Patent Application
20210290517
The invention relates to body and hair cleansing compositions which are lamellar structured and which contain oil-based moisturizers such as petrolatum and triglyceride oils (hereinafter “moisturizers”). Such moisturizers are typically added to cleansing compositions as neat materials or in a pre-emulsified form. Compositions of the invention also contain cationic deposition polymers used typically to enhance deposition of the moisturizers. Such cationic deposition polymers will typically interact with anionic structuring polymers, also typically used in such lamellar structured moisturizing compositions; such interaction between cationic deposition polymers (“CDP”) and anionic structuring polymers reduces deposition efficiency of the CDP such that less moisturizer is deposited.
Skin and hair cleansing formulations that are moisturizing and also less damaging to skin and hair are highly desired by consumers. Lamellar cleansing compositions that are formulated with mild surfactants meet the above criteria as lamellar structures provide lotion like consistency that cues moisturization, and mild surfactants cause less damage to skin and hair. Additionally, unlike isotropic formulations, lamellar formulations can also hold large amounts of hydrophobic emollients such as triglyceride oils and petrolatum that provide clinical moisturization benefits. The deposition of these moisturizers is promoted by the addition of cationic deposition polymers such as guar hydroxypropyl trimonium chloride (U.S. Pat. No. 5,085,857).
Lamellar formulations that contain high loading of emollient oils (moisturizers) have been exemplified in several patents assigned to Puvvada et al. See, for example, U.S. Pat. Nos. 5,952,286, 5,962,395, 6,150,312 and 6,426,326. However, none of these references disclose use of anionic polymeric structurants, hydrophobically modified or non-hydrophobically modified, to stabilize sub-micron sized moisturizer droplets that can be deposited efficiently in lamellar liquids comprising cationic deposition polymers.
U.S. Pat. Nos. 8,105,996 and 8,158,566 to Wei et al., teach the use of hydrophobically modified anionic polymers in lamellar formulations containing moisturizers (e.g., emollient oils). However, lamellar formulations exemplified in these references are structured with a significant amount of non-ionic emulsifiers.
They further require use of high levels of salt to form the lamellar structures. By contrast, our compositions have levels of 0.4%, preferably 0.35% and below of nonionic emulsifier of HLB from 1.4 to 13 Further, the high salts seen in compositions of Wei are also not desirable in formulations of our invention as they can cause corrosion to equipment during manufacturing. Our formulations, in contrast, are formulated with 2.75%, preferably 2.7% of sodium chloride or less. Additionally, there is no recognition in these Wei references how the structuring polymers affect deposition of moisturizers; and also of what role does the mildness of the formulation play in the deposition of such moisturizers. Compositions of our invention have a defined mildness value (measured by CIM value using Corneosurfametry), a methodology defined later.
As indicated above, cationic deposition polymers are typically used to promote deposition of oil based moisturizers in lamellar liquids. As also indicated, anionic polymers are used to structure the liquids, but these typically interact with the cationic deposition polymers to lower deposition.
Unexpectedly, applicants have found that specific types of structuring polymers, more particularly anionic structuring polymers especially particular cross-linked hydrophobically or non-hydrophobically modified anionic polymers, interfere minimally in deposition of sub-micron sized moisturizer droplets by cationic deposition polymer, while providing excellent stability.
More specifically, applicants have found that the hydrophobically or non-hydrophobically modified anionic polymer of the invention can be defined by a combination of (a) viscosity measured in 2% polymer solution at specified pH level; and (b) slope of viscosity of the shear rate curve of the polymer solution. While not wishing to be bound by theory, these variables are believed to be linked to the anionicity and the molecular weight of the polymers. When polymers fall within ranges defined by the values (a) and (b) noted above, enhanced moisturizer deposition is found in the presence of cationic deposition polymers.
The effect is further influenced by mildness of formulation (formulations have corneosurfametry calorimetric Index of Mildness, CIM, greater than 53, preferably greater than 55). As also noted above, compositions of the invention comprise 0.4% or less, preferably 0.3% or less, more preferably 0.2% or less and most preferably 0.1% or less of non-ionic emulsifier of HLB 1.4-13 while maintaining stability of lamellar compositions. By contrast, compositions of Wei require greater than this amount of emulsifier to maintain lamellar stability (see Table 6 at end). Compositions of our invention also preferably comprise 2.7% or less, preferably 2.5% or less, more preferably 2% or less, e.g. 0.1 to 2% by wt salt.
More particularly, the composition of the invention can be defined as follows.
They are lamellar structured cleansers with mild surfactant systems that comprise:
wherein the slope of the viscosity shear rate curve is in the range of −0.6 to −1.2, more preferably in the range of −0.7 to −1.1 and most preferably in the range of −0.8 to −1.0; and
wherein the cleansing formulation comprises 0.4% or less, preferably 0.3% or less, more preferably 0.2% or less and most preferably 0.1% or less of nonionic emulsifiers of HLB 1.4 to 13, and 2.7% or less, preferably 2.5% or less and more preferably 2% or less of salt, especially sodium chloride, and preferably has a corneosurfametry calorimetric Index of Mildness, CIM, of 53 or greater, preferably 55 or greater and more preferably 55 to 65.
Except in the 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.”
As used throughout, ranges are used as shorthand for describing each and every value that is within the range. Any value within the range can be selected as terminus of the range. The use of “and/or” indicates that any one from the list can be chosen individually, or any combination from the list can be chosen.
For the avoidance of doubt, the word “comprising” is intended to mean “including” but not necessarily “consisting of” or “composed of.” In other words, the listed steps or options need not be exhaustive.
Unless indicated otherwise, all percentages for amount or amounts of ingredients used are to be understood to be percentages by weight based on the active weight of the material in the total weight of the composition, which total is 100%. (see page 15)
The compositions of the invention are lamellar structured liquid cleansing compositions that comprise moisturizing conditioning agent, also referred to as moisturizers (e.g., petrolatum, triglyceride); and further comprise cationic deposition polymers.
In the presence of anionic thickening polymers, the cationic deposition polymers will typically interact with such thickener, and this interaction will negatively impact deposition of the moisturizer.
Unexpectedly, applicants have discovered that, when specific hydrophobically or non-hydrophobically modified anionic cross-linked thickening polymers are selected (defined both by viscosity at defined conditions, and slope of the viscosity shear rate curve), deposition of moisturizer is significantly enhanced relative to use of anionic structuring polymers generally. Quite surprisingly, the effect of enhanced deposition is further strengthened by the mildness of the composition as measured by CIM. Further, compositions of the invention use 0.4% or less, preferably 0.3% or less, more preferably 0.2% or less and most preferably 0.1% or less of non-ionic emulsifiers of HLB 1.4 to 13 and 2.7% or less, preferably 2.5% or less and more preferably 2% or less of salt, especially sodium chloride, while maintaining stability of lamellar composition. Higher levels of salts can be corrosive to machinery used in preparation of the composition.
More particularly, compositions of the invention comprise:
wherein the cleansing formulation comprises 0.4% or less, preferably 0.1 to 0.35% nonionic emulsifiers of HLB 1.4 to 13; and 2.7% or less, preferably 2.5% or less and more preferably 2% or less of salt, especially sodium chloride, and preferably has a corneosurfametry calorimetric Index of Mildness, CIM, of 53 or greater, preferably 55 or greater and more preferably 55 to 65.
The compositions are described more particularly below:
The surfactant system of the subject invention comprises 1 to 50% by weight, preferably 2 to 30%, more preferably 5 to 20% by wt. of the composition and comprises:
The anionic surfactant (which may comprise 2 to 40% by wt. of total composition) may be, for example, an aliphatic sulfonate, such as a primary alkane (e.g., C8-C22) sulfonate, primary alkane (e.g., C8-C22) disulfonate, C8-C22 alkene sulfonate, C8-C22 hydroxyalkane sulfonate or alkyl glyceryl ether sulfonate (AGS); or an aromatic sulfonate such as alkyl benzene sulfonate, and the like.
The anionic may also be an alkyl sulfate (e.g., C12-C18 alkyl sulfate) or alkyl ether sulfate (including alkyl glyceryl ether sulfates), and the like. Among the alkyl ether sulfates are those having the formula:
RO(CH2CH2O)nSO3M
wherein R is an alkyl or alkenyl having 8 to 18 carbons, preferably 12 to 18 carbons, n has an average value of greater than 1.0, preferably between 2 and 3; and M is a solubilizing cation such as sodium, potassium, ammonium or substituted ammonium. Ammonium and sodium lauryl ether sulfates are preferred.
The anionic may also be alkyl sulfosuccinates (including mono- and dialkyl, e.g., C6-C22 sulfosuccinates); alkyl and acyl taurates, alkyl and acyl sarcosinates, sulfoacetates, C8-C22 alkyl phosphates and phosphates, alkyl phosphate esters and alkoxyl alkyl phosphate esters, acyl lactates, C8-C22 monoalkyl succinates and maleates, sulphoacetates, and acyl isethionates, and the like.
Sulfosuccinates may be monoalkyl sulfosuccinates having the formula:
R4O2CCH2CH(SO3M)CO2M
amido-MEA sulfosuccinates of the formula:
R4CONHCH2CH2O2CCH2CH(SO3M)CO2M
wherein R4 ranges from C3-C22 alkyl and M is a solubilizing cation;
amido-MIPA sulfosuccinates of formula:
RCONH(CH2)CH(CH3)SO3M)CO2M
where M is as defined above.
Also included are the alkoxylated citrate sulfosuccinates; and alkoxylated sulfosuccinates such as the following:
wherein n=1 to 20; and M is as defined above.
Sarcosinates are generally indicated by the formula RCON(CH3)CH2CO2M, wherein R ranges from C8 to C20 alkyl and M is a solubilizing cation.
Taurates are generally identified by formula:
R2CONR3CH2CH2SO3M
wherein R2 ranges from C3-C20 alkyl, R3 ranges from C1-C4 alkyl and M is a solubilizing cation.
Another class of anionics are carboxylates such as follows:
R—(CH2CH2O)nCO2M
wherein R is C8 to C20 alkyl; n is 0 to 20; and M is as defined above.
Another carboxylate which can be used is amido alkyl polypeptide carboxylates such as, for example, Monteine LCQ® by Seppic.
Another surfactant which may be used are the C8-C18 acyl isethionates. These esters are prepared by reaction between alkali metal isethionate with mixed aliphatic fatty acids having from 6 to 18 carbons atoms and an iodine value of less than 20. At least 75% of the mixed fatty acids have from 12 to 18 carbons and up to 25% have from 6 to 10 carbon atoms.
Acyl isethionates, when present, will generally range from about 0.5-15% by weight of the total composition. Preferably, this component is present from about 1 to about 10%.
The acyl isethionate may be an alkoxylated isethionate such as is described in U.S. Pat. No. 5,393,466, titled “Fatty Acid Esters of Polyalkoxylated Isethionic Acid” issued Feb. 28, 1995 to Ilardi et al., herby incorporated by reference into the subject application. This compound has the general formula:
wherein R is an alkyl group having 8 to 18 carbons, m is an integer from 1 to 4, X and Y are hydrogen or an alkyl group having 1 to 4 carbons and M+ is a monovalent cation such as, for example, sodium, potassium or ammonium.
Another preferred class of anionics are N-acyl derivatives of amino acids. In the same preferred form, there is substantially no surfactant containing sulfate, preferably 0.1 or even 0.05% or less. Preferably sulfate containing surfactant is absent altogether.
Preferred surfactants are acylglutamate, acylaspartate, acylglycinate and acylalaninate surfactants. Preferably, these are potassium and/or sodium salts of acylglutamate or acylaspartate or acylglycinate or acylalaninate, wherein greater than 65% of the acyl chains has chain length C14 or less, e.g., C8 to C14 (e.g., derived from coconut fatty acid). The acyl chains preferably have greater than 75%, more preferably greater than 80% C14 or less chain length. Preferably, greater than 75%, most preferably greater than 80% of the chain length are C12, C14 or mixtures thereof.
There are two formats of amino acid surfactants commercially available. One is powder or flake format, which is typically more expensive and high in purity. Examples of solid dicarboxylic amino acid surfactants include:
Examples of solid monocarboxylic amino acid surfactants include:
Liquid amino acid surfactants typically contain 20-35% surfactant active, and are high in pH and inorganic salt (e.g. 3 to 6% NaCl). Examples include:
Zwitterionic surfactants are exemplified by those which can be broadly described as 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 about 8 to about 18 carbon atoms and one contains an anionic group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate. A general formula for these compounds is:
wherein R2 contains an alkyl, alkenyl, or hydroxy alkyl radical of from about 8 to about 18 carbon atoms, from 0 to about 10 ethylene oxide moieties and from 0 to about 1 glyceryl moiety; Y is selected from the group consisting of nitrogen, phosphorus, and sulfur atoms, R3 is an alkyl or monohydroxyalkyl group containing about 1 to about 3 carbon atoms; X is 1 when Y is a sulfur atom, and 2 when Y is a nitrogen or phosphorus atom; R4 is an alkylene or hydroxyalkylene of from about 1 to about 4 carbon atoms and Z is a radical selected from the group consisting of carboxylate, sulfonate, sulfate, phosphonate, and phosphate groups.
Examples of such surfactants include:
Amphoteric detergents which may be used in this invention include at least one acid group. This may be a carboxylic or a sulphonic acid group. They include quaternary nitrogen and therefore are quaternary amido acids. They should generally include an alkyl or alkenyl group of 7 to 18 carbon atoms. They will usually comply with an overall structural formula:
where R1 is alkyl or alkenyl of 7 to 18 carbon atoms;
R2 and R3 are each independently alkyl, hydroxyalkyl or caboxyalkyl of 1 to 3 carbon atoms;
n is 2 to 4;
X is alkylene of 1 to 3 carbon atoms optionally substituted with hydroxyl, and
Y is —CO2— or —SO3—
Suitable amphoteric detergents within the above general formula include simple betaines of formula:
and amido betaines of formula:
where m is 2 or 3.
In both, formulae R1, R2 and R3 are defined as previously. R1 may in particular be a mixture of C12 and C14 alkyl groups derived from coconut so that at least half, preferably at least three quarters of the groups R1 have 10 to 14 carbon atoms. R2 and R3 are preferably methyl. A suitable betaine is cocoamidopropyl betaine.
A further possibility is that the amphoteric detergent is a sulphobetaine of formula:
where m is 2 or 3, or variants of these in which
In these formulae R1, R2 and R3 are as discussed previously.
Amphoacetates and diamphoacetates are also intended to be covered in possible zwitterionic and/or amphoteric compounds which may be used, especially C8-C20 amphoacetates or mixtures thereof, and the like. A suitable amphoacetate is sodium laurylamphoacetate.
The amphoteric/zwitterionic surfactant, when used, generally comprises 0.1 to 30%, preferably 1 to 20% by weight, A preferred surfactant system of the invention comprises the following: anionic surfactant (e.g., alkali metal alkyl ethersulfate)—2-50%; amphoteric surfactant (e.g., alkyl betaine or alkyl amphoacetate)—1-20%.
The surfactant system may also optionally comprise a nonionic surfactant. As noted, a characteristic of the invention is that, even if level of nonionic emulsifier is 0.4% or less, the composition still maintains lamellar structure.
The nonionic which may be used includes in particular the reaction products of compound shaving a hydrophobic group and a reactive hydrogen atom, for example aliphatic alcohols, acids, amides, or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Specific nonionic detergent compounds are alkyl (C6-C22) phenols-ethylene oxide condensates, the condensation products of aliphatic (C8-C18) primary or secondary linear or branched alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine. Other so-called nonionic detergent compounds include long chain tertiary amine oxides, long chain tertiary phosphine oxides and dialkyl sulphoxides, and the like.
The nonionic may also be a sugar amide, such as a polysaccharide amide. Specifically, the surfactant may be one of the lactobionamides described in U.S. Pat. No. 5,389,279 titled “Compositions comprising nonionic glycolipid surfactants” issued on Feb. 14, 1995 to Au et al. which is hereby incorporated by reference or it may be one of the sugar amides described in U.S. Pat. No. 5,009,814 titled “Use of n-polyhydroxyalkyl fatty acid amides as thickening agents for liquid aqueous surfactant systems” issued on Apr. 23, 1991 to Kelkenberg, hereby incorporated into the subject application by reference.
Other surfactants which may be used are described in U.S. Pat. No. 3,723,325 to Parran Jr. and alkyl polysaccharide nonionic surfactants as disclosed in U.S. Pat. No. 4,565,647 titled “Foaming surfactant compositions”, issued on Jan. 21, 1986 to Llenado, both of which are incorporated into the subject application by reference.
Preferred alkyl polysaccharides are alkylpolyglycosides of the formula:
R2O(CnH2nO)t(glycosyl)x
wherein R2 is selected from the group consisting of alkyl, alkylphenyl, hydroxyalkyl, hydroxyalkylphenyl, and mixtures thereof in which alkyl groups contain from about 10 to about 18, preferably from about 12 to about 14, carbon atoms; n is 0 to 3, preferably 2; t is from 0 to about 10, preferably 0; and x is from 1.3 to about 10, preferably from 1.3 to about 2.7. The glycosyl is preferably derived from glucose. To prepare these compounds, the alcohol or alkylpolyethoxy alcohol is formed first and then reacted with glucose, or a source of glycose, to form the glycoside (attachment at the 1-position). The additional glycosyl units can then be attached between their 1-position and the preceding glycosyl units 2-, 3-, 4- and/or 6-position, preferably predominantly the 2-position.
The nonionic may comprise 0 to 10% or 0 to 5% by wt. of the composition. However, in preferred embodiments, the non-ionic emulfiers of the type exemplified by Wei comprises 0.4% or less, preferably 0.3%, more preferably 0.2% or less and most preferably 0.1% or less by wt. of the composition. Unlike Wei reference discussed above, the lamellar structure remains stable even at these low levels of non-ionic emulsifier.
The composition of the invention utilize about 0.1 to 20% by wt., preferably 1 to 10%, more preferably 2 to 5% by wt. of a structuring agent which works in the compositions to form a lamellar phase. Such lamellar phase enables the compositions to suspend particles more readily (e.g., emollient particles) while still maintaining good shear thinning properties. The lamellar phase also provides consumers with desired rheology (“heaping”).
The structurant is preferably a fatty acid or ester derivative, thereof, a fatty alcohol, or trihydroxystearin, and the like. More preferably the structurant is selected from the group consisting of caprylic, capric, lauric acid, myristic acid and mixtures thereof.
Examples of fatty acids which may be used are C8-C22 acids such as the following: lauric acid, oleic acid, isostearic acid, linoleic acid, linolenic acid, ricinoleic acid, elaidic acid, arachidonic acid, myristoleic acid and palmitoleic acid, and the like. Ester derivatives include propylene glycol isostearate, propylene glycol oleate, glyceryl isostearate, glyceryl oleate and polyglyceryl diisostearate, and the like.
One of the principle benefits of the invention is the ability to suspend oil/emollient particles in a lamellar phase composition (and ability to do so in presence of low amounts of non-ioinc. The following oil/emollients, for example, may optionally be suspended in the compositions of the invention.
Various classes of oils are set forth below.
Vegetable oils: arachis oil, castor oil, cocoa butter, coconut oil, corn oil, cotton seed oil, olive oil, palm kernel oil, rapeseed oil, safflfower seed oil, sesame seed oil, sunflower seed oil and soybean oil, and the like.
Esters: butyl myristate, cetyl palmitate, decyloleate, glyceryl laurate, glyceryl ricinoleate, glyceryl stearate, glyceryl isostearate, hexyl laurate, isobutyl palmitate, isocetyl stearate, isopropyl isostearate, isopropyl laurate, isopropyl linoleate, isopropyl myristate, isopropyl palmitate, isopropyl stearate, propylene glycol monolaurate, propylene glycol ricinoleate, propylene glycol stearate, and propylene glycol isostearate, and the like.
Animal fats: acetylated lanolin alcohols, lanolin, lard, mink oil and tallow, and the like. Other examples of oil emollients includes mineral oil, petrolatum, silicone oil such as dimethyl polysiloxane, lauryl and myristyl lactate, and the like.
The emollient/oil is generally used in an amount from about 1 to 25%, preferably 1 to 10% by wt. of the composition.
The composition comprises 0.01 to 5%, preferably 0.1 to 2% by wt. of a cationic deposition polymer (cationic conditioner).
Cationic conditoners may include Quatrisoft® LM-200, polyquaternium-24, Merquat® plus 3330, polyquaternium-39 and Jaguar® type polymers. They may further include cationic cellulose type polymers such as Polyquaternium 10 (UCare Series from Dow) and synthetic cationic polymers such as Polyquaternium 49 and polyquaternium 51. (Merquat Series from Lubrizol)]
Cationic deposition polymers may also include hydrophobically modified cationic cellulose polymers such as SoftCat Series from Dow Chemical Company.
In addition, the compositions of the invention may include optional ingredients as follows: Organic solvents, such as ethanol; auxiliary thickeners, sequestering agents, such as tetrasodium ethylenediamine-tetraacetate (EDTA), EHDP or mixtures in an amount of 0.01 to 1%, preferably 0.01 to 0.05%; and coloring agents, opacifiers and pearlizers such as zinc stearate, magnesium stearate, TiO2, or EGMS (ethylene glycol monostearate); all of which are useful in enhancing the appearance of cosmetic properties of the product.
The compositions may further comprise antimicrobials such as 2-hydroxy 4,2′4′ trichlorodiphenylether (DP300); preservatives such as dimethyloldimethylhydantoin (Glydant XL1000), parabens, sorbic acid, etc.
The compositions may also comprise coconut acyl mono- or diethanol amides as suds boosters.
Antioxidants such as, for example, butylated hydroxytoluene (BHT) may be used advantageously in amounts of about 0.01% or higher if appropriate.
Another optional ingredient which may be added are the deflocculating polymers such as are taught in U.S. Pat. No. 5,147,576 title “Liquid Detergent Composition in the Form of Lamellar Deoplets Containing a Deflocculating Polymer”, issued on Sep. 15, 1992 to Montague, hereby incorporated by reference.
Other ingredients which may be included are exfoliants such as polyoxyethylene beads, walnut sheets and apricot seeds, and the like.
The compositions of the invention, as noted, are lamellar compositions. In particular, the lamellar phase comprises 20 to 80%, preferably 30 to 65% of the total phase volume. The phase volume may be measured, for example, by conductivity measurements or other measurements which are well known to those skilled in the art. While not wishing to be bound by theory, higher phase volume is believed to provide better suspension of emollients.
The structuring polymers of the invention are hydrophobically modified anionic cross-linked polymers. Such polymers are also referred to as “associative” polymers.
These polymers are constituted by a hydrophilic main chain and hydrophobic side-chains. Their behaviour in solution is a result of competition between the hydrophobic and hydrophilic properties of their structure. The hydrophobic units lead to the formation of aggregates constituting linkage points between the macromolecular chains. From a rheological viewpoint, these generally water-soluble (e.g. typically soluble under slightly acidic or alkaline conditions) polymers have a very high viscosifying power in water and retain their viscosity well in a saline medium. In mixed polymer and surfactant systems, surfactant aggregates can form, which are stabilized by different types of interactions: electrostatic interactions, dipolar interactions, or hydrogen bonds. The typically water-soluble polymers can interact more specifically with surfactants due to their hydrophobic portions.
The hydrophilic main chain of these polymers can, in particular, result from polymerization of a hydrophilic monomer containing functions onto which hydrophobic chains can subsequently be grafted, for example acid functions. This method of preparing the polymers is described in particular in the “Water Soluble Polymers”, ACS Symposium Series 467, ed. Shalaby W. Shalaby et al., Am. Chem. Soc. Washington (1991), pp. 82-200. However, a water-soluble polymer of natural origin, or a natural polymer rendered water-soluble by chemical modification, can also be used. Polymers can also be formed by copolymerization of hydrophilic monomers and hydrophobic monomers. These hydrophobic polymers, introduced into the reaction medium in a much smaller quantity than the hydrophilic polymers, generally comprise a fatty hydrocarbon chain. This method of preparation is described in the publication by S. Biggs et al., J. Phys. Chem. (1992, 96, pp 1505-11).
Examples of these polymers are acrylic polymers, polyethers, and polyosidic chains which may be partially substituted. The hydrophilic main chain is constituted as monomers carrying highly hydrophobic pendant groups. The molar percentage of monomers carrying hydrophobic pendant groups is termed the modification percentage of the hydrophilic chain. The hydrophobic pendant groups can be any hydrophobic pendant group which is conventionally used to prepare the polymers. In one aspect, the hydrophobic groups used comprise a backbone containing at least 8 carbon atoms, preferably 10 to 28 carbon atoms.
Particular examples of these hydrophobic groups are linear, branched, saturated or unsaturated hydrocarbon chains which may or may not contain cycles. Preferred examples of hydrophobic groups are hydrocarbon chains, in particular alkyl chains, containing 8 to 28 carbon atoms, preferably 12 to 22 carbon atoms. Modified units are advantageously in the form of an ether, ester or amide. This is particularly the case when the main chain of the associative polymer is an acrylic chain. The associative polymers used can have a mass average molar mass in the range 104 to 107.
The concentration of polymer in the composition is generally in the range about 0.01% to about 5 or from about 0.05 to about 2.0% by weight, preferably from about 0.1% to about 1.0% by weight or from about 0.1% to about 0.5% by weight of the composition. Preferred associative polymers include hydrophobically modified polyacrylates; hydrophobically modified polysaccharides; hydrophobically modified urethanes. Non-limiting examples of polymers include Acrylates/Vinyl Isodecanoate Crosspolymer (Stabylen 30 from 3V), Acrylates/C10-30 Alkyl Acrylate Crosspolymer (Pemulen TR1 and TR2), Ammonium Acryloyldimethylaurate/Beheneth-25 Methacrylate Crosspolymer (Aristoflex HMB from Clariant), Arylates/Beheneth-25 Methacrylate Copolymer (Aculyn 28 from Rohm and Haas)); Acrylates/Steareth-20 Methacrylate Copolymer (Aculyn 22 from Rohm and Haas), PEG-150/Decyl Alclhol/SMDI Copolymer (Aculyn 44 from Rohm and Haas), PEG-150 Distearate (Aculyn 60 from Rohm and Haas), Acrylates/Steareth-20 Methacrylate Crosspolymer (Aculyn 88 from Rohm and Haas).
In one embodiment, the polymer is a crosslinked alkali swellable, associative polymer comprising acidic monomers and associative monomers with hydrophobic end groups, where the polymer comprises a percentage hydrophobic modification and a hydrophobic side chain comprising alkyl functional groups having a length. Without intending to be limited by theory, it is believed that the acidic monomers contribute to the ability of the polymer to swell in water upon neutralization of the acidic groups; and associative monomers (e.g. monomers with hydrophobic chains) anchor the polymer into structured surfactant hydrophobic domains, e.g., lamellae, to confer structure to the surfactant compositions and keep the polymer from collapsing and losing effectiveness in the presence of electrolyte. The crosslinked associative polymer comprises a percentage hydrophobic modification, which is the mole percentage of monomers expressed as a percentage of the total number of all monomers in the polymer backbone, including both acidic and other non-acidic monomers. The percentage hydrophobic modification of the polymer, hereafter % HM can be determined by the ratio of monomers added during synthesis, or by analytical techniques such as proton nuclear magnetic resonance (NMR). The alkyl side chain length can be determined similarly. Monomers comprising only 2 or fewer alkyl hydrocarbons (e.g., ethyl, methyl) are not considered associative for the purposes of the present invention, all side chains having more than 2 carbons being associative. Associative alkyl side chains comprise for example butyl, propyl, stearyl, steareth, cetyl, lauryl, laureth, octyl, behenyl, beheneth, steareth, or other linear, branched, saturated or unsaturated alkyl or alketh hydrocarbon side chains.
Preferred polymers of the invention are hydrophobically or non-hydrophobically modified crosslinked polyacrylates rather than hydrophobically modified linear polyacrylates. Their viscosity is typically much lower.
More specifically, viscosity of a 2% solution (e.g. in water), (measured at pH 6.35 and shear rate 5 S−1, and further measured at 25 deg C., using a rheometer), is in range of 1 to 100 centipoise, more preferably 10 to 80 centipoise and most preferably 20 to 60 centipoise. Moreover, slope of the viscosity shear rate curve is in the range of −0.6 to −1.2, more preferably in the range of −0.7 to −1.1 and most preferably in the range of −0.8 to −1.0.
The slope measures the shear thinning nature of the polymer, wherein the higher the slope (more negative), the more shear thinning the polymer is.
Composition of the invention contain 0.4% or less, preferably 0.3% or less, more preferably 0.2% or less, most preferably 0.1% or less of HLB 1.4-13 nonionic emulsifiers such as those used in U.S. Pat. Nos. 8,105,996 and 8,158,566 to Wei et al noted above.
Further compositions of the invention comprise 2.7% or less, preferably 2.5% or less and more preferably 2% or less of salt, especially sodium chloride.
The following compositions were prepared. The petrolatum emulsion was prepared as noted in Table 2 and in the explanation of preparation set forth below Table 2.
1. The aqueous phase was mixed and heated in a stirred tank mixer, and oil phase was heated in a separate beaker. Once heated, the oil phase was added to the aqueous phase containing stirred tank mixer. Both oil phase and aqueous phases were heated to 75 degrees C., either separately and combined, or after they have been combined.
After the phases were combined and completely covered, the homogenizer was turned up to 1000 rpm.
2. After addition of the phases, the composition was mixed and homogenized for 10 minutes at 4000 rpm
3. The compositions was passed (one pass) through a nano DeBee, a bench scale sonolator, at 5000 psi.
Table 3 above demonstrates that mildness of composition can vary depending, for example, on surfactant composition.
From table 4, it can be seen that deposition is a function of the type of structuring polymer used.
More specifically, it is seen from Table 4 that deposition is inversely proportional to the viscosity of the 2% polymer solution measured at @ pH 6.35 and a shear rate of 5 s-1. The relationship is linear with a confidence level of over 90%, irrespective of whether the hydrophobic polymer is linear or cross linked. It is also seen that crosslinked polymers, hydrophobically or non-hydrophobically modified, deposit much higher levels of petrolatum than hydrophobically modified linear polymers.
The procedure used for determining petrolatum deposition was as follows:
An 8×8 inch piece of silk was washed with 12 ml of body wash base formula containing no PJ emulsion. A blank deposition value was obtained by subtracting the weight of the untreated silk piece from the weight of the washed and dried silk. Next, another silk with body wash containing PJ emulsion was washed. Overall PJ deposition is measured as the weight of silk after washing and drying minus the initial weight of the silk minus the blank deposition.
Table 5 shows that the deposition depends on the polymer used for those formulations of Examples 1 through 3 which statistically have the same level of mildness (see Table 3). By contrast, in Formulation of Example 4, a formulation which is statistically harsher than the other formulations, deposition is not affected by the polymer used. This demonstrates that the effect on deposition is a function of mildness as defined by CIM value. The polymers of lower viscosity (e.g., Pemulen TR versus Aculyn 88) enhance deposition of oil when composition has CIM value, for example, 55 or greater, but do not enhance viscosity when composition has CIM value below 55.
The inventive example #2 on Table 3 in U.S. Pat. No. 8,158,566 B2 using Aculyn 28 as the associative polymer was reproduced following the procedure enumerated in the patent at different levels of Trideceth-3 (non-ionic emulsifier). Also, comparative Example A-3 was reproduced. The results are shown in Table 6. The results show that the Youngs Modulus applicants obtained without the associative polymer is 22.4 Pa compared to the value 90 Pa indicated in the patent. In other words, their Young's Modulus of 90 approximately equals our Youngs Modulus of 22.4 and the scaling factor thus would be 90 divided by 24 which equals 4.1. Therefore, we can show that anything below approximately 24.4 Pa in our example will be below the corresponding target value of 100 Pa indicated in the footnote of Table 3 in U.S. Pat. No. 8,158,566 B2, that is 100 divided by scaling factor 4.1 equals 24.4 Anything under such 100 Pa value (equivalent to 24.4 Pa in our reproduced experiments) fails because stability is compromised and composition is therefore undesirable.
The inventive Example 1 on Table 3 in U.S. Pat. No. 8,158,566 B2 using Stabylen as the associative polymer was reproduced following the procedure enumerated in the patent at 0.35% Trideceth-3 (non-ionic emulsifier) at two different salt levels of 3.3% and 2.7%. These results show that at 0.35% non-ionic emulsifier and a salt level of 2.7% the Youngs Modulus falls well below the threshold value of (24.4) Pa (which is equivalent to 100 Pa in Wei patent). Also, the sample at 0.35% non-ionic emulsifier and a salt level of 2.7% was unstable and showed complete phase separation after two weeks.
Based on these results, below a non-ionic, Trideceth-3, level of 0.4%, in particular 0.35%, and a salt, sodium chloride, level of 2.7% define the thresh hold value of Youngs Modulus.
| Number | Date | Country | Kind |
|---|---|---|---|
| 18186321.8 | Jul 2018 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2019/068536 | 7/10/2019 | WO | 00 |
