coconut and palm kernel oils are the most commercially developed, while others are less commercially developed. Preferred oils in the inner phase of the present invention are coconut oil, palm kernel oil and mixtures thereof. Typically, the bay oil of the invention has an IV of 50 or less, for example from 0.5 to 50.

Coconut oil is an edible oil derived from coconut tree (coconut nutifera). Palm kernel oil is extracted from the kernel of oil palm. Both contain high levels of medium and long chain saturated fatty acids. Both oils are rich in lauric acid, but differ in the levels of caprylic (8:0), capric (10:0) and oleic (18:1) acids. Coconut oil is more saturated than palm kernel oil, so the iodine value of the former is lower than that of the latter, 6-10 and 14-21 respectively. This is well below the typical iodine value found in the above mentioned oils, such as sunflower and soybean oil, of above 50, usually 80 to 140. Because the highly saturated lauric oils of the present invention are high in saturation, they oxidize slowly compared to other vegetable oils. Slow oxidation is an important component of our invention.

The following table lists the fatty acid composition of a typical bay oil of the invention.

Gusstone, w.hamm and r.j.hamilton, eds., edit Oil Processing, Sheffield Academic Press, Sheffield, u.k.,2000, pages 1-33.

The coconut oil and palm kernel oil have melting points of 23 ℃ to about 26 ℃ and 23 ℃ to about 30 ℃, respectively.

The bay oil may be hydrogenated (i.e., made even more saturated) to further enhance its stability and color. Hydrogenation raises the melting points of coconut oil and palm kernel oil to about 32 ℃ and about 40 ℃, respectively.

Although these bay oils are excellent moisturizing oils, these oils are typically semi-solid at ambient temperature due to their high degree of saturation, and are therefore not expected to be used in oil-continuous clear cleaning compositions.

As used herein, the lauric oil is typically in the range of 5% to 40% by weight of the total nanoemulsion composition (assuming all oils in the oil phase are lauric oils). The droplets preferably have a volume mean diameter (measured as D4, 3) of 100nm or less, preferably from 20 to 95 or from 30 to 85 or from 40 to 75. This is also the final oil range of the co-pending invention, but the initial concentrated emulsion contains more than 45% to 80% of the oil of the emulsion.

Surprisingly, the applicant found that, unlike the bay oil of the present invention, not all triglyceride-based oils form transparent compositions, even when the compositions and methods of the present invention are used. For example, in one composition example, applicants demonstrated that the use of sunflower oil (a high oleic oil with an iodine value of 87) in the same composition (except that coconut oil is used) had a turbidity value of 163NTU compared to 32.8NTU when more saturated coconut oil is used (see comparative example a and example 1). It should be noted that a slightly smaller amount of non-lauric triglyceride oil, which typically has a higher level of unsaturation (iodine value greater than 50), such as sunflower oil, grape seed oil, argan oil, etc., may be used as a partial replacement for 5-40% lauric oil in the nanoemulsion oil phase. However, in order to maintain transparency, they should not replace more than 30% of such bay oils, and at least 5% of the oil (i.e., at least 5% of the total bay and non-bay oils) is present. In particular, if 5% of the total oil is present as a percentage of the nanoemulsion, the theoretical oil phase may comprise 1.5% of non-bay oil (30% of 5%) and 3.5% of bay oil. Thus, the total bay oil may be 3.5% to 40% bay oil. In contrast, the 5% to 40% of the oil in the oil phase may be 100% bay oil.

Cuphea oil is another bay oil that may be used. It is extracted from seeds of several species of the Cuphea genus. For example, c.painteri is rich in caprylic acid (73%), whereas cuphea japonica (c.carthaganensis) oil contains 81% lauric acid and c.koehneana oil contains capric acid (95%). These oils are highly saturated and suitable for use herein either alone (e.g. high lauric cuphea) or as oil blends of high lauric with high caprylic and/or capric cuphea oil. As mentioned above, if used in a blend, the total lauric acid content in the oil blend is at least 30% for the purposes of the present invention.

Bay oils suitable for use in the present application may be produced by genetic engineering techniques. From

The laurel oil of (1) is an example.

In addition to the defined oils, the oil phase may also contain oil-soluble skin benefit actives such as vitamin a, vitamin E, sunscreens, perfumes, retinol palmitate, esters of 12-hydroxystearic acid, conjugated linoleic acid; an antibacterial agent; a mosquito repellent; essential oil, etc. in an amount of 0.01 to 5%.

Another ingredient that may be present in the oil phase is an oil phase stabilizer. For example, small amounts (0.01 to 2%, preferably 0.1 to 1% by weight of the nanoemulsion) of antioxidants may be used. A preferred antioxidant is Butylated Hydroxytoluene (BHT).

Finally, in one aspect of the invention, the invention provides a composition comprising 0.1 to 7 wt.% of a fatty acid (which has a melting point of-10 ℃ to 30 ℃, preferably-5 ℃ to 25 ℃ or 0 ℃ to 20 ℃) of a nanoemulsion composition; or a mixture of fatty acids having a melting point of the mixture of-10 ℃ to 30 ℃, preferably-5 ℃ to 25 ℃ or 0 ℃ to 20 ℃. This is a component required by the co-pending application in connection with the concentrate-dilution method. It should be noted that the fatty acids discussed herein are free fatty acids and are not to be confused with the fatty acid esters linked to a glycerol moiety in the triglyceride oils discussed previously.

Fatty acids or fatty acid mixtures having melting points of-10 ℃ to 30 ℃ suitable for use in the present application are listed below.

Saturated branched fatty acids generally have a low melting point compared to their linear counterparts. Their solubility in organic solutions is high, as are their corresponding salts in aqueous solutions. A typical example is isostearic acid (methylheptadecanoic acid), which is a liquid isomer of stearic acid consisting of a mixture of monobranched fatty acids. Commercially available isostearic acids include, for example, those produced by Emery Oleochemicals having up to 80% isostearic acid and isopalmitic acid3875 and Prisorine from Croda^TM3505. Cosmetic grade isostearic fatty acid is water white, has an iodine value of about 3.0 or less, and a melting point of about 6 ℃.

Unsaturated fatty acids with a single double bond, such as myristic acid, have a melting point of about 4 ℃ and oleic acid has a melting point of 16 ℃. Unsaturated fatty acids having two or more double bonds with melting points of about 0 ℃ to 30 ℃, such as linoleic acid, are also suitable for use herein.

Saturated straight chain fatty acids with a chain length of less than 10 carbons, such as octanoic acid, have a melting point of 17 ℃.

The fatty acid mixture suitable for use herein may be a mixture of fatty acids each having a melting point below 30 ℃ mixed in any ratio.

A fatty acid having a melting point higher than 30 ℃ and a fatty acid having a melting point lower than 30 ℃ may be mixed in a specific ratio such that the melting point of the mixture is lower than 30 ℃. For example, isostearic acid and lauric acid were mixed in a ratio of 70/30 (wt%).

Another way to obtain a fatty acid mixture with a melting point below 30 c is to mix fatty acids that can form a binary eutectic mixture (with its lowest melting temperature). For example, the capric acid-lauric acid binary system suitable for use herein forms a eutectic that melts at 20 ℃ below 32 ℃ (melting point of capric acid) and 44 ℃ (melting point of lauric acid) at a 66:34 (wt%) mixing ratio (neither of which is within the scope of this application). As another example, oleic acid may form a eutectic with lauric and myristic acid, respectively, the eutectic having a melting point of about 10 ℃.

Also suitable for this application are coconut fatty acids or palm kernel fatty acids, which are C with a melting point of 22-26 deg.C₈To C₂₂A mixture of fatty acids.

For example, lauric acid alone has a melting point greater than 40 ℃, and does not produce the desired transparent nanoemulsion. However, a 50:50 mixture (wt%) of lauric acid and isostearic acid has a melting point below 25 ℃ and produces the desired transparent nanoemulsion, as defined by the NTU values.

Aqueous phase

The aqueous phase comprises a water soluble surfactant system comprising a water soluble surfactant selected from the group consisting of anionic surfactants, amphoteric surfactants and mixtures thereof, wherein the anionic surfactant comprises 15% or more, preferably 40% or more of anionic surfactant. Although these may be 100% anionic, it is preferred that at least some amphoteric surfactant is present and that the anion comprises from 15% to 95% or from 40% to 85% of the surfactant system.

One class of anionic surfactants that can be used are the alkyl and alkyl ether sulfates having the corresponding formula ROSO₃M and RO (C)₂H₄O)_xSO₃M, wherein R is an alkyl or alkenyl group of about 8 to 18 carbons. X is an integer from 1 to 10, and M is a cation, such as ammonium; alkanolamines such as triethanolamine; monovalent metals such as sodium and potassium.

Other suitable anionic surfactants are water-soluble salts of organic sulfuric acid reaction products, which correspond to the formula [ R ]¹-SO₃-M]Wherein R is¹Is a straight or branched chain saturated aliphatic hydrocarbon group having from about 8 to about 24, preferably from about 10 to about 18 carbon atoms; and M is a cation as described above.

Other suitable anionic detersive surfactants are the reaction products of fatty acids esterified with hydroxyethanesulfonic acid and neutralized with potassium hydroxide, wherein, for example, the fatty acids are derived from coconut oil or palm kernel oil; potassium salts of fatty acid amides of methyl taurines, wherein for example the fatty acids are derived from coconut oil or palm kernel oil.

Other anionic surfactants suitable for use in the composition are succinate salts, examples of which include disodium N-octadecyl sulfosuccinate; disodium lauryl sulfosuccinate; diammonium lauryl sulfosuccinate; tetrasodium N- (1, 2-dicarboxyethyl) -N-octadecyl sulfosuccinate; diamyl esters of sodium sulfosuccinic acid; dihexyl ester of sodium sulfosuccinic acid; and dioctyl esters of sodium sulfosuccinic acid.

Other suitable anionic surfactants include olefin sulfonates having from about 10 to about 24 carbon atoms. In addition to the true olefin sulfonates and a proportion of hydroxyalkanesulfonates, the olefin sulfonates may contain small amounts of other materials, such as olefin disulfonates, depending on the reaction conditions, the proportions of the reactants, the nature of the starting olefin and impurities in the olefin feed and side reactions during sulfonation.

Another class of anionic surfactants suitable for use in the compositions are beta-alkoxy alkane sulfonates. These surfactants correspond to formula (1):

wherein R is¹Is a straight chain having from 6 to about 20 carbon atomsAlkyl radical, R²Is a lower alkyl group having 1 to 3 carbon atoms, preferably 1 carbon atom, and M is a water-soluble cation as described above.

Preferred anionic surfactants for use in the compositions include ammonium lauryl sulfate, ammonium laureth sulfate, trimethylamine lauryl sulfate, trimethylamine laureth sulfate (trithylamine laureth sulfate), triethanolamine lauryl sulfate, triethanolamine laureth sulfate, monoethanolamine lauryl sulfate, diethanolamine lauryl sulfate, sodium laureth sulfate, sodium lauryl sulfate, sodium laureth sulfate, potassium lauryl sulfate, potassium laureth sulfate, sodium lauryl sarcosinate, sodium lauroyl sarcosinate, ammonium cocoyl sulfate, ammonium lauroyl sulfate, sodium cocoyl sulfate, sodium lauroyl sulfate, potassium lauryl sulfate, triethanolamine lauryl sulfate, monoethanolamine cocoyl sulfate, triethanolamine lauryl sulfate, triethanolamine cocoyl sulfate, monoethanolamine cocoyl sulfate, triethanolamine lauryl, Monoethanolamine lauryl sulfate, sodium tridecylbenzene sulfonate, sodium dodecylbenzene sulfonate, and combinations thereof.

Another preferred class of anionic surfactants are salts of N-acyl derivatives of amino acids.

Preferred emulsifiers are acyl glutamate, acyl aspartate, acyl glycinate and acyl alanate surfactants. Preferably, these are potassium and/or sodium salts of acyl glutamic acid or acyl aspartic acid or acyl glycine or acyl alanine, wherein more than 65% of the acyl chains have C₁₄Or smaller chain lengths, e.g. C₈To C₁₄(e.g., derived from coconut oil fatty acids). The acyl chain preferably has a C of more than 75%, more preferably more than 80%₁₄Or shorter chain lengths. Preferably, more than 75%, most preferably more than 80%, of the chain lengths are C₁₂、C₁₄Or mixtures thereof.

There are two forms of amino acid surfactants commercially available. One is in the form of a powder or chips, which are generally more expensive and of high purity. Examples of solid dicarboxylic acid amino acid surfactants include:

sodium N-cocoyl-L-glutamate (e.g. of Ajinomoto)CS-11)

Sodium N-lauroyl-L-glutamate (e.g. of Ajinomoto)LS-11)

N-myristoyl-L-glutamic acid sodium salt (of Ajinomoto)MS-11)

Potassium N-cocoyl (cocoacyl) l-glutamate (e.g. of Ajinomoto)CK-11)

N-myristoyl-L-glutamic acid potassium salt (of Ajinomoto)MK-11)

N-lauroyl-L-glutamic acid potassium salt (of Ajinomoto)

LK-11)

Sodium lauroyl aspartate (amino Foamer from Asahi Kasei Chemical Corporation)^TMFLMS-P1)

Sodium lauroyl glutamate (amino aspect from Asahi Kasei Chemical Corporation)^TMALMS-P1/S1)

Sodium myristoyl glutamate (amino surface from Asahi Kasei Chemical Corporation)^TMAMMS-P1/S1)

Examples of solid monocarboxylic amino acid surfactants include:

sodium cocoyl glycinate (e.g. of Ajinomoto)GCS-11)

Potassium cocoyl glycinate (e.g. of Ajinomoto)

GCK-11)

Liquid amino acid surfactants typically comprise 20% to 35% surfactant active, high pH and inorganic salts (e.g., 3% to 6% NaCl). Examples include:

·ECS-22 SB: disodium cocoyl glutamate (30% aqueous solution)

·

CS-22: disodium cocoyl glutamate sodium cocoyl glutamate (25% aqueous solution)

·

CK-22: potassium cocoyl glutamate (30% aqueous solution)

·LT-12: TEA-lauroyl glutamate (30% aqueous solution)

·CT-12: TEA-Cocoyl glutamate (30% aqueous solution)

·ACT-12: TEA-Cocoyl alanine salt (30% aqueous solution)

·

ACS-12: sodium cocoyl alanine (30% aqueous solution)

·

GCK-12/GCK-12K: potassium cocoyl glycinate (30% aqueous solution)

·Aminosurfact^TMACDS-L: sodium cocoyl glutamate (25% aqueous solution)

·Aminosurfact^TMACDP-L: potassium cocoyl glutamate (22%) + sodium cocoyl glutamate (7%)

·Aminosurfact^TMACMT-L: TEA-Cocoyl glutamate (30% aqueous solution)

·AminoFoamer^TMFLDS-L: sodium lauroyl aspartate (25% aqueous solution)

Amphoteric surfactants preferably include derivatives of aliphatic secondary and tertiary amines in which the aliphatic radical can be straight or branched chain and wherein one of the aliphatic substituents contains from about 8 to about 18 carbon atoms and one contains an anionic group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate. Preferred amphoteric surfactants for use in the present invention include cocoamphoacetate, cocoamphodiacetate, lauroamphoacetate, lauroamphodiacetate, and mixtures thereof. Preferred zwitterionic surfactants are derivatives of aliphatic quaternary ammonium, phosphonium, and sulfonium compounds, in which the aliphatic radicals can be straight or branched chain, and wherein one of the aliphatic substituents contains from 8 to 18 carbon atoms, and one contains an anionic group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate. Zwitterionic compounds such as betaines are preferred.

Further, in the present application, the external aqueous phase comprises 55-90% by weight of the nanoemulsion of water and glycerol, wherein the ratio of glycerol to water is at least 2.5:1, preferably 2.8:1 to 10:1, most preferably 3:1 to 5: 1.

For co-pending applications, the final diluted composition also has 55% to 90% water and glycerin, with a ratio of glycerin to water of at least 2.5:1, preferably 2.8:1 to 10:1, most preferably 3:1 to 5: 1. However, as previously mentioned, the initial ratio of glycerin to water in the concentrated emulsion is 1:2 to 2: 1.

In the composition of the present invention comprising an anionic surfactant and bay oil, the applicant found that the minimum base level (minimum floor level) of glycerin is important to ensure transparency. If the glycerol content is too low (e.g., glycerol to water ratio below 2.5:1), the transparency disappears.

Due to the high glycerol content, the water activity level is in the range of inhibiting bacterial growth and potentially allows the use of fungicides only or even no preservatives in the nanoemulsion as the final product.

It has been found that another factor in maintaining transparency is the use of processing the composition at least 1 time, preferably 2 times (or more if desired) through the high pressure homogenizer. The homogenization pressure is preferably 7000 pounds per square inch (psi) or less (482.6 bar or less), preferably 6000psi or less (413.6 bar or less), preferably 1500-.

In another aspect, the invention relates to an energy efficient method, which involves only one pass through a high pressure homogenizer, in the subject of a different application. The process involves the inclusion of additional fatty acids in the oil phase and a concentrated emulsion of glycerol and water in the aqueous phase at a lower ratio (1:2 to 2: 1). As described below, the process involves forming a concentrated emulsion of glycerol and water with a high oil content (greater than 45% to 80% by weight of the composition) and a lower ratio in the aqueous phase (1:2 to 2:1), thoroughly mixed by a conventional rotor/stator high shear device at a rotor speed of 3000 to about 7000rpm, diluted to the desired oil concentration (5% to 40% by weight of the composition) and the desired glycerol-water ratio (at least 2.5:1, preferably 2.8:1 to 10:1, most preferably 3:1 to 5:1), and then subjecting the final composition to only one round of homogenization while still obtaining better transparency values than those obtained once by the high pressure homogenizer of the present invention.

The compositions and methods according to our invention have a clarity value of 100NTU or less, preferably 90NTU or less, more preferably 60 or less. According to the method of the co-pending application, the NTU value is at the low end (e.g., less than 45, preferably 35 or less), but only one pass is used. Such low values are also achieved using the method of the present application, but two passes are required.

In another aspect, the invention relates to a composition obtained by a process wherein the ingredients are pumped directly to the homogenizer 1 or 2 cycles at a pressure of 7000psi or less, preferably 6000psi or less.

Preparation of the nanoemulsion

This application

The nanoemulsion is typically formed in a two-stage process.

The first mixing stage is used to form a coarse emulsion. Separately heating the oil and water phases from ambient temperature to 60 ℃ to make each phase transparent and homogeneous; the oil phase was then mixed with the water phase in a conventional mixer with thorough mixing. Thorough mixing can be accomplished by conventional means, including mixing the materials in a stirred tank, and passing the mixture through a rotor/stator mixer (e.g.High shear in-line mixers) or in a mixer with high shear (e.g. high shear mixers)

Turbon mixer). Alternatively, the crude emulsion may be formed by using a continuous high shear mixing device, such as a standard conditioner device manufactured by Sonic Corporation of Connecticut. These standard sonolators are typically run at pressures of 200-500psi (13.8 to 34.5 bar) to form a crude emulsion.

The second stage of the process is to pass the crude emulsion through a high pressure homogenizer to form a nanoemulsion. Suitable high pressure homogenizers are the Nano DeBee homogenizer from BEE International (Massachusetts, USA) and the high pressure sonolator apparatus also manufactured by Sonic Corporation of Connecticut, USA. These devices can be operated at up to 1500-. For bay oils, such as coconut oil or palm kernel oil, only one or two passes through Nano DeBEE or high pressure solator are required to achieve the desired nanoemulsion particle size and clarity, regardless of the presence of fatty acids in the oil phase.

Separate co-pending application

In another aspect, in the subject matter of the separate application, a concentrated emulsion is first prepared comprising a fatty acid or a mixture of fatty acids having a melting point of 30 ℃ or less. The oil present in the oil phase is greater than 45% by weight of the nanoemulsion, preferably from 50% to 85%. The concentrate is also prepared with an aqueous phase comprising glycerol and water, wherein the ratio of glycerol to water is from 1:2 to 2: 1. The concentrate is thoroughly mixed by conventional rotor/stator high shear devices at a rotor speed of 3000 to about 7000 rpm; the concentrate is then diluted by mixing water, a solution of glycerol or another surfactant in a separate container and with the concentrated emulsion to obtain the final emulsion, wherein the oil is present at a level of 40% or less, preferably 5 to 40%, and the ratio of glycerol to water is at least 2.5:1, preferably 2.8:1 to 10:1, most preferably 3:1 to 5: 1. Preferably, the 5% to 40% oil is bay oil. As mentioned above, up to 30% (0 to 30%) of the 5 to 40% oil may be non-bay oil, so that the oil (after dilution) may comprise from 3.5% (30% of 5% or 1.5% may be non-bay oil) to 40% (assuming 100% bay oil at the beginning). Finally, the diluted mixture is passed once through a high pressure homogenizer at 6000psi or less (413.6 bar or less), preferably 1500 to about 5000psi (103.4 to 344.7 bar). Surprisingly, these nanoemulsions have much lower NTU and higher viscosity than fatty acid-containing nanoemulsions prepared without the concentrate-dilution process.

In the examples, the following terms are defined as follows:

through #: number of passes of the emulsion through the high pressure homogenizer.

D [4,3 ]: volume mean diameter or volume mean size determined by a Malvern Mastersizer.

Turbidity: measured by a turbidimeter HACH 2100N at ambient temperature.

Viscosity: by Discovery Hybrid Rheometer at 25 ℃ and 4s^-1And (4) measuring.