CA1077851A - Method for producing a urea-based bath bead composition - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A non-segregating, free-flowing bath bead composi-tion, based on prilled urea in combination with active bath components, is produced by admixing urea prills with an oily liquid emollient to distribute the emollient substantially uniformly on the prills and then adhering a powdered surfact-ant to the emollient-bearing prills to produce free-flowing bath beads. If desired, color can be imparted to the prills by providing moisture-containing prills and commingling the prills with a powdered, water-soluble dye prior to the distribution of the emollient thereon.

Description

The present invention rela~es to a method ~or producing bath bead compositions ~hich utilize urea prills or beads which possess skin soothing characteristics as carriers for an oil liquid emollien~ and other active bath components.
At the present time, bath compositions are commercially available - in the ~orm of powd0rs having a particle size ranging from ine powders to coarse granules. Such powders are usually constituted by an alkaline detergent material~ such as anhydrous sodium tripolyphosphate, combined with small amounts of oils, perfumes, and dyes, to provide attractive coloration.
Such products areoccasionally irritating to portions of the human body due to the alkalinity that is imported to the bath water upon use.
; An attractive bath bead composition is known which is use~ul at approximately neutral pH and which provides good emolliency without irritation to the skin or mucous membranes. The composition is of very low toxicity if ingested and, since it is in the form of beads instead of a powder, the composition presents a more pleasing and appropriate appearance in view of the fact that bath compositions are usually sold under the designation "bath beads" Moreover, a composition in bead form rninimizes undesirable dusting during manufacture and dispensing.
, 20 Other known bath bead compositions aTe primarily constituted by prilled urea combined with a dye and a minor proportion, generally from 0.1-25%, preferably from 0.5-15%, of the weight of the composition, of at least one active bath composition ingredient such as an emollient, a surfactant, and the like. If desired, fragrances and/or germicides can also be present in the composition. It is also desirable to include, as an optional constituent, an anti-caking agent, such as hydrolyzed protein or water soluble cornstarch.
It has now been found that h;~h quality bath bead c~mpositions based on prilled urea can be produced i~ the various active ~ath co~ponents are compounded with the urea prills in a certain manner.
lhe present invention providcs a method ~or producing a Free-flowing

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bath bead composition which comprise.s admixiTIg urf3a prills ~lith an anhydrous `~ oily liquid emollient in an amount of at least about 0 2 to about 10 weight percent, based on the weight of the prills, distributing said emollient substantially uniformly on said prills to provide emollient-bearing p~ills, adding to said emollient~bearing prills while their suraces are sticky~ a powdered surfactant in an amount to provide about 1 to about 15 weight per-cent, based on the weight of the composition, and agitating the mixture of emollient-bearing prills and powdered surfactant while said emollient is absorbed or adsorbed into said prills to produce a free-flowing particulate composition in which the surfactant remains associated with the bea~s in a non-segregating fashion, said prills constituting at least 50% o~ the weight of the bath bead composition. To produce dyed bath beads, moisture-contain-ing urea prills are commingled with a water-soluble dye, preferably in dry powder form, to distribute the dye over the external surface of the prills prior to the distribution of the emollient on the prills.
In another aspect, the invention provides a free-flowing bath bead composition comprising urea prills admixed with about 0.~ to about 10 weight percent, based on the weight of the prills, of an anhydrous oily liquid emollient and about 1 to about 15 weight percent, based on the weight of the composition of a powdered surfactant, said emollient being absorbed or adsorbed uniformly into or onto said prills to provide emollient-bearing prills and the surfactant being associated with the prill beads in a non-segregating fashion having been added to said emollient-bearing prills while their surfaces are sticky, said prills constituting at least 5U% of the weight of the bath bead composition.
If desired, additional ingredients such as fragrant substances, buffering agents, germicides, preservatives and/or :

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anti-caking agents can also be incorporated in~o the bath bead composition.
Description of Preferred Embodiments The urea beads or prills which constitute the major portion of the bath bead composition are commercially avail-able under the designation "prilled urea." The urea prills are round, relatively hard beads having capacity to absorb or retain a small amount of an oily liquid such as an emol-lient and/or fragrance that may be utilized in a bath bead ; , .
10 composition. The particle size distribution for the prills can vary considerably. Pre~erably at least about 98 percent of the beads pass through Sieve No. ~ of U.S. Sieve Series ; and are retained on Sieve No. 20 of U.S. Sieve Series. Thus, the average prill diameter usually is in the range of about i 0.13 inch to about 0.035 inch.
. The compositions of this invention, when dissolved in water in an amount to provide a urea concentration of approximately 1.0 weight percent, do not significantly modify the pH of norm~lly neutral bath water but give a bath pH in the range of 5-8, preferably 5.5 to 7. If desired, a buffer-ing agent can be included in the composition to further sta-:..
bilize the pH. The composition is used in the bath in a concentration of 0.05-0.5 weight percent.
The prilled urea constitutes at least 50 weight per-; cent of a bath bead composition. In general, urea does not irritate the skin or mucous membranes and, if ingested, acts as a mild diuretic.
Urea in powder form ls not appropriate because, ln that physical ~orm, urea is strongly hygroscopic, whereas, the prilled urea has a much smaller surface area per unit . . .

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wei~ht and is only slightly hygroscopic. For ~he production ; o~ colore~ ba~h beads, it is important that the urea prills contain some moisture, particularly on the external sur~aces thereof. Enough moisture must be present to solubilize at least some of the powdered water-soluble dye that is commin-gled with the prills so as to provide dyed prills. Pre~erably ; the moisture content of the prills is about 0.02 percent by weight to about 0.1 percen-t by weight.
Inasmuch as prilled urea does have a limited tendency ` 10 to absorb moisture, the small amount of water absorbed or adsorbed on the urea beads from ambient atmosphere usually is . su~ficient to solu~ilize the amount of powdered water-soluble dye which is combined with the prills to provide a desired coloration for the bath beads and ultimately for the bath water. In such a case the dye can be applied by simply commin-gling or mixing the urea prills and the water-soluble dye (usually in the form of a dry powder). If the surface moist-ure content of the urea prills is too low, the prills can be pre-moistened by temporary storage in open containers in a relatively humid atmosphere, or by subjecting the prills to a fine mist or spray o~ water prior to or during commingling with the dye.
In instances where the moisture content o~ the urea . prills is very low and it is desired to produce colored bath beads, the water-soluble dye can also be dissolved in water and the resulting solution sprayed as a fine mist over a pre-` determined amount of prills contained in a tumbling barrel, a rotating pan mixer, or the like mixing vessel as the prills are agitated therein. Care should be exercised however, to limit the amount o~ water that is introduced so as to avoid caking.

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: , Water-solu~le dyes s~itable for the present purposes are food, drug and cosmetic dyés or drug and cosmetic dyes, ` these being normally used as color additives in beverages, co~lfeetlc~s, a~d/o~ rhar~.aceutlcal~. The dyes ca~ be of ~n7 desired color, in finely divided solid or crystalline state, - ancl can be selected from nitro, monoazo, diazo, phthalocy-' anine, quinoline, xanthene, triacrylmethane, indigoid, vege-table dyes, and the like. Blue and green dyes are preferred as being generally more attractive for the present purposes.
Illustrative suitable dye is FD&C Blue No.l,e.e., a color additive which is principally the disodium salt of ethyl~4-{p-[ethyl(m-sulfoben~yl)amino]-~-(o-sulfophenyl)benzylidene}-2~s-cyclohe - a~ien-l~ylidene}(m-sulfobenzyl)a~monium hydroxide inner salt h smaller amounts of the isomeric disod.ium salts o~ eth~l{~-tp-[ethyl(p-sulfobenzyl)amino]-a-(o-sulfophen~l)benz~lidene}
~` 2,5-cyclohexadien-1-ylidene}(p-sulfo~enzyl)L~mmonium hydroxide inner salt and ethyl{4-{p-[ethyl(o-sulfob~nzyl)amino]-c~-(o-sulfophenyl)benzylidene}-2,5-cyclohexadien-1-ylidene}(o-sulfo- I
ben~yl)ammonium nydroxide inner s~lt.
The urea prills, whether dyes or undyed, posses a limited capacity to absorb oily liquids, especially emollients and additionally a fragrant substance such as a perfume or a scent. In the present process, an oily liquid, e.g., an emollient, ~ith or without other substances such as fragrances, perfumes, scents, germicicles or the like, is added to the urea ` prills and distributed thereover. If colored bath beads are the desired end product, the dye is d:i.stributed on the pri.lls be~ore the oily liquid.
To introduce the emollient, the pril.ls are agi tLI ted with the oily liquicl emollient to un:iform:ly distribute the .. I

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''' oily liquid over the surface of the prills. Agitation is preferably continued to permit the prills to absorb and/or adsorb at least a por~ion of the oily liquid emollient which is used in an amount of at least 0.2 percent, prefer-ably about 0.5 to about 10 weight percent, based on the weight of the prills. The maximum amount in each case will depend on the nature of the emollient and the absorptive i- and/or adsorptive capacity of the prill. In any event, the ~'! amount of emollient applied to the prills should nat exceed the amount which can be absorbed or adsorbed since this causes the prills to remain sticky which prevents the forma-tion of a free-flowing powder.
Suitable emollients for the present purposes are the lower alkanol esters of saturated fatty acids such as - isopropyl palmitate, isopropyl myristate, methyl laurate, ; ethyl stearate, and the like. Also suitable are the gly-cerol esters of saturated fatty acids, e.g., glyceryl mono-" stearate, glyceryl monolaurate, glyceryl tripalmitate, the cholesterol esters of saturated fatty acids, C12 1~ alcohols, -` 20 e.g., cetyl alcohol, stearyl alcohol, lauryl alcohol, and ~ adducts of C12 18 alcohols with 1 to 4 moles of ethylene :'~ oxide, e.g., ethoxylated lauryl alcohol containing about 1 mole of ethylene oxide per mole of lauryl alcohol, oily liquids, P.g., the vegetable oils such as olive oil, cotton-seed oil, corn oil, almond oil, peanut oil, and the like, hydrocarbons such as mineral oils, light liquid petrolatum and the like, and similar absorbable substances which soften - the skin. These are used as water-free liquids and the term "oily" denotes the presence of a long hydrocarbon chain and the absence of water.
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: In preparing the bath bead compositions the oily liquid emollient is admixed with the prills to distribute the emollient i.n contact with a predetermined amount of the prills to form an initially sticky mass or mixture. Urea prills normally have a relatively dull surface which becomes ` shiny when the oily emollient is distributed thereon, and this shine can be used to measure the uniformity o~ distri-bution of the oily liquid. Thus, after addition of the emollient, the combination is mixed or agitated until the - 10 prills present a substantially uniform shiny appearance.
Preferably, the pril.l-and-emollient combination is tumbled or otherwise agitated until the emollient is at least par-tially absorbed or adsorbed and individual emollient-bearing prills begin to move relative to one another or separate from one another.
~ on-absorbable emollients, germicides, fragrances, and the like, can be introduced into the bath beads by first encapsulating such substances in a water-soluble sheath or powder, e.g., water-soluble starch or dextrin, and there-. 20 after adhering the encapsulated substances to the emollient-bearing prills while the surface thereof is still somewhat sticky, i.e., before all of the liquid emollient has been ; absorbed within the prills. ~ suitable commercially avail-able germicide is 2,4,4'-trichloro-2'-hydroxy-diphenyl ether.
The germicide can be present in an amount of about 0.1 to . about 3 percent by weight of the composition.
- It is important that the bath beads include a sur-.
; factant which is uniformly distributed and which does not segragate on storage. For this purpose, the sticky surfaces of the emollient-bearing prills are coated with a powdered `::

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surfactant having a particle size which is substantially less than the slze of the urea prills. If a foaming action is desired, a foaming surfactant is utilized for this purpose.
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The coating operation can be carried out in a tumbling barrel, " a rotating pan mixer, an inclined open-ended rotary drum, by passing the prills through a fluidized bed of the surfact-ant powder, or in any other convenient manner. The powdered surfactant should be added to the emollient-bearing prills after the emollient thereon has been substantially distributed because otherwise the surfactant powder will absorb emollient yielding lumps which interfere with the uniform distribution of emollient and surfactant. If the emollient-bearing prills are agitated without addition of surfactant, the emollient will be taken up by the prills to form a free-flowing powder, and it is now too late to add the powdered surfactant since it will not associate with the prills and the mixture segre-gates on storage.
Continued agitation after addition of the surfactant permits the absorption or adsorption of the oily liquid to continue until a free-flowing particulate mixture is obtained.
The finely divided surfactant particles surprisingly remain associated with the urea prills even though there is no longer enough oily liquid on the surface to cause these prills to stick together. The same amount of oily emollient would not : serve to associate the surfactant with the prills if the sur-factant is added too late as noted previously.
The average particle size of the surfactant particles ; is preferably up -to a~out l/~th ~he average diameter of the - urea prills, and is rnore pre~era~ly less than 1/8th its di-ameter.

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~ The surfactants which may be used may vary consid-,.
erably, but since a foaming action is pre~erred so as to - provide a bubble bath e~fect, anionic surfactants are the preferred surfac~ants. A particularly preferred foaming sur-factant is sodium lauryl sulfate powder, in particular sodium lauryl sulfate powder at least about 75% of which passes through Sieve No. 60 J U. S. Sieve Series.
Any non-irritating high foaming solid detergent can be used. Particularly suitable are the anionic sulfates and sulfonates. Illustrative of such detergents are magnesium lauryl sulfate powder, alphaolefin sulfonate flake or powder, ; nonyl phenyl sulfonate (flake or powder), or mixtures of these materials. If the surfactant is a liquid, the surfactant is converted to a powder form, e.g., encapsulated, before use.
The foaming surfactant can be used in any desired amount, preferably in an amount of about 1% to about 15% of the weight of the composition. If desired, an anti-caking ` agent or other ingredien~s can be combined with the powdered surfactant and the emollient-bearing prills coated with the produced combination.
` The anti-caking agents which may be used to prevent sticking as a result of water absorption include finely divided .. modified proteins, water-soluble polysaccharides such as corn-starch and the like, natural gums, and similar substances.
,: Salts which absorb moisture by forming hydrates and which do ~ not induce significant alkalinity in the small proportions : utilized can also be used, for example, anhydrous magnesium .
sulfate. Anti-caking agents are well known, per se, and their use is i~self conventional.
, `. 30 To stabilize the pH o the bath water, powdered ,~
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7~78S31 buffering agents such as citric acid, fumaric acid, tartaric acid, and the like, can also be adhered onto the emollient-bearing prills together with the powdered surfactant. Simi-larly, powdered preservatives such as the lower alkanol esters of parahydroxybenzoic acid, e.g., methyl paraben, propyl para-ben, mixtures thereof, and the like, can be incorporated into the bath bead combination when practicing the present inven-tion.
Either in the presence or absence of the high ~oam-ing surfactant, tests indicate that no oily film or ring isleft in the bathtub after continued use of the compositions o this invention. These compositions are also not affected by hard water which would usually form scum on or in the bath water.
The following illustrative bath bead compositions can be made by the method of the present invention.
EMOLLIENT BAT-~ BEAD COMPOSITION
Component Parts by Weight : Prilled urea 94.3 -~ 20 Oil-soluble, ethoxylated lauryl alcohol2 0 Sodium lauryl sulfate powder 2.5 Fumaric acid (buffering agent) 0.5 Perfume 0.5 Mixture (2:1) of methyl paraben and propyl paraben 0.2 Water-soluble dye (FC&C) ~lue l~o. 1)trace 100 . 00 lcontains about 1 mole of ethylene oxide per mole of lauryl alcohol.
2about 90 percent passing through Sieve No. 40, U.S. Sieve Series.

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' EMOLLIENT BUBBLE BATH COMPOSITION
Component Parts by Weight ~ Prilled urea 89.2 :. Isopropyl palmitate 2.0 Alpha-olefin (C12_14) sulfonate 8.0 Perfume 0.8 Water-soluble dye (FD&C) Blue No. 1) trace ~` 100. 00 EMOLLIENT BUBBLE BATH WITH DEODORANT ACTION
:: lO Component Parts by Weight .
; Prilled urea 89.0 2,4,4'-trichloro-2'-hydroxy-diphenyl ether (germicide) 0.2 Isopropyl myristate 2.0 : Alpha-olefin (12-14) sulfonate 8.0 . Perfume 0.8 ` Water-soluble dye (FD&C) Blue No. 1) trace .: 100. 00 The present method is further illustrated by the - following process examples.
EXAMPLE 1: Preparation of Emollient-Bearing, Urea-Based Bath Beads : Prilled urea (about 100 pounds) passing through a - No. 6 Sieve and retained on a No. 20 Sieve (U.S. Sieve Series) - is introduced in~o a powder mixer and power to the mixer is .i~ turned on so that the urea prills are agitated. Thereafter ~ .:
`~ oil-soluble ethoxylated lauryl alcohol (about 2.25 pounds) is : sprayed onto the agitated prills, and the agitation is con-tinued until the urea prills develop a substantially lmiformly shiny surface. Thereafter, powdered sodium lauryl sulfate . 30 passing through IJ.S. Sieve Series No. 40 Sieve (about 2.75 .

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,, pounds) is mixed in with the e~ollient-bearing prills, and agitation is continued Imtil sur~actant-coated, free-flowing prills are produced.
EXAMPLE 2: Preparation of Colored Bath Beads Urea prills (about 95 pounds) passing through a No. 6 Sieve and retained on a No. 20 Sieve (U.S. Sieve Series) are introduced into a power mixer and agitated. During agita-tion powdered, water-soluble dye (FD&C Blue No. 1, about 0.1 : pound) is added ~o the power mixer, and the produced admixture is agitated for about 10 minutes until a substantially uniform blue color develops on the prills.
Thereafter, ethoxylated lauryl alcohol (about 2 pounds) and a perfume (about 0.5 pound) are sprayed onto the produced dyed prills until individual prills begin to separate from one another and tumble free of each other. At this time sodium lauryl sulfate powder (about 2.5 pounds; about 90%
passing through U. S. Sieve No. 40 Sieve) is introduced into ~` the mixer and the formed mixture is agitated until the prills are free-flowing.
EXAMPLE 3: Preparation of Colored, Urea-Based Bath Beads Urea prills (abou~ 100 pounds) having substan~ially the same particle size distribution as in Example 2 but a very low moisture content (less than about 0.02 weight per-cent) are introduced into a power mixer and agitated. Dry, ~` powdered dye (FD&C Blue No. 1) is added to the mixer and the `. produced mixture is agitated for about 10 minutes. Thereafter, water (about 0.06 pound) is sprayed as a fine mist onto the agitated mixture, and agitation ls continued ~or an addi-tional time period o~ about 10 minutes to fully ~evelop the color on the prills.

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After the prills in the power mixer exhibit a substantially uniform blue color, isopropyl palmitate ; (about 2.25 pounds~ and a perfume (about 1 pound) are sprayed onto the colored prills, and agitation is continued until the ~: prills become shiny. Then a powdered alpha-olefin (C12-C14) sulfonate (about 8 pounds) is added to ~he mixer and the mi~er contents further agitated until freely flowing, blue-colored prills are produced.
The foregoing discussion and the examples are in-`: 10 tended as illustrative and are not to be taken as limiting.
. Still other process variations are possible without departing from the spirit and scope of the present invention.

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Claims (16)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for producing a non-segregating, free-flowing bath bead composition which comprises admixing urea prills with an anhydrous oily liquid emollient in an amount of at least about 0.2 to about 10 weight percent, based on the weight of the prills, distributing said emollient substantially uniformly on said prills to provide emollient-bearing prills, adding to said emollient-bearing prills while their surfaces are sticky, a powdered surfactant in an amount to provide about 1 to about 15 weight percent, based on the weight of the composition, and agitating the mixture of emollient-bearing prills and powdered surfactant while said emollient is absorbed or adsorbed into said prills to produce a free-flowing particulate composition in which the surfactant remains associated with the beads in a non-segregating fashion, said prills constituting at least 50% of the weight of the bath bead composition.

2. The method in accordance with claim 1 wherein a fragrant substance is distributed onto the prills with said oily liquid emollient.

3. The method in accordance with claim 1 wherein a powdered buffering agent is added to the emollient-bearing prills.

4. The method in accordance with claim 1 wherein a powdered preservative is added to the emollient-bearing prills.

5. The method in accordance with claim 1 wherein an anti-caking agent in dry powder form is commingled with the powdered surfactant prior to addition of the surfactant to the emollient-bearing prills.

6. The method in accordance with claim 1 wherein the powdered sur-factant is added to the emollient-bearing prills in an amount to provide about 1 to about 15 weight percent, based on the weight of the composition.

7. The method in accordance with claim 1 wherein admixing of the urea prills with the liquid emollient is carried out by agitating the prills and and spraying the emollient onto the prills while the prills are agitated.

8. The method in accordance with claim 1 wherein the urea prills have an average diameter in the range of about 0.13 inch to about 0 035 inch.

9. The method in accordance with claim 8 wherein said surfactant has an average diameter up to about 1/4th the average diameter of said prills.

10. The method in accordance with claim 1 wherein said urea prills are dyed with a water-soluble dye prior to the addition of said liquid emollient.

11. A method of producing a free-flowing bath bead composition which comprises:
admixing urea prills with an absorbable anhydrous oily liquid emollient in an amount of at least about 0.2 to about 10 weight percent based on the weight of the prills;
agitating the mixture to distribute the emollient substantially uniformly on said prills, and continuing said agitation until individual emollient-bearing prills begin to separate from one another; and then adhering on the surface of said emollient-bearing prills while the prills surfaces are tacky a powdered surfactant, said prills constituting at least 50 weight percent of the bath bead composition.

12. A method of producing a bath bead composition which comprises:
providing urea prills having moisture on the surface thereof in an amount sufficient to solubilize a water-soluble dye; said prills constituting at least 50 weight percent of the bath bead composition, commingling said prills and a water-soluble dye to distribute said dye over the surface of said prills thereby producing dyed prills;
contacting the dyed prills with an absorbable anhydrous oily liquid emollient to provide on the dyed prills at least about 0.2 to about 10 weight percent of the emollient, based on the weight of the prills to provide emollient-bearing prills; and coating the emollient-bearing prills, while the prills surfaces are tacky, with a powdered surfactant in an amount to provide about 1 to about 15 weight percent, based on the weight of the composition, to provide non-segregating substantially free-flowing bath beads.

13. The method in accordance with claim 12 wherein the prills have a moisture content of about 0.02 to about 0.1 weight percent, based on the weight of the prills.

14. The method in accordance with claim 12 wherein the dye in dry powder form is distributed substantially uniformly over the entire surface of the prills.

15. The method in accordance with claim 12 wherein the emollient is sprayed onto the prills while the prills are agitated.

16. A free-flowing bath bead composition comprising urea prills admixed with about 0.2 to about 10 weight percent, based on the weight of the prills, of an anhydrous oily liquid emollient and about 1 to about 15 weight percent, based on the weight of the composition of a powdered surfactant, said emollient being absorbed or adsorbed uniformly into or onto said prills to provide emollient-bearing prills and the surfactant being associated with the prill beads in a non-segregating fashion having been added to said emollient-bearing prills while their surfaces are sticky, said prills constituting at least 50% of the weight of the bath bead composition.