MXPA99009491A - In-situ generation of zinc pyrithione - Google Patents

Abstract

Disclosed is a personal care composition comprising:(a) water or an alcohol, (b) at least one dispersant or surfactant, and (c) as an antimicrobial or preservative additive, particles of an in-situ transchelation reaction product of a zinc compound selected from the group consisting of zinc salts of organic acids, zinc salts of inorganic acids, zinc hydroxide, zinc oxide, and combinations thereof, said zinc compound being soluble in said water or alcohol, with pyrithione acid or a pyrithione salt that is soluble in said water or alcohol. Also disclosed is a process for preparing the personal care composition, and a coated substrate containing a coating of the personal care composition.

Description

The main applications of zinc pyrithione are its use as an antidandruff agent in shampoo.

The feüs: irirtione of "zinc ** • is typically found in the production plant of sodium pyrithione by reacting sodium pyrithione with a zinc salt, such as zinc sulfate, to form a precipitate of sodium. zmc pyrithione, as described, for example in US Pat. DO NOT. No. 2,809,971, which is typically washed and then dispersed in water to form an aqueous dispersion of zinc pyrithione in water. This conversion of sodium pipthione to form the dispersion of zinc pyrithione in the antiphilic production is an intensive work. In addition, the resulting zinc pyrithione dispersion is subjected to settling problems, since zinc pyrilane tends to be physically deposited out of the dispersion during transport or storage prior to the use of the dispersion. This settlement problem necessitates the mixing of the dispersion by the manufacturer of the personal care compositions containing the dispersion, to ensure the homogeneity of the dispersion in the composition. In addition, the Jfc settlement problem may result in "agglutination" of zinc pyrithione at the bottom of the drum, in which it is stored and transported, particularly when this product is stored for several months and is subjected to large fluctuations in temperature. the room temperature. * § »group consisting of skin, hair and combinations thereof, and a coating on the substrate, the coating comprises zinc pyrithione particles, the particles are produced by an in situ transquelation reaction of pyrithione acid or a soluble pyrithione salt with a zinc compound selected from the group consisting of zinc salts of organic acids, zinc salts of inorganic acids, zinc hydroxide ,. zinc oxide, and combinations thereof. and í These and other aspects will become apparent in the content of the following detailed description of the invention.

It has now surprisingly been found in accordance with the present invention that the in situ formation of zinc and pyrithione, either in a composition for the care Personal or in a precursor component of the composition for Tp. '*, -? personal care, provides several advantages over the use of preformed zinc pyrithione of the prior art in these * < - - formulations. First, the present invention overcomes the settlement problem discussed above associated with fe- ^ ft "-; - aqueous dispersions of zinc pyrithione, since zinc pyrithione ^ is formed in situ in the composition for personal care. Zinc pyrithione particles formed in situ were found to be stable in the personal care composition. These compositions (for example, shampoos in the form of liquid, gel or cream, medicines for the care of the skin in T "**" form of liquid, gel or cream, and soaps in the form of liquid, gel or cream) typically contain one or more surfactants, and faith has a relatively high viscosity. This high viscosity and? The presence of surfactant (s) ensures that zinc pyrithione prepared in situ is stable against settlement in the personal care composition. Second, the transport of a pyrithione solution (eg, aqueous sodium pyrithione) to the manufacturer of the personal care product eliminates the likelihood of a freezing / settling problem that exists when the product is transported. appropriately in the process and composition of the present invention, while commercial dispersions of aqueous zinc pyrithione typically require 60% by weight of water, thereby allowing only 40% by weight of zinc pyrithione. This allows the manufacturer to transport less water to the manufacturer of the personal care composition, thus saving on transportation costs.

The reactants used to prepare zinc pyrithione in-situ in the personal care composition, according to and with the present invention, are appropriately selected to provide not only zinc pyrithione, but also a thickening agent for the composition for personal care By way of illustration, sodium chloride is commonly used as a thickening agent in personal care compositions. By selecting zinc chloride, and sodium pyrithione for in situ translocation in the personal care composition, or in its precursor, to form the desired zinc pyrithione, sodium chloride is also formed, providing the added benefit of a Thickening agent in the composition. Other thickeners and useful agents that are produced in situ in an analogous manner include ammonium chloride and sodium sulfate. On the other hand, it is desired to have no saline, different from zinc pyrithione, incorporated into the composition for care. By virtue of the transkelation reaction, then the acid of pyrithione and zinc oxide or zinc hydroxide are appropriately employed as the transkelating reactants.These reactants produce only zinc pyrithione and water as reaction products.

He . The zinc compound used as a transkelation reactant according to the present invention is appropriately selected from the group consisting of zinc salts of organic acids, zinc salts of inorganic acids, zinc hydroxide, zinc oxide, and combinations thereof. , with the proviso that the zinc compound is soluble in the composition for personal care. Exemplary zinc salts include zinc chloride, zinc sulfate, zinc acetate, and combinations thereof. Zinc chloride is preferred. The term "soluble in the personal care composition" is intended to indicate that the zinc compound is soluble in the personal care composition in an amount of at least 100 ppm, preferably at least 1000 ppm. 1 The pyrithione reactant used in the process and composition of this invention is suitably a pyrithione salt, such as sodium pyrithione, potassium pyrithione, lithium pyrithione, chitosan pyrithione, magnesium disulfide pyrithione, ammonium pyrithione, combinations of them, and the like, or pyrithione acid, or a combination thereof. The preferred pyrithione salt is sodium pyrithione. Although the molar ratio of the pyrithione reactant relative to the zinc compound is not narrowly critical, it is preferred that between 1 and 1.5 moles of zinc compound be employed per 2 moles of pyrithione used. The amount of pyrithione acid or water-soluble pyrithione salt which is soluble in the transquelation reaction mixture can vary over a wide range. A preferred amount of water-soluble pyrithione or pyrithione salt is from about 1% to about 50% by weight, based on the total weight of the reaction mixture.

The reaction medium useful for the transkelation reaction of the present invention includes water, organic solvents, and combinations thereof. Useful organic solvents include alcohols, such as methanol, ethanol, amines, such as diethanolamine, ethers, esters, and the like.

Additional materials, such as dispersants, dispersant / surfactant mixtures, and the like can be added to the reactants either before, or during, the precipitation reaction to prevent agglomeration of the pyrithione salt particles formed under of the reaction, yes it is desired. Alternatively or additionally, a dispersant or other dispersing agent provides dispersion characteristics to the pyrithione salt particles formed during the transkelation wording, it may be added at the termination of the reaction to prevent particle agglomeration. Exemplary dispersants include sodium salts of the polymerized alkyl naphthalene sulphonic acids, such as "DARVAN" (RT Vanderbilt), "DEMOL N" (Kao Chemicals), "DAXAD 11" (Hampshire Chemicals), or "TAMOL N" ^ (Rohm and Haas).

The dispersant is used appropriately alone or in combination with a surfactant. Suitable surfactants include linear alcohol alkoxylates, such as alcohol-linear ethoxylates, ethoxylated / propoxylated block copolymers, ethoxylated / propoxylated fatty alcohols, and polyoxyethylene cetyl ethers, and the like. If desired, the alcohol alkoxylates are appropriately coated with a lower alkyl group, and such product is commercially available as POLY-TERGENT® SLF-18 available from Olin Corporation.

The useful anionic surfactants, which are suitably employed in the compositions of the present invention, include alkyl diphenyl ether disulfonates, alkyl phenyl ethoxylated phosphate esters, linear alcohol alkoxylates. carboxylated, linear alkylbenzenesulfonic acid, diisobutyl sulfosuccinate, and alkyl sulfonates.

Other useful anionics are the polycarboxylated alcohol alkoxylates, preferably these are selected from the group consisting of the organic or inorganic acids or salts of the following: polycarboxylated linear alcohol alkoxylates, polycarboxylated branched alcohol alkoxylates, alkoxylates. of polycarboxylated cyclic alcohols, and combinations thereof.

Exemplary cationic surfactants include alkyltriamonium halide, non-linear alkyldimethyl halide and surfactants containing alkyldimethylbenzylammonium halide. Illustrative amphoteric dispersants include polyglycol ether derivatives, ethoxylate oxazoline derivatives, lauramidopropyl betaine, and lecithin.

As will be appreciated by those skilled in the art, appropriate mixtures can be employed in the process of the present invention based on various combinations of the surfactants described above. The dispersant or dispersant / surfactant mixture is preferably employed in a total amount of between about 0.05.05 and 10%, more preferably between about 0.1 and 5%, most preferably. preferable between about 0.5 and about 1.5% by weight, based on the total weight of the reaction mixture.

The personal care compositions of the present invention appropriately also contain thickening agents. Illustrative thickening agents include cellulose derivatives 30, for example methyl, hydroxyethyl, hydroxypropyl and carboxymethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, poly (acrylic acid) salts and salts of copolymers of acrylic acid / acrylamide.

To increase the stability against freezing, electrolytes can be included in the composition for personal care. Suitable electrolytes include monomers, such as 1,2-diols, for example glycol, 1,2-propylene glycol and 1,2-butylene glycol, or polymers thereof, or ethoxylated compounds. For example the reaction products of ^ ethylene oxide with long chain alkanols, amines, alkyd phenols, poly (propylene glycol), or poly (butylene glycol), or a combination thereof, or the like.

The minimum temperature of the film formation can be reduced by adding solvents, such as ethylene glycol, butyl glycol, ethyl glycol acetate, ethyl diglycol acetate, butyl diglycol acetate, benzene or alkylated aromatic hydrocarbons. Suitable defoaming agents are, for example, poly (propylene glycol) and polysiloxanes. Optionally other antimicrobial additives may be additionally incorporated into the personal care compositions of the present invention. Illustrative of other antimicrobial additives are polymyxin E, polymyxin B, lower alkyl esters of para-hydroxybenzoic acid (also called "parabens"), salts thereof, and combinations thereof. These other optional antimicrobial additives are appropriately employed in a weight ratio of 1 to 10,000 to 10,000 to 1, based on the amount of pyrithione employed in the personal care composition. Useful optional solvents include methyl isobutyl ketone (herein referred to as "MIBK"), xylene, ethylbenzene, methanol, and combinations thereof.

The temperature employed in the transkelation reaction according to the present invention is suitably from about 0 ° C to about 100 ° C, preferably from about 20 ° C to about 90 ° C. The pressure used in the reaction is appropriately between one and two atmospheres, although they can be used if higher pressures are desired. Advantageously, this reaction can be carried room temperature (that is, 20 ° C to 25 ° C), and atmospheric pressure.

Personal care compositions prepared according to the present invention containing dispersed particles of zinc pyrithione are suitably employed in any of a variety of personal care applications, in a liquid or solid expandable form, alone or in combination with a inert carrier, __ such as water, liquid hydrocarbons, ethanol, isopropanol, or the like. These can be employed "using conventional methods to control bacteria and fungi on substrates, such as the skin or hair, and can be applied in an antimicrobial amount by conventional procedures, such as spraying, immersion, impregnation by wetting, and the like. In the substrate, as well as in the personal care composition, the zinc pyrithione particles appropriately have a shape selected from the group consisting of platelets, rods, needles, cylinders, cones, ellipsoids, prisms, parallelepipeds, , - "- pyramids, cubes, and combinations thereof These zinc pyrithione particles are appropriately crystals having a selected triclinic, monoclinic, orthorhombic, tetragonal, cubic, trigonal, hexagonal configuration since they have a shape selected from the group consisting of platelets, rods, needles, cylinders, cones. ellipsoids, prisms, parallelepipeds, pyramids, cubes, and combinations thereof.

Illustrative examples of typical shampoo formulations comprise: A typical anti-dandruff shampoo comprises the following: (a) Water in an amount of 43.8% (b) Pyrithione zinc in an amount of 3% (c) DEA of cocamide in an amount of 1% (d) _ Lauryl-triethanolamine sulfate in an amount of 40% A typical premium anti-dandruff shampoo comprises the following: (a) Deionized water in an amount of 76% (b) __ Amide of tallow acid of tallow di (hydrogenated) in and an amount of 5% (c) Preservative * _ (d) _ Citric acid, 50% aqueous solution of sodium hydroxide OR (50% solution) (e), _ Ammonium Chloride - - A typical antidandruff shampoo with conditioner is as follows: _ ^ (a) l_ Deionized water in an amount of 76% (b) Amide of dihydric tallow phthalic acid in an amount of 5% (c) _ Preservative (d) Citric acid, 50% aqueous solution of sodium hydroxide OR ( 50% solution) (e) Ammonium Chloride Another typical anti-dandruff shampoo with conditioner is as follows: (a) Deionized water in an amount of 23.85% (b) Sodium Laureth Sulfate in an amount of 30% (c). Tricetylammonium chloride in an amount of 0.50% * - i (d) ^ MEA of cocamide in an amount of 1.70% (d) Preservative in an amount of 0.05% (f) Citric acid, 25% aqueous solution An anti-dandruff shampoo "extra body" is the following: (a) Deionized water in an amount of 64.6% (b) ^ MetiIparaben in an amount of 0.30% (c) Triethanolamine lauryl sulfate in an amount of 20% "(dj Hydrolyzed animal protein of cocodimony in an amount of 1% (e) Blue No. 1 of FD &C (f) Citric acid, 50% aqueous solution.

The following examples are intended to illustrate, but in no way limit the scope of the present invention. Unless otherwise indicated, the "parts" and "%" are "parts by weight" and "percent by weight", respectively.

EXAMPLE 1 Translocation of Zinc Chloride with Sodium Pyrithione In-situ in a Shampoo to Produce Zinc Pyrithione Particles in a Cubic Shape A sample of a commercial two-in-one shampoo and conditioner shampoo was slowly heated to about 60 ° C with constant shaking. The shampoo contains the following ingredients in the specified approximate amounts in percent by weight based on the weight of the shampoo: approximately 40% water, approximately 20-30% ammonium laureth sulphide surfactant, approximately 15% surfactant ammonium lauryl sulfate, glycol distearate, ^ ^^ dimeticpna, fragrance, ammonium xylenesulfonate, approximately 3% cocamide MEA foam stabilizer, from 2% to 4% cetyl alcohol and stearyl alcohol, approximately 0.5% poly-anionnion-10 conditioner, approximately _1% of mineral oil lubricant, sodium phosphate, stearyl alcohol, about 0.5% hydantoin preservative of DMDM, about 1% sodium phosphate and disodium phosphate buffer, sodium chloride thickener, and yellow no. 10 FD &C and blue no. 1 of FD &C. An aqueous solution of zinc chloride was mixed in the heated shampoo. With stirring, an aqueous solution of the sodium salt of sodium hydroxide was added over a period of 30 minutes. Í -? - 2 -mercaptopyridine-N-oxide. The stoichiometry of the reactants is such that there was a slight excess of zinc chloride. The mixture was stirred to ensure homogeneity and cooled to room temperature. A sample of zinc salt shampoo from 2-mercaptopyridine-N-oxide prepared in situ analyzed the size of the particles and the shape of the crystals formed by means of a scanning electron microscope (MES). The particles were found to be cubes that have dimensions of approximately 5 by 5 by 5 microns.

EXAMPLE 2 ^ Platelet Form in the Shampoo 32 g of hydroxypropylmethylcellulose suspension agent was mixed in water (198 ml) and heated to 70 ° C for 30 minutes. Zinc chloride (3.4 g) was added to the above mixture. The sodium salt of 2-mercaptopyridine-N-oxide (18.6 g) was added to the above mixture over a period of 5 minutes and stirred at 70 ° C. In a separate vessel, with molten cocoamide DEA, a mixture of sodium lauryl sulfate was added. . ^ * triethanolamine, triethanolamine, yellow no. 5 of FD &C, blue no .__ 1 of FD &C and distearate of ethylene glycol. The two i-mixtures were stirred together at 1500 rpm and the temperature was decreased to room temperature. A portion of the shampoo thus formed was analyzed by the size and shape of the 2-mercaptopyridine-N-oxide particles generated in-situ. He - - ^ - Analysis with a scanning electron microscope showed that these particles had a platelet shape. The average particle size obtained by laser light scattering showed that the particles were in the form of platelets having an average particle size of 3 μm, with a particle size distribution in the range from 0.7. up to 10 microns. _ While the invention has been described above with reference to the specific embodiments thereof, it is apparent * that many changes, modifications and variations can be made without departing from the inventive concept described herein. Accordingly, it is intended to understand all changes, modifications and variations that fall within the spirit and broad scope of the amended claims.

It should be noted that with regard to this date, the best method known to the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following is claimed as property.

Claims (21)

1. CLAIMS A process for preparing a personal care composition containing zinc pyrithione, characterized in that it comprises reacting, in a personal care composition, pyrithione acid or a pyrithione salt different from zinc pyrithione, or a combination thereof, "with a zinc compound which is soluble in the composition for personal care, the zinc compound is selected from the group consisting of zinc salts of organic acids, zinc salts of inorganic acids, zinc hydroxide , zinc oxide, and combinations thereof, thereby causing the in-situ transquelation of the pyrithione salt with the zinc salt to form the composition for personal care containing zinc pyrithione.
2. 2. The process according to claim 1, characterized in that the personal care composition is a shampoo comprising water or an alcohol, and at least one surfactant.
3. 3. JE1 process according to claim 1, characterized in that the personal care composition is a soap comprising water or an alcohol, and at least one surfactant. 4. - The process according to claim 1, characterized in that the composition for personal care is a medication for personal care comprising water or an alcohol, and at least one surfactant. 5. The process according to claim 1, characterized in that the zinc salt is selected from the group consisting of zinc sulfate, zinc chloride, zinc acetate, and combinations thereof. __ 6. The process according to claim 1, characterized in that the pyrithione salt is selected from the group consisting of magnesium pyrithione, strontium pyrithione, copper pyrithione, zinc pyrithione, cadmium pyrithione, zirconium pyrithione, and combinations thereof. same. 7. * A process for preparing a personal care composition containing zinc pyrithione selected from the 3fc: group consisting of shampoo, soap, skin care medicament, and combinations thereof, characterized in that the process comprises contacting water or an alcohol with at least one surfactant and with a product of transquelation __r ~ Z produced, by reacting pyrithione acid, or a pyrithione salt which is soluble in the composition for personal care, or a combination thereof, with a zinc compound selected from the group consisting of zinc salts of organic acids, zinc salts of inorganic acids, zinc hydroxide, zinc oxide, and combinations thereof, the zinc compound is soluble in the composition for personal care. ^ 8. The process according to claim 7, characterized in that the zinc salt is selected from the group consisting of zinc sulfate, zinc chloride, zinc acetate, and combinations thereof. 9. The process according to claim 7, characterized in that the pyrithione salt is selected from the group consisting of magnesium pyrithione, strontium pyrithione, copper pyrithione, zinc pyrithione, cadmium pyrithione, zirconium pyrithione. , and combinations thereof. 10. A composition for personal care, characterized because it contains: __ (a) water or alcohol, (b) at least one dispersant or surfactant, and (c_) as an antimicrobial or preservative additive, particles of an in-situ transquelation reaction product of a zinc compound selected from the group consisting of zinc salts of organic acids, zinc salts of inorganic acids, zinc hydroxide, oxide of zinc, and combinations thereof, the zinc compound is soluble in water or alcohol, with pyrithione acid or a pyrithione salt which is soluble in water or alcohol. 11. The personal care composition according to claim 10, characterized in that the zinc salt is selected from the group consisting of zinc sulfate, zinc chloride, zinc acetate, and combinations thereof. 12. The composition for personal care according to claim 10, characterized in that the pyrithione salt is selected from the group consisting of magnesium pyrithione, strontium pyrithione, copper pyrithione, zinc pyrithione, cadmium pyrithione, pyrithione zirconium, and combinations thereof. 13. The composition for personal care according to claim 10, characterized in that the component (a) is presented in the personal care composition in an amount from about 5% to about 70%, wherein the component (b) is presented in an amount from about 2% to about 50%, and wherein component (c) is presented in an amount from about 0.1% to about 2%, based on the weight of the composition for personal care, with the proviso that the total of component (a) plus component (b) plus component (c) does not exceed 100%, and where the reaction product is in the form of solid particles in the composition for personal care, the solid particles they are amorphous or crystalline particles in a form selected from the group consisting of rods, needles, cubes, platelets, and combinations thereof. 14. The composition packs personal care according to claim 10, characterized in that the surfactant comprises sodium lauryl sulfate, sodium laureth sulfate, or a combination thereof. 15. The composition for personal care according to claim 10, characterized in that the alcohol is selected from the group consisting of isopropyl alcohol, benzyl alcohol, ethanol, and combinations thereof. 16. _ A coated substrate comprising a substrate selected from the group consisting of skin, hair and combinations thereof, and a coating on the substrate, characterized in that _the coating contains zinc pyrithione particles, the particles are produced by a transquelation reaction in-situ pyrithione acid or a soluble pyrithione salt with a zinc compound selected from the group consisting of zinc salts of organic acids, zinc salts of inorganic acids, zinc hydroxide, zinc oxide, and combinations ^ thereof. 17. and The coated substrate according to claim 16, characterized in that the zinc salt is selected from the group consisting of zinc sulfate, zinc chloride, zinc acetate, and combinations thereof. 18_ The coated substrate according to claim 16, characterized in that the pyrithione salt is selected from the group consisting of magnesium pyrithione, strontium pyrithione, copper pyrithione, zinc pyrithione, cadmium pyrithione, zirconium pyrithione, and combinations thereof . 19. _____. The re-coated substrate according to claim 16, characterized in that the zinc pyrithione particles have a shape selected from the group consisting of platelets, rods, needles, cylinders, cones, ellipsoids, prisms, parallelepipeds, pyramids, cubes, and combinations of the same . twenty . AND? coated substrate according to claim 16, characterized in that the zinc pyrithione_ particles are crystals having a selected triclinic, jnpnoclinic, orthorhombic, tetragonal, cubic, trigonal, hexagonal configuration since they have a __ form selected from the group consisting of platelets, rods, needles, cylinders, cones, ellipsoids, prisms, parallelepipeds, pyramids, cubes, and combinations thereof. 21. The composition according to claim 10, characterized in that it additionally contains a complementary antimicrobial additive selected from the group consisting of polymyxin E, polymyxin B, lower alkyl esters of para-hydroxybenzoic acid, salts thereof, and combinations thereof .