US3574823A

US3574823A - Dentifrice containing visible agglomerated particles of polishing agents

Info

Publication number: US3574823A
Application number: US750028A
Authority: US
Inventors: Francis D Roberts; John J Steinke
Original assignee: Colgate Palmolive Co
Current assignee: Colgate Palmolive Co
Priority date: 1968-08-05
Filing date: 1968-08-05
Publication date: 1971-04-13
Anticipated expiration: 1988-04-13
Also published as: USRE29634E

Abstract

DENTIFRICE CONTAINING VISIBLE, PALPABLE AND ESTHETICALLY PLEASING SUBSTANTIALLY WATER-INSOLUBLE AGGLOMERATED PARTICLES OF POLISHING AGENTS. THE PARTICLES ARE REDUCED TO SMALLER IMPALAPABLE SIZE BY MILD MECHANICAL ACTION SUCH AS BY TOOTHBRUSHING. THE AGGLOMERATES INCLUDE WATER INSOLUBLE POLISHING AGENT SUCH AS INSOLUBLE SODIUM METAPHOSPHATE OR DICALCUIM AND MAY ALSO CONTAIN A BINDING AGENT SUCH AS GUM ACACIA, GLEATIN, STARCH, CARBOXYMETHYL CELLULOSE OR THE LIKE.

Description

United States Patent 3,574,823 DENTIFRICE CONTAINKNG VISIBLE AGGLQM- ERATED PARTICLES 0F POLISHING AGENTS Francis D. Roberts, Millington, and John J. Steinlre III,

Somerville, N.l., assignors to Colgate-Palmolive Company, New York, FLY. No Drawing. Filed Aug. 5, 1968, Ser. No. 750,028

Int. (Cl. A611 7/16 US. Cl. 424-49 15 Claims ABSTRACT OF THE DISCLOSURE This invention relates to novel dentifrice preparations containing visible, palpable and esthetically pleasing substantially water-insoluble agglomerated particles of polishing agent.

Dentifrices of the prior art commonly contain waterinsoluble polishing agents which facilitate cleansing of the teeth. Since these agents are water-insoluble, they have been used in small particle sizes, substantially all of which are typically less than 177 microns in size and often even less than 10 microns. Such small sized particles help avoid too much abrasiveness, palpability and retention of particles in the oral cavity even after rinsing which would be expected if larger particles of waterinsoluble polishing agent were employed. However, these small particles, being individually invisible, could not contribute to the esthetic appearance of the dentifrice.

It has now been found that dentifrice containing agglomerates of water-insoluble polishing agent of desirable polishing power can be prepared in a size visible to the naked eye which agglomerates are substantially waterinsoluble and palpable, have desirable abrasiveness and are easily reduced to fine particle size upon being subjected to mild mechanical action, such as toothbrushing, so that the reduced size particles are easily cleared from the oral cavity. The agglomerates, being visible, contribute markedly to the visual and esthetic appeal of a dentifrice composition.

It is an object of this invention to provide dentifrice preparations ocntaining agglomerated particles of waterinsoluble dental polishing agent which are easily reduced to fine size by mild mechanical action.

Other objects of the invention will be apparent from consideration of the following detailed description and claims.

In accordance with certain of the aspects, this invention relates to dentifrice comprising a dental vehicle and an agglomerated material containing water-insoluble polishing agent, particles of said agglomerated material being visible, said agglomerated material being palpable and substantially water-insoluble, and easily reducible to individual particles of polishing agent, each of which is fine, non-visible and non-palpable upon being subjected to mild mechanical action.

The agglomerated particles of polishing agent employed in the instant invention are present on the surface of and within a dentifrice. When the dentifrice is a transparent or translucent toothpaste, all agglomerated parti cles are visible to the naked eye. When it is opaque, the particles on the surface are visible. The particles are visibly distributed throughout a toothpowder also.

Translucent and transparent toothpastes as well as opaque toothpastes contain a dental vehicle which forms a gel or creamy mass of a consistency which can be desirably extruded from a collapsible tube such as an alun1 inurn tube or a lead tube. The vehicle contains liquids and solids. In general, the liquid portion comprises Water, glycerine, sorbitol, propylene glycol, polyethylene glycol 400 or the like including suitable mixtures thereof. It is usually advantageous to use a mixture of both Water and a humectant, such as glycerine, sorbitol, propylene glycol or the like. The total liquid content is generally about 20-89.5% by weight of the toothpaste. In transparent and translucent toothpastes the liquid content of the toothpaste may be about 2089.5% by weight while in opaque toothpastes the total liquid content is usually about 20-50%.

The solid portion of the vehicle is a gelling agent, such as the natural and synthetic gums and gum-like materials,

such as Irish Moss, gum tragacanth, alkali metal carboxymethyl cellulose and hydroxymethyl carboxyethyl cellulose, polyvinyl pyrrolidone, starch, Water soluble, hydrophilic colloidal carboxyvinyl polymers, such as those sold under the trademark Carbopol 934 and 940. The solid portion of the vehicle is typically present in an amount up to about 10% by weight of the toothpaste and preferably about 0.55% by weight.

The substantially water-insoluble agglomerated particles on the surface of and within the dentifrice contain a water-insoluble polishing agent and, in accordance with preferred embodiments of the invention, a binding agent.

Water-insoluble polishing agents of the prior art may be agglomerated in accordance with this invention. The polishing agents thus include insoluble phosphate salts, such as insoluble sodium metaphosphate, insoluble potassium metaphosphate, calcium pyrophosphate, magnesium orthophosphate, trimagnesium orthophosphate, tricalcium phosphate, dicalcium phosphate dihydrate, anhydrous dicalcium phosphate and the like. Other poishing agents include calcium carbonate, magnesium carbonate, hydrated alumina, silica, zirconium silicate, aluminum silicate including calcined alumnium silicate and polymethyl methacrylate. Combinations of polishing agents may be employed. The preferred polishing agents are the .dicalcium phosphates and insoluble sodium metaphosphate.

The insoluble alkali metal metaphosphates are preferably the insoluble sodium and potassium salts of polymetaphosphoric acid. These materials are known in the art with the insoluble sodium metaphosphate having been suggested as a polishing agent as previously indicated. Such materials may be formed in any suitable manner, as illustrated by Thropes Dictionary of Applied Chemistry, vol. 9 (4th ed.), pp. 5105ll. The forms of insoluble sodium metaphosphate known as Madrells salt and Kurrols salt are further examples of suitable materials. These metaphosphate salts exhibit only a minute solubility in water, and are commonly referred to as insoluble metaphosphates, therefore. There is present a minor amount of soluble phosphate material as impurities, usually of the order of a few percent such as up to about 4% by weight. The amount of soluble phosphate material which is believed to be a soluble sodium trimetaphosphate in the case of insoluble sodium metaphosphate may be reduced by washing with water if desired.

Binding agents which may be employed to assist formation of polishing agent into agglomerated particles include water-soluble materials such as gum acacia (arabic), gelatins, starches, alkali metal carboxymethyl celluloses, polyethylene glycols, glucose, sucrose, methyl cellulose, carboxyethyl hydroxymethyl celluloses, sodium alginate, polyvinyl pyrrolidone, polyvinyl alcohol, Irish Moss, gum tragacanth, magnesium aluminum silicate gel and the like. Mixtures of binding agents may be employed too. When the polishing agents are freed from binding with these agents upon application of mild pressure, typically a toothbrush applied in the oral cavity, these water-soluble agents are easily solubilized in saliva.

Typically, the polishing agent comprises about 75 100% by Weight, preferably about 75%-98%, of the finished agglomerate. The binding agent when present preferably comprises about 2%25% by weight of the finished agglomerate.

When employed the binding agent is blended with the polishing agent. The binding agent may be blended in dry powdered form or in solution in water or alcohol. The agglomerate may be formed in a dry process known as slugging or in a wet granulation process.

In the dry process or slugging process, the blend of polishing agent particles, substantially all of which typically have an individual particle size of less than 250 microns, and optionally binding agent, are compressed on a tablet press. The large tablet thereby formed typically has dimensions of about 6 mm. to 25 mm., although it may be even larger. The tablet is then broken into visible granule agglomerates having particle sizes, preferably up to about 2380 microns, most preferably about 420-840 microns, typically in a mill, granulator or comminutor.

When the dry or slugging process is employed, the blend to be agglomerated preferably also includes a lubricant such as talc, magnesium stearate, calcium stearate, stearic acid and the like. The lubricant facilitates agglomeration.

When dry powdered binder is blended with polishing agent in the wet granulation process, solvent, such as water or ethanol or a solution of additional binding agent, is contacted with the blend in suflicient amount to Wet the mass.

The wet granulation process may be performed by wetting a powder blend of water-insoluble dental polishing agent particles typically having a particle size of less than 74 microns and binding agent in continuous contact on a Dravo pan, in a Hobart mixer or other suitable powder-wetting mixing device thereby forming a Wet mass. The wetting may be performed by contact of the polishing agent with solid binder followed by moistening or with a solution of the binder.

The wet mass formed from the polishing agent and binding agent is forced through a screen having uniform openings which may be from 420 microns to 2380 microns in size and dried as agglomerates. Typically in air or an oven. The agglomerates may then be segregated into desired sizes such as between 420 and 840 microns by pass ing through appropriately sized screens. It is noted that when the wet mass is formed in a Dravo pan, the forced screening may be unnecessary.

It is desirable that the agglomerates formed be easily introduced into the oral cavity in a dentifrice, such as a toothpaste, and comfortably maintained there until reduced in size during toothbrushing. Therefore, visible particles, generally having a particle size larger than about 2380 microns, are preferably separated from the agglomerates. In order to maximize the 'esthetic appearance of the agglomerates when they are incorporated into a dentifrice, it is desirable also to separate fines having a particle size smaller than about 420 microns. However, any agglomerates containing the components of the invention which are visible to the naked eye are within the scope of the invention.

If desired, the blend to be agglomerated, by wet or dry procedures, may also contain a non-abrasive diluent or filler, such as lactose, starch, mannitol, and the like, in amounts of about 1%5% by weight of the agglomerate, in order to ameliorate the polishing power of the agglomerate. Furthermore, the blend may include ancillary components, such as a color dye or pigment, particularly for an opaque toothpaste or a toothpowder. Typical dyes and pigments include F, D&C dyes and lakes and the like. Color material when employed, generally is present in amounts of 110%.

Due to the nature of the water-insoluble polishing agent which comprises the major proportion of the agglomerate, the agglomerate is characterized as being substantially water-insoluble. In the oral cavity it is quickly reduced in size from the visible, palpable agglomerates introduced into individual invisible, fine, non-palpable particles upon subjection to mild mechanical action, such as by rubbing on the teeth, gums or other portions of the oral cavity with a toothbrush, the tongue, a finger or the like.

The agglomerated particles are generally incorporated into a toothpaste in amount about 575% by weight of the dentifrice, preferably 10-75%. Typically, they comprise up to about 50% by weight of a transparent or translucent toothpaste.

In addition to the vehicle and agglomerates, the dentifrice may contain water-insoluble invisible polishing agent having a particle size typical of that employed in the prior art, such as less than about 74 microns, if it is desired to increase polishing power beyond that provided by the agglomerates.

The dentifrice may also contain surface-active agent. It is preferred that the total amount of surface-active agent be about 0.05-5% by weight, preferably about 1-3%, of the dentifrice. Surface-active agent may include watersoluble sulfates of compounds having long chain alkyl radicals (e.g., chains of 10 to 18 carbon atoms) are suitable. One preferred material is -a long chain fatty acid monoglyceride sulfate, such as the sodium salt of hydrogenated coco fatty acid monoglyceride sulfate used alone or in combination with sodium lauryl sulfate. Other suitable materials are the fatty acid amides of amino acids such as sodium N-lauroyl sarcosinate.

Various other materials may be incorporated in the oral preparation of this invention. 'Examples thereof are coloring or whitening agents, preservatives, silicones, chlorophyll compounds, ammoniated materials, such as urea, diammoniumphosphate and mixtures thereof, and other constituents. Each of these adjuvants may be typically incorporated in the instant toothpastes in amounts up to about 5%. Where coloring is employed, the agglomerates may be colored with a suitable contrasting color.

The toothpaste may also contain antibacterial agents in amounts of about 0.015%. Typical examples of such agents are guanidines, biguanides and amines such as:

N -(4-chlorobenzyl) -N -2,4-dichlorobenzylbiguanide;

p-Chlorophenyl biguanide;

4-chlorobenzhydryl biguanide;

4-chlorobenzhydrylguanylurea;

N-3-lauroxypropyl-N -p-chlorobenzylbiguanide;

1,6-di-p-chlorophenylbiguanidohexane;

1- lauryldimethylammo nium 8.- p-chlorobenzyldimethyl ammonium) octane dichloride;

5,6-dich1oro-2-guanidinobenzimidazole;

N -p-chlorophenyl-N -laurylbiguanide;

5 -amino-1 3-bis (2-ethylhexyl -5-methyll1exahydrg-.

pyrimidine;

and their non-toxic acid addition salts.

Suitable flavoring or sweetening sialagogues may be employed in formulating a flavor for the compositions of the present invention. Examples of suitable flavoring constituents include the flavoring oils, e.g., oils of spearmint, peppermint, Wintergreen, sassafras, clove, sage, eucalyptus, marjoram, cinnamon, lemon and orange, as well as sodium methylsalicylate. Suitable sweetening agents include sucrose, lactose, maltose, sorbitol, sodium cyclamate and saccharine. Suitably, flavor and sweetening agent may together comprise from about 0.01 to 5% or more of the compositions of the instant invention.

The compositions of the present invention suitably may also contain a fluorine-containing compound having a beneficial effect on the care and hygiene of the oral cavity, e.g., diminution of enamel solubility in acid and protection of the teeth against decay. Examples thereof include sodium fluoride, stannous fluoride, potassium fluoride, potassium stannous fluoride (SnF -KF), sodium hexafluorostannate, stannous chlorofluoride, sodium fluorozirconate and sodium monofluorophosphate. These materials, which dissociate or release fluorine-containing ions in water, suitably may be present in an effective but nontoxic amount, usually within the range of about 0.01 to 1% by weight of the water soluble fluorine content thereof.

The toothpaste of the invention is formed by preparing a toothpaste containing no agglomerates and separately preparing the agglomerates in accordance with procedure set forth above. Thus, a gelling agent such as sodium carboxymethyl cellulose or Carbopol 934 and a preservative such as sodium benzoate, if employed, is dispersed with a humectant such as glycerine. Water may also be present. Additional humectant and water, as a 70% sorbitol solution, may then be mixed with the dispersion and heat is applied at about 40-65 C., say 50 C. to form a paste, gel or cream. Surface-active agent, such as sodium lauryl sulfate, if employed, is then dispersed in the mixture. The preparation is then deaerated and cooled. Desired flavor may then be added and the paste again deaerated.

The agglomerates are then dispersed in the toothpaste with minimal mechanical agitation, insufiicient to substantially break them down. The toothpaste, including the esthetically pleasing substantially Water-insoluble agglomerated particles of polishing agent, is then deaerated and tubed.

The following specific examples are further illustrative of the nature of the present invention, but it is understood that the invention is not limited thereto. The amounts and proportions of compositions described in the examples are by weight unless otherwise specified.

EXAMPLE I 220 parts of dicalcium phosphate dihydrate having an average particle size of about 4.2 microns are moistened with 91 parts of a aqueous solution of gum acacia while blending the components in a Hobart mixer to uniformly wet the blend. The wet mass thereby formed is forced through a screen having uniform openings of 2380 microns and oven dried for 1 hour at 65 C. The dried agglomerates are then screened through a screen having uniform openings of 840 microns onto a screen having uniform openings of 420 microns. 132 parts of agglomerated dicalcium phosphate dihydrate are retained on the screen having uniform openings of 420 microns. 132 parts of agglomerated dicalcium phosphate dihydrate are retained on the screen having uniform openings of 840 microns and 37 parts pass through to the screen having uniform openings of 420 microns.

20 parts of the agglomerate particles which pass through the screen having uniform openings of 840 microns and which are retained on the screen having uniform openings of 420 microns are blended with 80 parts of a translucent toothpaste having the following formulation:

Similar dentifrices may be formed using aggregates formed by blending with a 10% gum acacia solution; hydrated alumina having an average particle size less than about 2.5 microns; calcium carbonate having particles substantailly all of which are less than about 7.4 microns in size; anhydrous dicalcium phosphate having particles substantially all of Which are less than about 7.4 microns in size; and insoluble sodium metaphosphate having an average particle size of about 4.8 microns.

The toothpastes described in this example are translucent and esthetically pleasing. There are dispersed in the toothpastes visible particles of the agglomerate polishing agents. During tooth brushing the agglomerated parti cles are at first palpable and are then easily reduced to individual particles of polishing agent of fine size upon application of mild pressure with the toothbrush.

EXAMPLE II 6000 parts of anhydrous dicalcium phosphate particles having sizes indicated in Example I are blended with 150 parts of gum arabic powder and 50 parts of gum tragacanth. The blend is then moistened with a 10% aqueous solution of gum arabic. The agglomerates are then formed and screened in the manner set forth in Example I.

20 parts of the agglomerate particles described above are blended with parts of a transparent toothpaste having the following formulation.

Percent Glycerine 10.00 Sodium carboxymethyl cellulose 2.00 Sodium benzoate 0.50 Sodium saccharin 0.20 Sodium lauryl sulfate 2.50 Color 0.10 Ethanol 10.00 Flavor 1.30 Sorbitol solution (70%) 73.40

Similar dentifrices may be formed using aggregates in which the anhydrous dicalcium phosphate, gum arabic powder and gum tragacanth are moistened with (A) a 20% solution of gum arabic, (B) a 10% solution of polyvinyl pyrrolidone, (C) water, (D) ethanol or (E) glu-- cose solution.

The toothpastes described in this example are translucent and esthetically pleasing. There are dispersed in the toothpastes visible particles of the agglomerate polishing agents. During toothbrushing the agglomerated particles are at first palpable and are then easily reduced to individual particles of polishing agent of fine size upon application of mild pressure with the toothbrush.

EXAMPLE III Agglomerates are made by slugging blends of the following components:

ing uniform openings of 2380 microns and oven dried for 1 hour at 65 C. The dried agglomerates are then screened Parts Polishing agent:

Diealeium phosphate dihydrate 800 910 Calcium carbonate 440 865 Insoluble sodium metaphosphate 450 865 805 900 Hydrated alumina 890 790 Binder: Polyethylene glycol 6000 100 100 100 200 100 Lubricant:

Magnesium stearate 10 10 10 10 Tale 35 Stearie acid parts of each of the agglomerate particles described above are blended with 80 parts of a transparent toothpaste having the following formulation:

EXAMPLE IV 99 parts of unmilled dicalcium phosphate dihydrate having an average particle size of about 118:33 microns are blended with 1 part of magnesium stearate lubricant. The powder blend is compressed on a rotary tablet press to form agglomerate slugs 6 mm. X mm. in size. The slugs are then granulated in an oscillating granulator to form smaller agglomerate particles. These particles are screened with screens having uniformly spaced openings of 840 microns and 420 microns. 20 parts of the agglomerate particles which pass through the screen having uniform openings of 840 microns and which are retained on the screen having uniform openings of 420 microns are blended with 80 parts of a translucent toothpaste having 7 the following formulation:

The toothpaste described in this example is translucent and esthetically pleasing. There are dispersed in the toothpaste visible particles of the agglomera-te polishing agents. During toothbrushing the agglomerated particles are at first palpable and are then easily reduced to individual particles of polishing agent of fine size upon application of mild pressure with the toothbrush.

EXAMPLE V 200 parts of anhydorus dicalcium phosphate particles having sizes substantially all of which are less than about 7.4 microns and 1 part of D&C Lake Red No. color, are moistened with 40 parts of a 10% aqueous solution of gum acacia in a Hobart mixer for 10 minutes. The dyed wet mass thereby formed is forced through a screen havthrough a screen having uniform openings of 840 microns onto a screen having uniform openings of 420 microns.

10 parts of the dyed agglomerate particles Which pass through the screen having uniform openings of 840 microns and which are retained on the screen having uniform openings of 420 microns are blended with 90 parts of an opaque toothpaste having the following formulation:

Percent Glycerine (99.3%) 19.950 Sodium carboxymethyl cellulose 0.850 Sodium saccharin 0.200 Sodium benzoate 0.500 Tetrasodium pyrophosphate 0.250

Water 19.986

Trimagnesium phosphate 0.200 Calcium carbonate 5.000 Dicalcium phosphate dihydrate 46.550 Sodium N-lauroyl sarcosinate (35%) 5.714 Flavor 0.800

The opaque toothpaste described in this example has visible particles of the agglomerates distributed over its surface. During toothbrushing the agglomerated particles are at first palpable and are then easily reduced to individual particles of polishing agent of fine size upon application of mild pressure with the toothbrush.

Although this invention has been described with reference to specific examples, it will be apparent to one skilled in the art that various modifications may be made thereto which fall within its scope.

We claim:

1. A toothpaste comprising (1) a dental vehicle comprising water, a humectant and a gelling agent and (II) about 575% by weight of said toothpaste of visible, palpable particles of substantially water-insoluble agglomerated material consisting essentially of material selected from the group consisting of (a) water-insoluble dental polishing agent; (b) mixtures of about -98% by Weight of water-insoluble dental polishing agent with (b1) water-soluble binding agent, (b-2) water-soluble binding agent and a lubricant, (b-3) water-soluble binding agent and a non-abrasive diluent, and (b-4) water-soluble binding agent, a lubricant and a non-abrasive diluent; and (c) mixture of about 99% by weight of Water-insoluble dental polishing agent with a lubricant.

2. The toothpaste claimed in claim 1 wherein said particles of agglomerated material have particle sizes between 420 microns and 840 microns.

3. The toothpaste claimed in claim 1 wherein said water-insoluble polishing agent is dicalcium phosphate.

4. The toothpaste claimed in claim 1 wherein said toothpaste is transparent and said dental vehicle has a liquid content of water and humectant of about 2089.5% by weight of said toothpaste.

5. The toothpaste claimed in claim 4 wherein said dental vehicle contains as humectant sorbitol and as gelling agent sodium carboxymethyl cellulose.

6. The toothpaste claimed in claim 1 wherein said substantially water-insoluble agglomerated material consists essentially of a mixture of about 75-98% by weight of water-insoluble dental polishing agent with water-soluble binding agent,

water-soluble binding agent and a lubricant,

Water-soluble binding agent and a non-abrasive diluent,

or water-soluble binding agent, a lubricant and a nonabrasive diluent.

7. The toothpaste claimed in claim 6 wherein said water-insoluble dental polishing agent is calcium carbonate.

8. The toothpaste claimed in claim 6 wherein said Water-insoluble dental polishing agent is hydrated alumina.

9. The toothpaste claimed in claim 6 wherein said water-soluble binding agent is gum acacia.

10. The toothpaste claimed in claim 6 wherein said water-soluble binding agent is polyvinyl pyrrolidone.

11. The toothpaste claimed in claim 6 wherein said water-soluble binding agent is polyethylene glycol.

12. The toothpaste claimed in claim 11 wherein said substantially water-insoluble agglomerated material consists essentially of a mixture of about 75-98% by weight of water-insoluble dental polishing agent with water-soluble polyethylene glycol binding,

agent and a lubricant or with water-soluble polyethylene glycol binding agent, a lubricant and a non-abrasive diluent.

13. The toothpaste claimed in claim 6 wherein said 5 Water-insoluble dental polishing agent comprises an insoluble phosphate salt.

14. The toothpaste claimed in claim 13 wherein said insoluble phosphate salt is insoluble sodium metaphos- 10 phate.

2,196,150 4/1940 Heald et al. 57424 RICHARD L. HUFF, Primary Examiner