Manufactoring process of a toothpaste.

PATENT AS AFRICAN AND MALAGASY

INDUSTRIAL PROPERTY

P. 887

yaoundê (Cameroon) International Patent Classification : HAS 61 NO. 03923

23 REQUESTED THE November 1971 to 16 hr 10 min

to FO.A.M.P.I. (PP.V. № 54,417 ) by the company said:

Aogtao Research Company in residing in the United States of America.

PRIORITY : Patent applications deposited in UK by n^I56 575/70, 56 576/70, 56 577/70

the 27 November 1970 on behalf of the applicant.

A method of manufacturing a toothpaste.

The present invention relates to toothpaste. More particularly, it relates to dentifrice appearance substantially clear and containing visible gas bubbles.

Although most dentifrices sold worldwide is opaque, usually because of having polishing components insoluble and opaque, it has been observed that some consumers prefer undoubtedly toothpastes of clear appearance, transparent or translucent. There are many years, when some liquid dentifrices clear have been sold on the market, they had the disadvantage of not have agent suitable polishing and the teeth brushed with dentifrice such accumulated deposits of scale, films and spots, despite the presence of excellent detergents in the toothpaste. Recently, this disadvantage has been overcome by introducing polishing agents that can be incorporated into toothpastes and allow the toothpaste presenting a clear appearance, even in the presence of a significant proportion of polishing agent. These polishing agents are intrinsically transparent and have refractive indices in the same range as the refractive indices of the vehicle and the rest of the dentifrice composition.

Accordingly, the light path is unobstructed through the particle polishing agent and the gel toothpaste appears clear to a viewer.

It has been found that clear appearance of dentifrices despite being attractive to most people, cause a certain consumers adverse reaction, with respect to properties of the toothpaste. For some, the product does not provide a uniform and transparent printing a effective cleaning agent. Some of these consumers as well as other prefer a clear product which is intersected by intervals of different materials. This gives the product more than "character", will be easier to distinguish it from other dentifrices and making it even more attractive to the eye. Most of materials that can be suspended in a dentifrice is palpable, insoluble and cakey and may not be acceptable by the consomamateur. On the other hand, the dispersions of the dentifrice portions of different colors or of gas in the main body of the toothpaste are not unpleasant. Although the colors dispersed solids or gels can be suitable, the gas retain a distinct appearance in the toothpaste, and this aspect lasts indefinitely in the products of the present invention. They also have other advantages, since it is possible to adjust the density of the product and solid substances per unit length extradited by incorporating in the dentifrice formula different proportions of gas.

During production dentifrices and other thick products in which solid dispersed in a liquid medium, air can sometimes be dissolved in the medium or trapped in the product. This air is undesirable in dentifrices, particularly in toothpaste clear, since it becomes apparent to the consumer and may render the product non-attractive. This is because the air is often unevenly distributed and has a particle size which makes the product troubled, or is in irregular shapes that are less attractive than perfect spheres. Accordingly, these gas dispersed can be removed intentionally dental formulations. However, at present, by the method of the present invention, produced bubbles uniformly distributed in a desired shape and size and their presence enhances the appearance of clear gels.

According to the present invention, a method for manufacturing a toothpaste containing gas bubbles comprises manufacturing a gel or toothpaste free or substantially free of gas, viscous, which can be extruded, comprising a polishing agent, a gelling agent and a vehicle, and mixing with the dentifrice gas bubbles having a size of between 0.1 and 4 mm diameter of a sphere equivalent whereby there is 2 to 100 of these bubbles per cubic centimeter of toothpaste, the dentifrice having a viscosity sufficient to maintain the slurry bubble. Preferred products produced are toothpastes as gels containing clear appearance, to the distributed state, visible gas bubbles with diameters of 4 mm I to and distributed throughout the dentifrice so that there is 2 to 20 Pa at bubbles^{the R} cubic centimeter of toothpaste, which toothpaste contains a polishing agent, a gelling agent and a vehicle, and has a viscosity sufficient to maintain the slurry bubble.

The clear gels of the present invention contain polishing agents, gelling agents and vehicles, more usually, a detergent or foaming agent.

Other adjuvants are ordinarily present to contribute to the color, flavor, the antibacterial action, preservation, the buffering and other desirable effects, and an insoluble gas, it is to say a gas which does not dissolve in a manner undesirable in the medium of the toothpaste, although a certain amount of the gas can be already dissolved, is present in the dentifrice to create the bubble effect or spheres dispersed.

Polishing agents for toothpastes Why clear appearance of powder materials are usually finely divided water insoluble of particle sizes such that they pass the wire mesh width of 110 microns thick. Preferably, the particles have a diameter less than 100 microns thick or 65, they are substantially spherical or have lengths and CAT corresponding widths, they are transparent and have a refractive index similar to that of the rest of the medium of the dentifrice. Preferably, the particles have a diameter of I to 40 micrometers, and most preferably have a diameter of 2 microns to 20 has; the distribution of particle sizes is normal in the ranges described and in narrower ranges.

Among the most useful polishing agents that satisfy these conditions, include complex aluminosilicates as 1' sodium aluminosilicate and the silica xerogels which are smoldering partially hydrated, e.g. to 20 $. These materials provided by! * of refractive indices between 1.4 and 1.5, preferably between 1.44 and 1.48 and usually between I,^J - i6 and 1.47. The xérognl silica and other silicas colloidal or amorphous silicon hydrides or b-■often have a contact surface of 200 to 1000 the IP/C.:^{the R} t-generally of 200 to 500 m2/gm. These ranges of contact surfaces per unit weight are advantageous for polishing agents of the present invention. Colloidal silicas described are sold by the TX by dividing Attrition Index of Chemical OC, under the designation "Syloid". The xerogels and the hydrogels "Syloid" are identified by numbers and it was found that the "Syloid 65", "Syloid 72" and "Syloid 74" are useful in the practice of the present invention as are related materials sold under the designation "Santocels", e.g. "Santocel 100". Apparent densities of SEA compounds are usually 0.05 to 0.4 g/crn3 about and it is established that they can be easily and uniformly suspended in the gels. Among the other polishing agents excellent for applications of the invention, there may be mentioned metal aluminosilioates synthetic amorphous complex, in particular alkali metal salts such as sodium salts, and the alkaline earth metal salts such as a calcium salt. These materials contain up to 20 % by weight about humidity and up to 10 % weight approximately alkali metal oxide or alkaline earth metal. They are sold under the trademark "ex Degussa", for example "ex Degussa p820". Complex aluminosilicates which appeared to contain silica and alumina bonded, having links ai-O-Si bond, are described by Tamels in "joining technology ' of imprinted surface and such close intimate aluminium-spout and the cracking Catalysts" published in "discussion of imprinted the Faraday Society in", η⁰ 8, page 270 - 279 (95 ΐ θ), in particular on page 273, and in the article of Milliken and his collaborators. item entitled "tea chemicals series computer simulation structure section of the cracking Catalysts", page 279 - 290 of the same publication, in particular page 284 and 285.

One may also use other polishing agents or agents that become clear clear in a particular environment. The principle requirement is that the refractive index corresponds to that of the other constituents and that the materials are of suitable hardness and a particle size similar to those disclosed herein to provide good polishing action without scratches.

Although the methods of the present invention are particularly suited for making clear gels of bubble, can also be used in dentifrices opaque bubble uniform for adjusting the density and, in this case, the various polishing agents used in these preparations may be present. As examples, include various insoluble phosphate, preferably quantifiable, e.g. dicalcium phosphate, tricalcium phosphate, insoluble sodium metaphosphate, magnesium phosphate, calcium pyrophosphate, crystalline silica, colloidal silica, 1 'aluminum hydroxide, - I' alumina trihydrate, magnesium carbonate, calcium carbonate, bentonite, talc, calcium silicate, calcium aluminate, aluminum oxide and aluminum silicate. The various polishing agents are described in textbooks such as "Ingredients" conventional: forensic science Technology, of Sagarin, second Edition, 1963, published by Interscience Publishers on, Inc is.

The gelling agents which may be useful for gelling or thickening the toothpaste of the present invention are known in practice and include natural and synthetic gums and like materials, as carboxymethyl eellulose alkali metal, e.g. sodium carboxymethyl eellulose, the hydroxyéthyl-to-earboxyméthyl-to-eellulose, polyvinylpyrrolidone, carrageen, tragacanth, 1 'hydroxypropyl-methylcellulose, methyl-eellulose, starches, the starch glycolates, polyvinyl alcohol, alginates, locust bean gums, the hydrophilic colloidal carboxyvinyl polymers such as those sold under the trademarks "carbomer 934" and Carbopol 940 ", diatomaceous earth, bentonite and other natural clays, proteinaceous materials, either animal, or plant, the mineral clay-synthetic such as clays siliceous sold under the trademarks" MC "and" as Laponite as Laponite SPs " and formula/' SigMgp. jhi_Q human ghY 5 °2 ^ DEGREES^, ^ '"^{The Na} the O 6^{and if; 1} -^bHCI colloidal as aerogels comprising "Syloid 244" and "Syloid 266" and "aerosil R812-d-a-200"; and the pyrogenic silicas sold under the name "Cab-O-Sil biosensor". The gel-forming materials used are capable of forming a gel with the polyalcanols such as glycerol and sorbitol, and with the oaualeanols and the lower. Normally, the gels are formed when there is at least a small amount of water. The liquid or the vehicle portion of the composition may contain water, a lower alkanol and a polyol. Although tmisoe use the propylèneglyeol, it is normally preferable that 3 major components bone vehicle are constituted by " AE pc.lyoln as glycerin, sorbitol and mixtures of glycerol and the sorbitol, in admixture with a little water. These vehicles have refractive indices between 1.44 OD and 1.48 and, accordingly, are well suited for use with the silica xerogels or polishing agents aluminosilicate complex.

Although this is not absolutely necessary, it is usually advantageous that toothpastes contain of. agents are organic surfactants, generally because of their properties as a detergent or foaming agents. The cationic detergents can be used, but typically are replaced by agents anionic surfactants, nonionic surfactants and amphoteric surfactants. Among them, particularly preferred are the anionic surfactants. Anionic detergents or foaming agents lower polyalkoxy groups contain long chain fatty more hydrophilic groups. They are usually in the form of salts, in particular water-soluble salts of metals aûüoaljns or alkaline earth metal. Among the anionic detergents useful, include monosulphates of monoglycerides of higher fatty acids such as the sodium salts of the monosulphate fatty acid monoglycerides of hydrogenated coconut oil, higher alkyl sulfates such as sodium lauryl sulfate, alkyl aryl sulfonate as the upper linear dodecylbenzene sulfonate sodium, the olefin sulfonates such as sodium olefin sulfonates in which the olefinic group has 12 to 21 carbon atoms, alkyl-sulfoacétates upper, esters of higher fatty acids of 1.2 to-Propanesulfonic sulfonates, amides to aliphatic acyl groups' top of amino-acids substantially saturated lower aliphatic such as those having 12 to 16 carbon atoms in the alkyl radicals or fatty acyl, alkyl poly (lower alkoxy) sulfate (10 to 100 alkoxy groups), higher fatty acid soaps, and the like herein, for a question of convenience and presentation, soluble soaps are considered synthetic organic detergents. Examples amides mentionned include n-lauroyl sarcosine and sodium salts, potassium and n-lauroyl-ethanolamine -, or n-myristoyltransferase or n-palmitoyl sarco.sines. In the above-mentioned descriptions, the term "upper" refers to the chain lengths of 12 to 22 carbon atoms, preferably 12 to 18 carbon atoms, more preferably 12 to i6 carbon atoms. The term "lower" denotes 2 to 4 carbon atoms, preferably 2 or 3 carbon atoms, and most preferably 2 carbon atoms. In a more detailed description of anionic detergents useful, include sulfuric reaction products which contain long chain hydrophobic groups and hydrophilic groups. For more detail, see the work "active surface agent", volume of the II (1958) Schwartz, Perry and Berch.

The nonionic detergents include those containing chains of lower alkylene oxide, for example ethylene oxide, propylene oxide, in which there is 10 to 100 moles or more

-'d ' for the TOF oxycfe of aükyJène&ïbrmi. these materials, include block copolymers of ethylene oxide, propylene oxide and propylene glycol sold under the designation "Pluronics", the alkylphenyl-polyéthoxyéthanols sold under the designation "igepals", the mixed copolymers of ethylene oxide and propylene oxide sold under the name "UL", and various other nonionic detergents well known derivatives of fatty alcohols or acids and polyoxyethylene. Ampholytic or amphoteric agents and the cationic detergents include quaternized imidazole derivatives as the "Miranols", for example "lesser inhibition was CMM", and cationic germicides as chloride di-isobutylphénoxyéthoxyéthyldiméthyl benzyl ammonium salts, chloride of benzyl dimethyl stearyl ammonium, and tertiary amines having higher fatty alkyl polyoxyethylene copolymers groups attached to the nitrogen atom. Naturally, with reference to the text mentioned, there are other examples of detergent surfactants suitable foaming and components that may be used in the dentifrice compositions. Are improved by materials surfactans for ' adjusting properties and to obtain favorable effects. In these blends, it is generally desirable to avoid using together the anionic agents and cationic agents.

Various adjuvants may be used in the dentifrice of the present invention. Among them, the most important are the flavoring agents may be which are normally essential oils but they also include various aldehydes, ester, alcohols and the like flavor, known in practice. Examples of essential oils include oils of spearmint, peppermint, of wintergreene, sassafras, clove, sage, eucalyptus, of marjoram, cinnamon, lemon, and orange. Can sometimes incorporate solvents to solubilize the flavoring agents and achieve effective treatment of interest in the practice of the present invention occurred wherein the trapped are iniiilenient removed from the product prior to addition is made adjusted gas bubbles. Certain solvents have fragrance properties and, among them, chloroform is sometimes used because it acts to flavor and "to provide taste" product. Other solvents include ethanol, methylene chloride -, and halogenated hydrocarbons such as chlorinated hydrocarbons and fluorinated, including dichloromethane, the tetrachlorethane, the dichlcrodifiuorométhane, and hydrocarbons comprising cyclobutane. In most cases, the solvents must have boiling points at atmospheric pressure of 80 °c or less, to provide the best effects of gas withdrawal.

A preferable range is between 40 or 50 to 70 °c,

Other adjuvants useful include buffers as tetrasodium pyrophosphate, which also exerts a cleaning effect, the preservatives such as sodium benzoate, le formaldehyde, the - bactericides, fungicides, and therapeutic materials, e.g. the fluorinated compounds that protect the teeth caries. In examples are sodium fluoride, stannous fluoride, potassium fluoride, ammonium fluoride and complex fluorides, in particular sodium monofluorophosphate. The antibacterial agents which are useful include n^I (4-chIorobenzyI) - - the n ^ - (2.4 a-ammonium) - biguanidine, P-chlorophenyl biguanide, the 4 a-chlorobenzhydrylguanylurée, the 1.6 bis - (2 a-éthylhexylbiguanide) hexane diisocyanate, 3rd ' the L, 6 a-b3s - (P ehlorophénylbiguanido) hexane and the 5 amino-I-, 3a (2 a-ethylhexyl) - 5 a-méthylhexahydropyrimi * Dines, and their addition salts with non-toxic acids.

Other adjuvants useful bleaching agents include dyes, pigments, other preservatives, silicones, compounds chlorophylés, àmmoniacés, e.g. urea, the. diammonium phosphate, suspended matters in decorative, for example the nacre finely divided, fillers (soluble salts), lubricants, e.g. mineral oils and the like, and stabilizers compositions. Of course, with most builders, the proportions used of insoluble materials having refractive indices different from that of the rest of the toothpaste must be maintained sufficiently low as not to interfere with or hinder the clarity of the product.

The gas used for forming the bubbles in the toothpaste can be any suitable gas, the principle requirement is that it should not be sufficiently soluble in the dentifrice composition such that the bubbles disappear in the composition by dissolving. This does not want to say that a certain degree of solubility is not acceptable and not in all instances be desirable. For example, if the solubility of the gas is sufficiently small that a proportion of this gas dissolves in the toothpaste, the bubbles can be reduced in size to a desirable value and it may be possible to use the equipment for forming bubbles which need not be adjusted as accurately to permit introduction of microscopic bubbles. Such use of larger bubbles would be acceptable due to their decreasing size after being distributed in the toothpaste. However, normally it is preferred to use gas that are soluble to a degree less than 10 % the dentifrice composition, and those in which the solubility is less than 5 % appear to give the best results. Among the gas that can be used, include nitrogen, argon and air. Among these gas, nitrogen is preferred, but due to its availability and because it provides almost the same results, often used air. In addition to these gas, it is possible to use other e.g. aerosol propellants, which are halogenated hydrocarbons, provided they are not too soluble. In this respect, there can be mentioned that the carbon dioxide is sometimes useful and can impart an effervescent effect or toothpaste to provide taste.

The proportions of the various constituents of the dentifrice UIC dye sticks are such as to produce a gel properly an extrudable or like product which substantially retains its shape after being discharged from the dispensing container. The product contains a sufficient amount of polishing agent for cleaning teeth correctly, but does not contain information to the point at which a gritty or interfering with the uniformity of the gel. Similarly, a present vehicle may be a vehicle compatible with the other components and which behaves as a medium in which they are dissolved or dispersed. The vehicle need not be present in an amount too high to make the product too fluid, or in a proportion so small that the toothpaste losing its smoothness appealing. The detergent or the foaming agent is used in a small amount sufficient to elicit a proper foam assist in cleaning teeth and is not large enough to make the product disorder or opaque. Similarly, the agent élification~present thickens the dentifrice sufficiently constrain it to hold its shape and retain the gas bubbles contained therein at room temperature, but need not be present in such quantities that it renders the dentifrice rubbery, lumpy or opaque. The proportion of gelling agent used is advantageously the viscosity dentifrice more than 100,000 OPC to 25 °c and, preferably, greater than 200,000 or I 000,000 OPC.

For the materials having non-Newtonian characteristic, the viscosity measurements cannot be a true indication of the fluidity or the ability to hold the bubbles in place. In this case, the product must be sufficiently firm that, although it is extrudable at ambient temperature (25 °c), it maintains the bubbles and does not leave the join in the upper portion of the toothpaste contained in the container. For Newtonian fluids, the values of centipoise data measurements are of such property satisfactory. As is will describe further, viscosity, fluidity and firmness of the composition must be less at high temperatures, so that the gas bubbles can be shaped globular at such temperatures even if the initial bubbles introduced in the toothpaste are not perfectly round.

The proportions of materials that typically is used to obtain the properties described in the paragraphs can vary within a wide range, but experience has shown that certain ranges are very advantageous for manufacturing

- the best products; thus, it is known to use 5 to 50 % polishing agent, 0.5 to 5 % a gelling agent or thickener, 30 to 85 % polyol, 5 to J.>0% water and 0.5 to 5 % detergent or foaming agent. A preferred range is 5 to 40 % polishing agent, 0.5 to 3^gelling agent, 50 to 75 % (e) of polyalcanol, 10 to 20 % water, and I to 3# detergent. In the EAS dentifrices opaque may be manufactured according to the method of the invention, if desired, the proportion of the polishing agent can be higher, for example 20 to 75 with fo, the proportion of water can be higher, for example 5 to 40 %, and that of the polyalcanol may be lower and is usually 10 to 35 %, Other materials and additives can be present for imparting uatres desirable properties for the treatment or the end use. Thus, the flavorings and dyes make the toothpaste more appealing to the consumer and the solvents can facilitate preliminary degassing. Generally, is not used more than 10 % of each of these materials and usually 0.1 to 5 is used % in most cases, preferably 0.1 to 3 % " the total of these materials comprising less than 20 %.

In proportions described, can be made excellent toothpaste with properties appropriate holding bubbles. Following the method of the present invention, can be manufactured dentifrices containing bubbles which are substantially clear despite interruptions that present the product, caused by both the gaseous substances and solids contained therein.

The impact of the bubble against the substanee solid does not alter its shape undesirably, and it does not occur unevenness appearance due to changes in light paths through the material.

Although bubbles can may have occurred aecidentellement in dentifrices according to known methods, were found to be considered unfavorable and it is attempted to suppress it, because they were not very pleasing, irregularly shaped, unevenly distributed and tended to cause density variations in the toothpaste. Also, in the case of clear toothpaste, the bubbles may cause haze. Following the method of the present invention, these disadvantages are avoided and a dentifrice product clear having bubbles distributed such attractive and uniform in the dentifrice.

As the first stage of the manufacture of such a product, is' prepares a dentifrice that is substantially free of entrained gas and preferably also free of dissolved gas. This degassing can be performed by any known technique, usually using the vacuum during the mixing of the various ingredients of toothpaste or after the preparation of the toothpaste. The voids used are normally of 500 to 750 mm of mercury (50 to 260 mm Hg absolute, absolute pressure), but may also need, for degassing faster, to voids larger, up to 760 mm mercury 759. If the toothpaste completed must be degassed and preliminary vacuum that operations are not performed, it takes 2 to 5 hours for properly removing the dissolved gas and entrained product. This removal is facilitated by the use of devices such as mixers DOPP which, UnimixVersator and OD in which thin films, for example less than 0.2 cm, toothpaste are exposed to low pressure. A degassing faster is possible by subjecting the various constituents or premixes dentifrice before and/or voids during mixing.

The removal of gas is promoted by the use of heat or volatile solvents (which I 10 %, preferably I to 5 % solvents, or volatile flavoring used often) to render the compositions more fluent and to promote coalescence of gas bubbles and their elimination. In a particularly preferred method, used for the manufacture of gel dentifrice clear, using heat, with or without the present vacuum, deaerating or degassing for a mixture surfaetifpolyalcanol and agent (detergent or foaming agent) and its mixing, under vacuum, with the rest of the composition previously degassed.

The intermediate degassed is manufactured by applying a vacuum to a blend of gelling agent and vehicle, by mixing with the polishing agent and by degassing during and after this mixture. In this process, that may be modified by the addition of solvents or flavoring agents which are volatile, having boiling points of 40 to 70 °c, a dentifrice is obtained substantially free of gas.

The dentifrice free gas is preferably at an elevated temperature or otherwise adjusted so that its viscosity is sufficiently low to allow gas dispersed therein intentionally form spherulite. The dentifrice, at this stage, is less viscous than when it is finally conditioned and is at the temperature, ambient. However, it is sufficiently viscous that the bubbles dispersed therein do not easily contact with other bubbles and do are removed from the toothpaste or moved to a portion thereof.

They remain sufficiently dispersed for a period of time long enough to allow the packing and cooling or other packaging operation to provide the final product an extrudable although retaining its shape. It is generally preferable to use heat as fluidizing means and cool the product to cure, but other techniques, such as the use of solvents and curing agents time sensitive, can also be applied.

After performing the toothpaste containing gas substantially free of preferably less gas than is required to produce a bubble of 2 mm diameter per cubic centimeter (0.5 less % in volume), and preferably less of a bubble of I mm in diameter per cubic centimeter, the temperature of the dentifrice is adjusted, or another variable is set, so as to render it sufficiently fluid to allow the formation of spherulites injection of gas bubbles. Preferably, for the Newtonian fluids, this corresponds to a viscosity of 25,000 OPC or less, usually more than 1000 OPC and preferably more than 5,000 OPC. With these viscosities, the gas bubbles to disperse in the toothpaste are added so as adjusted and are distributed throughout the toothpaste, the addition of bubbles would be continued until the desired concentration is reached, at which time the dentifrice is charged into a container end use as for toothpaste tubes, and is cooled in the container for holding the gas bubbles in the toothpaste. The gas bubbles have diameters added spherical equivalent of the order of 0.1 to 4 mm, preferably of 1 to 4 mm and more preferably 2 to j5nm. They feel added ' until there are 2 to 100 Û of these bubbles per cubic centimeter of these bubbles per cubic centimeter of toothpaste, preferably 2 to 40 bubbles per cubic centimeter.

Various methods of producing accurate bubble dimensions cited and distributing these bubbles in the toothpaste, may be used, but that is considered to be simple and yet very effective includes adding the bubbles by passages having approximately the desired final diameter of the bubbles.

The linear velocities of adding the bubbles, although its habi of I cm to 50 cm tuellement/second, preferably more than 0.1 meters/second, may vary in a wider range, provided that the gas bubbles are disaggregated to correct length to produce spherulites of desired diameter. Thus, it is usually preferable that the passages through which the gas passes into the body of the dentifrice is spaced at least I or 2 diameters and toothpaste moves by agitation or other means so that the velocity component perpendicular to the path of the gas inlet is at least twice the velocity of the gas at the point of entry. This separates the bubbles in shear to the length approximately equal to the desired diameter and prevents agglomeration. By adjusting the flow of the gas, by changes in the pressure and changes the speed of the toothpaste, and by varying the speed of the mixer or apparatus for circulating, obtained dimensions and concentrations of bubbles desired. Numerous types of mixers, but usually the propeller mixers, paddle, to pump and circulate impart satisfaction. Naturally, the mixers usually should be prevented high shear or thin film. For good production rates, the linear velocity of the gas is at least 0.1 meters/second, and the pressure of the gas, although low, is adjusted to provide proper speed. The passages through which the gas is added to the toothpaste can be constituted by fine individual tubes had may be incorporated into a one-piece member as a porous plate or a diffuser. Which may either be mechanical disintegration devices for generating the bubbles, but they may not be as accurate as the method utilizing lumens. During operations, the technique of the invention and variants thereof to obtain particular products will be obvious for a technician.

Viscosities to toothpaste to which the gas is added at an elevated temperature, e.g. OJ to 60 °c, the bubbles do not agglomerate and are not restrained by the polishing agent dispersed insoluble. The particles of the polishing agent, which have a diameter less than 100. micron, preferably I to 65 microns thick, and more preferably 20 microns thick which I, do not weaken the bubbles and do not provide sites of agglomeration of these bubbles to other bubbles, as would be expected based. It is considered that larger particles of the polishing agent are disadvantageous in this respect also.. and by its very nature is palpable undesirable. Because of the low content of the gas originally in the dentifrice, there occurs a few bubbles whose diameter lies beyond the ranges from the changes desired temperatures and, because the gas addition is preferably carried out at an elevated temperature, there is a slight tendency of bubbles during cooling, since the gasses are generally more soluble cold and hot. An advantage of the present dentifrice of the present invention is the presence, in the gas bubbles, of volatilized matter which can enhance the flavor of the flavoring and smell, at least as regards the flavorings whose effects are mainly olfactory.

After manufacture, the dentifrice containing bubbles is introduced in its container as soon as possible, usually within one hour, preferably within ten minutes. It is cooled to room temperature 5 additional hours, preferably 2 hours, and is ready for shipment.

Although the disclosed process for making gels containing a gas is highly preferred, other methods may also be used. Thus, in some cases, the bubbles may be mechanically dispersed by a mixer or even caused by chemical means. Introducing the cooled product without the containers of uitlisation final may be preferable in certain operations, and provided that the bubbles are ' êphériques during introduction and that the device can manipulate the thickened, is. can produce good toothpaste by this method. Also, the toothpaste can be vacuum packaged, either by subjecting it to a vacuum during filling, or by introducing the dentifrice heated and causing a pressure decrease by contraction, upon cooling. In some cases, can be created intentionally bubbles and irregular.

in this case, it may not be desirable that the dentifrice, upon the addition of the gas, is fully mobile enough to produce spheres of gas. Clear toothpaste of the present invention can be manufactured by the method of the invention or by other techniques provided that the gas bubbles have a diameter of 4 mm and I are distributed throughout the dentifrice so that there is 2 to 20 bubbles per cubic centimeter of toothpaste, preferably uniformly distributed, in the clear gels containing a polishing agent is insoluble, a gelling agent and a carrier. In these products, the gas which is dispersed preferably contains a major proportion of ar zote, and most preferably consists entirely of nitrogen, although air also gives satisfactory. The dentifrices are introduced preferably in tubes of transparent flexible plastic, e.g. polyvinyl chloride, or polypropylene, have a final viscosity of 200,000 OPC, and contain 5 to 10 bubbles of globular j5 to 2 mm in diameter per cubic centimeter. In particular, products highly interesting are those in which the polishing agent is 1' sodium aluminosilicate of I to 20 microns in diameter and having a refractive index of 1.44 to, 1.48, the gelling agent is a clay mineral synthetic silica-containing type "as Laponite", the vehicle is an aqueous solution of glycerol and sorbitol wherein the ratio of 1:5 to 5:1 glycérolrsorbitol is, the proportions of the constituents are of 5 to 50^polishing media, 0.5 to 5^gelling agent, 30 to 85 % of polyalcanol, 5 to. 50 % water and 0.5 to 5 f.> of foaming agent.

It is evident that in the foregoing description, when making mention of individual materials of certain types, it is also contemplated that mixtures of these materials can be used for best properties from each component.

The following examples are illustrative, but not limiting of the invention. Unless otherwise stated, all parts are expressed by weight and all temperatures in °C.

SUCH AS I

Components parts Glycerin

The sorbitol (70 to aqueous solution %)

50

55

' Components parts "SPs as Laponite" 2 sodium aluminosilicate_V. 20 N-lauroyl sarcoside sodium 2 flavoring agent (essential oils) synthetic sweetener (saccharin) 1.0 0.1 stain solution (green dye aqueous to I $) 1.0. Sodium monofluorophosphate 0.8 water 10.1.

Sodium aluminosilicate used is a complex having a refractive index of 1.47, a moisture content of 10 % and about. an alumina content of 8 %, and. it contains 78 with fo silica and 10 %. sodium oxide. The particle size is between I and 20 microns thick.

The "as Laponite SPs", the flavorant, the sweetener and the coloring agent are mixed with about 1/3 of glycerin and 1/5 sorbitol plus half of the water, and a vacuum of 700 mm of mercury is applied for 10 min. Then, used 1/3 1/3 glycerin and sorbitol and half water to disperse sodium alumino silicate and sodium monofluorophosphate, and a vacuum is applied like during the same time period for e. nlever any entrained air. Then mixed n-lauroylsarcoside sodium in the rest of glycerin and sorbitol.

Material is heated to 50 °C and maintains it for 5 hours without applying vacuum or for ten minutes with the same vacuum as previously mentioned. Then, the part is mixed with the gelling polyalcanolagent ride-agent polissagefluorure, at a temperature of 40 °c by applying a vacuum of 700 mm Hg for 5 min, after which the mixture is agitated of surfactant using the same vacuum, and maintained for about 10 min. The mixing is carried out in a blender "Unimix" equipped with scraper blades in "of Teflon" which dispose in the walls of the mixer to less than 0.2 mm to leave only a very thin film of toothpaste thereon. The resulting product is essentially free from gas, contains less than 0.1 % in entrained air volume. Its pH is about 8. (The pH of the product of the invention are between 5 and 9). The resulting product is a mouthwash of clear appearance and attractive.

Fabricated of like free-gels

gas and clear appearance by increasing the proportion of sorbitol so that it constitutes 70 % the polyalcanol content, by replacing the "as Laponite SPs" by I section carboxymethylcellulose sodium (by adding sorbitol to compensate for the other part of "as Laponite" omitted), by replacing 1' sodium aluminosilicate by the silica xerogel (Syloid 63), by replacing the sarcoside by lauryl sodium sulfate, and replacing sodium monofluorophosphate by 0.2 part of sodium fluoride, by completing the remaining 0.6 part by water. The composition described above and are degassed by maintaining a vacuum of 740 mm Hg for 4 hours while mixing in a mixer of DOPP which provided with a scraper blade for cleaning the interior walls. All products described, they are fabricated by vacuum stages, sometimes with the aid of heat as in the deaeration of the detergent mixture, or by venting the total final toothpaste, gels are clear appearance. In some cases, the deaeration is voluntarily terminated before completion so that the product contains a small proportion of air bubbles or nitrogen, for example a small proportion, preferably less than 20 of the final content of bubbles of the dentifrice.

Toothpastes described are heated to 40 °c, temperature at which the viscosities are of 5000 to 25,000 OPC and values equivalent, so that the gas bubbles added to the dentifrice become spherical in shape. Then, air is blown by the base of the mixing pallets containing various toothpaste compositions degassed by means of a diffuser having multiple passes of 2 mm in diameter and spaced I centimeters. The linear velocity of the air flow (nitrogen is used for some experiments) is 10 cm/second and the speed of the mixer is such that the average tangential speed of the dentifrice relative to the passage for air to the exit point of the air is of 50 cm/second. Air is added during the I minute until there is 10 bubbles per cubic centimeter of toothpaste, each bubble having a 2 mm diameter.

Five minutes after the addition of the air, the dentifrice is introduced into polyvinyl chloride pipes and transparent, two hours after, it is cooled to 25 °c, temperature at which its viscosity is about 500,000 OPC.

The products are packaged and sent to storage and, mêfae after extended periods of storage, e.g. six months to a year, they are still useful and attractive, they glow brightly and contain air bubbles uniformly re * parts the same points during their manufacture.

In a variation of these assays, the carrageenan is used instead of sodium carboxymethylcellulose and replacing 1/4 of the foaming agent by Igepal CA 6j50 " (nonyl phénoxypolyéthoxy-ethanol). This produces a product having similar properties to those dentifrices previously described. Also, when using a silica aerogel or pyrogenic silicic acid in addition to the gelling agent, or partially replaced, usually in an amount of less than 50 the dentifrice resulting is of satisfactory transparency and bubbles it contains behave satisfactorily. However, when the polishing agent is replaced with a polishing agent having a refractive index outside the range of 1.4 to 1.5 or whose particles are greater than 100 micron, it becomes apparent in the toothpaste and clarity is suppressed. In some cases, it is regarded as advantageous, to allow a small percentage of the polishing agent from exceeding 100 microns in size and be located outside of the range tolerable described refractive index so as to be seen, but in all instances, its proportion should not exceed 20/of the polishing agent the total present. Although the vehicle can be completely formed by sorbitol or glycerol with a small amount of water, and that in some cases, the water can be eliminated completely and that the product is further clear and maintains gas bubbles well dispersed, the best results are obtained with mixtures of sorbitol, of glyoérol and water, sometimes with low proportions of polypropylene glycol. Instead of air, nitrogen is used, argon and "freons" (chlorofluorinated lower alkanes) and also achieved good toothpaste clear.

EXAMPLE 2

A gel is prepared toothpaste appearance substantially clear according to the following formula and any amount of entrained air is removed by applying a vacuum of 700 mm Hg for two hours, using 2 with fo solvent (ethanol, chloroform, or acetone) to promote the removal of air bubbles trapped.

The formula used is as follows:

Components parts The sorbitol (70 to aqueous solution %) 50 Glycerin 26 Components parts Sodium aluminosilicate 20 sodium lauryl sulfate 2.0 flavoring (clove bud oil) 1.0 0.5 sodium carboxymethyl cellulofee derivative sodium saccharin 0.1 0.1 formaldehyde aqueous dye solution (I- %) 0.5

Sodium aluminosilicate used is a complex having a refractive index of 1.45, 10 % moisture, 8 % alumina, about 70 % silica, 7 _% sodium oxide, a particle size such that 98 $particles have a diameter less than 50 microns and a bulk density of 0,114 grams/cm. ^. Using the same apparatus as in example I and, with individual pass tubes having diameters of I mm and spaced 5 mm, air is blown in the toothpaste until there about 20 bubbles per cubic centimeter, each having a diameter of I mm thick. The bubbles are globular and in the same time as those discussed to such as I, the dentifrice is introduced into tubes, and the tubes are cooled and sent to storage.

The resulting products are toothpastes having excellent clear bubbles apparent. The bubbles are uniformly dispersed and have a diameter of I mm approximately. In a variation on this test, instead of using passageways of X; " the n, .

use is made of 0.5 mm and 5.0 mm passages, with about double the number of the smaller passageways. With this technique, there is obtained a toothpaste having a mixture of two bubbles, size, diameter 0.5 mm and 5.0 RAM. In some cases, it is preferred these mixtures provided that bubbles are globular and that the distribution of the bubbles of two different dimensions is uniform.

In variations of this assay, argon is used instead of air and are dyed. gels in different colors and the flavored with different flavoring agents. In some cases, incorporated the I % chloroform in the product for its effect flavoring. All these products are clear appearance of gels having bubbles argon very well dispersed.

EXAMPLE 5

Components 25 Glycerin parts Components parts The sorbitol (70 to aqueous solution %) . 47 Sodium aluminosilicate 16 "aerosil R812 d 200" 3 N-lauroyl sarcoside sodium■2 "as Laponite SPs" 2 flavoring and sweetener 1.2 2.8 water I-coloring aqueous solution

'The aluminosiiicate sodium is a complex having a refractive index of 1.46, a content of moisture-' 6 % about, an alumina content of 8.2 a silica content of 72 a sodium oxide content of 7 %, an average particle size of about 20 microns and a bulk density of about 0.07 g/cm3 after screening.

When degassed according to the methods of examples I and 2 and when are incorporated therein air bubbles from 0.5 to 4 mm in diameter, using a diffuser for introducing air and by following the methods further examples I and 2, the resulting product is a dentifrice acceptable clear appearance.

EXAMPLE 4

Components parts The sorbitol glycerin 23.9 (aqueous solution at 70 %) 45 Carboxymethyl cellulose sodium 0.7 "Syloid 244" 5 sodium aluminosilicate 16 sodium lauryl sulfate ' 2 sodium benzoate 0.5 saccharin derivative 0.2 coloring aqueous solution (the I %) 0.2 Flavoring oil based essential 1.0 2.5 water 3 chloroform

The aluminosiiicate sodium used is that of the example 2. The product is prepared according to the process of example I and it gives a mouthwash clear bubble having an attractive appearance.

EXAMPLE 5

Components parts 25 Glycerol

Sodium carboxymethyl cellulose

(Hercules Viscosity i2m ' 3ip) 0.6 0.5 sodium benzoate as sorbitol (70 to aqueous solution %) 43 * 9 Dye (aqueous solution to I 0.8 deionized water 3 * 0 derivative sodium saccharin 0.2 pyrogenic silica (Cab-O-Sil m 5) - 2.0 silica aerogel (Syloid no. 244) 4.0 sodium aluminosilicate (82 ex Degussa Ρ θ) 16 sodium lauryl sulfate 2.0 flavoring (essential oils) 1.0 1.0 chloroform

A gel is prepared toothpaste clear according the process of example I and found that it constitutes an excellent agent for cleaning teeth, attractive appearance and flavor, with good foaming and excellent storage stability.

The bubbles are uniformly distributed therein and retain their storage location for a time of six months in a flexible delivery tube, clear, polyvinyl chloride.