IL32764A - Calcinated sodium aluminum phosphate,method for its preparation and dentifrice compositions containing it - Google Patents

Description

Calcined sodium aluminum method for its preparation and dentrifice compositions contained it CHEMICAL COMPANY 2 This invention relates to phosphates suitable for use as polishing agents in dentifrice to their and to dentifrice compositions containing Dentifrice formulations have been ranging from liquids and powders to the highly popular pastes or dental The dental creams are by far the most difficult to compound They require careful balancing of polishing sweeteners and therapeutic agents to produce a smooth homogeneous Most modern dental cream formulations use one of several phosphate materials as the polishing Examples of the phosphate polishing agents are dicalcium anhydrous dicalcium tricalcium thermally converted dicalcium phosphate and insoluble sodium The amount of phosphate materials added to the dental formulations will range between 30 and by The most widely used humectants in toothpaste are glycerine and Propylene glycol is also used in small amounts and to a very limited The primary function of humectant as part of the liquid phase is to retain moisture which provides good texture and maintains an attractive glossy appearance when the paste is exposed to The binder employed therein is to prevent separation of the liquid and solid The most conventionally used binders are the seaweed colloids and synthetic derivatives of specifically Carrageenan and sodium carboxymethyl Others such as gums have been Combinations of these binders Since the natural and synthetic water dispersions of organic binders are subjected to microbial or mold relatively small amount of preservatives added to the Examples of preservatives used in the industry are the esters of parahydroxyl The function of the detergents within the dental formulation is to provide greater cleansing action due to the lowering of the surface tension and the sudsing action in the Among detergents used are sodium sodium lauryl sodium and sodium dioctyl Since toothpaste flavoring probably represents the greatest single factor in consumer great care has been employed in selecting balanced blends of different essential These are if used Combinations of principal flavors are and sassafras and are used with secondary oils such as olove and Saccharin and sodium cyclamate are widely used to improve taste and enhance the flavor qualities of the The synthetic sweeteners may be used in combinations to obtain optimum sweetness and absence of Their desirable properties are obtained at very low concentrations and consequently they have negligible influence on the toothpaste Since water is such a common elemen it is in obtaining stable toothpaste formulations to employ tially pure water It is common practice to demineralize the water that is The therapeutic agents within the dental cream are to prevent decay of the tooth and are commonly in the form of stannous fluorides and sodium fluoride Difficulties have been encountered in using combinations of the above materials in modem dentifrice fluoride ions by the phosphate polishing agents have been in formulating a dentifrice a polishing agent must be selected to provide excellent polishing properties and have a very high degree of compatibility with the fluoride and in particular should not scavenge the fluoride The invention provides a new calcined complex alkali containing the aluminum and phosphorus in atomic ratios of about This has been found to possess the desired polishing The invention also provides a process for the manufacture of such calcined complex alkali wherein an alkali carbonate or bicarbonate and reactive aluminum oxide or hydroxide are in any desired with aqueous phosphoric in proprotions as to precipitate a product having the atomic ratios of alkali metal taluminum phosphorus indicated the reaction mixture heated until a crystalline product and the latter is separated from the reaction and Sodium or potassium which are the equivalent of mixtures of hydroxide or potassium hydroxide with aluminum oxide or may also be used for the The proportions of the reactants in the reaction mixture may vary within fairly wide the atomic ratio of alkali aluminum may be from about to about and the atomic ratio A preferred atomic ratio of the three elements in the reactio alkali is about Sodium is the preferred alkali but others may be used especially or mixtures of sodium and potassium Preferably the temperature at which the reaction mixture is is in the range from 45 to The calcining temperature should be from 300 to preferably 400 to It is surprising that the calcined phosphates of the present invention can function as a polishing agent within aqueous dentifrice formulations since known similar were not were water In carrying out the process according to the for preparing alkali metal aluminum phosphate according to the present phosphoric may diluted with water to provide a phosphoric acid containing from about 40 up to about by weight of The acid solution charged to a reaction vessel equipped with a stirrer and a reflux sufficient alkali metal such as sodium or potassium or alkali metal such as sodium or potassium a mixture is charged to this phosphoric acid while the desired atomic ratio of alkali of After the solution a reactive aluminum or or mixture is to the mixture in such an amount tha the final ratio of alkali hosphorus is about The temperature of the reaction is to appromixately 80 to and maintained at this temperature for approximately six hours with After this the temperature dropped below and maintained at this level for approximatel fifteen The resulting slurry is poured into a filter and the solids removed from the cake so recovered ia immediately slurried with water and again filtered and repeated as Cold water used in the washing until the pH is above about Excess water in the filter cake is drawn product is effectively dried at a temperature o about 110 to to a constant The material so has been by its pattern diffraction as corresponding to a compound whose alkali hosphorus ratio is about The dry alkali metal aluminum phosphate is then calcined at a temperature of from about 300 to about and preferably at a temperature from about 400 to abou until constant weight is In order to enhance the utilit of the calcined alkal phoephate as a polishing agent in dentifrice is preferably screened to obtain relatively uniform A 200 or smaller mesh screen can be effectivel used to produce grain size In a dentifrice composition this material can be used to replace all or part of the abrasive or polishing agent in the dentifrice The invention is by the following to which it is not All otherwise are by Example 1 2350 Oram of aqueous phosphoric acid is added to 1104 grams of water in a 5 liter reaction flask fitted with a stirrer and reflux grams of sodium carbonate is added the temperature adjusted to of aluminum hydroxide is then added and temperature is allowed to rise to 85 Crystallization is complete in 24 The product recovered by filtration and washed with cold Washing is continued to the final wash above The crystals are oven dried at 90 to to near constant weight and then calcined at for 16 The calcined phosphate is broken up and sieved wet through a 325 mesh 2 The calcined phosphate prepared in accordance with Example 1 is formulated as a polishing agent a toothpaste havin the following composition by Glycerin Water Polishing agent Commercial Commercial Detergent Peppermint Oil Flavor Preservative Stannous fluoride Saccharin a mixture of the and two thirds of the glycerin is heated to to effect complete and then cooled back to room polishing saccharin and stannous fluoride are then added The paste is and It is then subjected to vacuum and the detergent dispersed in the remaining glycerol is added last with a minimum of Standard compatibility tests were conducted on this toothpaste by adding one part by weight of the polishing agent to a solutio of stannous The mixture was agitated for one hour and then centrifuged sufficiently to produce a clear supernatant liquid Fluoride and The percent compatibility is defined as the concentration of fluoride or stannous ions remaining in the liquid extract compared to the concentration originally present in the stannous fluoride solution times These tests indicated an compatibility with the fluoride ion and compatibility with the stannous 3 Grams of aluminum hydroxide is reacted with 2350 grams of phosphoric The temperature is raised slowly to and held there until the solution is This clear solution is diluted at with one liter of containing 10 milliliters of 7 phosphoric A solution of grams of sodium carbonate and 1440 grams of water is added into the stirred aluminum phosphate The temperature of the resulting slurry is raised to about and held there for 16 The mother liquor is filtered and the cake slurried with cold distilled Subsequent calcining and classifying are conducted in the manner set forth in Example Example The calcined phosphate prepared as described in Example 3 is formulated as a polishing agent into a toothpaste having following composition by Glycerin Sorbitol Water Polishing agent Gum Carboxymethyl cellulose Oil Methyl Salicylate Preservative Stannous fluoride Saccharin In the standard compatibility tests of Example 83 and were indicated the and stannous Example The abrasive properties of a polishing agent according to this invention were studied and compared to the abrasive property of commercially available polishing the antimony abrasion tests were conducted thereon by forming a slurry of the dentifrice or polishing agent with water containing sufficient carboxymethyl cellulose to ensure that the polishing agent remained in suspension during mild The slurry was placed in a series of cups into which previously weighed strips of cast antimony metal had been The metal strips were then brushed with standard toothbrush by means of a mechanical brushing The antimony strips were and The abrasion value is defined as the milligrams antimony lost after double brush An average values are indicated 1 Antimony Abrasiqn Values Polishing agent Abrasion Value Dicalcium phosphate dihydrate 3 phosphate 2 Example 19 E insufficientOCRQuality

Claims (1)

1. CLAIMS Calcined alkali phosphates having an atomic ratio alkali hosphorus of about Phosphates according to Claim wherein the alkali metal is sodium or A process for the manufacture of calcined alkali metal aluminum phosphates according to Claims 1 wherein an alkali metal carbonate bicarbonate and reactive aluminum oxide hydroxide in any with aqueous phosphoric in proportions so as to precipitate a product having the atomic ratios alkali hosphorus of about the reaction mixture is heated until a crystalline product and the latter is separated from the reaction mixture and A process according to wherein the proportion of used the that in the reaction mixture the atomic ratio of alkali hosphorus is about A process according to 3 or wherein the temperature at which the reaction mixture is in the range from 45 to A process according to Claims 4 or wherein calcining temperature is the range from 300 to preferably 400 to according to Claim substantially as described herein with reference to Example 1 and Example Dentifrice containing as a polishing agent a calcined alkali phosphate as claimed Claims 1 or or prepared by a process according to any one of Claims 3 to Dentifrice formulations according to Claim containing the polishing agent in an amount from 30 to Dentifrice formulations according to Claims 8 containing conventional ingredients suc as a and a therapeutic Dentifrice substantially as herein with reference to Example 2 and Example PARTNERS insufficientOCRQuality