CA1191093A

CA1191093A - Functional agglomerated speckles, method for manufacture thereof and dentifrices containing such speckles

Info

Publication number: CA1191093A
Application number: CA000412498A
Authority: CA
Inventors: Jordan B. Barth; James Norfleet
Original assignee: Colgate Palmolive Co
Current assignee: Colgate Palmolive Co
Priority date: 1981-09-30
Filing date: 1982-09-29
Publication date: 1985-07-30
Also published as: US4376763A; PH18191A

Abstract

FUNCTIONAL AGGLOMERATED SPECKLES, METHOD FOR
MANUFACTURE THEREOF AND DENTIFRICES CONTAINING SUCH SPECKLES

ABSTRACT OF THE DISCLOSURE:
Functional agglomerated speckles, for incorporation in dentifrices, include agglomerates of a water insoluble powdered functional material and water insoluble, ethanol soluble ethyl cellulose. Such speckles satisfactorily maintain their integrity and identity during processing of the dentifrice after addition of the speckles to the main dentifrice body but on storage, after packaging of the dentifrice in dispensing tubes, soften sufficiently so as to become essentially impalpable to one utilizing the denti-frice in brushing his teeth. Despite such softening the speckles continue to maintain their identity as speckles in the dentifrice. The speckles are especially useful in translucent or transparent gel dentifrices which contain components, such as flavoring and surface active agents, which may controllably soften the speckles on storage. Also described in the specification are methods for the manufacture of the mentioned speckles, dentifrices incorporating them, methods for manufacturing such dentifrices and such denti-frices packaged in end use dispensing containers.

Description

f;, ~9~ 3 This invention relates to functional agglomerated speckles for incorporation in dentifrices. More particularly, it relates to such speckles and to dentifxices containing them, wherein the speckles are made from a'water insoluble powdered functional material, such as a dental polishing agent, and water insoluhle, ethanol soluble ethyl cellulos~.
The inventlon also relates to methods for manufacturing such speckles and such dentifrices and to such dentifrices packaged in dispensing containers, such as transparent or translucent containers through which the speckles in a ~;-transparent or tran~lucent gel dentifrice may be ~iewed. To obtain desired visual effects the speckles will usually be of a color which contrasts with the xest of the dentifrice.
Prior art toothpastes and gels which inoorporated contrastingly colored speck~es are known. Although such speckles in sorne cases are primarily for aesthetic effects, they may be based on functional components, such as polish-ing agents, and they can perform desired functions in the dentifrice, in addition to making it of attractive appearance.
Various colors and combinations thereo in ~he speckles may serve to identify the particular type of dentifrice, such as fluoride and non-fluoride dentifrices. Incorporation of materials in the speckles may help to prevent reaction or premature reàctio~ with other dentifrice co~ponents.
~hen the speckles comprise mostly water ins~luble material, such as a polishing agent, they can be prese~t in a trans-parent or transluceIIt gel dentifrice without objectionablyclouding the gel. Thus, the gel remains clear, with the speckles beinq visible therein, and the spe~k3es provide a decorative and aethestically improved appeasance for the produc-t.

~,.,.

f~, In the past various speckled de~ti~rices h~ve includcd speckles which were initially palpable but became impalpable during toothbrushing. Although such products ha~e met with t~chnlcalaPproval it has also been found desirable to market 5 another type of speckled dentifrice, like that of this inven- ;
tion, in which the speckles, although readily visible and discrete, are impalpable initially and subse~uently during brushing of the teeth.
Among the various prior art references showing dentifrices incorporating speckles and other dispersed solids therein, the closest to the present invention ~hat are known to applicants are U.S. patents Re. 29,634; 3,929,988;
4,003r971, 4,089,943; and 4,220,552.. The reissue patent de~cribes a dentifrice containing visible and palpable, substantially water-insoluble, agglomerated particles of polishing agents. Binding ayents are employed in the manufac-ture of the described speckles and among the water soluble binders methyl cellulose is mentioned. However, methyl cellulose is water soluble and therefore does not provide a speckle which maintains integrity during lengthy processing and eventually softens to an impalpable unit on storage in a dentifrice. U.S. patent 3,929,988 r lates to a dentifrice co~taining encapsulated sweetener. Ethyl cellulose is mention-ed among various other materials useful for coating the sweet-ener to make the capsules or spheres, which may be visible or"micro-size", and are dispersed in the dentifrice. U.S. patent, 4,003,971 teaches making dentifrice speckles and describes the advantages of water-insoluble binders for such speckles.
The patent mentions the use of gums as water insolubie binders but does not disclose or suggest ethyl cellulose.
U.S. patent 4,089,943 teach~s toothpaste formulations having dispersed therein visible agglomerated particles of dental polishing agent. Tne advantages of both water soluble and water insoluble agglomerating or binding agents are mentioned in the patent but e~hyl cellulose is not suggested for use as a binder. E'inally, U.SO patent 4,220,552 teaches micro-encapsulation of sodium fluoride by lower alkyl cellulose-, such as ethyl cellulose, and dispersing of the capsules in a dentifrice. The patent does not relate to agglomerates and the employment of ethyl cellulose as an encapsulating agent does not make obvious its use as an agglomerating agent useul in making the present speckles.
The present invention is one wherein ethyl cellulose, which is water insoluble but ethanol soluble, is utilized as an agglomerating agent for a fun~tional water insoluble powdered material made into dentifrice speckles of improved properties. Prior speckles, made with water soluble binders, such as methyl cellulose, could disintegrate during processing after mix~ing in with other den~ifrice components, such as those in previously formulat~d gel or paste media, if the speckled dentifrice was held too long in the processing equipment~ which can happen, as when mechanical breadkdowns of processing equipment occur. Such 9 1~9 3 losses of i~tegrity of the speckles could take place because such dentifrices contai~ water~which can solubilize the water s~luble binders of the speckles and lead to separation of the componcnt particles of the speckles. ~he dissolving of the bin~er can be minimized in such cases by prompt processing but when filling line hol~ps cause processing times to be increased losses of product could r~sult.
Dentifrice speckles made with ordinary water insoluble binding agents, as disclosed in the art (such art does not disclose ethyl cell~lcse), when dispersed in denti~
frice gels or pastes, tend to be palpable, and alLhQugh that may cften be desirable, in some dentifrices, e.g., those intended for use by persons with sensitive gingiva, it is not.

The ethyl cellulose employed as a binder for functional speckles in acccrdance with the present invention satisfac-torily maintains the integrity of the speckles in aqueous d~ntifrice media for a sufficiently long time to allow processing after incorporation of the speckles in the dentifrice. Yet, apparently because of the presence of compo-nents of the dentifrice which tend to soften the speckles onstorage, such as flavoring agents, and in some cases, surface active agents, ~he speckles in the d~ntifrice are softened sufficiently during storage so that, although they maintain their integrity and independence and their distinctly separate appearances until they are used, they are impalpable and are readily disintegrated during toothbrushing.

In accordance with the present invention functional agglomerated speckles, for incorporation in dentifrices, comprise agglomerat~s of a water insoluble powdered functional materi~l and water insoluble, ethanol soluble ethyl cellulose..

3~9~3 Preferably, the functional ma-terial is a dental polishing agent and comprises 75 to 98% of the speckles, with the ethyl cellulose comprising 2 to 20% thereof and with the product optionally including a coloring agent which may be 0 to 5% thereof, more preferably 0.05 to 1%, when present.
Also claimed in this application are a dentifrice containing such speckles, methods for the manufacture of the speckles and of the dentifrice, and a packaged gel dentifrice containing the invented speckles dispersed therein.
The invention will be readily understood from the present specification, including the detailed description herein with reference to the drawing, Figure 1, which is a perspective view of a packaged dentifrice of this invention.
The functional agglomerated speckles are comprised of two essential components, a water insoluble powdered functional material and a water insoluble, ethanol soluble ethyl cellulose. The first may be characteri~ed as the functional bodying agent and the second as the binder.
Various functional materials, all of which are preferably water insoluble, or at least, slowly soluble, can be employed, including colorants, such as pigments, germicides, ion exchange agents, polymerlc materials (which may contain other active components, sometimes water soluble materials), and flavorings, but it is highly preferred that the functional base material for the speckles be a polishing agent or include a major proportion thereof. Of the polishing agents, . !~
9~

normally utilized in dry powder form to make the agglomerated speckles, those preferred are dicalcium phosphate, tricalcium phosphate, insoluble sodium metaphosphate, alumina, sili.ca, magnesi~m carbonate, calcium carbonate, calcium pyrophosphate, bentonite and zirconium silicate, and suitable mixtures thereof. Both anhydrous or calcined forms of these materials, such as calcined alumina, and hydrated forms, such as dicalcium phosphate dihydrate, may be employed but the anhydrous or ~
calcined materials are often preferred. Because the agglomerates lQ will normally desirably be opaque there is no need to match refractive indices with those o the dentifrice vehicles ~including other components, too~ but "transparent" polishing agents, with such a matching refractive index, e.g., 1.44 to 1.47, may be used to make transpa~ent or translucent speckles, as well as being used in making a clear gel dentifrice body containing polishing agent. Such "transparent" polishing agents include colloidal silicas and those sold under the mark Syloid, as.Syloids 63, 65, 72 and 74, under the mark Santocel, as Santocel 100 and as Zeo's 49, 113 and 119, and Zeodent*
Also, synthetic alkali metal aluminosilicate complexes may be particularly useful, because they have refractive indices close t.o those cf dental vehicles including water, glycerol, sorbitol and gelling agent, which are those normally employed in the manufacture of dentifrices.
The water insoluble, powdered ~unctional material utllized to make the present speckles will normally be of initial parti.cle sizes in the range of 0.5 to 20 microns t *Y'rade ~ark 9~

preferably being with.in the range o 1 to 10 mi~rons, and more preferably of 2 to ~ microns. However, in some instances larger parti.cle sizes may be employed, as when the agglomerat-ing operation tends to size-reduce some of the powder, as may happen in mixing be~ore actual agglomeration begins.
The binding agent for the present speckles is ethyl cellulose. This effective binder is water insolu~le but is soluble in ethanol, and is gradually soluble in an ~ueous glycerol-sorbitol medium which also contains "solvents"
for it, such as flavor.ingsand surfactants,which are usually present in the dentifrices of this invention. Such ethyl cellulose will usually have an e~hoxy content in ~he range o about 45 to 50~, preferably 48 to 50~ or 48 to 49.5%.
In a preferred ethyl cellulose, suçh as that marketed by The Dow Chemical Company under the trade name Ethocel* Standard 10 Premium Ethyl Cellulose, the ethoxyl content is in the range of 48.0 to 49.5~; the viscosity is 9 to 11 centipoises;
the moisture content i5 ~ maximum; chloride, as NaCl is 0.15~ maximum and ash content is 0.15~ maximum. The test methods employed for the foregoing analyses are those incor-porated in Test D914 of the American Society For Testing Materials (ASTMj. Because the ethyl cellulose is intended for oral use the maximum content of arsenic, as As2O3, is three parts per million (p.p.m.~, that of lead is 10 p.p.m.
~5 and that of heavy metals is 40 p.p.m., all by Food Chemicals Codex (FCC) testing.

*l'rade Ma ~k In the 18-page Dow Chemical Company booklet entitled ETHOCEL Ethylcellulose Resins - Tough, Rugged Coatings, Adhesives, Hot Melts, copyrighted 1974~ 1975 and 1978, suitable ethyl cellulose resins for use as binders for the present speckles are described. Ethyl cellulose is supplied commercially as a white to light tan gran~llar powder of a degree of etherification such that there are 2.25 to 2.58 ethoxy groups per anhydroglucose unit, which corresponds to 45.0 to 49.5% etho~y content (by weight). Of two grades of ethyl cellulose commercially available the "standard" materials, which are preferred for the practice of the present invention, have ethoxy contents in the range of 48.0 to 49.5% (by weight), and the less preferred "medium" materials have ethoxy contents in the 45.0 to 46.5%
range. Of course, such products are availab] e in different viscosity ranges, usually from 3 to 110 centipoises, with the medium material tending to be more viscous.
The standard grade of ethyl cellulose tends to be solukle in aromatic hydrocarbons, hydroaromatic ilydrocarbons, chlorinated aliphatic hydrocarbons and naval stores. It is also soluble in monohydric aliphatic alcohols, such as ethanol; monohydric cyclic alcohols, such as benzyl alcohol phenylethyl alcohol and pine oil; ether alcohols, such as glycol ethers; ethers, such as diethyl cellosolve; esters, ;; ~ f 9~

especially acetates, such as isopropyl acetate and seC-amyl acetate and esters of hydroxy acids, such as methyl salicylate;
and ketones, such as cyclohexanone and acetophenone.
Generally, the medîum ethoxy grade of ethyl cellulose is less soluble than the standard grade and so may be more suited for use when greater proportions of solubilizing materials are present in ~he dentifrice formula. ~-~
Among other physical properties of ethyl celluloses are: a specific gravity of about 1.1; water absorption after twenty-four hours i~nersion of about 1~; an impact strength, expressed as energy to break, of about 1 to 12 ft. lbs./sq.
in. of notch; a tensile strength of about 6,000 to 9,000 lbs./sq. in.; an elongation of ab~ut 10 to 40%; a ~ockwell hardness of about 70 to 110; a compression ~olding tempera~
ture of about 320 to 350F., a compression molding pressure of a~out 30G to 6,000 lbs./sq. in.; and a specific heat of about 0.3 to 0.46. Ethyl cellulose is heat stable, light stable, colorless, odorless and tasteless.
Although it might have been expected that the b~st speckles would be made from the least soluble binder material, it has been found that ethyl cellulose, as described in this invention, makes speckles o~ ideal properties, which maintain .1 () !.

their individuality and integrity w~ile being processed and during storage, but which are also essentially impalpable during use of the dentifrice in brushing. If desired, the character of the speckles may be changed~ as by modifying the d~gree of ethoxy content of the ethyl cellulose and~or by ~lending with it other substantially water insoluble binders of known types, some of which are mentioned in the patents previously referred to, the disclosures of which are incorporated herein by reference. The properties of the l~ speckles may also be regulated by adjusting the proportions of functional material and the binder, as will be referred to subsequently. Thus, agglomer~tes may be made which will he stable durin~ processing after mixing, such as deaerating and filling, yet which will break up rapidly after the dental cream is extruded from its container or, if desired, such breaking up may be retarded so that the agg~omerates will feel haxder ancl somewhat firmer to the user during brushing of his teeth. Of course, it is normally highly preferable for the speckles to be essentiallyimpalpable on use, while still maintaining theix identity in the dentifrice.
The binder will normally be of particle size like that of the functional powdered material of the speckles, especially if the agglomerates are to he made, at l~ast in part, by compacting of powdered materials However, because normally the speckles will be made by utilizing an alcohoiic solution of the ethyl cellulose, the particle siz2s thereof ., !J
~9~93 are of relatively little importance.
The speckles, while sometimes white or colorless and possibly even translucent or transparent, or approaching such appearances, may also be colored, normally due to contain~
S ing a suitable proportion of dye or pigment or a mixture of dyes and/or pigments. Any non-toxic dye or pigment oE a suitable color, usually a strong color, such as one of a suitable hue, with a Munsell chroma great~r than 4 and a Munsell value in the 4 to 7 range, may be utilized,and in some instances weak colors or pastels may be satisfactory or desirable. It is usually best to employ a dye or pigment which is approved for drug and cosmetic use (D&C) or for food, drug and cosmetic use (FD&C3. Representative of ~uitable dyes are D&C Reds No's. 2, 3, 6, 7, 8, 9, 10, 11, 15 12, 13, 19, 30, 31, 36 and 37; D&C Blue No. l; FD&C Blues No's. 1 and 2; FD&C Reds No's. 1, 2 and 3; FD&C Yellow No. 5;
cosmetic green oxide; and cosmetic red oxide. Pigments of the foregoing dyes) known as lakes, are also suitable for use in coloring the speckles but normally the dyes will be preferred.
~o The mentioned pigments are often composed of dyes supported on a finely powdered insoluble carr~er and the pigments are dispersed rather than dissolved in the medium to be colored. I
The particle sizes of pigments employed may be within the range previously given for the polishing agents or may be sized like the binder. Sizes may be finer, e.g., in the 0~01 to 1 micron range. Particle sizes of dyes may be similar but f~, !t because they are normally employed in dissolved state, in water or solvent, preferably being oil soluble and being dissolved in the appropriate solvent, sizes are not important as long as the powder or particles are small enough so as to make S the dye readily soluble in the solvent chosen.
The speckles of this invention may be made by any suitable method, either wet or dry processes. Employin~ a ' wet granulation process, the ethyl cellulose, in dry powder form, is first preferably blended with polishing agent and dye or pigment, if present, and ethanol. Water and/or lipophilic solvent may be pxesent with the ethanol and a dye or pigment for coloring the speckles may also b~ present.
Alternatively, and often preferably, an ethanol solution of ethyl cellulose may have a suitable dye or pigment and the polishing agent admixed with it. The proportions of components will be such as to resul~ in speckles of the desired composition and the proportion of solvent(s) will normally be rom 5 to 50% of the mi~s, preferably 5 to 25% thereof. The production of the dispersion may he by means of a Hobart mixer, Dravo pan, or other suitable mixing device or granulator for wetting powder(s), and the order ~f addition of the various components of the dispersion may be adjusted as best befits the mixing or blending apparatus employed. A preferred way of producing the speckles is by forcing the "we~ted" mix of polishing agent and etnyl cellulose (with dye or pigment; if used) through a screen having uniform openings, which usually will ~ 13 -!~ f be in the range of about 150 to 2,000 microns (about in the No. 10 to lO0 sieve range, U.S. Sieve Series~ and the "extruded"
agglomerates are then dried, usually either in air or in an oven. Instead of screens other means, such as pressure extruders, may be employed for extruding or otherwise pelletiz-ing the mix, after which the particles resulting are dried.
The particles are then classified into desired size ranges, normally in the No's. lO to 80 range, preferably No's. 40 to `-80 and more preferably No's. 30 to 60 (U.S. Sieve Series).
0~ course, if the wet mass is formed in a Dravo pan the forced screening or other extruding may be omitted. Generally, when the particle sizes are larger than 2,000 microns ~No.
10 sieve~ they will be less satisfactory for in~roduction into the oral cavity of a user ard when less than about 177 microns in diameter (No. 80 sieve) they will not be as readily apparent and hence, will not be of as attractive an appearance.
Instead of employing the wet granulation process a dry or slugging ~rocess may be utilized, wherein the components of the speckles may be pressed to large tablet size and such tablet may then be broken up, with particles thereof in the desired size range being separated from the others. In such ~ableting process it may be desirable to employ a water insoluble lubricant, such as talc, magnesium stearate, calcium stearate or stearic acid, which also helps to facilitate agglomeration. Similarly, such materials and other water insoluble adjuvants may be present when wet granulation methods axe used. The speckles made are prefer-ably dry, containing no moisture, but moisture contents of up to 10~, e.g., 1 to 5%, may be present without causing any serious adverse effects on the properties of the speckles.
The proportions in the speckles of water insoluble powdered functional material, such as dental polishing agent, and ethyl cellulose, will be such that the ethyl cellulose will be the minor component of the speckles and the powdered functional material will be the major component thereof ~although allowance should be made for the presence of other materials toot such as.colors and adjuvants).
Generally, the dental polishing agent or functional material is from 75 or 80 to 98~ of the speckles, preferably 85 to 97%
thereof, the ethyl cellulose will be 2 to 23% of the speckles, preferably 3 to lS~ thereof and the colorant will be 0 to 5~
of the speckles, such as about 0.05 to 1% thereof, all on a dry basis, ~ree of water and ethanol or other solvent.
The dentifrice in which the speckles are distributed may be any suitable such product, because in the present invention it acts primarily as the medium for the speckles, maintaining them independent, individual and separate, while performing its normal dentifrice functions. Opaque dentifrices are useful media for the present speckles but 2S it is highly preferred that the dentifrice be transparent or translucent and normally be of a type characterized as a gel. Dentifrices normally comprise water, humectant, gelling agent, dental detergent and a dental polishing agent, usually with flavoring and~or coloring too. Among various functional adjuvants are fluorides, stabilizers, anti-caries agents and antibacterial compounds.
The water employed will preferably be deionized water, although city waters, both soft and hard, may also be utilize~. The gelling ~gent is normally a water soluble natural or synthetic gum or gum-like material, among which are carrageenan, gum tragacanth, xanthan gum, alginates, alkali metal carboxymethyl cellulose (preferably sodium carboxymethyl cellulose), hydroxymethyl carboxyethyl cellu-lose, polyvinyl pyrrolidone, starch, and hydrophilic colloidal carboxyvinyl polymers, such as those sold under the trademarks 15 Carbopol 934 and 940. Althou~h various polyols may be utilized as humectants those preferred are of 3 to Ç carbon atoms and 3 to 6 hydroxyls per molecule, and those of choice are glycerol and sorbitol. The glycerol is in normal liquid state, generally being about 99% or more pure, and sorbitol, normally being a solid, is frequently utilized as a 70%
aqueous solution thereof (70~ sorbitol, 30~ water). The three mentioned components may be considered as he main constituents of the dentifrice vehicle, in wnich flavor and detergent may also be incorporated. Such detergent may include a soap but normally will be a non-soap synthetic organic surface active agent having detersive properties.
Preferably such detergent will be of the anionic type, although nonionic detergents are also useful, ampholytic detergents can be employed, and cationic detergents can be acceptable under some circumstances.
The preferred anionic detergents are especially useful because they combine excellent cleaning action and foaming properties. Normally, such compounds include hydro-philically and lipophilically balanced moieties, with the lipophilic moiety usually being a higher fatty alkyl or acyl of 10 to 18 carbon atoms, preferably 12 to 16 carbon atoms, and the hydrophile being alkali metal, e.g., sodium,potas-sium,or ammonium or lower alkanolammonium. Suitable such anionic detergents are: the water soluble salts (normally alkali metal and preferably sodium or potassium) of higher fatty acid monoglyceride sulfates, such as the sodium salt of the monosulfated monoglyceride of hydrogenated coconut oil fatty acids; higher alkyl sulfates, such as sodium lauryl sulfate; alkylaryl sulfonates, such as sodium linear dodecyl benzene sulfonate; higher alkyl sulfoacetates;
higher fatty acid ester 1,2-dihydroxypropane sulfonates; the sodium salts of sulfated polyethoxylated alcohols; and the substantially saturated higher aliphatic acylamides of lower aliphatic aminocarboxylic acid compounds, such as N-lauroyl sarcosine, and the sodium, potassium and ethanolamine salts of N-lauroyl-, N-myristoyl-, and N-palmitoyl sarcosine, all of which sarcosine compounds are preferably substantially free from soap or similar higher fatty acid material.
Among the nonionic detergents, ethoxylated sorbitan mono-stearate, with approximately 20 mols of ethylene oxide per mol; condPnsates of ethylene oxide with propylene oxide and *

propylene g1ycol (Pluronics); polyethoxylated higher fatty alcohols, such as the Neodols (23-6.5 and 45-11, for example);
and condensation products of alpha-olefin oxides containing 10 to 20 carbon atoms, polyhydric alcohols containing 2 to 10 carbon atoms and 2 to 6 hydroxyl gxoups, and either ethylene oxide or heteric mixtures of ethylene oxide and propylene oxide, are useful. Quaternized imidazoyl derivatives, such as Miranol C2M, and other Miranols represent useful amphoteric detergents and the quaternary ammonium halides~
such as dimethyldicetyl ammonium bromide, represent cationic 15 detergents.
The various polishing agents, which are dispersed in the dentifrice vehicle (or vehicle plus detergent and any other adjuvants) are those previously described for conversion to speckle form. Also useful in such group of materials are synthetic finely divided silicas, such as those sold under the trademarks Ca~O-Sil M-5, Syloid 244, Syloid 266, Aerosil D-200, Zeosyl 200 and Zeothix 265, which are normally utilized for only a small percentage of the polishing agent, normally being no more than 1 to 9% by weight of the total dentifrice, and which are useul for thickening or gelling ~he vehicle and improving the clarity of the dentifrice.

*Tr~de Mark !~

The den~ifrices of this invention will normally contain suitable flavoring and/or sweetening materials, Examples of fla~ors include the flavoring oils, such as those of spearmint, peppermint~ wintergreen, sassafxas, S clove, sage, eucalyptus, cinnamon, lemon and orange, and the sweetening agents include sucrose, lactose, maltose and saccharin. Desirably for fluoride dentifrices there wiil also be present sodium fluoride, stannous fluoride, potas~
si~n fluoridel potassium stannous fluoride, sodium hexafluoro-stannate, stannous chlorofluoride and/or sodium monofluoro-phosphate.
The flavoring materials include various well known essential oils, mainly terpenes; esters; alcohols, aldehydes, ketones,and other aromatic substances, many of which emit lS aromatic odors and fragrances. Because flavor is a simultaneolls physiological and psychological response obtained from the presence of a substance in the mouth and depends on the senses of taste, smell and feel, with smell often being of primary importance, it is not surprising that aromatic materials are important components of flavors. In the present instances advantage is taken of this fact and of the chemical natures of such materials which, as was previously indicated in the discussion of solubilitie~ of ethyl cellulose, permit the ethyl cellulose binder in the present speckles to be slowly solubilized by the solubilizing substances in the flavoring material, causing softening of the speckles but not causing their disintegration. For example the ~ '1 terpenes, which are hydrocarbons and which constitute an important class of perfumery or flavor materialsO are good solvents for the ethyl cellulose of this invention, as are many other flavoring materials, such as those previously named ~as flavoring oils) above, and others well known to the perfumery and flavoring arts. By utilizing the flavoring essences in the dentifrice composition to soften the ethyl cellulose speckles and thereby make them impalpable, which is an aim of this invention, it is unnecessary to add another - ~ponent to the dentifrice or the speckles for this purpose.
Also, because of the relatively small proportion of flavoring material normally present in a dentifrice, with the proportion of the lipophilic part of the flavor often beinglower, a desirable slow softening of the speckle particles-can result, usually due to a relatively low mass transfer rate for the "solvent" material, which transfer rate is especially slowed due to the gelatinous nature of the dentifrice. Thus, even-if some flavoring material at ~he interface with the speckle started to soften the ethyl cellulose thereof while the denti-frice was being blended,the flavor solution of ethyl cellulosewould soon become saturated and this would inhibit further quick dissolving of the ethyl cellulose. Still with the passage of the normal time a dentifrice spends in s~orage before sale and use, which time will often be at least about 2 weeks and sometlmes more (with certain dentifrice formulas it i5 deslrable to allow them to a~e to improve flavor and product uniformity), the speckles becom~ impalp-able, yet remain distinct~

-- ~0 -~gl~3 Although it is considered that the flavoring materials, particularly the lipophiles, which exert substantial solvent action on ethyl cellulose, are the most important slowly solubi-lizing components of the present dentifrice, the surface active agent component, which includes a lipophilic moiety~ may also have an appreciable solubilizing effect and by means of its wetting action, may promote mass transfer in a dentifrie tube ahd thereby increase the solubility rate of the ethyl cellulose.
lt is also possible that combinations of other constituents of the dentifrice, including some of the sweetening agents and vehicle components, will further assist in solubilization of the ethyl cellulose to the extent desired, while not promoting premature softening of the speckle~.
Colorants, such as those previously mentioned with respect to the speckles, may be employed, normally in lesser proportion, so as to provide a base which contrasts with the speckles. Various other adjuvant materials may be present in the dentifrice, including preser~ativesr silicones, chlorophyll compounds and ammoniated materials. Normally, when a gel dentifrice is made which is intended to be transparent or translucent, the polishing agent chosen will be one having a~ index of refraction closely matching that of the rest of the dentifrice medium. Of course, in such clear gel formulations the amount present of insoluble materials which would cloud the gel will normally be minimiæed.
When the pH of the dentifrice is adjusted, and ~he pH is desirably within the range of 3 to 10, more desirably from 3.5 to 5 when stannous ions are present and 4.5 to 7 in the ~ 21 --q~

absence of such ions, organic acids, such as citric, malonic, and fumaric acids, may be employed.
In the dentifrice of this invention a dental polish-ing agent is uniformly distributed throughout the vehicle of 5 water, humectant and gelling agent, with a dental detergent and the desired proportion of fla~or alxeady in it. Then the speckles, which also preferably contain a polishing agent (and often of a different type from that in the body of the de~tifrice), are uniformly distributed throughout the dentifrice, usually comprising 0.1 tc 10~ of the dentifrice, preferably 0.5 to 5~ thereof, more preferably 1 to 3% thereof and most preferably 1.5 to 2.5% thereof. ~The dental base will usually comprise: about 5 to 30% water, preferably lQ to 25% and more pxeferably 10 to 20~; about 20 to 70% of humectant, preferably polyol humec~ant, more preferably 45 to Ç5% thereof and mos~
preferably 50 to 60~ thereof; and about 0.1 tc 5% of gelling agent, preferably 0.1 to 1% and more preferably 0~2 to 0.5%
thereof. The humectant is preferably a mixture of glycerol and sorbitol wherein the glycerol content is 5 to 40% of the dental base, preferably 20 to 30%, and the sorbitol content is 5 to S0~, preferably 25 to 35%. The preferred gelling agent is sodium carboxymethyl cellulose, and a preferred proportion thereof utilized is about 0.3 to 0.4%~ The dental detergent content will normally be from 0.5 to 5%, preferably 0O5 to 3~, and a preferred such detergent is sodium lauryl sulfate. The polishing agent in the dentifrice base, exclusive of that in the speckles, is normally 10 to 40O~ preferably 15 to 30 - 22 ~

and most preferably 20 to 25%t including Syloid 244 type silicas, which are also employed for thickening. Various other materials, including flavors ~usually 0.5 to 2~), color, pr~servatives, sweeteners,and tooth hardeners (fluorides) will normally total no more than 10~ of the dentifrice, preferably being from 2 to 7% thereof. Utilizing the propor-tions of the various constituents within the ranges given, with respect to the speckles and the medium in which they are distributed, results in an attractive product which is stable during storage and in which the speckles are uniformly and attractively distributed.
To prepare the speckled dentifrice, after first producing the speckles, is comparatively simple but an impor-tant consideration is ~hat minimaL mechanical agitation should be employed 50 as to prevent or delay any disintegra-tion, softening and solubilization of the speckle~ in the denti~riceO It is considered that lipophilic materials and solvents present, such as those in flavoring oils, will 510wly solubilize ethyl cellulose, but not to an objectionable extent in the absence of vigorous agitation in proessing.
If the dentifrice is at an elevated temperature during such mixing, possibly due to manufacturing limitations in process-ing,it is even more important to minimize agitation. However, with the ethyl cellulose binder of this invention employed in the manufacture of the speckles,manufacturing restrictions may be less stringent,but care should still be exercised~

- ~3 -t3 Suitable equipments for distributing the speckles throughout the dentifrice include Banbury* or dough mixers operated at low speeds but other gently operated blenders may also be used providing that mixing is controlled so as to prevent substantial breakdowns, dissolvings or disintegrations of the speckles. Normally mixing blade speed will be on the order of one to five r.p.m. and mixing will last from one to five minutes. After completion of the blending the dentifrice is deaerated and filled into containers, such as resilient or collapsible tubes. If vacuum is employed during mixing operations deaeration may be omitted.
The manufacturing method described in the preceding paragraph is a standard method for making speckled dentifrices, with the exception of the processing of the present speckles in such dentifrice and the requirement for the presence of slowly solubilizing lipophilic material in the base of the dentifrice, together with the speckles bound together by ethyl cellulose. However, recently new methods have been invented for facilitating blendlng of the speckles into the dental gel body without excessive agitation. Such methods and the apparatuses by means of which they are practiced are the inventions of Edward J. Gibbons and John F. Smith, respectively, and are the subjects of Canadian patent applications Serial Nos. 412,492 and 412~457 respectively.
In such methods the dentifrice is fed through an orifice to form a falling, curving ribbon onto which speckles are uniformly dropped at a constant rate, after the speckled gel dentifrice is transported *Trade Mark ~t - 24 -to filling equipment by mcans of a positive displacement variable walled pump, such as one of the Moyno type.
Although normal collapsible aluminum tubes with capped dispensing opening~ r through which the dentifrice may s be squeezed, are most commonly employed, it is often pre~erred to make the packaged dentifrice by utilizing a deformable tube of clear or translucent synthetic organic po1ymeri~
material, such as polyvinyl chloride, polyethylene, poly-vinylidine chloride or similar material through which the attractive appearing speckled dentifrice may be viewed.
In FIG. 1 there is shown a plan view of the clear walled container 11, which is made of transparent polymeric material (PVC)~ including body 13, ~houlder 15, threaded neck 17 and cap 19, wit~ the cap having been removed from lS the tube~ As illustratedO some of the dentifrice 21 is being dispensed rom tube 11 through neck 17 onto the bristles of a toothbrush 12. In the dentifrice there are clearly shown invented speckles 23 in the continuous denti-frice medium 25. It i5 noted that such speckles are initially impalpable although they are easily visible.
During toothbrushing they break down into smaller entities of essentially the same sizes as the componen~ polishing agent. Of course, the speckle polishing ~gent acts together with that in the dental gel to help clean and polish the teeth.
The following examples illustrate but do no~ limit the in~ention. Throughout the specification, including the working e~amples, and in khe claims, all parts are by weight, unless otherwise indicatecl~

-- 2r, EXAMPLE_1 (Actual~
Five parts of ethyl cellulose(10 centipoises3, of the physical characteristics described previously in the specification and in powder Eorm, are dissolved in five parts of ethanol (95~) and are mixed in a Hobart mixer with 95 parts of calcined alumina ~l~icrogrit WCA 9F) of particle sizes in the range of Q.5 to 10 microns and an average particle size in the range of 3 to 5 microns. Mixing is continued for about four minutes until the blend is uniform, after which the mix is forced through a No. 10 (U.S. Sieve Series) screen and the "extruded" material is oven dried for one hour at 65C. The dried agglomerates are then screened through a No. 30 screen and the cut that rests on a No. 60 screen, the dried speckles comprising the calcined alumina and ethyl cellulose, is collected. The speckles produced are of angular shapes, with the ratios of maximum length to maximum width usually being within the 1 to 2 range and most of the particles being of such a ratio within the 1.1 to 1.5 range. The angularity of the particles may be a factor in making the dentifrices so attractive in appearance, at least for some consumers.
A transparen~ ~cr translucent) dentifrice base (all components except speckles), is made of the following formula:

39;3 Component ,Parts by Weight Glycerol (99.3% pure) ~5.00 Sodium carboxymethyl cellulose 0.35 Sorbitol (70~ aqueous solution~ 36.04 Polyethylene glycol 600 3.00 Water 3-00 Sodium saccharin 0.25 Sodium benzoate 0.50 Blue dye ~FD&C Blue No. 1, 1% aqueous0.20 lQ solution) Sodium mono~luorophosphate ~1 to 60 mîcrons~ ~.76 Silicon dioxide (Zeo 49) 18.00 Synthetic silica ~Syloid 244) 5.50 Sodium lauryl sulfate 1.20 15 Flavor(spearmint, peppermint, wintergreen, 1.20 clove, etc., as desired~

Five parts of the described speckles, with particle sizes -30 ~60 (U.S. Sieve Series), are gently blended in a slow moving mixer (about two r~p.m.~ with 95 parts of the described dentifrice base, after which the mix is deaerated and automatically filled into capped collapsible tubes which are then sealed. During the mixing, dearation and tube filling steps the speckles, which are substantially evenly distributed through the dentifrice, remain discrete, indepen-dent and undissolved in the dentifrice base so that whenthe tube is opened, after filling~and preferably, after ~7 -!~ ~
1~9~C~

storage for about a month, and the dentifrlce is squeezed through the discharge opening thereof, the speckles appear to have retained their initi~l integrity, contrasting with the bluish gel. When the product is evaluated immediately after filling, and without being stored, the speckles are palpable but, upon storage before use, for periods from two weeks to a year or more,are sufficiently softened, as by solubilization of the ethyl cellulose by the flavoring oil, sometimes with the aid of the dental detergent or other surface active agent that may be present, and other components, so as to appear distinct and not "smeared", but yet to be-satisfactorily impalpable. During toothbrushing with the dentifrice the speckle particles are readily reduced in size, are not irritating to the glngiva,and are readily dischargeable from the oral cavity on completion of brushing.
Although the presence of the anionic detergent in the dental base may be of assistance, it is thought that the controlling component of such base is the 1.2% of flavoring agent present. A proportion of such an agent or a mixture thereof from 0.5 to 2%, preferably 0.8 to 1.5%, of which at least half is normally active as a solvent for ethyl cellulose, is desirable for best speckle dispersions, and the flavor will usually include over 50~ and often over 80% of solubiliz-ing hydrocarbons, esters, alcohols and aldehydes.

- 2~ -The manufacturing method described Eor the denti-frice, in which the speckles are dispersed in the body of the gel, is one in which the mixing operation should be watched to make sure that the speckles are not disintegrating and, at any sign of this happening mixing should be halted and, providing that the dentifrice appearance is not signifi-cantly adversely affected, usually by being made unaccept-ably cloudy, filling of the tubes should be undertaken promptly. Instead of employing the described mixing method it will often be preferable to utiliæe the Gibbons or Smith techniques, previously referred to herein, wherein a regulated even "fan" of speckles is deposited by means of gravity on a continuously falling extruded ribbon of gel, to which the speckles adhere, so as to obtain uniformity of distribution of the speckles in the dentifrice.
When the speckled dentifrice of this invention is packed in a collapsible aluminum tube the speckles in the dentifrice are not visible until discharge from the tube but at that time they are maintained discrete in the toothpaste extruded and impart to it an attractive and distinctive appearance. However, when instead of the normal aluminum tubes one employs resilient transparent tubes, such as tubes ~' ~- It' g3 of polyvinyl chloride or other suitable polymer, the speckles can be seen through the tubes and through the trans-parent gel dentifrice base, and their movements, on dis-charge, can be observed. This provides an additional aesthetic benefit and helps ~o make too~hbrushing more interesting, at least for children. Additionally, the functional speckles act as a reminder to the person using the dentifrice of the presence of polishing agent or other functional constituent in the dentifrice and thereby help to remind him of the importance of brushing so that such component may be efective.
The formula gi~en above is one for a gel dentifrice in which the normal 41.04% of sorbitol solution had been reduced to 35.04% to allow for the introduction of the 5%
15 of speckles. The effect of this change in the formulation is to maintain the perc~ntages of the other dentifrice components the same as in an unspeckled product, with the exception of the major component, the sorbitol solution.
It is considered that with other variations in the contents of speckles in such dentrifrices such procedure for modify-ing the formula may continue to be followed. However, it is also feasible to start with the initial gel formulation, e.g., containing 41.04% of sorbitol solution,and reduce each of the components pro~ortionately to allow for the introduction of the desired percentage of speckles.

!~

~ S,~'3 In a ~ariation of the above described experiment 1~ of ultra~arine ~lue pigment may be employecl in place of 1% of ~he Microgrit, so that the speckles are of a definite b ue coloration. In place of the described proportion of u~tramarine blue one may use 0.5 to 2.0% of that pigment or mixtures of pigment(s) and polishing agent~s) of propor-tions from 1:10 to 10.1 may ~e used. ~lternat~vely, about 0.1 to 1% of any suitable water insoluble ~or oil solublel dye may be employed. In such cases the dye solution may be omitted from the dentifrice base formula or may be present, providing enough contrast between the speckles and the base is obtainable.

Of course, the variou~ components of the formula may be replaced by others, such as those previously described, and useful products will also be obtained. For example, the different mentloned pigmen~s and dyes may be employed, the sodium lauryl sulfate may be replaced by sodium ethoxylated higher fatty alcohol sulfate or sodium hydrogenated coconut oil fatty acids monoglyceride monosulfate, and the polishing agents may be replaced ~y dicalcium phosphate dihydrate and/or dicalcium phosphate (anhydrous) or mixtures thereof.

Proportions of the various components may be modified ilO~, ~20%, and +30%, so long as they are maintained withi~ the ranges previously recited, and the results are satis~actory products of similar properties, although those of the propor-tions of this e~ample are preferred.

~ 3~J~

EX~MPL~ 2 ~Actual) 75 Parts of anhydrous dicalcîum phosphate ~nd 15 parts of dicalcium phosphate ~ihydrate, both having average ultimate particle sizes of about 4 microns, are mi~ed with 10 parts of ethyl cellulose and 10 parts of ethyl alcohol in a Hobart mixer. Alternatively, and preferably, ethanol and ethyl cellulose may be premixed and then may be cldmixed with a previously made blend of the dicalcium phosphates. '~he mass formed is forced through a screen having uniform openings 10 of 25000 microns and is then oven dried for one hour at 65C.
The dried agglomerates are then screened through a screen having uniform openin~s of 420 microns and those agglomerates which do not pass through a screen having uniform openings of 177 microns are collected. Ne~t, the agglomerated functional particles resulting are mi~ed with a dentifrice base of the formula given in Example 1, with the eY.ception -that the polishing agent in such base is replac~d by sodium aluminosillcate, such as that mar~eted under the trade name Zeolite*4A, and the percentage of speckles in thc final product is 2ro (with the sorbitol solution present being increased by 3'~
In variations of this formula thcre may be substi-tuted for the polishing agent O r the spec~lcs, hydrated alumina having an average particle sizc lcss than about 10 microns, calcium carbona~c havln~ pa-ticlcs substantially all of which are lcss tt-~an about 7.4 microrlC; in diametcr, or insolublc sodillm meta~hosptl3te havin~ an avcrac3c particlc size of * 'Ir~de Mark about S microns (all such sizes being ultimate particle sizes).
The dentifrices of this example are speckled, transparent or translucent products and are aesthetically pleasing in appearance. The visible particles of the agylo-merated polishing agents (for which other functional insoluble materials may k~e substituted in whole or in part) are substan-tially uniformly dispersed in the dentifrice base as visibly separate entities and are not substantially impalpable upon use, after ~hree months' storase.

EXAMPLE 3 (Actual) The ~unctional polishing agent constituent of Example 2 is replaced by a mixture of ten parts of anhydrous dicalcium phosphate and 90 parts of calcium carbonate, with the same total proportion of polishing agent being employed;
otherwise the same procedure is followed. The produc~s resulting are similarly satisfactory in functional affects and are aesthetically pleasing in appearance. Similar results are obtained when the other disclosed polishiny agents are substituted for the present mixture in the speckles.

EX~PLE 4 (Theory) Instead of dissolv1ng the ethyl cellulose in the ~thanol or other suitable solvent, agglomerates are made by bl~nding the polishing agent and ethyl cellulose, sometimes with a reduced proportion of ethanol present, to form a powder blend. Such blerld is compressed in a rotary tablet !~ ~

press to form slugs, about 6 mm. thick and 25 mm. in dia-m~ter. Th~ slugs are then s~anulated in an os~illating granl1lator to form smaller particles, preferably such as will pass through a NoO 3Q screen and rest on a No. 60 or S No. 80 screen. This technigue for making the speckles may also be applied to any of the speckle formulas given in the preceding examples. Although the binding effect of the ethyl cellulose might not be as great, the products oE this example are also satisfactory for incorporation in dentifrices to con~ribute their aes~hetic advantages and functional effects. If the binding effect of the ethyl cellulose in the foregoing formulas i5 not sufficient/ the proportion thereof present may be increased, sometimes up to 100 or 200%, but such increases involve additional expenses and therefore the 'iwet"
method~ in which solutions of ethyl cellulose in ethanol or other suitable solvents are employed, is often preferred.
With respect to all the preceding examples, the manufacturer will take care to adjust the formulation ~o obtain the desired type of speckle, of the desired solubility or "resistance to solubility" in the dentifrice. This may be accomplished by choosing the parti~ular ethyl cellulose in accordance with the amount of solubilizing flavoring agent (and detergent and any other lipophile) present. For example, the medium ethyl cellulose previously mentioned may be employed when larger propcrtions of flavoring agent are present, with the standard ethyl cellulose being us~d for -~ 3~ -!~ ~
.3~3 lesser amounts of the flavoriny agent (and other lipophiles).
Mixtures of the t~o and miY~tures with ethyl cellulosesof other characteristics may be made to obtain intermediate properties. Also~ the nature of the lipophilic portion of the dentifrice body may be adjusted, where possible, so as to increase or decrease solubili~ing effects so that the suspended speckles behave in the desired manner~ resisting early disintegration but becoming impalpable thereaf-ter.
The invention has been described with respect to lQ various illustrations and embodiments thereof but is not to be limited to these because it is evident that one of skill in the art with the present specification before him would be able to utilize substitutes and equivalents without depart-ing from the inventionO

Claims

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

1. Functional agglomerated speckles, for incorporation in dentifrices, which comprise agglomerates of a water insoluble powdered functional material and water insoluble ethanol soluble ethyl cellulose.

2. Speckles according to claim 1 wherein the water insoluble powdered functional material is a dental polishing agent which constitutes a major proportion of the speckles, and wherein the ethyl cellulose is a minor propor-tion of the speckles.

3. Speckles according to claim 2 wherein the water insoluble dental polishing agent is selected from the group consisting of dicalcium phosphate, tricalcium phosphate, insoluble sodium metaphosphate, alumina, silica, magnesium carbonate, calcium carbonate, calcium pyrophosphate, bentonite and zirconium silicate, and mixtures thereof, of particle sizes in the range of 0.5 to 20 microns, and the speckles are of sizes to pass through a No. 10 U.S. Sieve Series sieve and be retained on a No. 80 sieve.

4. Speckles according to claim 3 wherein the dental polishing agent comprises 75 to 98% of the speckles, the ethyl cellulose comprises 2 to 20% thereof and coloring agent, when present, comprises up to 5% thereof.

5. Speckles according to claim 4 which comprise 85 to 97% of the dental polishing agent, 3 to 15% of ethyl cellulose, and 0.1 to 1% of coloring agent and which are of such particle sizes that they pass through a No. 30 U.S.
Sieve Series sieve and are retained by a No. 80 sieve.

6. A method of making speckles for incorporating in dentifrices which comprises moistening a water insoluble functional powdered material, for incorporation in a dentifrice, with a solution of water insoluble ethyl cellulose in a volatile solvent, compacting the moistened powder and converting it to particulate form, drying the particles and collecting those that pass through a No. 10 U.S. Sieve Series sieve and are retained on a No. 80 sieve.

7. A method according to claim 6 wherein the water insoluble functional powdered material is a dental polishing agent selected from the group consisting of di-calcium phosphate, tricalcium phosphate, insoluble sodium metaphosphate, alumina, silica, magnesium carbonate, calcium carbonate, calcium pyrophosphate, bentonite and zirconium silicate, and mixtures thereof and is of particle sizes in the range of 0.5 to 20 microns, the volatile solvent is ethanol, compacting and converting of the moistened powder to particulate form is effected by forcing it through a screen or similar sizing device and the dried particles collected are those that pass through a No. 30 U.S. Sieve Series sieve and are retained on a No. 80 sieve.

8. A method according to claim 7 wherein an alcohol soluble, water insoluble dye is present in the ethyl cellulose solution, and the proportions of dental polishing agent, ethyl cellulose and dye in the moistened polishing agent before conversion thereof to desired particulate speckle form are, on a solids basis, 75 to 98% of dental polishing agent, 2 to 20% of ethyl cellulose and up to 5% of dye.

9. A method according to claim 8 wherein the moistened powder is compacted and converted to particulate form by passing through a screen of a size within the No. 10 to 60 U.S. Sieve Series range, after which the material resulting is dried at an elevated temperature and particles thereof in the No. 30 to 60 range are collected.

10. A dentifrice comprising water, humectant, gelling agent, detergent and flavor, all of which are constituents of a gelled vehicle of the dentifrice, and a dental polishing agent, uniformly distributed throughout the vehicle, and visible functional speckles distributed through the dentifrice which are agglomerates of a water insoluble powdered functional material and water insoluble, ethanol soluble ethyl cellulose binder.

11. A dentifrice according to claim 10 which is in the form of a transparent or translucent gel, with the speckles visible therein and in which the speckles comprise from 0.1 to 10% or the dentifrice.

12. A dentifrice according to claim 11 wherein the speckles are comprised of a major proportion of dental polishing agent and a minor proportion of water insoluble, ethanol soluble ethyl cellulose.

13. A dentifrice according to claim 12 wherein the speckles are 0.5 to 5% of the dentifrice and are comprised 75 to 98% of dental polishing agent, 2 to 20% of ethyl cellulose and 0 to 5% of coloring agent.

14. A dentifrice according to claim 13 which comprises 5 to 40% of glycerol, 5 to 50% of sorbitol, 5 to 30% of water, 0.1 to 5% of gelling agent, 0.5 to 5% of dental detergent, 0.5 to 2% of flavor and 10 to 40% of water insoluble dental polishing agent in a continuous phase, and the speckles comprise 75 to 98% of a dental polishing agent which is an oxide or a salt selected from the group consisting of dicalcium phosphate, tricalcium phosphate, insoluble sodium metaphosphate, alumina, silica, magnesium carbonate, calcium carbonate, calcium pyrophosphate, bentonite and zirconium silicate, and mixtures thereof, 2 to 20% of ethyl cellulose and 0.1 to 1% of water insoluble coloring agent, and the proportion of speckles in the dentifrice is 1 to 3

15. A dentifrice according to claim 14 which comprises 20 to 30% of glycerol, 25 to 35% of sorbitol, 0.1 to 1% of gelling agent, 1 to 5% of polyethylene glycol, 0.5 to 3% of sodium lauryl sulfate dental detergent 0.8 to 1.5%
of flavoring agent,, 15 to 30% of a dental polishing agent selected from the group consisting of silicon dioxide and sodium aluminosilicate, and mixtures thereof, and 10 to 25%
of water in a continuous phase, in which dentifrice the speckles comprise 85 to 97% of a dental polishing agent selected from the group consisting of anhydrous dicalcium phosphate, dicalcium phosphate dihydrate, zirconium silicate and calcined alumina, 3 to 15% of ethyl cellulose and 0.1 to 1% of water insoluble dye, and in which the proportion of speckles in the dentifrice is from 1.5 to 2.5%.

16. A process for preparing a dentifrice comprising water, humectant, gelling agent, detergent and flavor, all of which are constituents of a dental vehicle of the dentifrice, and a dental polishing agent, uniformly distributed throughout the vehicle, and visible functional speckles distributed through the dentifrice which are agglomerates of a water insoluble powdered functional material and water insoluble, ethanol soluble ethyl cellulose binder, which comprises forming said speckles by moistening the water insoluble powdered functional material with a solution of water insoluble ethyl cellulose in a solvent, compacting the moistened powder and converting it to particulate form, drying the particles and collecting those that pass through a No. 10 U.S. Sieve Series sieve and are retained on a No. 80 sieve, dispersing the speckles in the continuous phase of the dentifrice and deaerating the dentifrice subsequently or concurrently.

17. A packaged dentifrice comprising a dispensing container containing a dentifrice comprising water, humectant, gelling agent, detergent and flavor, all of which are consti-tuents of a dental vehicle of the dentifrice, and a dental polishing agent, uniformly distributed throughout the vehicle, and visible functional speckles distributed through the dentifrice, which are agglomerates of a water insoluble powdered functional material and water insoluble, ethanol soluble ethyl cellulose binder.

18. A packaged dentifrice according to claim 17 wherein the dispensing container is a deformable tube of clear or translucent synthetic organic polymeric material, the dentifrice is a clear or translucent gel with opaque impalpable speckles distributed throughout, and such speckles are visible through the dispensing tube.