CH624297A5 - Toothpaste - Google Patents

Description

624 297

2nd

PATENT CLAIMS

1. Toothpaste containing sodium bicarbonate as an abrasive, characterized in that it contains as abrasive (1) a smaller proportion of sodium bicarbonate and (2) a larger proportion of water-insoluble abrasive which is compatible with the bicarbonate.

2. Toothpaste according to claim 1, characterized in that the insoluble abrasive consists of silicon dioxide, aluminum oxide, silicates or carbonates and makes up at least 20% by weight of the toothpaste, and that the abrasive is dispersed in an aqueous, moisture-retaining medium.

3. Toothpaste according to claim 1 or 2, characterized in that the sodium bicarbonate makes up 1 to 25% by weight of the toothpaste.

4. Toothpaste according to one of claims 1 to 3, characterized in that the insoluble abrasive makes up 20 to 50% by weight of the toothpaste.

5. Toothpaste according to one of claims 1 to 4, characterized in that the insoluble abrasive is calcium carbonate and consists of precipitated calcium carbonate, has a density of 0.7 to 0.9 g / cm3 and about 99% a sieve with a pore opening of 44 microns happens.

6. Toothpaste according to one of claims 1 to 5, characterized in that the aqueous medium consists of water-glycerin in a ratio of 0.4: 1 to 0.7: 1.

7. Toothpaste according to one of claims 1 to 6, characterized in that the sodium bicarbonate largely has a particle size of over 150 microns and a diameter of less than 0.4 mm.

8. Toothpaste according to one of claims 1 to 7, characterized in that it additionally contains 0.2 to 0.6% by weight of titanium dioxide.

9. Toothpaste according to one of claims 1 to 8, characterized in that it additionally contains a fluoride-containing anti-caries agent, selected from a group consisting of sodium fluoride and sodium monofluorophosphate.

10. Toothpaste according to one of claims 1 to 8, characterized in that it additionally contains a compatible surface-active agent selected from a group consisting of (a) sodium lauryl sulfate and a higher fatty acid sar cosinate, (b) sodium lauryl sulfate and a higher olefin sulfonate and (c) a higher olefin sulfonate.

11. Toothpaste according to claim 1 for filling into non-lined aluminum tubes, characterized in that it contains silicon dioxide, dissolved or dispersed in the aqueous carrier.

12. Toothpaste according to claim 1 for filling into non-lined aluminum tubes, characterized in that it additionally contains anhydrous dicalcium phosphate.

13. Toothpaste according to claim 1 for filling into non-lined aluminum tubes, characterized in that it additionally contains calcium pyrophosphate.

14. Toothpaste according to claim 1 for filling into non-lined aluminum tubes, characterized in that it additionally contains zirconium silicate.

15. Toothpaste according to claim 1 for filling into non-lined aluminum tubes, characterized in that it contains phosphate ions in an amount that prevents gas formation on the aluminum wall of the tube.

German Offenlegungsschrift No. 2,347,787 describes a toothpaste which contains a large part of sodium bicarbonate as an abrasive and a water-insoluble abrasive which is compatible with sodium bicarbonate in the toothpaste.

It has now been found that advantageous toothpastes can also be obtained if, in contrast to the toothpastes described above, the abrasive consists to a smaller extent of sodium bicarbonate and to a greater extent of water-insoluble abrasive which is compatible with the sodium bicarbonate.

Sodium bicarbonate is used in many fields and is a common household ingredient. In recent years, its use in dentifrices, especially tooth powders, has been proposed. However, it has not been particularly well received in general. Typical dentifrices that have been purchased in substantial quantities by consumers in recent years are toothpastes with a high content of water-insoluble abrasives, such as dicalcium phosphate or other insoluble phosphates in an aqueous, moisture-retaining carrier.

The development of a practical and effective toothpaste containing sodium bicarbonate which is accepted by the consumer poses a number of problems. The factors to be considered include the special chemical, physical and cosmetic properties of sodium bicarbonate when used as part of a tooth-25 pasta. For example, it is relatively water soluble and tends to release carbon dioxide in an aqueous system. The taste is extremely salty, which is probably one of the more important factors in the purchase and use of a specific product. Other factors when formulating a suitable product are the overall cleaning and polishing power of the product, its stability and appearance, the special care with which it must be made, etc.

When formulating a dentifrice on the Ba-3s sis of precipitated calcium carbonate, the incompatibility of the calcium carbonate with acids and most fluoride salts must be taken into account. Thus, when a dentifrice contains both sodium bicarbonate and calcium carbonate, several problems need to be considered. The aim of the present invention was to develop a toothpaste containing sodium bicarbonate as an abrasive, in which the above-mentioned difficulties have been overcome. In particular, such a toothpaste should also be suitable for filling into non-lined aluminum tubes, which are preferred because of their relatively low cost and light weight. Namely, when previously known toothpastes are filled into non-lined aluminum containers, it sometimes happens that the containers corrode and / or the toothpaste becomes inconsistent, so the subject of the present invention is a toothpaste containing sodium bicarbonate as an abrasive, which is characterized in that it is known as Abrasive contains (1) a smaller amount of sodium bicarbonate and (2) a larger amount of water-insoluble abrasive that is compatible with the bicarbonate.

In the toothpastes according to the invention, the insoluble abrasive preferably consists of silicon dioxide, aluminum oxide, silicates or carbonates, and it makes up at least 20% by weight of the toothpaste, the abrasive 60 in an aqueous, moisture-retaining medium, for example a medium made of water + glycerin in a ratio of 0.4: 1 to 0.7: 1.

In preferred toothpastes according to the invention, the insoluble abrasive 65 makes up 20 to 50% by weight, based on the weight of the toothpaste, and a preferred sodium bicarbonate content is 1 to 25% by weight, based on the weight of the toothpaste. The total content of the toothpaste

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Abrasive is preferably 20 to 60% by weight, based on the weight of the toothpaste. If the toothpaste according to the invention contains calcium carbonate as the water-insoluble abrasive, then this is preferably a precipitated calcium carbonate with a density of 0.7 to 0.9 g per cm 3, and it has a particle size such that it can pass 99% through a sieve with a Pore opening of 44 microns passes through.

The preferred particle size of the sodium bicarbonate contained in the toothpastes according to the invention is in the range from over 150 microns to below 0.4 mm.

If the toothpaste according to the invention is to be filled into non-lined aluminum tubes and it also contains aluminum oxide as an abrasive, then it is advantageous if about 0.05 to 0.25% by weight, based on the weight of the toothpaste, is dissolved in silicate or are dispersed to improve the compatibility of the toothpaste with the unlined aluminum container. The calcium carbonate also acts as a stabilizing agent for the composition and retains active fluoride. Toothpaste containing calcium carbonate is more effective in removing stains from teeth.

The calcium carbonate can be used in the form of chalk. Chalk in the form of a powder with a particle size between 1 and 10 microns is preferred. It is also advantageous to use calcium carbonate with a moderate apparent specific gravity of, for example, about 0.7 to 0.9. If desired, calcium carbonate with a higher apparent specific weight of, for example, 1.19 to 1.29 can also be used. The "apparent specific weight" refers to the unamped specific weight of calcium carbonate. Calcium carbonate, especially in the form of chalk, often contains magnesium carbonate as an impurity. Calcium carbonate, which contains only small amounts of magnesium carbonate, for example about 0.1 to 0.3%, tends to impair the durability of a toothpaste containing fluoride. The resistant toothpastes according to the invention allow small amounts of impurities, for example magnesium carbonate, in amounts of less than about 1%. However, the magnesium carbonate should preferably make up about 0.1 to 0.5%, based on the calcium carbonate, especially if fluoride is present.

The presence of magnesium carbonate impurities in calcium carbonate or chalk also affects the compatibility of the toothpaste with unclad aluminum surfaces. If magnesium carbonate is present in an amount of at least about 0.1% of the total calcium carbonate, between about 0.025 and 0.25% of silicate is advantageously dissolved or dispersed in the toothpaste in order to increase its compatibility with non-lined aluminum containers.

According to the invention, it has now become possible to produce a toothpaste containing sodium bicarbonate which can be filled into aluminum tubes, which promotes hygienic conditions in the oral cavity and which corresponds to consumer wishes. This dentifrice has acceptable cleaning, polishing and other desirable properties and therefore a good effect on the parts of the dental system (including the teeth and their surrounding or adjacent areas such as plaque, tartar, gums, mucous membranes, saliva, etc.). In particular, it leaves the consumer with a desired fresh mouthfeel. The product according to the invention can be formulated in such a way that it is stable during storage without releasing substantial amounts of carbon dioxide bubbles or being subjected to undesired segregation or other reactions. When using certain amounts of bicarbonate, it is possible, partly because of the essentially homogeneous distribution of the macroscopic crystalline bicarbonate particles in an otherwise smooth, continuous carrier, to produce and maintain granules of non-crystalline appearance.

An object of the invention is to produce a toothpaste containing abrasives which consists to a large extent of water-insoluble abrasives or their mixtures and to a smaller extent of sodium bicarbonate. For example, the abrasive can consist of a larger amount of calcium carbonate, which preferably makes up about 20 to 60% of the toothpaste, and a smaller amount of sodium bicarbonate. Chalk, silica, alumina, zirconium silicate, sodium aluminosilicate, or other compatible silicate or carbonate that does not react with the bicarbonate, or a mixture of two or more of these water-insoluble abrasives can be used as the water-insoluble abrasive. The amount of water-insoluble abrasive is advantageously more than 20% and in particular at least about 25% of the toothpaste, usually about 25 to 50% and more preferably about 25 to 35%.

Although the sodium bicarbonate particles are relatively soft compared to most conventional abrasive particles used in toothpastes, they have a mechanical cleaning effect on the teeth. For example, in a radioactive dentin grinding test (RDA), a toothpaste containing about 50% sodium bicarbonate as the only abrasive can show an RDA value of about 100, while examination of the abrasive-free wearer of this toothpaste showed an RDA value of only about 50.

The toothpastes according to the invention preferably contain 1 to about 25% and in particular about 10 to 20% sodium bicarbonate. The particle size of the sodium bicarbonate particles can vary. It is preferably largely below 0.40 mm with a larger proportion by weight of over 0.01 mm. The carrier in which the sodium bicarbonate particles are dispersed is preferably aqueous, but its amount and nature are preferably selected so that the sodium bicarbonate is mainly in the undissolved solid state in the toothpaste. Of course, when brushing the teeth, the sodium bicarbonate particles will tend to dissolve in the saliva.

According to a preferred embodiment of the invention, the water-insoluble abrasive is present in chalk. This ingredient has been found to greatly improve the cleaning power of sodium bicarbonate. In addition, the presence of chalk appears to increase the resistance of the toothpaste to aging at elevated temperatures, so that the essential oils used as flavorings tend to separate from the toothpaste during aging at 43 or 49 ° C, for example when the sodium bicarbonate particles are relatively large, and for example have a diameter of over 150 microns, is reduced.

The use of the water-insoluble abrasives, such as chalk, silicon dioxide, aluminum oxide, zirconium silicate and the like or mixtures thereof, results in a toothpaste containing sodium bicarbonate which, in addition to a lack of tendency to separate the flavors and to form gas during storage, has improved cleaning power. In contrast, using conventional abrasives such as dicalcium phosphate or insoluble sodium metaphosphate in the sodium bicarbonate toothpaste, considerable amounts of gas can be generated even with short storage (for example at 49 ° C) if the sodium bicarbonate is present in sufficient quantities.

The average particle size of the chalk is preferably less than 20 microns and especially less than 10 microns and more than 1 micron, as already stated. Tables 1 and 2 show the ranges of particle sizes and the densities s

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of various types of chalk which can be used according to the invention.

Table 1 precipitated calcium carbonate particle size, 3 diameters, fi

Art

0-3

3-6

6-10

over 10

apparent density, g / ml slightly

80%

14%

4%

2%

0.351-0.430

medium

67

17th

12

4th

0.500-0.588

tight

55

21st

16

8th

0.727-0.851

extra

tight

50

20th

20th

10th

0.870-1.050

a Obtained by microscopic count.

Table 2

Particle size distribution of the precipitated calcium carbonate (USP)

Weight below the specified size,% Art

Diameter, u heavy medium light extra light

10.0

85.3

97.7

98.6

98.8

7.5

66.4

92.9

96.8

98.8

5.0

30.6

61.4

85.7

95.6

4.0

14.9

43.7

77.5

93.1

3.0

7.3

32.1

52.1

70.6

2.0

3.6

19.7

20.0

27.7

1.0

2.1

10.1

10.2

10.5

0.5

-

5.1

5.2

5.5

A particularly suitable aluminum oxide consists of flat flakes of a-aluminum oxide crystals in the form of disks or platelets, the flakes having an average (weight) particle diameter of less than about 7 fi (for example about

2 to 7 fi). These flat a-alumina crystals and a process for their manufacture are described in US Pat.

. 3 121 623. The dentifrices according to the invention are preferably essentially free of anhydrous aluminum oxide particles with diameters of more than 15 μm and a thickness of more than about 2 μm. Although it is most advantageous to use alumina flakes with an average particle diameter of less than 5 [beta] (for example about 3 to 4 /.i), alumina flakes with a larger diameter but of a similar thickness can also be used within the scope of the invention, for example alumina flakes that are described in the aforementioned U.S. Patent

3,121,623 have average diameters of 9, 12 or 15 or more microns, free of particles larger than 40 microns in diameter (preferably free of particles larger than about 20 microns in diameter) and substantially free of particles about 3 microns thick. According to a preferred embodiment of the invention, the a-alumina flakes are not coated and do not adhere to other material particles. The invention also encompasses the use of other α-aluminum oxides or other abrasives with a Mohs hardness of over 6 in a mixture with the α-aluminum oxide flakes. For example, about half of the alumina flakes can be replaced with irregularly shaped powdered a-alumina having an average particle size of about 3 to 4 microns (all of these irregular particles being less than about 7 microns in their largest dimension). Accordingly, the toothpaste can contain 3% of the flakes and 2% of the irregular particles.

A typical alkali or alkaline earth metal aluminosilicate consists of a complex with a refractive index of about 1.45, a moisture content of about 5 to 20% (for example 10%), an aluminum oxide content of up to about 10% (for example 8%), a silica content of at least about 70%, a sodium oxide (or other alkali metal or alkaline earth metal oxide, e.g. calcium oxide) content of up to about 10% (e.g. 7%) and a particle size below 40 microns, preferably about 1 up to 20 microns.

Examples of mixtures are mixtures of chalk and hydrated aluminum oxide in, for example, equal proportions or in a ratio of about 25:75 or about 75:25.

The toothpaste can also contain a small amount of titanium dioxide powder, which, when used in the sodium bicarbonate toothpaste, has a pronounced polishing effect on the 20 teeth.

The titanium dioxide particles generally make up more than about 0.1% by weight of the toothpaste in the toothpaste. The titanium dioxide can be incorporated in amounts of up to about 6.0, preferably from about 0.2 to 0.6% by weight of the toothpaste . The particle size of the titanium dioxide is preferably about 0.1 to 1 micron.

The carrier for the toothpaste consists of a suitable liquid, which preferably contains a thickening agent (for example a gelling agent). As already indicated, the carrier is preferably aqueous, but the invention also encompasses the use of non-aqueous carriers. Generally, the liquid contains a humectant or other viscous, water-miscible material, such as glycerin, sorbitol, polyethylene glycol, mannitol, or mixtures thereof. If water is present, it preferably makes up about 5 to 35% (e.g., about 10 to 30%) of the total carrier. Advantageous results (for example a better taste) are achieved if the proportion of water is relatively small, for example about 10 to 20% of the total toothpaste 40, for example if the water / glycerol ratio is in the range of about 0.4 : 1 to 0.7: 1.

Gelling agents for toothpaste carriers are known. Often these are highly polymeric substances (e.g. rubber or other thickeners) that are soluble or swellable in water or aqueous media. Excellent results are obtained with sodium carboxymethyl cellulose. Other suitable substances are gum tragacanth, gum arabic, gum karaya, sodium alginate, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, Karra-50 geen and other polysaccharides, polyvinylpyrollidones or thickeners such as «Veegum» (a complex magnesium aluminum silicate). The amount of the plastering agent used according to the invention is preferably sufficient to give the mixture paste-like consistency, body and a non-sticky nature which is characteristic of the conventional toothpastes or toothpastes. As is known, these toothpastes can be squeezed out of ordinary compressible toothpaste tubes into sections of substantial thickness (e.g., about 1 cm) that remain unchanged at 60, essentially maintaining their original thickness over a period of 1 minute or longer, and not substantially into the bristles of the toothpaste Toothbrush penetrate if they lie on the ends of these bristles for a similar period of time, but preferably brushing or deforming, for example if you lightly touch them with your finger, do not provide any significant resistance and are not sticky, that is not tend to pull strings when you pull your finger away from the section. The

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The proportion of the thickener is often in the range from about 0.5 to 20%, for example from about 0.8 to 1.5%, of the toothpaste.

An organic surface-active agent is preferably used in the compositions according to the invention in order to improve the prophylactic effect and the careful dispersion of the composition in the oral cavity as well as the cosmetic suitability and the cleaning and foaming properties. These surfactants include water-soluble salts of higher alkyl sulfates, such as sodium lauryl sulfate, or other suitable alkyl sulfates having 8 to 18 carbon atoms in the alkyl group; water-soluble salts of sulfonated monoglycerides of higher fatty acids, such as sodium coconut monoglyceride sulfonate or other suitable sulfonated monoglycerides of fatty acids with 10 to 18 carbon atoms; Salts of amides of higher fatty acids (for example those with 12 to 16 carbon atoms) with lower aliphatic amino acids (for example taurine or sarcosine) or other amino acids with 2 to 6 carbon atoms, such as sodium N-methyl-N-palmitoyl tauride, sodium N-lauroyl, -N-myristoyl or -N-palmitoylsarcosinate; water-soluble salts of esters of such fatty acids with isothionic acid or with glycerol monosulfate, such as the sodium salt of the monosulfated monoglyceride of hydrogenated coconut oil fatty acids; water-soluble salts of olefin sulfonates, for example alkenesulfonates or hydroxyalkanesulfonates or their mixtures having 12 to 18 carbon atoms in the carbon chain of the molecule; water-soluble soaps of higher fatty acids, for example those with 12 to 18 carbon atoms, such as coconut fatty acids. The cation of the salt can be, for example, sodium, which is preferred, potassium or mono-, di- or triethanolamine. Mixtures of surfactants can also be used. A particularly advantageous mixture, which gives high foaming power with little or no irritating effect, contains a higher alkyl sulfate and a higher fatty acid sarcosinate, for example in a ratio of about 1: 2 to 2: 1, such as 1: 1, where instead of all or a higher fatty acid monoglyceride sulfonate may be present in part of the sarcosinate.

Other suitable surfactants are nonionics such as condensation products of sorbitan monostearate with about 60 moles of ethylene oxide, condensation products of ethylene oxide with propylene oxide condensation products of propylene glycol (available under the trademark "Pluronics") and amphoteric agents such as quaternized imidazole derivatives “Miranol”, for example, are available as Miranol C2M. Cationic surfactant germicides and antibacterial compounds can also be used. These compounds include di-isobutylphenoxyethoxy-ethyl-dimethylbenzyl-ammonium chloride, benzyl-dimethyl-stearyl-ammonium chloride, tertiary amines with a fatty alkyl group (having 12 to 18 carbon atoms) and two nitrogen-bonded polyoxyethylene groups (typically total contain about 2 to 50 ethyleneoxy groups per molecule) and their salts with acids and compounds of the general formula

(CH2CH20) zH (CH2CH20) xH

R-N-CH2CH2CH2N (CH2CH20) H

in which R is a fatty alkyl group with about 12 to 18 carbon atoms, x, y and z together mean 3 or a higher number, and their salts with mineral or organic acids. Preferably, about 0.05 to 5% by weight of the above surface-active compounds, in particular about 1 to 3%, for example 1V2 to 2%, are used in the dental care compositions according to the invention.

Cationic antibacterial agents are also incorporated into the compositions according to the invention, for example:

N1- (4-chlorobenzyl) -Ns- (2,4-dichlorobenzyl) biguanide;

p-chlorophenyl biguanide;

4-chlorobenzylhydryl biguanide;

4-chlorobenzylhydrylguanyl urea; N-3-LauropropyI-Ns-p-chlorobenzyl biguanide; l- (lauryldimethylammonium) -8- (p-chlorobenzyldimethyl-

ammonium) octane dichloride; 5,6-dichloro-2-guanidinobenzimidazole; N1-p-chlorophenyl-Ns-lauryl biguanide;

5-amino-1,3-bis- (2-ethylhexyl) -5-methylhexahydro-

pyrimidine-cetyl-pyridinium chloride and their non-toxic acid addition salts, in particular their fluorides and dihydrofluorides. 1,6-Di- (p-chlorophenyl-biguanidohexane) is particularly preferred. These agents can be used in amounts of about 0.01 to 5% by weight of the dentifrice.

All suitable agents can be used as flavoring and sweetening agents. Examples are oils such as spearmint oil, peppermint oil, wintergreen oil, sassafras oil, clove oil, sage oil, eucalyptus oil, marjoram oil, cinnamon oil, lemon oil and orange oil and methyl salicylate. Suitable sweeteners are lactose, maltose, sorbitol, sodium cyclamate, perillartin, saccharin and ammonized glycyrrhizin (for example its monoammonium salt). The flavors and sweeteners together suitably make up about 0.01 to 5% or more of the compositions according to the invention. Preferably the amount of flavoring oil is more than 0.3%, for example 0.8 to 1.2%.

A sweetener from the Neohespe-ridindihydrochalkongruppe can be added in equal amounts.

The toothpaste can also contain a fluoride-containing anti-caries agent. There are many water-soluble inorganic salts that are suitable as a source of fluoride ions. These include sodium, potassium, ammonium, manganese, lithium and amine fluorides. The monofluorophosphates are also useful and include Na4P309F, K4P309F, (NH4) P309F, Na3KP309F, (NU,) NaP309F and Li4P3OsF. Likewise, water-soluble fluoride-containing salts, such as fluorosilicate (that is Na2SiF6), fluoizirconate (that is Na2ZrF6), fluorostannite (that is KSnF3), fluoroborate (that is NaBF4), fluorotitanate (that is NaTiFs) and fluororgermanate (that is, usable). The fluoride ion can also be supplied by an organic fluoride that provides fluoride ions in water. Suitable organic compounds are mono-, di- and triethanolamine hydrofluoride. These compounds are present in an effective but non-toxic amount, usually in an amount that gives the dentifrice about 0.01 to 1 percent by weight of the water soluble fluorine content. Sodium fluoride and sodium monofluorophosphate are the preferred compounds.

Various other materials can also be incorporated into the dental care products according to the invention. Examples of these are dyes and whitening agents, preservatives, silicones, chlorophyll compounds and their mixtures and other constituents. These auxiliaries are added in amounts which do not significantly impair the desired properties and are selected depending on the particular type of preparation.

The following examples illustrate the invention. Unless otherwise stated, all proportions in them relate to weight.

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6

example 1

Toothpaste is made by mixing a gel-forming agent, in this case sodium carboxymethyl cellulose ("CMC") with glycerin and water (in the presence of a sweetener, sodium salt of saccharin, a flavoring agent and a preservative, sodium benzoate) , Sodium bicarbonate, chalk and titanium dioxide powder are added to the gel and the mixture is then degassed under vacuum. The following were used: 10% sodium bicarbonate, 35% chalk, 0.4% titanium dioxide, 16.1% deionized water, 34.0% glycerol, 1.2% CMC, 2% of a solution of 35% sodium N-lauroyl sarcosinate in a mixture of 35% water and 30% glycerin, 0.98% sodium lauryl sulfate, 0.5% sodium benzoate, 0.2% sodium salt of saccharin and 0.9% flavor.

The sodium bicarbonate powder had U.S.P. purity and the following particle size distribution, the percentages designating the portion accumulated on the specified screen and the screen sizes conforming to the US standard: No. 45 gauge screen; 70 sieve (210 micron sieve opening) 27%; Sieve # 80 (sieve opening 177 microns) 66.5%; Sieve No. 100 (sieve opening 149 microns) 92.5%; Sieve No. 170 (sieve opening 88 microns) 99%.

The chalk consisted of U.S.P. precipitated calcium carbonate containing at least 98% CaC03 and no more than 0.2% dilute hydrochloric acid insolubles. Their particle size was such that over 99% passed a No. 325 US sieve (sieve opening 44 microns). The particles were mainly 1 to 10 microns in size, the average particle size was about 3 microns. A U.S.P. Fer-Al chalk with similar properties can also be used if the gelling agent and viscosity are adjusted accordingly.

The titanium dioxide consisted of a sand-free anatase powder, of which at least 99.0% passed a No. 325 US standard sieve (sieve opening 44 microns) and whose average particle diameter (measured on a Kahn sedimentation balance) was less than 1 micron. Microscopic measurements showed an average particle diameter of 0.3 microns.

The toothpaste had good cleaning properties and whiteness and aged well in tests at -13.3 ° C, 4.5 ° C, 43 ° C and 49 ° C. The toothpaste had a pleasant smell during brushing. Although the large particles of sodium bicarbonate are moderately palpable, they break easily into smaller particles under the pressure of the toothbrush and under the influence of saliva.

Example 2

Example 1 is repeated with the difference that the proportion of chalk is reduced to 25% and the proportion of sodium bicarbonate is increased to 20%.

Example 3

Example 1 is repeated with the difference that 5% of the chalk is replaced by hydrated aluminum oxide. The proportion of sodium bicarbonate remains the same. A mixture of essential oils, mainly peppermint oil, is used as a flavoring.

The hydrated alumina had the following particle size distribution and consisted of a-alumina trihydrate:

28 to 40% finer than 5 microns

56 to 67% finer than 10 microns

85 to 93% finer than 20 microns

94 to 99% finer than 30 microns

Example 4

Example 3 is repeated with the difference that the 5% of the hydrated aluminum oxide is replaced by 5% zirconium silicate powder with the following particle size distribution:

80% finer than 1.25 microns 90% finer than 1.77 microns 95% finer than 2.15 microns 99% finer than 2.50 microns

10th

Example 5

Example 3 is repeated with the difference that instead of the 5% hydrated aluminum oxide, 5% micronized silicon dioxide is used. In addition, half of the sodium bicarbonate is replaced by a more finely divided sodium bicarbonate with the following particle size distribution (the percentages indicate the amount that has accumulated on the specified sieve; the sieve sizes correspond to the US standard): Sieve No. 45 (sieve opening 20 350 micron) track; Sieve No. 100 (sieve opening 149 microns) 0.5%; No. 170 sieve (88 micron sieve opening) 20%; No. 200 sieve (74 micron sieve opening) 35%; No. 325 sieve (44 micron sieve opening) 70%; Sieve No. 400 (sieve opening 37 micron) 80%. The invention also encompasses the use of calcium 25 pyrophosphate (for example in the B or y form or of mixtures thereof in various proportions, for example in a ratio of about 1: 1, such as 53% B, 47% y) with a average particle size below about 20 microns, for example about 1 or 2 to 10 microns, for a portion of the water-insoluble abrasive in the toothpaste.

Another feature of the invention relates to the degassing of toothpastes containing sodium bicarbonate particles. It has been found that when such toothpastes are subjected to a high vacuum, for example over 600 mm Hg, 35, the toothpaste forms and expands, but does not contract to essentially their original volume during further vacuum treatment like the conventional toothpastes, but continues to expand. It has now been found that an excellent deaerated product 40 with good durability and desirable theological properties can be produced by subjecting the toothpaste containing sodium bicarbonate to a vacuum of at least 660 mm Hg so that it expands to a volume that is at least 150%. (for example, about 200%) is 45% of its volume at atmospheric pressure, and the high vacuum treatment is interrupted when the expanded mixture begins to contract, but its volume is still at least 150% of the volume at atmospheric pressure.

50

Example 6

This example explains the degassing treatment according to the invention. 18.3 parts of glycerin, 1.1 parts of sodium carboxymethyl cellulose, 0.5 part of sodium benzoate, 0.2 part of the 55 sodium salt of saccharin and 15.4 parts of water are mixed at 43 to 46 ° C for 20 minutes and placed in a vertical Given cylindrical container, which is equipped with a stirrer, in particular a double mixer, which has a series of counter-rotating mixing rods, which are mounted radially along its height. Then 25 parts of calcium carbonate (chalk), 20 parts of sodium bicarbonate and 0.4 parts of titanium dioxide are added, and the mixture is slowly mixed using a vacuum of 699 mm Hg. Then the stirring speed is increased. During this vacuum treatment, which lasts at least about 5 minutes, the batch expands to a volume which is about 2/3 larger than the volume before the vacuum treatment. Then the volume will decrease somewhat. Subsequently

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the mixture is brought to atmospheric pressure, 0.975 parts of sodium lauryl sulfate and 2 parts of a solution of 35% sodium lauroyl sarcosinate in a water-glycerol (35 9 ^ -30%) mixture are added, a vacuum of 716 mm Hg is applied and the mixture is held approximately 5 minutes under vacuum, stirring. During this time the volume of the batch increases and decreases somewhat. It is only slightly larger than the volume observed during the previous vacuum treatment. The mixture is then brought to atmospheric pressure. 15.1 parts of glycerin are then added and the mixture is stirred under a vacuum of 711 mm Hg for about 5 minutes. During this treatment, the volume increases by more than 100% (that is, it increases to more than 200% of the original volume) and then begins to decrease somewhat. After these 5 minutes, the container is vented to the atmosphere. The volume of the mixture is then still about 75 to 100% larger than the volume immediately before the vacuum treatment. Part of the essential oils are then added and the mixture is stirred again using a vacuum of 724 mm Hg. Stirring is continued for about 12 minutes under this vacuum. The container is then vented to the atmosphere. During this 12 minutes, the mixture expands in a manner similar to that during the immediately preceding vacuum treatment. Before the mixture is vented to the atmosphere, the expansion is still visible.

It is advantageous to interrupt the vacuum treatment, despite the possibly further expansion, before the change in the pH value (pH value of the vacuum-treated mixture minus pH value of the non-vacuum-treated mixture) reaches a pH unit and preferably less, for example V2 unit. This prevents decomposition of the sodium bicarbonate and the formation of sodium carbonate during the degassing.

According to a further embodiment of the invention, the toothpaste can be produced and degassed as follows:

The carboxymethyl cellulose is added to the stated amount of glycerol with stirring without the use of heat. Mix for two minutes, then add the saccharin and sodium benzoate. Then another minute is mixed. The specified amount of water, sodium lauryl sulfate and flavorings are then added. Then stirring is continued for 15 minutes and mixing continues until the batch is ready for filling. The lid of the double mixer is closed and a vacuum of 711 mm Hg is applied. The vacuum valve is then closed. At this point, half of the gel mixture is in the mixer. The mixer is then turned off, the vacuum released, and the appropriate amounts of titanium dioxide and sodium N-lauroyl sarcosinate are added to the formulation, then a vacuum of 711 mm Hg is applied and the vacuum is maintained until the level of the cream drops. The other half of the gel mixture is then added and deaerated at 711 mm Hg for 5 minutes. The mixer is turned off, the vacuum is released and the calcium carbonate and sodium bicarbonate are added. Vacuum is then applied while mixing. Mixing is continued under full vacuum for 15 minutes. With the mixer running at a lower speed, the vacuum is released and the cream is then removed.

Example 7

This example illustrates the use of alumina flakes in toothpaste containing sodium bicarbonate.

The toothpaste is made, for example, using the method according to Example 1 from 10% sodium bicarbonate powder from Example 1, 30% chalk, 5% α-aluminum oxide flakes,

0.4% titanium dioxide of Example 1, 33.4% glycerol, 15.4% deionized water, 1.1% carboxymethyl cellulose (Hercules 7MF), 2% of a solution of 35% sodium N-lauroylsarcosinate in a mixture of 35% water and 30% glycerin, 1% sodium lauryl sulfate, 1% flavor (water-insoluble essential oils, for example a mixture of essential oils rich in peppermint oil), 0.5% sodium benzoate and 0.2% of the sodium salt of saccharin.

The α-alumina flakes have an average (by weight) particle diameter of approximately 4 microns, with all particles having a diameter of less than 10.1 microns, approximately 85 to 95% by weight of a diameter of less than 6.0 microns and approximately 30 to 35% Have a diameter of less than 3.5 microns.

The properties of the toothpaste of this example are similar to those given in example 1. It is very resistant to the separation of the flavors.

Example 8

Example 7 is repeated with the difference that the toothpaste contains 0.22% sodium fluoride (the glycerol content is reduced accordingly by 0.22%). The toothpaste obtained has excellent aging properties, including a very good resistance to the separation of the flavors during aging and a very good maintenance of the fluoride content. Like the toothpaste of Example 7, it has a high polishing effect on the tooth enamel. Its re-polishing effect is 64%.

Re-polishing, expressed as a percentage, is determined by a test in which sections of human tooth enamel on which flat, matt areas have been applied are first polished, then matted with chalk and then brushed with a slurry of toothpaste using 5000 reciprocal brush strokes. A "Monsanto Tooth Reflectance Instrument" is used to determine the mirror reflection of the surface after each treatment stage. The matting of the surface is adjusted so that it is approximately 150 units (Monsanto Instrument) below that of the polished surface. The polishing power of the dentifrice is expressed by the following equation:

"... . ,,, (SR5000 lines "~ SR matted re-polishing effect,% = - —-

O-Kpoiiert ^ -K-mattiert where SR.pQiiert) ^^ mattiert And SR5Q00 strokes reflect the WCftC for the specular reflection of the enamel surface after the initial polishing, matting with chalk and brushing with the toothpaste slurry.

Example 9

Example 7 is repeated with the difference that the toothpaste contains 0.76% sodium monofluorophosphate (the glycerol content is reduced accordingly by 0.76%).

Example 10

Examples 7, 8, and 9 are repeated except that the a-alumina flakes have an average particle diameter of 5 microns, with essentially all of the particles being less than about 12 microns in diameter.

Example 11

This example illustrates the use of unlined aluminum tubes for various toothpastes containing sodium bicarbonate.

(a) A toothpaste is made, for example according to the method of Example 1, from 20% sodium bicarbonate powder of Example 1, 25% calcium carbonate of Example 1, 0.4% titanium oxide of Example 1, 34.02% glycerol, 16.1% deionization 5

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tem water, 1.2% carboxymethyl cellulose (Hercules 7MF), 2% of a solution of 35% water and 30% glycerin, about 0.9% sodium lauryl sulfate, 0.9% flavorings (water-insoluble essential oils, for example a mixture rich in peppermint oil essential oils), 0.5% sodium benzoate and 0.2% of the sodium salt of saccharin.

(b) Example 1 la is repeated with the difference that 0.5% of very finely divided silicon dioxide (Cab-O-Sil) is incorporated, the amount of calcium carbonate is increased to 35% and the amount of sodium bicarbonate is reduced to 10%.

(c) Example IIb is repeated with the difference that the amount of sodium bicarbonate is reduced to 5% with a corresponding change in the other constituents.

(d) Example 11 is repeated four times, additionally using different proportions of non-acidic dicalcium phosphate dihydrate, namely 0.04%, 0.2% and 08% (based on the weight of the formulation without phosphate); in the first case (0.04%) the titanium dioxide is omitted. The purity of the dicalcium phosphate dihydrate meets the requirements for dentifrices and has an average particle diameter of about 4 microns. Its pH (measured in 20% slurry in water) is in the range of 9.3 to 9.9. When in contact with water, it forms phosphate ions.

(e) Example IIa is repeated with the further incorporation of insoluble sodium metaphosphate in an amount of 0.8% (based on the weight of the formulation without the phosphate). The insoluble sodium metaphosphate meets the requirements for dental care products and has an average particle size of about 5 microns. Its pH (measured in 20% slurry in water) is in the range of 5.3 to 6.3. It forms phosphate ions on contact with water.

(f) Example IIa is repeated with the difference that 5% finely divided silica is used instead of 5% calcium carbonate, another essential oil as a flavoring in an amount of 0.9% and the glycerin in an amount of 33.5% is used.

(g) Example IIa is repeated with the difference that 3% finely divided silicon dioxide is used instead of 3% calcium carbonate and the toothpaste contains 0.9% essential oil as a flavor.

(h) Example IIa is repeated except that 5% precipitated silica is used instead of 5% calcium carbonate.

(i) Example IIa is repeated with the difference that 5% anhydrous dicalcium phosphate is used instead of 5% calcium carbonate. The toothpaste contains 0.9% essential oils as a flavoring. The anhydrous dicalcium phosphate consists of a fine non-acidic powder with the purity required for dentifrices. Its pH (measured on a 20% slurry in water) is 7.6 to 7.8. Upon contact with water, it forms phosphate ions in low concentrations.

(j) Example 1 la is repeated with the difference that 5% zirconium silicate from Example 4 is used instead of 5% calcium carbonate (with less change in the proportion and type of flavor).

(k) Example IIa is repeated with the difference that 5% / 3 calcium pyrophosphate is used instead of 5% calcium carbonate. Calcium pyrophosphate consists of a fine powder with the purity required for dentifrices. Its pH (measured on a 20% slurry in water) is 5.2 to 5.3.

Each of the above toothpastes was filled into a tube of high-purity uncoated aluminum (99.7% aluminum or more pure) and aged. During the aging at 49 ° C the tube filled with the toothpaste 1 la swelled or a foamy product film was found in contact with the inner aluminum wall of the tube. In the tubes filled with toothpastes 1 lb, c, d, f, g, h, i, j and k, 5 these phenomena were not observed. These toothpastes show essentially no tendency to react with the wall of the toothpaste tube.

The finely divided silicon dioxide (cf. Example 1 lb) is described, for example, in Encyclopedia of Chemical Technology, Kirk-lo Othmer, 2nd edition, volume 18, pages 62 and 67. The invention encompasses the use of this finely divided silica in toothpastes containing sodium bicarbonate which are filled into unclad aluminum tubes and from which the compatible water-insoluble abrasive 15 (such as calcium carbonate) is omitted. The use of very finely dispersed or dissolved silicon dioxide in other forms is also within the scope of the invention, for example as alkali metal silicate, such as sodium silicate, for example as hydrated sodium silicate in flake form with the ratio 20 Na2O: SiO2-H2O of about 1: 2 —3.2: 5, or in the form of sodium silicate solutions (water glass), for example those in which the Na2ö: SiÖ2 ratio is at least about 1: 2, or of sodium silicate that is baked in situ in the toothpaste, or of colloidal silicon dioxide or precipitated silicon dioxide (see Encyclopedia of Chemical Technology, Kirk-Othmer, 2nd edition, volume 18, pages 63 and 66 to 67) or of other silicate.

The dicalcium phosphate dihydrate of Example 11d is a commercially available stabilized material 30 with the purity required for dentifrices. A process for the preparation of such a dicalcium phosphate dihydrate and its stabilization is described in US Pat. No. 3,169,096, see also “Cosmetic Science”, Volume 1, 1972 (Wiley Interscience) by Balsam and Sagarin, 35 pages 477 to 479. A typical analysis of the dicalcium phosphate dihydrate indicates a water-soluble material content of 0.18% (its percentage of water-soluble substances, expressed as P2Ö5 is 0.11%). A typical stabilizer content is a mixture of about 1 to 2% sodium 40 calcium pyrophosphate and a minor amount, for example about 0.4%, pyrophosphoric acid.

The insoluble sodium metaphosphate of Example 11c is a commercially available material with dental care agent purity. Its production and properties are described in the already cited literature "Cosmetic Science" on pages 480 to 481 and in "Phosphorus and Its Compounds" by Van Wazer, volume 2.1961 (Interscience), pages 1652 to 1653.

The anhydrous dicalcium phosphate of Example 1 II and thus the calcium pyrophosphate of Example 1 lk with dentifrice purity are also commercially available, see “Phosphorus and Its Compounds”, page 1651 and “Cosmetic Science”, pages 479 to 480.

55 Example 12

Example IIa is repeated with the difference

that the toothpaste also contains anhydrous disodium phosphate (incorporated as a water-soluble powder) in an amount of (a) 0.05% and (b) 0.01% and the amount of water in the 60 toothpaste is set accordingly to 100%. In any case, the filled toothpaste tubes do not swell or develop gas when aging in unlined aluminum tubes (as in Example 11) and (after aging at 49 ° C. for 9 weeks) the inner wall of the tubes was gold-colored. The 65 color of the tube containing the toothpaste 12b was very light. When examining the inner wall of the non-lined aluminum tubes containing the toothpastes 1 ld (again after aging at 49 ° C. for 9 weeks), the test was carried out

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found that it was dark (if the toothpastes contained 0.8% or 0.4% dicalcium phosphate dihydrate) or gold (if the tubes had 0.4% and 0.2% dicalcium phosphate dihydrate). Examination of the inner wall of the non-lined aluminum tubes containing the toothpaste 11k showed that after 3 and 6 weeks of aging they were gold-colored at 49 ° and dark after 9 weeks of aging. It is believed that the toothpastes containing (or forming upon aging) the dicalcium phosphate dihydrate contain small amounts of dissolved phosphate ions (e.g. orthophosphate and / or pyrophosphate) which act on the aluminum wall or on the aluminum oxide layer on this wall, and forms a protective layer on it. The amount of dissolved phosphate ions present in the preferred composition is sufficient to prevent the gas formation reaction between the alkaline toothpaste and the aluminum wall of the tube, but the amount of the phosphate * or acidic component is insufficient to cause a gas-forming reaction (which, for example, causes swelling or burst tube) between the components of the toothpaste. The tendency towards the last-mentioned reaction can of course be examined by filling the composition into a suitably lined aluminum tube (the walls of which are accordingly essentially inert to the composition) and for several weeks (for example 9 weeks) at elevated temperature (for example 49 ° C) ages.

The storage of different toothpastes in non-lined aluminum tubes is explained in US Pat. Nos. 3,662,066 and 3,678,155 and in Austrian Patent 267,070. As is known, toothpaste tubes, which consist of relatively thin, flexible aluminum, can be pressed together and deformed to press the toothpaste out of the opening of the tube.

Example 13

This example illustrates the use of olefin sulfonate surfactants in sodium bicarbonate toothpaste. These olefin sulfonates lead to very good foaming when brushing the teeth, although the medium (saliva and toothpaste containing sodium bicarbonate) contains a relatively high concentration of dissolved electrolyte.

(a) The formulation of the toothpaste is the same as in Example 10, with the difference that about 0.7% of a sodium olefin sulfonate is used instead of the sarcosinate solution and the amount of water is increased to about 16.6%.

(b) The formulation of the toothpaste is the same as in Example 10, except that about 1.7% of a sodium olefin sulfonate is used in place of the sodium lauryl sulfate and the sarcosinate solution and the amount of water is increased to about 16.5%.

The olefin sulfonate used in Example 13 consists of a reaction product of SO3 and an olefin mixture (as is obtained, for example, when cracking paraffin wax) and contains approximately equal amounts of C1S, C16, C17 and C18-01efins. The average chain length is about 16V2 carbon atoms. Other toothpaste containing olefin sulfonates can also be used in toothpaste containing sodium bicarbonate. The olefin sulfonates are known compounds in the field of detergents. In general, they contain long-chain alkenyl sulfonates or long-chain hydroxyalkanesulfonates (the hydroxyl group being located on a carbon atom which is not directly bonded to a carbon atom carrying the S03 group). Usually the olefin sulfonate detergent contains a mixture of varying amounts of these two types of compounds, often together with long chain disulfonates or sulfate sulfonates. Such olefin sulfonates are described, for example, in US Pat. Nos. 2,061,618, 3,409,637, 3,332,880, 3,420,875, 3,506,580, British Pat 4, pages 247 to 253 (1970). There it is stated that the olefin sulfonates from straight-chain a-olefins, internal olefins, olefins in which unsaturation is present as a vinylidene side chain (for example dimers of a-olefins) etc.

or, more often, can be made from mixtures of these compounds, with the alpha-olefin usually being the major ingredient. The sulfonation is usually carried out with sulfur trioxide under low partial pressure, for example with S03, which is greatly diluted with an inert gas, such as air or nitrogen, or with S03 under vacuum. This reaction generally leads to an alkenylsulfonic acid, often together with a sulton. The acidic material obtained is then made generally alkaline and treated to open it to form a hydroxyalkanesulfonate and alkenyl sulfonate. The number of carbon atoms in the olefin is usually in the range from 10 to 25, more usually in the range from 12 to 20. Suitable mixtures are, for example, those which consist mainly of C12, C14 and Ci6-01efins and have an average of about 14 carbon atoms or mixtures of mainly C14, C16 and C18-01efins with an average of about 16 carbon atoms. The preferred olefin sulfonates are the sodium salts, but other water-soluble salts, for example ammonium * or potassium salts, can also be used in the context of the invention.

The sodium bicarbonate used in the examples is a product which is obtained by precipitation from a solution (for example by treating a sodium carbonate solution with carbon dioxide to precipitate the bicarbonate), subsequent drying, treatment with carbon dioxide gas and sieving to the desired particle size (generally without substantial downsizing or pulverization).

These particles generally consist of monoclinic crystals or tablets or conglomerates of these crystals (for example twin crystals), with some protruding spike-like parts of generally rhombo-noble shape with many protruding angles, see Figure 1, which is a photomicrograph of the crystals used in Example 1, and Fig. 2 showing a view of these crystals with an electron microscope. 3 shows a photomicrograph of the crystals used in Example 2.

The toothpastes of the above examples do not foam, that is, when diluted with water, they do not develop carbon dioxide bubbles.

The toothpastes according to the invention have an alkaline pH, generally in the range from about 8.5 to 10.0, usually from about 9.3 to 9.9.

Dentine abrasion with the toothpastes according to the invention can be modified using the radioactive technique described by Grabenstetter and co-workers in "Journal of Denral Research", volume 37, page 1060 (1958) in accordance with Stookey and co-workers in "Journal of Dental Research", volume 47 , Page 524 (July-August 1968).

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