CA2111525A1 - Preservative compositions - Google Patents

Abstract

ABSTRACT
The present invention is directed to a preservative composition comprising an aqueous dispersion of particles of at least one preservative wherein said particles have a surface modifier adsorbed on the surface thereof in an amount sufficient to achieve a particle size of less than about 400 nanometers (nm). The compositions of the present invention can contain other conventional ingredients.

Description

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PRESERVATIVE COMPOSITIONS
c Field of the Invention The present invention relatss to preservative containing compositions for uso in household and industrial products.
~; 5 ~ackaround o~ the In~en~ion A variety of preservative agent~ havs been ~ formulated into compositions that are marketed as ;; household products such as cleaners, floor polishes, 0 painta, stains, cosmetics, personal care products and industrial fluids such as metal working, secondary oil recovery, cooling tower, and pulp and paper procQssing composition~.
It is an object of the present invention to increase the dispersibility of these agents in aqueous media while minimizing or eliminating the need for organic solvent~.

Summarv of the Invention The present invention is directed to a preservative composition that comprises an aqueous dispersion of particles of at least one preservative wherein said particles have a surface modifier adsorbed on the surface thereof in an amount sufficient to achieve a particle size of less than about 400 nanometers (nm). The compositions of tha present `, invention can contain other conventional ingredients that are used in such compositions.
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; 30 Detailed ~escriDtio~ of the Invention The compositions of the invention comprise .~
; preservative containing nanoparticles. The preservative can be any of a variety of compounds such a~ glycerol, .
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monolaurate, parabens, pyrthione~, and insoluble guaternary amine complexes.
The particles of this invention contain a ; discrete phas~ of a pre~ervative a described abovehaving a RurfacQ modifier adsorbed on the sur~ace thereo~. Use~ul surface modifiers are believed to include those which physically adhere to the sur~ace o~
the preservativ~ but do not chemically bond to the ~ preservative.

3 lo Suitable surface modifiers can preferably be ~J selected from known organic and inorganic excipient~.
~i Such excipients lnclude various polymers, low molecular weight oligomers, natural products and sur~actants.
Preferred surface modifiers include nonionic and anionic surfactants. Representative examples o~ excipients include gelatin, casein, lecithin (phosphatides), gum acacia, cholesterol, tragacanth, stearic acid, benzalkonium chloride, calcium stearate, glyceryl ~ monostearate, cetostearl alcohol, cetomacrogol ;~ 20 emulsifying wax, sorbitan esters, polyoxyethylene alkyl ethers, e.g., macrogol ethers such as cetomacrogol 1000, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan fatty acid esters~ e.g., the commercially availabl~ Tweens, polyethylene glycols, polyoxyethylene stearates, colloidol silicon dioxide, phosphates, odium dodecylsulfate, carboxymethylcellulose calcium, carboxymethylcellulose sodium, methylcellulose hydroxyethylcellulose, hydroxypropylcellulose, `~ hydroxypropylmethycellulose phthalate, noncrystalline cellulo3e, magnesium aluminum silicate, triethanolamine, polyvinyl alcohol, and polyvinylpyrrolidone (PVP). Most o~ these excipients ara described in detail in the Handbook of Pharmaceutical Excipients, published jointly by the American Pharmaceutical Association and The ~ 35 Pharmaceutical Society o~ Great Britain, the i ,. !, " ' ~. . ' ~
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; 2 ~ 2 . ., ',3, Pharmaceutical Press, 1986, the disclosure o~ which is~, here~y incorporated by re~erence in it5 entirety. The surfacQ modi~iers are commercially available and/or can b~ prepared by techniques known in the art.
` 5 The surface modifier is adsorbed on the -1, surface o~ the preservative in an amount sufficient to maintain an effective averag~ particle ~ize of less than about 400 nm. The sur~ace modifier does not chemically react with the preservative or itsel~. Furthermore, the individually adsorbed molecules of the sur~ac~ modi~ier are essentially free of intermolecular crosslinkages.
As used herein, particle siz~ refers to a number averag~ particle size as measured by conventional particle size measuring techniques well known to those skilled in the art, such as sedimentation field flow fractionation, photon correlation spectroscopy, or disk centrifugation. By "an effectiv4 average particle size of les~ than about 400 nm" it is meant that at least 90%
of the particles have a weight average particle size of les~ than about 400 nm when measured by the above-noted techniques. In preferred embodiments of the invention, the effeçtive average particle size is less than about 250 nm. In some embodiments of the invention, an effective averag~ particle size of less than about 100 nm has been achieved. With reference to the effectiv~
average particl~ size, it is preferred that at least 95%
and, more preferably, at least 99% o~ the particle~ hav~
-~ a particle size less than the effective average, e.g., 400 nm. In particu~arly pre~erred embodiments, .~
essentially all of the particles have a size les than 400 nm. In some embodiments, essentially all of the particles have a size less than 250 n~.
The particles of this invention can be prepared by a method comprising the steps of dispersing .~i , .
~i 35 a preservative in a liquid dispersion medium and .
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`~; applyin~ mechanical mean~ in the prQsence o~ grinding ~`''!'' media to reduco th~ particle 8iZR 0~ the in~ction -i control agent to an effective avQrage particle size of ~, le88 than about 400 nm. The particle~ can be reduced in size in the presenc~ o~ ~ surfacQ modi~ier.
~lternatively, th~ particle~ can bQ contacted with a surface modifi~r ~fter attrition.
These mQthods are described in detail in U.S.
Patent No. 5,145,684.
The relative amount o~ preservativ~ and ~urface modi~ier can vary widely and thQ optimal amount o~ the surface modifier can depend, for exampl~, upon the particular preservative and sur~ac~ modi~ier ; selected, the critical micelle concentrat~on of the surface modifier if it ~orm8 micellQs, etc. The surfaca modifier prefer~bly i~ present in an amount of about 0.1-~0 mg per ~guare meter surface ~rea of the :~ halohydanto~n. The surfaco modifiQr can be present in an amount of 0.1-99.995%, preferably 20-60% by weight based on the total weight of the formulation.
m e nanoparticles of th~ present invention can be incorporated into conventional preserving and s~ microbiocidQ compositions, a3 ~or exampl~, thos~
disclosed in U.S. Patent Nos. 4,040,977; 4,379,137;

4,996,052 and S,023,267, th~ disclosure~ o~ which are incorporated herein. Additives such as perfumes, anticorrosivQ agent Q.g., benzotriazole, fungicides, biocide~ and other similar additives can b~ incorporated ~ in thesQ compositions.
-, 30 Representativ~ preservative~ lnclud~ a thiol~n 1 of the formul~:
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;-- wherein each o~ X and Y, which may b~ the ~ame or ~ di~ferent represents fluorin~, chlorine or bromine, an '3'',,~ alXylenebisthiocyanat~ and a 2-N-alky1-4-isothiazolin-3-`'-'~1 on~;
~ compound sQlected from the group con~isting o~ polymeric quaternary a~monium compound~ having the formula:

Rs-hO-CUI-A-cH~ ~ hO-Z-NO-CH~-A-CH~ R~.(2~+2)X~

~h~--Z--l'JO--CH2--A--CHI~ .2nX~

wherein Rl and R2, which can b~ tho same or differ~nt are alkyl having from 1 to 20 carbon atoms an~ having r"~ 20 from 0 to 1 hydroxyl substituent, benzyl, benzyl bearing on the benzene moiety one alkyl having from 2 to 20 ~ carbon a~oms; h~, R4 and R5, which can be th~ oam~ or- di~ferent, ar~ alkyl having ~rom 1 to 20 carbon atoms and having from 0 to 1 hydroxyl substituent, or R3 and - 25 R~ taken together with th~ nitrogen to which they are ~ attached ~orm a ~aturat~d het2rocyclic ring having from .ii 5 to 7 ring ato~s; Z and A, which can be the same or different, are divalent alkylen~ radicals o~ 2 to 10 carbon atom~ interrupted by from 0 to 1 oxygen atom and containing ~rom 0 to 2 ethylenic double bonds; n i3 a whols number ~rom 2 to 30; and X i~ ~ halogen; and ;:~
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a 3-i~othiazolone having the ~ormul~:

R'~N--Y

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wherein Y i8 ~lkyl having from 1 to 18 carbon atoms, . cyclohexyl, phenyl, halophenyl, benzyl or halobenzyl, and R', which can b~ the same or different, ar~
hydrogen, halogen, ~lXyl having from 1 to 6 carbon ~;~!; atom~, alkenyl o~ 2 to 6 carbon atoms or phenyl, or R
.~. and R' togeth~r with the carbon atom3 to which they are ,~.'r att~ched form a benzene ring, or a salt thereof with ~trong acid, or a 3-isothiazolone metal salt complex ~: 15 having the formula:
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~a [ s ' Yl (Ml~",) . 20 . wherein Y, R and R' are a~ de~ined above, M is a cation , o~ calcium or magnesium, B i~ a chloride anion or .~ nitrate anion, a i3 the whole number 1 or 2, and ~ i~
the nu~ber 2: wherein the ratio of component (a) to component ~b) is ~rom 1:200 to 200:1: and phosphate derivative~ o~ the following general `; formula:
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OH
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R may be alkyl, aryl, aralkyl and alkaryl group~ including, but not limited to, straight chain, branched chain or cyclic alkyl groups having fro~ 1 to 24 carbon atoms, polyoxyethylene or polyoxypropylene having from 2 to 32 ethylene oxide or propylene oxide units respectively, alkyl phenoxy polyoxyethylene containing 2 to 32 ethyleno oxide unit~, alkyl phenoxy polyoxyethylen~ containing ethylene oxide units and 1 to 24 carbon atoms in the phenolic alkyl chain, and polyhydroxy compounds, including but not limited to, 3 ethylene glycol, ylycerol or sorbitol.
X is selectQd from the group consisting of Group IA metals, Group IIA metals, tr~nsition metals, hydrogen and an organic ion. The positively charged ion is not necessary for microbiocidal activity.
Th~ compositions of the present invention can be illustrated by the following representative example.
Example 1 Preservative Floor Polish Ingredient Wt. %
Water 47 Nanoparticle preservatives0.01 - 1 Premixed plasticizer (Tributoxyethyl Phosphate) 1.2 `~ Diethylene glycol monomethyl ether 5.0 1% FC-129 ~olution 0.5 Texanol 0.34 Methyl Pyrolidone 0.55 Acrylic Polymer 33 Rosin Ester 3.3 Polyethylene Emulsion 8.2 The foregoing specification, including tho specific embodiments and example i8 intended to be illustrative of the present invention and is not to be taken a~ limiting. Numerous other variation~ and modifications can be effected without departing from the true spirit and scope of the present invention.

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Claims

We Claim:

1. A preservative composition comprising an aqueous dispersion of particles of at least one preservative wherein said particles have a surface modifier adsorbed on the surface thereof in an amount sufficient to achieve a particle size of less than about 400 nanometers (nm), a surfactant, a dye and a fragrance.