US2041473A - Dentifrice polishing base - Google Patents

Description

Patented May -19, 1936 2,041,473 nnn'rrmrcs romsnmo BASE Joseph Janota, In, Chicago Heights, 111., assignor to Victor Chemical Works, Chicago, 111., a corporation of Illinois No Drawing. Application October 11,1934,

Serial No. 747,983

8 Claims.

This invention relates to improvements in polishing bases for dentifrices, and particularly to polishing bases for powdered dentifrices.

Tricalcium phosphate has heretofore been frequently used as a polishing base-in the preparation of dentifrices. When used with tooth powders containing soap, however, tricalcium phosphate forms a curd upon moistening unless a relatively high proportion of soap or frothing agent is included. By the use of a large amount of soap it was possible to effect a partial emulsion of the curd-like precipitate and thus to overcome partially the unsatisfactory effect thereof.

It has now been discovered that the curd may be totally avoided without the use of an excessive amount of soap by including with the tricalcium phosphate a small proportion of an alkali metal pyrophosphate. For example, whereas formerly from 6 to per cent. of soap was required, by the use of a minor proportion of pyrophosphate this may be reduced to 4 per cent. or less, while still maintaining excellent emulsifying and frothing qualities.

A composition embodying the invention comprises a powdered tricalcium phosphate in which has been intimately mixed from 1 to 5 per cent. of powdered anhydrous tetrasodium pyrophosphate, and from 1 to 5 per cent. of powdered soap. Flavoring materials such as oil of cloves, oil of Wintergreen and the like may be added, if desired.

A typical dentifrice powder may be made up from 94 parts of tricalcium phosphate, 2 parts of anhydrous tetrasodium pyrophosphate and 4 parts of soap. When 2 grams of such a powder is shaken with 50 cc. of water, an excellent creamylike froth is obtained, and at the same time a considerable portion of the tricalcium phosphate remains dispersed throughout the solution for a considerable length of time after the shaking ceases. A similar powder without the tetrasodium pyrophosphate forms an undesirable flocculent curd-like froth, and the tricalcium phosphate not occluded in the curd-like precipitate settles almost immediately when shaking ceases. The pyrophosphate has the same efl'ect when used in connection with frothing agents of other types. For instance, 'sulfonated castor 011 (Turkey red oil) produces a similar curd-like precipitate in combination with tricalcium phosphate, and

this curd-like precipitate is overcome by the addition of an alkali metal pyrophosphate.

Calcium carbonate and magnesium carbonate produce a similar curd in the presence of a frothing agent, and this curd is overcome by the use of the alkali metal pyrophosphate, but not quite so satisfactorily as in the case of the tricalcium phosphate. With the calcium or magnesium carbonate a larger quantity of the pyrophosphate, for example, from 5 to 10 per cent., is used.

In the absence of soap or frothing agent, no foam is formed in a tricalcium phosphate powder, but the addition of the pyrophosphate is an advantage in that it causes an appreciable dispersion of a portion of the tricalcium phosphate.

The term alkali metal as herein used includes sodium potassium and ammonium. Either the crystalline or anhydrous phosphates may be used, but in the event that the crystalline material is used the amount is varied to represent the equivalent of the desired proportion of the anhydrous salt. While as little as 1% of soap and pyrophosphate may be used, it is generally preferred to use from 3 to 4% of soap and from 2 to 3% of the pyrophosphate. Higher proportions of alkali metal pyrophosphate may be used without detrimental effect.

The foregoing detailed description has been given for cleamess of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible, in view of the prior art.

I claim:

l. A dentifrice polishing. base comprising a powder of the class consisting of tricalcium phosphate and calcium and magnesium carbonate and a minor proportion of an alkali metal pyrophosphate, the amount of pyrophosphate being markedly less than suflicient to dissolve the calcium or magnesium present.

2. A dentifrice polishingbase comprising powdered tricalcium phosphate and a minor proportion of an alkali metal pyrophosphate, the amount of pyrophosphate beingmarkedly less than is required to dissolve the calcium.

3. A dentifrice polishing base as set forth in claim 2, in which the alkali metal pyrophosphate is tetrasodium pyrophosphate.

4. A base as set forth in claim 2, in which the pyrophosphate is present in the proportion of 1 to 5 per cent. of tricalcium phosphate.

5. A base as set forth in claim 2, in which the pyrophosphate is 2 to 3 per cent. of the tricalcium phosphate.

6. A polishing base as set forth in claim 1, in which the powder is calcium carbonate.

7. A polishing base as set forth in claim 1, in which the powder is magnesium carbonate.

8. A base as set forth in claim 1, in which the powder is calcium carbonate and the pyrophosphate is 5 to 10 per cent. of the calcium carbonate.

JOSEPH JANOTA, JR.