US2359326A - Dentifrice base - Google Patents

Description

Patented Oct. 3, 1944 DENTIFRICE BASE Henry V. Moss and Theodore W. Schilb, Kirkwood, Mo., assignors to Monsanto Chemical Company, a corporation of Delaware No Drawing. .Appllcatlon December 17, 1941, Serial No. 423,300

13 Claims.

This invention relates to a dentifrice base particularly suitable for use in powdered dentifrices. This application is a continuation-inpart of application Serial No. 201,936, filed April 14, 1938.

One object of the present invention is to provide a dentifrice base having an improved fiowability. Another object is to provide a dentifrice base having improved cleansing properties. A

further object is to provide a dentifrice base containing a tasteless wetting agent. Additional objects and advantages inherent in our improved composition will be apparent from the following description.

Powdered dentifrice bases are at present pre- 15 pared by grinding the base material to a fine state of subdivision, the degree of fineness chosen being that found desirable from the standpoint of abrasive efiect. It is known, for

example that in general the coarse powders have a greater abrasive or scratching effect, than do the finer powders. It may also be stated that the recent tendency has been to decrease the abrasive effect of the dentifrice base by decreasing the state of subdivision of the particles comprising the powder.

While many of the very fine powders thus demanded by the trade have been satisfactory from the standpoint of polishing effect or abrasiveness it became obvious that the fine state of subdivision now required by a dentifrice base decreased the fiowability of the powder to such an extent as to become a serious objection from the users standpoint.

We have now found after considerable study of this subject that it is possible to agglomerate the fine particles of the dentifrice base by the use of suitable sulfonation products, into granules or agglomerates of considerable size, in-

creased apparent density and of fairly regular shape, said granules having the property of rapidly disintegrating when moistened. We thus obtain the desired high fiowability of the base which is characteristic of large particles of regular shape and the fineness of the base de- One hundred grams of dica1cium phosphate dihydrate having a particle size of from 1 to 10 microns were spread out in a thin layer and sprayedwith a solution of 4 grams of a suifated alcohol, such as sodium lauryl sulfate in 25 cc. of water. The moistened material was rolled on the sheet to give small granules. The granulated product was dried at C. and the dried product sifted to give a product between 10 and 35 mesh. The screened product remained firmly agglomerated when dry but disintegrated completely when wet.

Example No. 2

To a water slurry of dicalcium phosphate having a particle size of from 1 to 10 microns, we add from 2. to 5 percent, calculated on a dry basis, of a soluble salt to act as a binding and wetting agent. We then spray dry the resulting slurry at a temperature below the decomposition temperature of the dihydrate of dicalcium phosphate. This temperature is approximately 60 C.

The product obtained by spray drying is screened to the desired size. The dicalcium phosphate remains filmly agglomerated when dry but rapidly disintegrates into the individual particles when wetted.

Effective wetting agents for the present purpose comprise generally the sulfonation products (0r soluble salts produced from such products) of long chain alcohols or hydrocarbons, particularly alkylated aromatic hydrocarbons, or alkyl esters of aromatic acids particularly of benzoic and salicylic acids. contemplated within the term sulfonation products we mean to include compounds of the type:

where R is an alkylated aromatic residue of the type: RAr, R beingan alkyl group of not less than 8 and not more than 18 carbon atoms, or mixtures thereof as derived from alcohol obtained by hydrogenation of coconut oil, commercially known as Lorol. Ar is an aromatic hydrocarbon nucleus, and Y, is selected from the group consisting of hydrogen, alkali metals, calcium and magnesium. X is hydrogen or hydroxyl or halogen, and m and n are whole numbers.

Specific examples of compounds contemplated herein are sodium or potassium salt of the alkylated benzene sulfonic acids, in which the alkyl group contains more than 8 and less than 16 carbon atoms, especially the decyl, dodocyl and tetradecyl benzene sulfonic acids and sodium salts thereof, sulfated octyl, decyl, dodecyl (lauryl), tetradecyl, hexadecyl, octadecyl alcohols or mixtures thereof (Lorol), the sulfated alcohols being sold under the name of Gardinol; the alkyl esters of sulfobenzoic or salicylic acid, in which the alkyl group may be either octyl, decyl, dodecyl, tetradecyl, hexadecyl or octadecyl or mixtures thereof (Lorol).

The wetting agents comprising the esters of sulfobenzoic and sulfosalicylic acid are particularly desired when producing dentifrice base products of substantially no or only slight taste or after-taste, especially in those compositions where taste cannot be masked by flavors, etc. These products have exceptional detergency, wetting and sudsing qualities and retain their favorable properties even when used in hard water, that is in the presence of calcium and magnesium ions.

Any of the ordinary dentifrice bases which are essentially insoluble powders such as dior tricalcium phosphate, precipitated chalk, calcium sulphate in the form of its various hydrates or magnesium carbonate, etc., as well as the insoluble form of sodium metaphosphate, may be utilized in the practice of my invention to produce an agglomerated dense free-flowing dentifrice base. The individual particles comprising the granules thereof are bound together by means of a water soluble salt, and have the additional property of disintegrating completely upon wetting.

The free flowing property and the increased specific gravity of our improved material are illustrated in, the following table showing the properties of an ordinary dentifrice base dicalcium phosphate dihydrate, as usually prepared and after having been granulated:

Measurements of rate of fiow were made using an ordinary powder flow-meter.

The above data on apparent specific gravity show twoimportant properties: (a) the loosely packed finely divided precipitated product shows an increase in apparent gravity of 0.296 gram/ cc. upon vibrating as would occur in a transported package; (1)) the granulated product shows a considerably higher density and a diministed packing eflfect upon vibration. Specifically the packing effect of the samples above average 0.122 gram cc. being somewhat less than half thatshown by the finely divided precipitated powder.

When a dentifrice base is prepared according to our invention, utilizing a wetting or emulsifying agent we obtain a third advantage of considerable utility. Upon wetting the granules, as is done when used as a tooth powder, the contained wetting or emulsifying agent serves the additional purpose of effecting a more efficient cleansing action upon the teeth. As thus liberated, these agents will be contained in the solution coating the individual particles causing a complete wetting of such particels and a more efiicient utilization of the ingredients thereof.

As an important feature of our invention we may use the water soluble salts such as the sodium salts of alkylated aromatic sulfonic acids, in which the alkyl group contains more than eight and less than sixteen carbon atoms as a binding agent to hold the individual particles in the granular form. Such a product will possess wetting, emulsifying and sudsing properties and will accordingly show rapid wetting and efficient cleansing properties.

What we claim is:

1. As a free-flowing dentifrice base, dry granules composed of finely divided particles of a dentifrice polishing agent and at least one wetting agent of the class consisting of compounds of the type:

where R is an alkylated aromatic residue of the type: R,Ar-, R being an alkyl group of not less than eight and not more than eighteen carbon atoms, Ar is an aromatic hydrocarbon nucleus, Y is selected from the group consisting of hydrogen, alkali metals, calcium and magnesium, X is selected from the group consisting of hydrogen. hydroxyl and halogen and m and n are whole numbers, said wetting agent binding said particles together in said granules.

2. As a. freej-fiowing dentifrice base, dry granules composed .of finely divided particles of a dentifrice polishing agent and a wetting agent of the class consisting of compounds of the type:

where R is an alkylated benzene residue of the type: R-Ar, R being an alkyl group of not less than eight and not more than eighteen carbon atoms, Ar is a benzene hydrocarbon nucleus, Y is selected from the group consisting of hydrogen, alkali metals, calcium and magnesium, X is selected from the group consisting of hydrogen, hydroxyl and halogen and m and n are whole numbers, said wetting agent binding said particles together in said granules.

3. The product defined in claim 2 in which the dentifrice polishing agent is dicalcium phosphate dihydrate.

4. As a free-flowing dentifrice base, dry granules composed of finely divided particles of a dentifrice polishing agent and a wetting agent comprising lauryl sulfate, said wetting agent binding said particles together in said granules.

5. As a free-flowing dentifrice base. dry granules composed of finely divided particlesof a dentifrice polishing agent and a wetting agent"; comprising lauryl benzene sulfonate, said wet ting agent nd ng Said particles together in said granules.

6. As a free-fiowing base, dry granules composed of finely divided particles of a dentifrice said wetting agent binding said particles together in said granules.

'7. The process for preparing a free-flowing dentifrice base which comprises moistening finely divided particles of-a dentifrice polishing material with an aqueous solution of a wetting agent, agglomerating the moistened material and then drying the agglomerated product, said wetting agent being selected from the class consisting of compounds of the type:

R s on;

a-o-s 0,Y; and

R-O CAr-( s 021')- where R is an alkylated aromatic residue of the type: R--Ar--, R being an alkyl group of not less than eight and not more than eighteen carbon atoms, Ar is an aromatic hydrocarbon nucleus, Y is selected from the group consisting of hydrogen, alkali metals, calcium and magnesium, X is selected from the group consisting of hydrogen, hydroxyl and halogen and m and n are whole numbers, said wetting agent binding said particles together in said agglomerated product.

8. The process defined in claim 7 wherein the product is dried at a temperature of about 60 C. and then screened to the desired size.

9. The process for preparing a free-flowing dentifrice base which comprises moistening finely divided particles of dentifrice polishing material with an aqueous solution containing lauryl ester of sulfobenzoic acid wherein the lauryl group is attached to the carboxyl group, agglomerating the moistened material and then drying the agglomerated product.

10. As a free-flowing dentifrice base, dry granules composed of finely divided particles of a dentifrice polising agent and a wetting agent iaving the following general formula:

where R, is an alkyl group of not less than 8 and not more than 18 carbon atoms, Ar is a benzene nucleus, Y is selected from the group consisting of hydrogen, alkali metals, calcium and magnesium, X is selected from the group consisting of hydrogen, hydroxyl and halogen and m and n are whole numbers, said wetting agent binding said particles together in said granules.

11. As a free-flowing dentifrice base, dry granules composed of finely divided particles of a dentifrice polishing agent and a wetting agent comprising the Ca to Cn-alkyl esters of sulfobenzoic acid wherein the alkyl group is attached to the carboxyl group, said wetting agent binding said particles toegther in said granules.

12. The process for preparing a free-flowing dentifrice base which comprises moistening finely divided particles of a dentifrice polishing material with an aqueous solution of a wetting agent, agglomerating the moistened material and then drying the agglomerated product, said wetting agent comprising at least one compound of the-following general formula:

where R is an alkyl group of not less than 8 and not more than 18 carbon atoms, Ar is a benzene nucleus, Y is selected from the group consisting of hydrogen, alkali metals, calcium and magnesium, X is selected from the group consisting of hydrogen, hydroxyl and halogen and m and n are whole numbers.

13. The process for preparing a free-flowing dentifrice base which comprises moistening finely divided particles of a dentifrice polishing material with an aqueous solution of a wetting agent, agglomerating the moistened material and then drying the agglomerating product, said wetting agent comprising the Ca to Cm-alkyl esters of sulfobenzoic acid wherein the alkyl group is attached to the carboxyl group.

HENRY V. MOSS. THEODORE W. SCHILB.

CERTIFICATE OF CORRECTION. Patent No. 2,359,526. October 191m.

HENRY v. moss, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, second column, line 25, for "filmly" read "firmlypage 2, first column, line 62-65, for "diministed" reed -diminished-; line 65, for "0.122 gram cc." read O.122 gram/cc.--; and second column, line 5, after "such" for "particels" read -particles-; page 5, second column, line 15, for "toegther" read -together-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 28th day of November, A. Dr 191414..

Leslie Frazer (Seal) Acting Commissioner of Patents.