NZ200995A - Dentifrice containing non-ionic polyoxyethylenepolyoxypropylene block copolymer - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £00995 ~~j£- Priority Date(s): ,4f. .6. .. z&fate, Complete Specification Filed: L^. .

Class: . Publication Date: : P ©. Journal1, Ha\ .., /.Zf.t Patents Fonn No. 5 PATENTS ACT 1953 COMPLETE SPECIFICATION DENTIFRICES Number Dated )t/We COLGATE-PALMOLIVE COMPANY a corporation organized under the laws of the State of Delaware, United States of America of 300 Park Avenue, New York, N.Y.10022, United States of America do hereby declare the invention for which Kwe pray that a Patent may be granted to rftfe/us, and the method by which it is to be performed, to be particularly described in and by the following statement: (followed by page la) £Kjuyyo j This invention includes foaming dentifrice and in particular a dentifrice in which the surface active agent employed is nonionic in nature.

Foam is a desirable characteristic of dentifrices since it spreads the dentifrice throughout the oral cavity during toothbrushing, thereby aiding in contacting the dentifrice with tooth surfaces and providing a characteristic mouth feel.

Foam, particularly full-bodied foam, is generally achieved by the use of an anionic surface active agent. Other surface active agents, and particularly non-ionic surfaco active : I* agents, typically do not foam as well as the anionic surface j active agents. Of the many anionic surface active agents only a j few have been used commercially in dentifrices; the most commonly used one being sodium lauryl sulfate.

• Anionic surface active agents may cause some mild side effects which some users may find somewhat undersirable. For j example some users may experience temporary moderate irritation j in the oral cavity, mild bitterness, sloughing of some oral j I mucosa or an unpleasant flavor reaction when drinking or eating J citrus shortly after toothbrushing, when a dentifrice containing an anionic surface active agent is used.

Although it has been known that surface active properties could be provided to a dentifrice by a nonionic surface active agent, such an agent has not been commonly used since foaming is lost, unless supplemented with an anionic surface agent. -la- I I t t 20099 Pf _ It: is an advantage of this invention that a dentifrice which is readily extrudible from a toothpaste tube which contains a nonionic surface active agent and a particular binding agent is employed in which desirable stable full-bodied foaming is obtained.

It :1b a further advantage of fchJr. .Invention th:ii. the dentifrice employed Is sweet without requiring the presence of a sweetening additive, and non-irritating, while also not being prone to cause users to experience sloughing of oral mucosa or have an adverse citrus flavor reaction after use of the dentifrice.

Further advantages of the invention will be apparent from consideration of the following specification.

In accordance with certain of its aspects, this invention relates to a dentifrice comprising about 20-80$ by weight of a liquid humectant vehicle, about 0.5-7? by weight of xanthan i gum, and about 1-10$ by weight of surface active agent which is a nonionic | polyoxyethylene-polyoxypropylene block copolymer surface active agent. Preferably up to about 5% by weight of resinous poly (ethylene oxide) is also present.

The nonionic surface active agent employed in the instant invention is a block copolymer containing polyoxyethy-lene and polyoxypropylene. Such block copolymers are available from Wyandotte Chemicals Corporation under the trademark "Pluronic". They may be liquid, paste or solid and are generally chemically defined in terms of the molecular weight of the polyoxypropylene hydrophobic moiety and the percent by weight of the polyoxyethylene hydrophilic moiety. The following block copolymers are available from Wyandotte: JU VV 7 7J| I I'l.UKON I (' I'llV,". ICAI. WT.

NUMBER CHARACTER HYDROPHIL HYDRQFUOBK L 131 I. I QU.I I) 10 '1000 i. ioi liquid .10 3;:".o L 81 LIQUID 10 2250 L 61 LIQUID 10 1750 L 31 LIQUID 10 950 L 122 LIQUID 20 4000 L 92 LIQUID 20' 2750 L 72 LIQUID 20 2050 L lj2 LIQUID 20 1750 L 42 LIQUID 20 1200 P 123 PASTE 30 4000 P 103 PASTE 30 3250 L 63 LIQUID 30 1750 L 43 LIQUID 30 1200 P 104 PASTE 40 3250 P 94 PASTE 40 2750 P 84 PASTE 40 2250 L 64 LIQUID 40 1750 L 44 LIQUID 40 1200 P 105 PASTE 50 3250 P 85 PASTE 50 2250 P 75 PASTE 50 2050; P 65 PASTE 50 . 1750 L 35 LIQUID 50 950 F 127 SOLID 70 4000 F 87 SOLID 70 2250 F 77 SOLID 70 2050 F 108 SOLID 80 3250 F 98 SOLID .80 2750 F 88 SOLID 80 2250 F 68 SOLID 80 1750 F 38 SOLID 80 950 ■ The preferred nonionic block copolymers are solid (or flake) materials and the most preferred are Pluronic 108 (80% polyoxyethylene: 3250 molecular weight polyoxypropylene) and F 87 (70$ polyoxyethylene: 2250 molecular weight polyoxypropylene). The nonionic surface active agent is employed in the dentifrice in amount of about 1-10% by weight, preferably about 2-5% and most preferably about 3%• The binding or gelling agent system of xanthan or xanthan and resinous poly (ethylene oxide) co-operates with the nonionic surface active agent to provide stable full-bodied foaming (even though the only surface active agent present is non-ionic) and desirable mouth feel characteristics to the dentifrice. Xanthan gum, in the concentrations described, permit a stable full-bodied foam. Moreover, in accordance with a further aspect of this invention, the mouth feel characteristics can be modified as described by the addition of resinous poly (ethylene oxide). The dentifrice has desirabl viscosity to permit its extrusion from a dentifrice tube in the form of a ribbojn Resinous poly (ethylene oxide) has been disclosed as a dentifrice gelling or binding agent in U.S. Patent 2,991,229 to Ivison. Its presence smooths the texture of the dentifrice.

The poly (ethylene oxides) employed in this invention are solid, colorless, water-soluble resins. They appear to form homogeneous systems in water in all proportions, although the relatively higher molecular weight ethylene oxide polymers merely swell on the addition of small amounts of water. On the addition of greater amounts of water, the polymers pass into solution. The water solutions, are viscous, the viscosity increasing both with the concentration of the polymer in the solution and the reduced viscosity of the polymer. The ethylene oxide polymers employed .in this invention show little change in melting point with increased reduced viscosity (an indication of increased molecular weight) and the melting point, as measured by change in stiffness with temperature, was found to be about 65° +2°C throughout the range of reduced viscosities of from about 1.0 to about 10, and greater. These polymers, upon X-ray examination, disclose a crystalline structure similar to that exhibited by polyethylene. The crystallization temperature, as determined from measuring the break in the cooling curve, is about 55°C.

Z U 0 9 9 To faci 1:1 tato the understanding of the instant invention, various terms will be defined. At the outset it should be noted that the word "poly (ethylene oxide)" as used throughout the specification and claims refers to ethylene oxide polymers which have a reduced viaooully in acelonJ tr.t lo of at leant O.'J and upwards to 75j and higher.

Unless otherwise stated, by the term "reduced viscosity as used herein, is meant a value obtained by dividing the specific viscosity by the concentration of the ethylene oxide polymer in the solution, the concentration being measured in grams of polymer per 100 milliliters of solvent at a given temperature, and is regarded as a measure of molecular weight. The specific viscosity is obtained by dividing the difference between the viscosity of the solution and the viscosity of the solvent by the viscosity of the solvent. The reduced viscosities herein referred to are measured at a concentration of 0.2 gram of poly (ethylene oxide) in 100 milliliters of acetonitrile at 30°C (unless stated otherwise).

Granular poly (ethylene■oxide) results from the suspension polymerization of an agitated reaction mixture comprising ethylene.oxide in contact with a polymerization catalyst therefor and in the presence of an inert organic diluent, e.g., heptane, in which ethylene oxide is soluble and the resulting poly (ethylene oxide) is insoluble. Granular poly (ethylene oxide) thus produced is obtained in a finely-divided solid particle state and resembles finely-divided sand in particle size. Unlike the granular poly (ethylene oxide) resulting from the suspension polymerization process, the bulk and solution polymerization processes yield a polymer which is substantially a homogeneous mass either conforming to the shape of the reaction vessel or, ^Ioo^l5 «i F'aT(.,nV drlvluc: olT I.lie nri':,'in I c mnMiiin, Ini' < • x: 1111 p I r , by iimtIi.-iiiI cm I extrusion, n.e,., Marshall Mill (under vacuum and at, si.! ir,M l..y elevated temperatures), resembles layers or sheets. This polymer subsequently can be reduced in particle size, for example, by dicing or the like.

The term "granular" refers to the particle size of the ethylene oxide polymers prepared by suspension polymerization. A granular product is one which is in a free-flowing state and comprises particles averaging less than 5 mesh in size (U.S. Standard Size Sieve). When present, the poly (ethylene oxide) comprises up to about 5% by weight of the dentifrice, perferably about 0.1-1.5$. ; Xanthan gum is a fermentation product prepared by action of the bacteria of the genus Xanthomonas upon carbohydrates. Four species of Xanthomonas, viz X. campetrls. X. phaseoll, X- rcalvocearum, and X. carotae are reported in the literature to be the most efficient gum producers. Although the exact chemical structure is not determined, it is generally accepted to be a heteropolysaccharide with a molecular weight of several million. It contains D-glucose, D-mannose, and D-glucuronic acid in molar ratio of 2.8:3". 2.0. The molecule contains 4.7$ acetyl and about 3% pyruvate. The proposed chemical structure configuration can be found in McNeely and Kang, Industrial Gums, ed. R.L. Whistler, CH XXI, 2nd Edition, New York, 1973. The procedure for growing, Isolating and purifying the xanthan gum is found in Manufacturing Chemist, May I960, pages 206-208 (including mention at page 208 of potential use of gums therein described for formulating toothpastes).

Use of special grades of xanthan gunj such as described in U.S.

Patent No. 4,263,399 are within the scope of this invention .A grade described in U.S. Patent No. 4,263,399 is a xanthan gum in which up to about 1,6% at the carboxyl groups are bound to calcium and the remaining carboxyl groups are bound to sodium , potassium, a mixture of sodium and potassium or other I non-calcium cations. c . w V ^ I " I The xanthan golling a^enl Is present In amount of about 0.5-7# by weight of the dentifrice, preferably about 1.5-3$.

Since the surface active agent used in the present invention is non-ionic in nature, the moderate "bitterness generally contributed by an anionic surface, active agent is not experienced by users. Accordingly, sweetening agents which are often added to dentifrices at least in part to overcome the bitterness, are less needed in the dentifrice of this invention in comparison with prior art practice. Indeed, sufficient satisfactory sweetness can be readily provided by the low sweetening character of many humectants which are commonly employed in dentifrice compositions. Such humectants are comprised in the liquid phase of the dentifrice, typically together with water. Typical humectants include sorbitol (as 70? aqueous solution), glycerine, maltitol, xylitol, polyethylene glycol hOO and polyethylene glycol 600. The liquid phase comprises about 20-80$ by weight of the dentifrice, preferably about 30-^0$, with water (if present) typically being in amount up to abou,t 60% and humectant typically being about 20-60?.

The liquid vehicle and gelling agent and other components of the dentifrice are proportioned to form a cream or gel mass of desired consistency which is extrudible from an aerosol or pump container or a collapsible tube (for example aluminum, lead or plastic).

The dentifrice typically contains a dentally acceptable polishing agent which is generally substantially water-insoluble of the type commonly employed in dental creams. 1 IC/rJ, Representative polishing agents include, for example, dicalcium phosphate, tr'icalcium phosphate, insoluble sodium metaphosphate, aluminum hydroxide including hydrated alumina, calcined alumina, colloidal silica, magnesium carbonate, calcium carbonate, calcium pyrophosphate, bentonite, etc. including suitable mixtures thereof. When employed, it is preferred to use the water insoluble phosphate salts as the polishing agent and more particularly insoluble sodium metaphosphate and/or a calcium phosphate such as dicalcium phosphate dihydrate in dental creams. When visually clear gels or opacified gels are employed, a polishing agent of colloidal silica, such as those sold under the trademark Syloid as Syloid 72 and Syloid 7^ or under the trademark Santocel as Santocel 100 and synthetic alkali metal aluminosilicate complexes or silica containing combined alumina may be particularly useful. When employed, the polishing agent content is generally in amounts from about 15 to 75$ by weight in a dental cream and about 5 to 50$ by weight in a clear or opacified gel.

The dentifrices of the invention may contain a siliceous polishing material, such as those mentioned in the foregoing paragraph and poly(ethylene oxide) as earlier described.

Based upon prior art considerations, as disclosed in U.S * Patent 3,020,230 to Smith, wherein silica material is stated to coagulate or flocculate in the presence of resinous poly(ethylene oxide) in order to precipitate it from a liquid suspension, one skilled in the dentifrice art would not have been led to use silica materials in a dentifrice containing resinous 200995 poly (ethylene oxide). Indeed, in U.S. Patent 2,991,229 to Ivison, polishing agents or abrasives disclosed in a toothpaste containing poly(ethylene oxide) were "tricalcium phosphate, dicalcium phosphate and calcium carbonate and the like"; but not silica materials.

Dentifrices of the invention which include a siliceous polishing material and poly (ethylene oxide) are provided with improved stain removal which has acceptable cosmetic rheology and dentin abrasion characteristics.

The polyoxyethylene-polyoxypropylene block copolymer and xanthan in the dentifrice assist in achieving desirable foaming.

A dentifrice may comprise about 5-50% by weight of a siliceous polishing material and about 0.05-5% by weight of a resinous poly(ethylene oxide), the dentifrice containing flocculated particles.':;of said siliceous polishing agent in the presence of said poly (ethylene oxide).

As mentioned above, with particular regard to a clear or opacified gel, the proportion of the siliceous polishing agent content is in the range from 5% to 50% by weight of the dentifrice, preferably from 10% to 30% such as from 10% to 25%. One such polishing agent is a complex alkali metal aluminosilicate having a refractive index of from 1.44 to 1.47 and containing at least 70% silica, up to 10% alumina, such as about 0.1-10%, e.g. about 0.1-3%, preferably up to about 20% of moisture, such as about 0.5-10%; and up to about 10% of alkali metal oxide. Typically this material has a particle size in the range of up to about 40 microns, preferably 1 to 4 microns. The preferred moisture content is from 5% to 20% measured by ignition at 1000°C and the typical content of alkali metal oxide is from 5% to 10%.

£UU77Q Generally, the polishing agent has a loose bulk density of up to 0.2g/cc, such as from 0.07 to 0.12g/cc. Another suitable type of polishing agent is porous amorphous silicic anhydride having an average particle size preferably below 20 microns and above 1 micron, a surface area of at least 200 m^/g, preferably at least 300 m^/g, and a bulk density of at least 0.15 g/cm^, preferably at least 0.30 g/cm^, such as a dehydrated silica hydrogel (i.e. a xerogel) , preferably of the well known regular density or intermediate density type. Examples of such amorphous silicic anhydride polishing agents are "Syloid 63", "Syloid 72", and "Syloid 74" (SYLOID is a trade mark) which are described in "The Davison Family of Syloid Silicas" published by their manufacturer, Grace, Davison Chemical Company. "Santocel 100" of Monsanto (SANTOCEL is a trade mark), is also a suitable dental abrasive. "Syloid 72" has a average particle size of about 4 microns, a surface area of about 340 m^/g bulk density of about 1.77 g/cm . For "Syloid 63" the corresponding figures are about 9 microns, about 675 m^/g and about 0.4 g/cm^. A grade of "Santocel 100" has a surface area of about 239 m2/g and a bulk density of about 0.24 g/cm^. These amorphous silicic anhydrides may be used singly or in mixtures.

As mentioned above, the poly (ethylene oxide) when present comprises about i 0.05-5% by weight of the dentifrice, preferably about 0.1-1.5%.

In the dentifrice, the siliceous polishing agent when present flocculates in situ in the presence of the poly (ethylene oxide). The, flocculated particles typically may agglomerate with each other and have apparent particle sizes up to about 250 microns or more, typically about 44 to 177 microns; in other words, the flocculated particles typically pass through a screen of U. S. Sieve No. 80 and are retained on a screen of U. S. Sieve No. 325.

In spite of the presence of the flocculated particles the dentifrice is readily formulated to have a desirable appearance and a rheolojgical texture without an undue "lumpy" appearance or "gritty" feel.

The liquid vehicle of the dentifrice of this aspect of the invention may be as indicated above and the components of the dentifrice are again proportioned to form a cream aX gel mass of desired consistency which is extrudible from an aerosol or pump container or a collapsible tube (for example aluminum, lead or plas* tic).

In addition to the resinous poly(ethylene oxide), further gelling or binding agent such as sodium carboxymethy1 cellulose, Irish moss, xanthan and the like may be present in amount of about 0.5-7%. Xanthan is preferred. The total amount of gelling or binding agent in the dentifrice can be about 0.1-12% by weight. The dentifrice may contain an anionic, nonionic, cationic or amphoteric surface active agent to achieve increased prophylactic action, assist in achieving thorough and complete dispersion of the instant compositions in the oral cavity and render the instant compos It ions more cosmetically acceptable.

A preferred surface active agent is the nonionic block copolymer containing polyoxyethylene and polyoxypropylene as described above.

Other nonionic surface active agents which may be employed' include condensates of sorbitan monostearate with approximately 20 i moles of ethylene oxide. Amphoteric agents include quaternized imidazole derivatives which are available under the trademark : "Miranol" such as Miranol C2M. -11- 2 OUV Suitable types of anionic detergents are water-soluble salts of higher fatty acid monoglyceride monosulphates, such as the sodium salt of the monosulphated monoglyceride of hydrogenated coconut oil fatty acids, higher alkyl sulphates, such as sodium lauryl sulphate, alkyl aryl sulphonates, such as sodium dodecyl benzene sulphonate, olefin sulphonates, such as sodium olefin sulphonate in which the olefin group contains 12-21 carbon atoms, higher alkyl sulphoacetates, higher fatty acid ester of 1,2-dihydroxy propane sulphonates, and the substantially saturated higher aliphatic acyl amides of lower aliphatic amino carboxylic acid compounds, such as those having 12 -. 16 carbons in the fatty acid, alkyl or acyl radicals, and the like< Examples of the last mentioned amides are N-lauroyl sarcosinc and the sodium, potassium, and ethanolamine salts of N-lauroyl, N-myristoyl or N-pa]mitoyl sarcosine, which could be substantially free from soap or similar higher fatty acid material which tends to substantially reduce the effect of these compounds. The use of these sarcosine compounds in dentifrice compositions of the present invention is particularly advantageous since these materials exhibit a prolonged and marked effect in the inhibition of acid formation in the oral cavity due to carbohydrates breakdown in addition to exerting some reduction in the solubility of tooth enamel In acid solution.

Cationic surface active germicides and antibacterial compounds such as di-isobutylphenoxyethoxyethyl dimethyl benzyl ammonium chloride, benzyl dimethyl stearyl ammonium chloride, tertiary amines having one fatty alkyl group (of from 12-18 carbon atoms) and two (poly) oxyethylene groups attached to the nitrogen (typically containing a total of from about 2 to 50 ethanoxy groups per molecule) and salts thereof with acids, and and compounds of the structure.

(CH2CH20)zH (CH2CH20)XH r-n-ch2ch2ch2n (CH2CH20)yH where R is a fatty alkyl group containing from about 12 to 18 carbon atoms, and x, y and z total 3 or higher, as well as salts thereof with mineral or organic acids, may also be used. It is preferred to use from about 0.05 to 5$ by weight of the foregoing surface-active materials in the instant dentifrice.

The liquid humectant vehicle may be-or comprise maltitol and the polishing material a complex alkali metal aluminosilicate. Such dentifrice is visually clear.

In recent years, visually clear dentifrices have been developed which contain a dental cleaning or polishing agent. Such dental cleaning or polishing agents generally have been siliceous in nature with refractive indices of about 1.M+-1.U7. Use of such materials has permitted preparation of dentifrices in which the refractive index of the liquid vehicle matches that of the siliceous polishing agent. This has been typically accomplished using glycerin and/or sorbitol as humectants in the liquid vehicle, since glycerin has a refractive index of 1.^73 and sorbitol (70$ water solution) of 1.1+60. However, since water has a refractive index of 1-333, only very little formula water (i.e. separate from that associated with other components such as sorbitol) could be/VIthout substantially reducing the refractive index and causing dimunition or loss of clarity.

Efforts have been made to develop visually clear dentifrices in which less glycerin and/or sorbitol could be tolerated. For instance: (1) In the U.S. Patent 3,81+2,167 to Block et al maltodextrin was added as a non-humectant component of the liquid phase to reduce the amount of glycerin and/or sorbitol § used needed; (2) in U.S. Patent 3,927,202 to Harvey et al various phosphate non-siliceous polishing agents were used which permitted modification of the refractive index range of the liquid vehicle; in U.S. Patent 4,007,260 to Kim a silica polishing agent having a refractive index of about 1.410 to 1.440 was used.

It is an advantage when dentifrices of the invention comprise maltitol as the humectant that a visually clear dentifrice is provided in which a liquid vehicle is present which comprises a humectant having a refractive index of about 1.48 (e.g. about 1,4750 to about 1.4849) and water.

Additionally increased free water can be used % above that previously used in visually clear dentifrices containing an alkali metal aluminosilicate polishing agent having a refractive index of about 1.44 to about 1.47 and a humectant having a refractive index of about 1.48. The amount of water is not so high as to result in undesirable drying of the dentifrice due to substantial evaporation of water, particularly in view of the presence of maltitol. Other advantages will be apparent from consideration of the following specification. 20093b Maltitol is essentially a glycosyl sorbitol i.e. 4-D- -D-glycopyranosyl-D-glucitol, having the structural formula: ch2oh H ho-ch HO O ho-ch ch2oh It is prepared by hydrogenation of maltose. In substantially pure form it is a glassy solid. It readily dissolves in minor amounts of water and its solutions containing at least about 73% of maltitol and up to about 2 7% of water are observed to have refractive indices of about 1.43. (i.e. about 1.4750 to 1.4849).

When incorporated into a dentifrice together with separately added water of refractive index of about 1.333, the liquid vehicle can be adjusted to provide a refractive index of about 1.44 to about 1.48. Typically, about 5-25% by weight of water can prodice such a refractive index, with the lower amounts of water producing a higher refractive index (e.g. about 1.47) and higher amounts of water (e.g. about 15-23%) producing a lower refractive index (e.g. near 1.44). Preferably, the refractive index of the liquid vehicle is about 1.44 to 1.47 and is attained with about 5-10% by weight of formula water. The water portion of the dentifrice refers to water which is separate or unassociated with water used to dissolve humectant.

Maltitol need not be pure in the sense of being the sugar alcohol derivative of pure maltose. Commercial maltitol consisting of maltitol with minor amounts of the sugar alcohols derived': from maltotriose, maltotetrose, and related low molecule weight maltodextrin portions of corn syrup and with minimal amounts of D-sorbitol. Thus a commercial "hydrogenated starch hydrolysate" made from high maltose content corn syrup would, also be useful.

Organic surface-active agents may be used in the compositions of this aspect of the present invention to achieve increased prophylactic action, assist in achieving thorough and complete dispersion of t;'. the instant compositions throughout the oral cavity, and render the instant compositions more cosmetically acceptable. The organic surface active material may be anionic, nonionic, ampholytic, or caticaiic in nature as indicated above, and it is desirable to employ as the surface active agent a detersive material which imparts to the composition detersive and foaming properties.

An alkali metal fluorine-providing compound may be employed in the dentifrices described herein. The alkali metal fluorine-providing compound includes sodium fluoride, stannous fluoride, stannous chloro-fluoride, potassium stannous fluoride (SnF2-KF), lithium fluoride, ammonium fluoride and ccmplex fluorides, such as potassium fluorozirconate, sodium hexafluoro stannate and alkali metal monofluorophosphates. These compounds have a benefical effect on the caxe and hygiene of the oral cavity, e.g. dimunition of enamel solubility in acid and protection of '' the teeth against decay, exhibit satisfactory retentions of soluble fluoride in dentifrices of the instant invention. In particular, the level of retention of monofluorophosphate ion as fluoride with the alkali metal monofluorophosphates is quite high. The fluorine-containing compound is employed in amount which provides am effective non-toxic amount of fluorine-containing ion to the dentifrice typically about 0.01-1% by weight preferably about 0.U fluorine. Thus, sodium fluoride is typically employed in amount of about 0.02-2% by weight, preferably about 0.2%, and sodium monofluoro-phosphate, Na2P03F, in amount of about 0.1-7.6% by weight, preferably about 0.76%.

The alkali metal monofluorophosphates which may be employed include sodium monofluorophosphate, lithium monofluorophosphate , potassium monofluorophosphate and ammonium monofluorophosphate. The preferred salt is sodium monofluorophosphate, Na2P03F, which, as commercially available, may vary considerably in purity. It may be used in any suitable purity provided that any impurities do not substantially adversely affect the desired properties. In general, the purity is desirably at least about 80%. For best results, it should be at least 85%, and preferably at least 90% by weight of sodium monofluorophosphate with the balance being primarily impurities or by-products of manufacture such as sodium fluoride, water-soluble sodium phosphate salt, and the like. Expressed in another way, the sodium monofluorophosphate employed should have a total fluoride content of about 12%, preferably about 12.7%; a content of not more than 1.5%, preferably not more than 1.2% of free sodium fluoride; and a sodium monofluorophosphate content of at least 12%, preferably at least 12.1%, all calculated as fluorine.

Other monofluorophosphate salts which may be used in the instant invention include monofluoropolyphosphates such as Na^Pg 0^F , K4P3C>9F, (NH4)4P309F, Na3KP3OgF, (NH^)3NaP3OgF and Li4P3°9F.

Any suitable flavoring or sweetening materials may be employed in formulating a flavor for the compositions of the present invention. Examples of suitable flavouring constituents include the flavouring oils, e.g., oils of spearmint, peppermint! mon , lemon and orange, as well as methylsalicylate. Suitable sweetening agents include, sucrose, lactose, maltose, sorbitol, sodium cyclamate, perilla'rtine and saccharine. Suitably, flavor and sweetening agents may together comprise from about 0.01% to 5% or more of the compositions of the instant invention. Chloroform may also be used. Sweetening agents are less necessary when no anionic surface active agent is present, since anionic surface active agents contribute slight bitterness to the dent-if rice.

Antibacterial agents may be <>ninloyed in the described dentifrice in an amount of about 0.01 to 5% by weight. Typical antibacterial agents inlude: N^-(4-chlorobenzyl)-N^-(2,4-dichlorobenzyl)biguanide; P-chloropheny1 biguanlde; 4-chlorobenzhydry1 biguanide; 4-chlorobenzhydrylguanylurea; j N-3-lauroxypropyl-N^-p-chlorobenzylbiguanide; i 1,6-di-p-chlorophenylbiguanid ohexane; 1,6-bis(2-ethylhexylbiguanido)hexane; l-(lauryld imct hylnmmonium)-.8-(p-chl.oro benzyl dim ethyl a mini) n 1 in ) octane diehlor ide5 5,6-dichloro-2-guanidinobenzimidazole; I N^-p--chlor oph eny l-N^-lau ry lb iguan id e ; -amino-l,3-bis(2-ethylhexyl)-5-methylhexahydropyt,imidl no; and their non-toxic acid addition salts.

Various other materials may be incorporated in the preparations of this invention. Examples thereof are colouring or whitening agents or dyestuffs, preservatives, silicones, chlorophyll compounds , nmmonintod inntort/iln micli ns uro.i, d I-ammoniumphosphate and mixtures thereof, and other constituents. The ndjuvnntB arc incorporated In the inntnnt compos LlInns In I amounts which do not Hubstnntlnlly adversely affcct the proper I I <" i nnd character 1st les desired niul arc selected anil used In proper amounts depending upon the particular type of preparation involved. I - 19 ~ Synthetic finely divided pyrogen!c silica such as those sold under the trademarks Cab-O-Sil M-5, Syloid 2kk, Syloid 266 and .Aerosil D-200 may also be employed in amounts of about 1-5% by ■weight to promote thickening or gelling of the described dentifrice The dentifrices should have a pH practicable for use. A moderately acid to alkaline pH is preferred.

The following specific examples are further illustrative of the nature of the dentifrices present invention, although it is understood that the invention is not limited thereto. All amounts are by weight unless otherwise indicated. 200995 EXAMPLES 1-2 The following opacified gel dentifrices are prepared: EXAMPLES l : Glycerine 10.0 10.0 Maltitol 15.0 15.0 Sodium aluminosilicate (silica combined with about 1% combined alumi.ia) Zeo A9B (Huber) 18.0 18.0 Pluronic 108 block copolymer -- 3.0 Sodium lauryl sulfate 1.0 Xanthan 2.0 2.0 Poly ox WSR 301 0.2 0.2 Sodium monofluorophosphate 0.76 0,76 Titanium dioxide 0.4 0.4 Low menthol flavor -- 0.5 Peppermint oil flavor 0.5 Sodium saccharin 0.2 Color solution (1%) 0.05 0.05 Water Q.S. to 100 Q.S. to 100 The dentifrice of Example 1 with sodium lauryl sulfate has desirable foam character . The dentifrice of Example "2.also has very good stable full-bodied foam character even though no anionic surface active agent is employed. The foam remains > throughout the oral cavity, with desirable mouth feel, when the dentifrice is brushed onto the teeth. Moreover, it has no bitter note even though low menthol flavor is present and no sweetener is added. The dentifrices have fine smooth texture and appearaQccj, effectively remove stain and have acceptable dentin abrasion • . I character. They contain flocculated particles of sodium alumino S silicate.

Similar desirabLe results are obtained wben xanthan of Example 2 is ref ■nlatied- with the low-calcium xanthan of Example 1 of U.S. Patent 263,399.

Similar fonm and fool is attained whan other hlook copolymers of polyoxyethylene and polyoxypropylene replace Pluronlc F-108, particularly Pluronlc F 87.

Polyox WSR-301 is available from Union Carbide Corp. as granules of water soluble poly (ethylene oxide) resin having a molecular weight of about *1,000,000 and a Brookfield viscosity of 1650-3850 cps. (25°C, spindle 1, speed 2 rpm) when in water at 1% by weight. Likewise, similar foam and feel is attained when other water-soluble poly (ethylene oxide) resins available from Union Carbide Corp. as Polyox WSR-N-10, WSR-N-80, WSR-N-750, WSR-N-3000, WSR-205 and WSR-1105 replace Polyox WSR-301, in different concentrations.

The silica 'with combined alumina Indicated in Examples is obtained from the J.M. Huber, Corp. of Havre de Grace, Maryland, as Zeo 49 (A or B).

The following clear gel (3 and *0 and opacified gel •*> (5 and 6) dentifrices are prepared: EXAMPLES 3-6 3 6 Glycerine .0 — .0 — Sorbitol . 16.0 — .0 — Maltitol (Active) 16.0 .0 .0 .0 Sodium aluminosilicate (silica with combined alumina) 22.0 18.0 18.0 1.8.0 Pluronlc F-108 Pluronic F- 87 Xanthan 3.0 1.5 '3.0 2.0 .0 2.0 3.0 2.0 Polyox WSR-301 0.2 0.2 0.2 0.2 V / V EXAMPLES Sodium monofluorophosphate Titanium dioxide Low menthol flavor Color solution (155) Water _3 o~JS l\ oTTS 77 oTTS o77f> — o.'i o Ji 0.5 0.5 0.5 0.5 0.05 0.05 0,05 0.05 Q.S.tolOO Q.S.tolOO Q.S.tolOO Q.S.tolOO The dentifrices of Examples 3 and 4 are clear and those of Examples 5 and 6 are opacified. They have smooth texture. All four have very good stable full-bodied foam, with that of the dentifrice of Example 5 being more full then with the dentifrices of .Examples 3 and 4. A higher amount of foam occurs with the dentifrices of Example 6. All foams provide desirable mouth feel throughout the entire oral cavity during tooth brushing. There are no bitter notes. The dentifrices effectively Jj remove stain and have acceptible dentin abrasion. They contain 'j flocculated particles of sodium aluminosilicate.

The following dentifrices are prepared: EXAMPLES 7-11 Maltitol (ACTIVE) 7 8 9 11 .. 0 .0 ■ 30.0 .0 .0 Sodium aluminosilicate (silica with combined alumina) 12.0 12.0 12.0 18.0 .0 Calcined alumina .0 .0 .0 .0 2.0 Pluronic F-108 3.0 3.0 3.0 3.0 . 3.0 Xanthan 2.0 2.0 2.0 1.7 2.0 Polyox WSR-301 WSR-1105 WSR-N-750 0.2 0.2 1.0 0.2 .0.2 Sodium monofluorophos-phate 0.76 0.76 0.76 0.76 0.76 Titanium dioxide 0.4 0.4 0.4 0.4 ■0.4 Low menthol flavor 0.5 0.5 0.5 0.5 0.5 Water 1 fa» Q.S.

Q.S.

Q.S.

Q.S. to 100 to 100 to 1-00 -to-'100 to--100^ C * \J \J / The dentifrices of Examples 7-11 provide high cJoanlnr. effectiveness and have good, stable, full-bodies foam. Tltoy /smooth hnvo/tcxturc, with the dcntlfri cats of Examples 7,10 and 11 containing' Polyox WSH-301 having the bout texture. All foam to provide desirable mouth fool throughout the entire oral cavity during toothbrushing. There are no bitter notes. They effectively remove stain and have acceptable dentin abrasion. They contain flocculated particles of sodium aluminosilicate.

The following dentifrices are prepared: EXAMPLES 12-15 ~12~ TT 14 15' Glycerine 10.0 10.0 10.0 10.0 Sorbitol 15.0 15.0 15.0 15.0 Maltitol(Active) 15.0 .15.0 15.0 15.0 Dicalcium phosphate dihydrate 30.0 30.0 15.0 15,0 Anhydrous dicalcium phosphate — — 10.0 ' ■— Calcined alumina — — — • 10.0 Pluronlc F-108 3-0 3.0 3-0 3-0 Xanthan 2.0 2.0 2 . 0 ?.. 0 Polyox WSR-301 ~ 0.2 0.2 0.2 Sodium monofluoro- phosphate 0.76 0.76 0.76 0.76 Titanium dioxide 0.1 0.1 0.1 0.1 Low menthol flavor 0.5 0.5 0.5 .0.5 Water Q.S.tolOO Q.S.tolOO Q.S.tolOO Q.S.tolOO The dentifrices of Examples 12-15 provide good, stable full-bodied foam. Those of Examples 13-15 (which contain the Polyox material) have particularly fine, smooth texture. The foam from all gives desirable mouth feel throughout the oral cavity during toothbrushing. Even though no sweetener is used, the dentifrices aro quite sweet in taste. / 200995 EXAMPLES 16-17 The following opacified gel dentifrices are prepared: PARTS 16 17 >0.00 *10.00 ' 18.00 18.00 3.00 3.00 1.70 1.70 0.20 V 0.1*0 0.U0 0.50 0.50 0.20 0.20 Q.S. TO 100 Q.S. TO 100 Both dentifrices provide stable full-bodied foam with good mouth feel; the mouth feel of dentifrice 16 being particularly satisfactory. "• When compared for ability to remove dental stain and in dentin abrasion, the dentifrice of Example 16 containing the Polyox material removes more stain with less dentin abrasion than the dentifrice of Example 17, without Polyox material. In the dentifrice of Example 17, flocculated particles of sodium aluminosilicate form in situ.

Maltitol (75$ solution) Sodium aluminosilicate (silica containing about 1$ combined alumina - Zeo ^9B-Huber) Pluronic F 108 Block Copolymer Xanthan Polyox WSE 301 (Union Carbide) Titanium dioxide Flavor Sodium saccharin Deionized water The results are as follows DENTIFRICE PERCENT STAIN REMOVAL RADIOACTIVE DENTIN ABRASION 16 14 17 22 39 In a stain removal test, sections of human dental enamel are etched with 0.IN HC1 for 2 minutes, rinsed with water, then wet with a dilute solution of stannous fluoride, wiped dry, and finally exposed to a stream of hydrogen sulfide gas which results in the deposition of a brown deposit of stannous sulfide. The amount of stain on the surface is measured with a Gardner Automatic Color Difference meter. The surface is then brushed with a mechanical brushing machine for 500 reciprocal strokes with a slurry of a dentifrice and the residual stain measured with the meter. Finally, the stain which remains is completely removed with dental pumice and the reflectance of this surface is read. The ability of a dentifrice to remove.the stain is expressed by the following equation.

Percent Stain removed' where Rdinitial, Rd 500 strokes, and Rdpumiced are respectively the reflectance values measured on the initially stained surfaces, after brushing for 500 reciprocal strokes and after removing the residual stain by pumicing.

The RDA values are obtained by a procedure based on a radioactive technique described in the literature; Stoo key, C. K. and: Muhler, J. C., J. Dental Research. 47 524 -538(1968).

^Rd 500 strokes " Rdinitial) 100 Rdpumiced " Rdinitial 1 3 f H^CErf VZD 26 EXAMPLE 18 The following dentifrice is prepared and compared with the dentifrice of Example 10.

Maltitol (75$ solution) Sodium aluminosilicate (silica containing about 1$ combined aluraina-Zeo 1+9B - Huber) Calcined alumina Pluronic F-108 Xanthan Titanium dioxide Flavor Sodium saccharin Deionized water PARTS UO.00 (30.00 active) 18.00 5.00 3.00 1.70 O.UO 0.50 0.10 Q.S, to 100 The dentifrices of Example 10 and 18 both provide stable full-bodied foam with good mouth feel; the mouth feel of dentifrice 1° being particularly satisfactory.

The following stain removal and radioactive dentin abrasion results were obtained with the dentifrices of Examples 10 and 18 evidencing superiority for the dentifrice of Example 10 containing the Polyox material with regard to higher stain removal with similar dentin abrasion.

DENTIFRICE 10 18 PERCENT STAIN REMOVAL. 65 RDA w W:

Claims (14)

WHAT WE CLAIM IS:

1. A dentifrice comprising 20-80% by weight of a liquid humectant vehicle, 0.5-7% by weight of xanthan gum and 1-10% by weight of a surface active agent, said surface active agent being a nonionic polyoxyethylene-polyoxypropylene block copolymer surface active agent.

2. The dentifrice claimed in claim 1 wherein resinous poly (ethylene oxide) is present in amount of 0.1-5% by weight.

3. The dentifrice claimed in claim 1 or 2 wherein said block copolymer is a solid material.

4. The dentifrice claimed in claim 3 wherein .said solid block copolymer contains 80% by weight polyoxyethylene and the molecular weight of said polyoxypropylene is 3250 or 70% polyoxyethylene and the molecular weight of said polyoxypropylene is 2250.

5. The dentifrice claimed in claim 2 wherein 1.5-3% by weight of xanthan and 0.1-1.5% by weight of said resinous poly (ethylene oxide) is present.

6. The dentifrice claimed in either of claims 1 and 2 wherein said liquid humectant vehicle comprises glycerine, sorbitol, maltitol or a mixture thereof.

7. The dentifrice claimed.in any one of claims 2 - 6, wherein said dentifrice contains 5-50% by weight of a siliceous polishing material, said dentifrice containing flocculated particles formed by said siliceous polishing material in the presence of said poly(ethylene oxide).

8. The dentifrice claimed in claim 7 wherein said resinous poly(ethylene oxide) has a reduced viscosity of at least 0.5 as measured at a concentration of 0.2 gram of said poly(ethylene oxide) in 100 milliliters of acetonitrile at 30°C.

9. The dentifrice claimed in claim 8 wherein said resinous poly(ethylene oxide) is present in an amount of 0.1-1.5% by weight.

10. The dentifrice claimed in any one of claims 7 to 9 wherein said siliceous polishing material is a complex alkali metal aluminosilicate having a refractive index of from 1.44 to 1.47.

11. The dentifrice claimed in claim 10 wherein said alkali metal aluminosilicate is sodium aluminosilicate wherein silica is combined with 0.1-3% alumina.

12. The dentifrice claimed in any one of claims 7 to 11 wherein said flocculated particles have an apparent particle size of 44 to 177 microns.

13. The dentifrice claimed in any one of claims 7 to 12 wherein maltitol is present :as humectant.

14. The dentifrice claimed in any one of claims 6 .to 12 wherein said dentifrice is visually clear. ATTORNEYS FOR THE APPLICANT - 29 -