Therapeutic dentifirices in unlined container and method

(74) Agent

Tandbergs Patentkontor AS, Oslo.

(56) Cited publications

<img file="NO149093B_D0001.tif" />

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a toothpaste containing a caries inhibiting fluorine compound, a liquid phase and a solid phase, which, after being packed in an unlined aluminum tube, will cause corrosion and staining of the tube, is stabilized so that no such staining occurs. of the tube during extended contact with the toothpaste.

Dental care agents such as toothpaste may contain a caries-inhibiting fluorine compound such as tin fluoride, monofluorophosphate or derivatives thereof, as well as polishes, humectants and other materials. These toothpastes are usually placed in aluminum or plastic tubes for sale on the market. It is generally preferred to use aluminum tubes, but it has been found that when such a toothpaste contains a caries-honing fluorine compound, a reaction occurs between the interior of the unpainted aluminum tube so that staining and other corrosive action occurs apparently due to a reaction or incompatibility between the clean aluminum surface and one or more of the materials in the toothpaste. This incompatibility comes in the form of gas production, tube swelling, corrosion and black spots on the inside of the unpainted aluminum container. Accordingly, the usual practice of marketing such toothpastes today has been to feed the aluminum tube with plastic, varnish or finished material, which therefore significantly increases the packaging costs and marketing of the toothpaste.

Many previous attempts have been made to solve this problem because unlined aluminum tubes are much more economical to use and generally lighter in weight than the spring tubes. U.S. Patent Nos. 3,662,060 and 3,624,199, for example, disclose dental care products which are said to overcome this problem. Further, U.S. Patent No. 3,678,155 discloses that monofluorophosphate ions prevent corrosion of unpainted aluminum tubes when the toothpaste contains ground α-alumina trihydrate as abrasive. Also, U.S. Patent 3,864,471 discloses a dentifrice containing a monofluorophosphate and a polishing agent containing alkaline earth metal carbonate and insoluble alkali metal phosphate, alumina, or mixture thereof, to reduce corrosion in unalloyed aluminum containers.

Accordingly, it is an object of the invention to overcome or otherwise mitigate these known problems.

The process of the invention is characterized by incorporating into the toothpaste a soluble alkaline earth metal compound in such an amount that 0.005 to 0.20% by weight of the alkaline earth metal is provided in the toothpaste. or that as part of the solid phase an amorphous precipitated silica prepared by acidifying an alkali metal silicate in a sulfate liquid medium is used and which has been reacted with a soluble alkaline earth metal compound in a sufficient amount to provide 0.005 to 0.20% by weight of alkaline earth metal in the toothpaste.

As previously stated, it has not been possible to produce a commercially usable product that can be packaged in unsealed aluminum tubes due to incompatibility problems between the aluminum surface and the other components of the dentifrice, especially fluorides, after the introduction of caries-inhibiting dentifrices. Although considerable work has been done in an attempt to overcome this problem as shown by the prior art, there are still problems in this field. The present invention overcomes problems of this type in a commercially feasible manner and so that fluoride-containing dentifrices can be packaged and sold in unalloyed aluminum tubes.

It has been found that the problem of corrosion of unlined aluminum tubes when formulated with a caries inhibitor dentifrice can be overcome by incorporation into the toothpaste of a controlled amount of an alkaline earth metal. The alkaline earth metal which is primarily considered in accordance with the present invention is especially calcium, but magnesium or strontium can also be used. Calcium is preferred because of its easy accessibility, relatively low price and the easy incorporation of the dentifrice. The metal can be incorporated into the toothpaste in any substantially water-soluble form such as nitrate, hydroxide or chloride. The most preferred materials for incorporation into the toothpastes include calcium nitrate, calcium hydroxide and calcium chloride. It should also be noted that organic salts such as calcium acetate and calcium formate can be used. Similarly, strontiurogenic magnesium salts can also be used. The only limitation with respect to the alkaline earth metal salt is that it is essentially soluble and that it stabilizes the toothpaste so that it does not corrode an unprocessed aluminum tube.

There are, of course, known dentifrices and other toothpaste preparations in the art that contain calcium salts in considerable quantities as described e.g. in U.S. Patent 3,864,471 containing 40-50% calcium carbonate, and U.S. Patent 3,624,199 containing 20-75% calcium carbonate. However, the calcium carbonate is generally insoluble and not effective in inhibiting the corrosion of the tube. Therefore, an important feature of the present invention is the carefully regulated amount of water-soluble alkaline ion incorporated into the toothpaste. According to the invention, the controlled amount of alkaline earth metal ion present must be sufficient to be effective and available to stabilize the toothpaste so that the aluminum tube does not corrode upon prolonged contact with the toothpaste but insufficient to stoichiometricly affect available fluoride in the toothpaste. According to the present invention, it has been found that the amount of alkaline earth metal that must be present to stabilize the toothpaste is at least 50 parts per minute. million, or 0.005% by weight, and not more than 2000 parts per mill. million, or 0.2% by weight to prevent the effect on available fluoride. Therefore, the amount of alkaline earth metal to be present ranges from 50 - 2000 parts per unit. million or 0.005 to 0.2% by weight based on the toothpaste.

As indicated above, the alkaline earth metal ion can be incorporated into the toothpaste as any water-soluble salt. However, it is also within the scope of the present invention to provide the alkaline earth metal ion in combination with silica (with silica is meant herein SiO₂). According to a feature of this embodiment, a controlled structure of amorphous precipitated silica can be incorporated into the toothpaste in sufficient amounts to supply the necessary alkaline earth metal, such as calcium ion, to stabilize it. These precipitated structured silica oxides of dentifrice grade contain calcium ions on the silica surface of the precipitated silica abrasive.

The precipitated silicon dioxides of regulated structure and of dental care grade are new products available from JM Huber Corporation and are silicon dioxide products of the type described e.g. in U.S. Patent Nos. 3,960,586 and 3,928,541 which have been treated with an alkaline earth metal salt to provide alkaline earth metal ions in the product. The products described in these patents are precipitated silicic acid or silica pigments which are prepared by acidifying an alkali metal silicate as sodium silicate and an acid as sulfuric acid, in the presence of a salt or electrolyte such as sodium sulfate. The precipitated silicates formed by the reaction in which sulfate is a necessary reagent in the process can be described as sulfate liquid products. After preparing the precipitated silica in the form of wet cakes, and after washing, these are resuspended in water and treated with a soluble alkaline earth metal salt such as calcium hydroxide, calcium nitrate or calcium chloride, in sufficient quantities to incorporate the required amount of alkaline earth metal ions directly into silicon dioxide. The reaction between silica and alkaline earth metal is carried out at ambient temperature and with stirring. The amount of alkaline earth metal ions introduced will be sufficient to provide the required amount of alkaline earth metal ions in the toothpaste, but be brought into line with any desired amount of alkaline earth metal ions incorporated directly into the toothpaste.

Thus, it is to be understood that the amorphous silica material is pretreated with the critical concentration of alkaline earth metal material and then incorporated into the toothpaste in the required amounts. These silica materials provide good cleaning properties at RDA values ​​of between 200 - 400 (RDA - Grabbenstetter et al. Jour, of Dental Research, 37, 1060, 1958).

The precipitated silica is preferably prepared by adding 3-15% by weight of aqueous solution of alkali metal sulfate, preferably sodium sulfate, to a reactor and adding an alkali metal silicate solution, preferably a sodium silicate solution, to raise the pH to 8-10.4. This leads to prepolymerization of alkali metal silicate. The aqueous sodium silicate solution should have a silicate concentration range of 10-25% by weight, and preferably 18 to 22% by weight, and a composition of

Now₂O-2.6 SiO₂ to get the best results. The aqueous solution is then heated to a temperature of 66 to 83 ° C and with continuous stirring of the solution and acidified by the addition of an aqueous solution of an inorganic acid with a concentration of 10 to 25% by weight at a substantially constant pH in the range of from 8 , 0 to 10.4. Preferably, the inorganic acid and the alkali metal silicate are added at the same time as described in US Patent 3,960,586. For the purpose of preparing base precipitated silica, reference is made to U.S. Patent Nos. 3,960,586 and 3,928,541. The inorganic acid is preferably sulfuric acid since sulfuric acid gives the best results as disclosed in U.S. Patent 3,960,586, but other acidifying agents such as nitric acid, phosphoric acid, hydrochloric acid and carbonic acid may also be used. The period of time over which the alkaline metal silicate and / or sulfuric acid is added to the reactor can be predetermined and is generally based on the volume of the reactor and the difficulties in regulating the volume of the reactor and difficulties in regulating the temperature and stirring.

After complete addition, the acidifying acid is added until the pH of the slurry falls below approx. 6.0 and preferably in the range of 4.8 - 5.0. The resulting slurry is the precipitated silica contained in the reaction medium.

After reaching a pH of less than 6.0, the slurry is heated again for a period of 10 to 30 minutes at a temperature of 10 to 30 ° C above the reaction temperature and the pH of the reaction mixture is adjusted again if necessary. The resulting slurry is then filtered and washed with additional water to remove any by-product such as sodium sulfate which may be contained in the silica product.

By filtration and washing of the wet silica wafer cake, the material is subjected to a treatment with alkaline earth metal ions. The wet-washed filter cake is re-suspended in its own water or by the addition of fresh water at ambient temperature with stirring. While this slurry is under stirring, it is treated with sufficient alkaline earth metal ions, and preferably calcium ions in the form of substantially soluble salt, to provide sufficient alkaline earth metal ions corresponding to 30 to 2000 parts per million. million parts, intimately associated with the Hi niiiic dioxide, this amount being based on 100 parts of dentifrice. The amount of alkaline earth metal ions added is based on the total weight of the dry product contained in the wet cake form which is firmly recyclable. Since the amount of abrasives may vary in dentifrices, the amount of alkaline earth metal salt will also vary.

The alkaline earth metal ion added at this step is preferably calcium ion due to its easy availability, low cost and easy incorporation into the silicon dioxide. The calcium ions can be incorporated into cilium dioxide. at this stage in any substantially water-soluble form such as nitrate, hydroxide or chloride, but calcium hydroxide is preferred. Nutritional quality salts should be used. By soluble salt is meant that any reasonably soluble salt of calcium can be used since it is only necessary to provide extremely small amounts of the calcium ions in the mixture. Also organic salts such as calcium acetate and calcium formate can be used. The corresponding strontium and magnesium salts of the alkaline earth metal classes can also be used. The only limitations imposed on the alkaline earth metal salt are that they are sufficiently water soluble to form ions and do not present any safety problems in the resulting toothpastes and provide the necessary fluoride compatibility.

After treatment with alkaline earth metal ion, the cake slurry is again vigorously stirred for 10-20 minutes, preferably 15 minutes to provide an effective concentration of alkaline earth metal for treating the surface of the silica abrasive. The resulting product is then filtered, spray dried, preferably at an inlet temperature of 483 ° C and an outlet temperature of 122 ° C as known in the art, and then milled to the desired degree of fineness.

The precipitated amorphous silica used in this embodiment can be characterized by the following combination of properties:

Absorption Rub-Out Method (ml / 100 g) = 80-120

BET surface area (m²/ g) = 7.5-325

MSA average aggregate size 3

Space density (kg / cm).

(/ U) = 1-10 = 160-480

49093

Other types of silica polishes, including xerogels as disclosed in U.S. Patent No. 3,538,230, may also be used. Commercially available xerogels such as Syloid 63 can be used when incorporated with controlled amounts of calcium ion or alkaline earth metal ions or pre-treated with calcium ion or alkaline earth metal ions as described herein. It is also to be understood that sodium aluminum silicate polishes can be formulated in the toothpastes when the sodium aluminum silicate materials are combined with the critical amounts of alkaline earth metal as described herein.

As known in the art, a dentifrice may contain e.g. wetting agents and binders to give the dentifrice a smooth texture and good flowability. The specific formulations of toothpastes are well known in the art and are e.g. disclosed in U.S. Patent Nos. 2,994,642 and 2,538,230 and numerous publications. A further detailed description of dentifrice formulations is given in U.S. Patent No. 3,726,961.

In this regard, dentifrice formulations have been prepared varying from liquids and powders to the very popular pastes or toothpastes. Toothpastes are more difficult to put together with a good result in that they require careful balancing of polish, wetting agent, water, binder, preservative, detergents, flavoring, sweetening and caries inhibitors to provide a smooth homogeneous paste.

Most toothpaste formulations use one or more phosphate materials as a polishing agent. Examples of phosphate polishes are dicalcium phosphate, anhydrous dicalcium phosphate, tricalcium phosphate, thermally converted dicalcium phosphate and insoluble sodium metaphosphate. The amount of phosphate materials added to the toothpaste formulations will vary between 5 and 60% by weight.

The most widely used moisturizers in toothpaste are glycerol and sorbitol. Propylene glycol is also used in small quantities and to a very limited extent. The primary function of the humectant as part of the liquid phase is to maintain moisture which provides good consistency and maintains an attractive glossy appearance when the paste is exposed to air.

The binder is used to prevent separation of the liquid phase and the solid phase. The most conventionally used binding agents are seaweed colloids and synthetic derivatives of cellulose, especially carrageenan and sodium carboxymethyl cellulose. Rubber has also been used. Combinations of these binders have also been used.

Since the natural and synthetic water dispersions of organic binders are subjected to microbial or mold attack, a relatively small amount of preservatives is added to the paste. Examples of preservatives used in the industry are the esters of parahydroxyl benzoates.

The function of the detergents in the toothpaste formulation is to provide greater cleaning effect due to the reduction of surface tension and foam effect in the mouth. Among the detergents used are sodium N-lauryl sarcosinate, sodium lauryl sulfate, sulfoculaurate, sodium alkylsulfoacetate and sodium dioctylsulfosuccinate.

As the flavoring in the toothpaste is likely to represent the factor in the toothpaste that is most important to the consumer, great care is taken when selecting balanced blends of various essential oils. These are rarely used, if at all, alone. Combinations of main flavors are winter green oil, peppermint and sassafras, and these are used with secondary oils such as pimento, spice and anise.

Saccharin and sodium cyclamate are widely used to improve the taste and enhance the taste quality of the toothpaste. The synthetic sweeteners can be used in combination to achieve optimum sweetness and aftertaste. Their desirable properties are obtained at very low concentrations and consequently have negligible influence on the consistency of the toothpaste.

Since water is such a common ingredient, it is important to obtain substantially pure water for obtaining stable toothpaste formulations. It is common practice to demetallize the water used.

It is also within the scope of the invention to provide the proper amount of alkaline earth metal in the toothpaste by pretreating the water with an alkaline earth metal compound so that the water used can serve as the alkaline earth metal source.

The invention is adapted to any of the caries inhibitors currently used in toothpastes including alkali metal fluorides such as sodium fluoride, sodium fluorophosphate and tin fluoride, all of which are well known.

In general, such dentifrices will normally contain 5 50% by weight of polishing agent, up to 1% by weight of fluoride-containing caries inhibitor, 30 - 40% by weight of deionized water, and the remainder being liquid phase carrier materials such as glycerol and sorbitol. As stated above, the toothpaste will also contain from 0.005 up to 0.20 parts of the alkaline earth metal ion, preferably calcium ion, based on the toothpaste. It has been found that this amount of alkaline earth metal ion is sufficient to stabilize the toothpaste, but is insufficient to affect the available fluoride in the toothpaste, and thus will not affect the caries inhibitory effect of the dentifrice.

Regarding the incorporation of the regulated amount of alkaline earth metal ion .. the toothpaste should be noted that in Degussa Technical Bulletin no. 49 there is a description of an Aerosil® 200 polishing agent for use in lime toothpaste, and it is stated on page 8 of this bulletin that in toothpastes containing the cheaper polishing agent lime, the use of Aerosil® 200 is advantageous to the extent that the less expensive unpainted aluminum tubes can be used since corrosion protection of unpainted aluminum tubes is obtained by forming very small amounts of insoluble calcium silicate from this agent. Minimum 1% Aerosil 200 is required. However, on page 8 of the same bulletin it is stated that even with the use of Aerosil® it is not possible to achieve effective corrosion protection for untreated aluminum tubes when the toothpaste contains fluorine in the form of monofluorosodium phosphate. However, this publication on page 8 states that when 3-5% by weight of slightly hydrated alumina W-16 is incorporated into the fluoride-containing toothpaste, corrosion protection can be achieved. Contrary to the teachings of this Technical Bulletin, it has now been found that fluorine-containing toothpastes can be placed in unaffected aluminum tubes if a controlled amount of alkaline earth metal ion is placed therein.

Regarding the incorporation of silica products into the dental care products, it should be understood that all silica products and raw materials have random amounts of calcium present. For example, trade publications for xerogels sold as Syloid 63 indicate the presence of 0.01% calcium as calcium oxide. This corresponds to 0.007% calcium or up to 70 parts per day. million in

Syloid® 63. However, since only up to 35% by weight of the silica products can be incorporated into the toothpaste, this inevitably indicates that the resulting dentifrices may contain only 0.0035% calcium oxide or 25 ppm calcium, an insufficient amount to provide corrosion protection. It should also be noted that the precipitated silica from JM The Huber Corporation, as described above, tends to absorb or react with calcium ions, making these process fruits very attractive for combination with the correct amount of calcium ions and incorporation into the toothpastes, since the silica also provides excellent abrasive properties to the toothpaste.

The silica abrasives disclosed herein are used at concentrations up to 15-30% by weight in the dentifrice. Therefore, they should contain a minimum of 168 ppm calcium at 30 wt%, and 336 ppm at 15 wt% to provide the minimum amount of calcium. However, they can also contain up to 7,000 ppm or more.

The following specific examples illustrate the invention. The toothpastes are prepared in a conventional manner and all amounts of the various ingredients are by weight unless otherwise indicated. In the following examples and throughout the description, parts are by weight, unless otherwise stated.

examples

In the following examples, toothpastes were prepared and compared with commercial products or control samples. When assessing the toothpastes, a diagram was used to grade the inner tube wall to determine the presence or absence of staining and corrosion. As a basis for the diagram, each paste was prepared and then aged at 49 ° C for 9 weeks. Percent soluble fluoride ion and tube compatibility data were determined periodically during the 9 week storage stability period. In this study, every three weeks under the aging conditions (49 ° C) corresponds to approx.

years of aging at room temperature. During the examinations, the unpainted tubes containing the toothpastes were periodically opened and examined for staining / corrosion on the inner tube wall. The following basis was used for grading the tube properties of the toothpastes;

<td colspan="2">grading</td><td colspan="2">Inner tube wall</td>

<td></td><td> 10</td><td>No air on the wall,</td><td>no discoloration on the wall</td>

<td> 8 -</td><td> 9</td><td>No air on the wall,</td><td>light gray stain on wall</td>

<td> 6 -</td><td> 7</td><td>Air on the wall,</td><td>light gray stain on the wall</td>

<td> 4 -</td><td> 5</td><td>Air on the wall,</td><td>gray stain on the wall</td>

<td> 2 -</td><td> 3</td><td>Air on the wall,</td><td>dark gray stain on the wall</td>

<td></td><td> 1</td><td>Air on the wall,</td><td>black staining</td>

with corrosion of the wall, the alkaline earth metal was calcium nitrate to

In all calcium, and to provide the following examples, was added as soluble indicated amount of calcium in each toothpaste.

Examples 1-4 Dental care agents in which calcium was added to the toothpaste

The following dentifrices were prepared with a low-structure silica polish which is an amorphous precipitated silica wavelength and a known concentration of calcium was added to give tube compatibility properties.

Examples 1-4

Composition

<td></td><td> 1</td><td> 2</td><td> 3</td><td> 4</td>

<td>Sodium monofluorophosphate</td><td> 0,76</td><td> 0,76</td><td> 0,76</td><td> 0,76</td>

<td>Lavstruktursiliciumdioxvd</td><td> 30,00+</td><td> 29,970</td><td> 29,941</td><td> 29,587</td>

<td>Calcium as water soluble</td><td></td><td></td><td></td><td></td>

<td>Ca (NO₃)₂ · 4H₂O ++</td><td> 0,00</td><td> 0,0295</td><td> 0,059</td><td> 0,413</td>

<td>Glycerol,</td><td> 23,00</td><td> 23,00</td><td> 23,00</td><td> 23,00</td>

<td>Natriumcarboxymethyl-</td><td></td><td></td><td></td><td></td>

<td>cellulose</td><td> 1,30</td><td> 1,30</td><td> 1,30</td><td> 1,30</td>

<td>Hydrated alumina</td><td> 1,00</td><td> 1,00</td><td> 1,00</td><td> 1,00</td>

<td>Sodium</td><td> 2,00</td><td> 2,00 '</td><td> 2,00</td><td> 2,00</td>

<td> benzoate</td><td> 0,50</td><td> 0,50</td><td> 0,50</td><td> 0,50</td>

<td> saccharin</td><td> 0,20</td><td> 0,20</td><td> 0,20</td><td> 0,20</td>

<td>Flavorings</td><td> 0,90</td><td> 0,90</td><td> 0,90</td><td> 0,90</td>

<td>Water (deionized)</td><td>Campfire-</td><td>Campfire-</td><td>Campfire-</td><td>Campfire-</td>

<td></td><td>regarded</td><td>regarded</td><td>regarded</td><td>regarded</td>

<td>Overall</td><td> 100,00</td><td> 100,00</td><td> 100,00</td><td> 100,00</td>

,,: see next page t ++: low-structure silica containing 5 ppm calcium ++: the conversion factor of calcium nitrate 4H-0 to calcium is 5.9. The molecular weight of CaiNO 2) 2^Η2θ ⁶³⁷ The aton weight for calcium is 40. Therefore, 236 parts of calcium nitrate · 4H0 gives 40 parts of calcium ion, or 236/40 or 5.9 parts of calcium nitrate · ΊΗ ^ Ο, ^z which is equivalent to one part of calcium.

In toothpastes 2, 3 and 4 were calcium nitrate. 41 µ0 added, which corresponds to a calcium concentration of 0.0295 / 5.9 or 50 ppm (0.005%); 100 ppm (0.01%) and 700 ppm (0.07%) respectively. The tube compatibility data for these examples are given in the following Table 1.

TABLE 1 Rating of tube properties-49 ° C aging study

<td></td><td></td><td></td><td>weeks</td><td></td><td></td>

<td>toothpaste</td><td> 0</td><td> 1</td><td> 3</td><td> 6</td><td> 9</td>

<td> 1</td><td> 10</td><td> 4</td><td> 3</td><td> 3</td><td> 1</td>

<td> 2</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

<td> 3</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

<td> 4</td><td> ' 10</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

It is clear from the above data that toothpaste 1 was unacceptable in terms of tube compatibility properties, because it did not contain the minimum critical calcium concentration in the caries inhibitor dentifrice.

Examples 5-8

The following dentifrices were prepared wherein the content of sodium monofluorophosphate in each is equivalent to 0.1% fluoride ion.

Composition

<td>Sodium monofluorophosphate</td><td> 0,76</td><td> 0,76</td><td> 0,76</td><td> 0,76</td>

<td>Lavstruktursiliciumdioxyd</td><td>30.00 (A)</td><td>30.00 (B)</td><td>30.00 (C)</td><td>30.00 (D)</td>

<td>glycerol</td><td> 23,00</td><td> 23,00</td><td> 23,00</td><td> 23,00</td>

<td>sodium</td><td> 1,30</td><td> 1,30</td><td> 1,30</td><td> 1,30</td>

<td>Hydrated alumina</td><td> 1,00</td><td> 1,00</td><td> 1,00</td><td> 1,00</td>

<td>Sodium</td><td> 2,00</td><td> 2,00</td><td> 2,00</td><td> 2,00</td>

<td> benzoate</td><td> 0,50</td><td> 0,50</td><td> 0,50</td><td> 0,50</td>

<td> saccharin</td><td> 0,20</td><td> 0,20</td><td> 0,20</td><td> 0,20</td>

<td>Flavorings</td><td> 0,90</td><td> 0,90</td><td> 0,90</td><td> 0,90</td>

<td>Water (deionized)</td><td> 40,34</td><td> 40,34</td><td> 40,34</td><td> 40,34</td>

<td>Total</td><td> 100,00</td><td> 100,00</td><td> 100,00</td><td> 100,00</td>

<td>(A)</td><td colspan="2">low-structure silicon dioxide i</td><td>toothpaste</td><td> 5</td><td>contained</td><td> 5</td><td>ppm</td><td>calcium</td>

<td>(B)</td><td>II</td><td>II</td><td>II</td><td> 6</td><td>II</td><td> 168</td><td>II</td><td>t!</td>

<td>(C)</td><td>it</td><td> 11</td><td>II</td><td> 7</td><td>II</td><td> 406</td><td> 11</td><td>II</td>

<td>(D)</td><td>II</td><td>II</td><td>tf</td><td> 8</td><td>II</td><td> 688</td><td> 11</td><td>II</td>

Low Structure Silicon Dioxide: Soft was used in Examples 5, 6, 7 and 8, characterized by the following combination of properties: 01 Absorption - Rub-Out Method (cc / 100 mg) = 80-120

BET surface area (m²/ g) = 75 -325

MSA mean aggregate size (microns) = 1-10

Space density (kg / m³) = 160 -480

The calcium treated low structure silica in toothpaste »

5, 6, 7 and 8 were prepared following the following procedure:

Dry sodium sulfate was added to 37.8 liters of water in a 750 liter reactor so that the sodium sulfate concentration in the reaction medium was 10%. The pH of the reaction medium was then adjusted to 9.0 by the addition of sodium silicate. The reaction temperature was 65 ° C. The sodium silicate solution had a SiO 2 · Na₂0 molar ratio of 2.5, and a concentration of 239 g / liter. Sodium silicate was then added to the reaction medium for 4 minutes. At this point, the sodium silicate addition was stopped and sulfuric acid at a concentration of 11.4% was added to the reaction medium until a pH of 9.0 was reached. At this point, the sodium silicate solution and the sulfuric acid solution were added simultaneously over a period of 35 minutes. At the end of this 35 minute period of silicon addition, the silicon addition was terminated and the acid addition continued until a slurry having a pH of 5.5 was obtained. The mixture was digested at 77 ° C for 20 minutes and the resulting wet cake recovered and washed.

The wet cake was then divided into four separate portions and processed according to the following procedure.

Each portion of wet filter cake was then resuspended without water addition at ambient temperature and with stirring. While the slurry was under stirring, it was treated with sufficient Codex (US purity food grade) hydrated lime (calcium hydroxide) to provide the amount of calcium ion as described in toothpastes 5, 6, 7 and 8. The amount of calcium hydroxide was based on the weight of dry, recyclable, solid product in the wet cake. After treatment with calcium ion, the cake slurry was vigorously stirred for 15 minutes to provide an effective degree of calcium ion treatment on the surface of the silica abrasive. Each resulting product was then spray dried at an inlet temperature of 483 ° C and an outlet temperature of 122 ° C, ground and characterized.

Toothpastes 5, 6, 7 and 8 were aged at 49 ° C for nine weeks and tube compatibility data were determined periodically during the nine-week storage period. The results for the tube compatibility properties are listed in the following Table 2.

o

TABLE 2 Rating of tube properties - 49 C aging study

<td></td><td></td><td></td><td>weeks</td><td></td><td></td>

<td>toothpaste</td><td> 0</td><td> 1</td><td> 3</td><td> 6</td><td> 9</td>

<td> 5</td><td> 10</td><td> 4</td><td> 3</td><td> 3</td><td> 1</td>

<td> 6</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

<td> 7</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

<td> 8</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

<td></td><td>It is observed</td><td>from</td><td>table</td><td>2 at</td><td>toothpaste 5 effected</td>

a severe degree of black staining and corrosion on the tube wall after 9 weeks of aging. Toothpaste 6, 7 and 8 were stable and showed excellent tube compatibility properties. Thus, it is clear that when a silica polish contains a minimum critical concentration of calcium, the unlined aluminum tubes do not corrode.

<td>Examples 9-11</td><td>Stabilization of calcium xerogel caries inhibitors</td>

Caries-inhibiting dentifrices were prepared with xerogel polishes. All toothpastes contained a known concentration of calcium ions (added as water-soluble calcium nitrate) with the exception of toothpaste 9. The toothpastes were prepared by known methods and packaged in unlined aluminum tubes. All amounts of the various constituents were by weight unless otherwise indicated.

The following toothpastes were prepared. The sodium monofluorophosphate content in each was equivalent to 0.1% fluoride ion.

Composition

Parts

<td></td><td> _9</td><td>K&gt;</td><td>n</td>

<td>Glycerol (99.5% solution)</td><td> 22,00</td><td> 22,00</td><td> 22.,00</td>

<td>Sodium benzoate</td><td> 0,50</td><td> 0,50</td><td> 0,50</td>

<td> saccharin</td><td> 0,20</td><td> 0,20</td><td> 0,20</td>

<td>CMC - 7 MF **</td><td> 1,00</td><td> 1,00</td><td> 1,00</td>

<td>Sodium monofluorophosphate</td><td> 0,76</td><td> 0,76</td><td> 0,76</td>

<td>Water (deionized)</td><td> 36,54</td><td> 36,54</td><td> 36,54</td>

<td>Xerogel (Syloid® 63)</td><td> 35,00</td><td> 34,82</td><td> 34,70</td>

<td>Hydrated alumina</td><td> 1,00</td><td> 1,00</td><td> 1,00</td>

<td>TiO₂</td><td> 0,50</td><td> 0,50</td><td> 0,50</td>

<td>Sodium</td><td> 1,50</td><td> 1,50</td><td> 1,50</td>

<td>Calcium nitrate 4Η £ θ +</td><td> 0,00</td><td> 0,18</td><td> 0,30</td>

<td>Flavored</td><td> 1,00</td><td> 1,00</td><td> 1,00</td>

+) 0.18% and 0.30% calcium nitrate · 4h₂O in tart paste 10 and equal to 0.18 / 5.9 or 0.03% calcium (300 ppm calcium) and 0.30 / 5.9 or 0.05% calcium (500 ppm calcium).

** Denture grade sodium carboxylmethyl cellulose It is observed that the toothpaste of Example 9 contained no calcium. The tube properties were then determined when the dentifrice_owere aged at 49 ° C for 9 weeks and graded at intervals of 1, 3, 6 and 9 weeks. The following Table 3 shows the degree of corrosion or staining on the unfinished aluminum tubes.

Table 3 Tube compatibility characteristics 49 ° C aging study

<td colspan="7">weeks</td>

<td>toothpaste</td><td> 0</td><td> 1</td><td> —3~</td><td> 6</td><td> 9</td><td></td>

<td> 9</td><td> 10</td><td> 7</td><td> 6</td><td> 6</td><td> 5</td><td></td>

<td> 10</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td><td></td>

<td> 11</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td><td></td>

<td>From</td><td>the data that</td><td>is</td><td>specified in</td><td colspan="2">Table 3 is</td><td>'clear that</td>

<td>toothpastes</td><td colspan="3">according to Examples 10 and</td><td> 11</td><td>exhibit</td><td>brilliant tube</td>

forenelighetsegenskaper. It should be noted that a rating of 10 means no discoloration of the unfilled tube container. Since toothpaste 9 does not contain the critical concentration of calcium, the tube compatibility properties were found to be unacceptable after 9 weeks of storage at 49 ° C.

According to the supplier's publications, Xerogel (R)

Syloid 63 has the following properties:

<td>Forbrenningstap</td><td> 6,5</td>

<td>5% slurry pH</td><td> 4,1</td>

<td>% Si0₂ on a burnt basis</td><td> 99,5</td>

<td>Particle size, / mi</td><td> 9,0</td>

<td>2 Surface area, m / g</td><td> 625</td>

<td>Absorbance, cm 2/100 g</td><td> 60</td>

<td>Space density, kg / m 2</td><td> 464</td>

In addition to the properties listed above, Syloid® has the following chemical composition (from supplier's publication):

Chemical analysis (dry basis)%

<td>Aluminum</td><td>which</td><td>^A12°3</td><td> 0,04</td>

<td>Titan</td><td>which</td><td>TiO₂</td><td> 0,03</td>

<td>Calcium</td><td>which</td><td>CaO</td><td> 0,01</td>

<td>sodium</td><td>which</td><td>Now₂0</td><td> 0,02</td>

<td>zirconium</td><td>which</td><td>ZrO</td><td> 0,01</td>

Trace element (oxides)

0,02

Example 12 Calcium effect on commercial toothpastes

Clear-gel, caries-like toothpaste with the trademark Aim® was packaged in a sprayed container to prevent corrosion and staining of the inner tube wall.

Colgate Dental Cream (CDC) was also packaged in a lined container to prevent corrosion and staining of the inner tube wall.

To check the effectiveness of calcium additives, both Aim and CDC were purchased from the department store, and each paste was divided into three parts.

®

Aim toothpaste was divided into parts A, B and C. Part A was packaged in an unfrozen aluminum tube without any addition of calcium to the toothpaste. Parts B and C were mixed with a known concentration. of calcium and then packed in unpainted aluminum tubes.

The Colgate Dental Cream CDC was also divided into three parts, D, E and F. Part D was packed in an unrefined aluminum tube without the addition of calcium. To parts E and F, a known amount of calcium was added. The data obtained with Aim and CDC packaged in unused containers are listed in Table 6, and the composition for each was as follows:

Example 12

Toothpaste (3)% calcium

Commercial Dental Care%

<td>A</td><td> 0,00</td><td> 100,00 (1)</td>

<td>B</td><td> 0,10</td><td> 99,41 (1)</td>

<td>C</td><td> 0,16</td><td> 99,16 (1)</td>

<td>D</td><td> 0,00</td><td> 100,00 (2)</td>

<td>E</td><td> 0,10</td><td> 99,41 (2)</td>

<td>F</td><td> 0,16</td><td> 99,16 (2)</td>

(1) Aim toothpaste purchased from department stores (2) Colgate Dental Cream, purchased from department stores (3) Added as Ca (NO)₂)₂'4 HjO

<td>Table 4</td><td>Tube Compatibility Properties - 49 ° C aging study</td>

weeks

<td>toothpaste</td><td> 1</td><td> 3</td><td> 6</td><td> 9</td>

<td>A</td><td> 5</td><td> 4</td><td> 3</td><td> 1</td>

<td>B</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

<td>C</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

<td>D</td><td> 5</td><td> 5</td><td> 4</td><td> 2</td>

<td>E</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

<td>F</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

Toothpaste B, C, E and F exhibited excellent tube compatibility properties as compared to toothpaste A and D. Thus, the addition of calcium seemed to stabilize these caries-inhibiting dental care agents.

Examples 13 - 17

The following dentifrices were prepared to illustrate the use of sodium aluminum silicates (SAS) as polishes.

<td colspan="6">The toothpaste of Example 13 was used as a control where nothing</td>

<td>calcium was added.</td><td colspan="3">Known amounts of calcium were</td><td>added</td><td>for dental</td>

<td colspan="3">the paste of Examples 14, 15, 16 and</td><td colspan="3">17. The compositions were</td>

<td>as follows:</td><td></td><td></td><td></td><td></td><td></td>

<td></td><td></td><td></td><td>Parts</td><td></td><td></td>

<td>Composition</td><td>ll</td><td> 14</td><td> 15</td><td> 16</td><td>Γ7</td>

<td>Glycerol (99.5%)</td><td> 22,00</td><td> 22,00</td><td> 26,00</td><td> 25,00</td><td> 30,00</td>

<td>Sodium benzoate</td><td> 0,50</td><td> 0,50</td><td> 0,50</td><td> 0,50</td><td> 0,50</td>

<td> saccharin</td><td> 0,20</td><td> 0,20</td><td> 0,20</td><td> 0,20</td><td> 0,20</td>

<td>MCM - 7 MF</td><td> 1,00</td><td> 1,00</td><td> 1,00</td><td> 1,00</td><td> 1,00</td>

<td>Natriummonofluor-</td><td></td><td></td><td></td><td></td><td></td>

<td>phosphate</td><td> 0,76</td><td> 0,76</td><td> 0,76</td><td> 0,76</td><td> 0,76</td>

<td>Calcium nitrate ·</td><td></td><td></td><td></td><td></td><td></td>

<td>4η 0 +</td><td> 0,00</td><td> 0,20</td><td> 0,20</td><td> 0,20</td><td> 0,24</td>

<td>Deionized water</td><td> 36,54</td><td> 36,34</td><td> 39,54</td><td> 38,54</td><td> 43,30</td>

<td>SAS polish</td><td>35.00 (A)</td><td>35.00 (A)</td><td>27.80 (B)</td><td> 29,80(0</td><td>20.00 (D)</td>

<td>Hydrated Aluminum</td><td></td><td></td><td></td><td></td><td></td>

<td>oxide may</td><td> 1,00</td><td> 1,00</td><td> 1,00</td><td> 1,00</td><td> 1,00</td>

<td>ten °₂</td><td> 0,50</td><td> 0,50</td><td> 0,50</td><td> 0,50</td><td> 0,50</td>

<td>Sodium</td><td> 1,50</td><td> 1,50</td><td> 1,50</td><td> 1,50</td><td> 1,50</td>

<td>Flavored</td><td> 1,00</td><td> 1,00</td><td> 1,00</td><td> 1,00</td><td> 1,00</td>

+) Note that in toothpaste 14, 15 and 16, 0.2% corresponds

Ca (NO ^) £ · 4H₂0 to 0.03% calcium ion and 0.24% Ca (NO 2)₉.4H₂O in toothpaste 17 corresponds to 0.04% calcium ion.

1.49093

<td>(A)</td><td>The SAS product used</td><td>in</td><td>toothpaste</td><td></td><td>13 and</td><td>I 14</td><td>has one</td>

<td></td><td>SiO₂/Eel₂O₃ ratio of</td><td> 11</td><td> »0</td><td></td><td></td><td></td><td></td>

<td>(B)</td><td>The SAS product used</td><td>in</td><td>toothpaste</td><td> 15</td><td>hair</td><td>a</td><td>Si0₂/Eel₂0₃</td>

<td></td><td>ratio of 2.5</td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>(C)</td><td>The SAS product used</td><td>in</td><td>toothpaste</td><td> 16</td><td>hair</td><td>a</td><td>SiO₂/Eel₂O₃</td>

<td></td><td>ratio of 130</td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>(D)</td><td>The SAS product used</td><td>in</td><td>toothpaste</td><td> 17</td><td>hair</td><td>a</td><td>SiO ₂/Eel₂O₃</td>

ratio of 400.

The preferred sodium aluminum silicates (SAS) have the following molar chemical composition:

x Na₂0 · Y A1₂O₃ * ^{z si0}2 ^{w H}2 ° where x represents moles of Na₂0 y ¹¹ Al 0, z SiO₂ w won.

When y is set to 1, the value of z corresponds to the silica / alumina molar ratio in SAS. The low-structure SAS abrasives and polishes have a silica / alumina ratio or z values ​​of 2.5 - 400.

The properties of the SAS polishes are:

Oil Absorption, Rub-Out Method (cm / 100 g) = 75 - 125

BET surface area (m 2 / g) - 50 - 300

MSA mean aggregate size (^) = 1-10

Space density (kg / m 2) = 192-560

Toothpaste 13 - 17 was aged at 49 ° C for nine weeks, and tube compatibility properties were assessed at intervals of 1, 3, 6 and 9 weeks, and the results are shown in the following Table 5. Table 5 Tube compatibility characteristics, 49 ° C

<td>Toothpaste.</td><td> 1</td><td> 3</td><td> 6</td><td> 9</td>

<td> 13</td><td> 1</td><td> 1</td><td> 1</td><td> 1</td>

<td> 14</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

<td> 15</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

<td> 16</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

<td> 17</td><td> 10</td><td> 10</td><td> 10</td><td> 10</td>

Note that toothpastes 14 - 17 have excellent tube compatibility properties.