Abstract:
Propellant free foamable aqueous dentifrice system which is capable of being delivered as a foam to a toothbrush and which is stable on the brush and when placed in the mouth and used for tooth cleaning, continues to generate more foam. The system is liquid and as such can not be used without being foamed because it is so thin that it falls beneath the bristles of the toothbrush.

Description:
RELATED APPLICATIONS  
       [0001]     This application claims priority of provisional application 60/74043 filed Nov. 29, 2005 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     Propellant free foamable aqueous dentifrice system.  
         [0004]     2. Prior Art  
         [0005]     The desirability of a foamable toothpaste is discussed at length in Fischer et al. U.S. Pat. No. 6,139,820. This patent discusses at length the advantage of the system with respect to prevention of fluoridosis in children because of the administration and ingestion of excess fluoride. Unfortunately children also have the mischievous habit of ejecting the content of pressurized foam containers in inappropriate locations. The present invention, by requiring a fresh pump stroke per ejection, avoids this and concomitant problems of the prior art.  
       SUMMARY OF THE INVENTION  
       [0006]     The propellant free foamable aqueous dentifrice system of the present invention is capable of being delivered as a foam to a toothbrush and is stable on the brush and when placed in the mouth and used for tooth cleaning, continues to generate more foam. The dentifrice suspension itself is liquid and as such can not be used without being foamed because it is so thin that it falls beneath the bristles of the toothbrush.  
         [0007]     There is provided a novel water based dentifrice suspension which is unusable on a toothbrush in an unfoamed state consisting essentially of  
         [0008]     negatively charged fumed Silica, positively charged fumed Aluminum Oxide, hydrated Silica abrasive and an anionic surfactant wherein said surfactant is other than Sodium Lauryl Sulfate, Sodium Lauryl Sulfoacetate an Acylglutamate or a Betaine, this suspension is readily foamable from a non-propellant pump spray container from which the thus produced foam is usable on a toothbrush in its foamed state as a dentifrice. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0009]     It is preferred to provide a secondary surfactant selected from the group consisting of nonionic solid block polymer surfactants. It is further desirable to include one or more of the following components an anti settling agent, a humectant as well as other usual components found in tooth pastes such as flavorants and anti cavity agents such as sodium fluoride. The composition however should not be considered as limited to the components recited.  
         [0010]     It is particularly desirable that the composition contain from about 50 to about 85%, suitably about 60-about 65% by weight of water.  
         [0011]     A foaming agent is added to the aqueous system so as to generate the initial foam and also the subsequent foam as the teeth are brushed. This can be used as such or can be augmented by the use of a secondary surfactant to aid in mouth feel and foam density.  
         [0012]     We have found that the use of surfactants is very critical to the stability of the system. We have identified one anionic surfactant as particularly workable, that being Sodium Lauroyl Sarcosinate as the primary foamer or surfactant, used from about 1-about 3% by weight suitably at about preferably about 1.25-about 1.50%. We have found that Sodium Lauryl Sulfate, Sodium Lauryl Sulfoacetate, Acylglutamates and Betaines interfere with the formation of the anionic/cationic complex formed by the fumed Silica and fumed Aluminum Oxide. As a result, upon extended storage, a formulation utilizing one of these surfactants forms a gelatinous mass and is unstable.  
         [0013]     From about 1 to about 3% by weight of fumed silica, suitably about 2% and from about 1 to about 3% by weight of fumed aluminum oxide, again suitably about 2%, are preferably used, it being especially desirable that the fumed components be provided in equal amounts.  
         [0014]     As abrasive, from about 1 to about 10% suitably from about 3-about 6%, by weight of hydrated silica, suitably amorphous synthetic precipitated silica of about 10-about 15 microns diameter, is preferably used. The hardness of the abrasive selected will depend on proposed usage, thus Degussa Sident® grade 8 (low hardness) composition is used for a children&#39;s dentifrice while Sident® grade 10 (high hardness) is used for adults.  
         [0015]     Where a secondary surfactant is desirable it is useful to employ from about 1-about 4% by weight, of nonionic solid block polymer surfactants suitably Poloximer 407®.  
         [0016]     The use of additional components in the system have been found useful, there include a concentration of about 0.1-about 2.0%, preferably about 0.2-about 1.0% of an anti settling agent such as an inorganic colloidal Magnesium Aluminum Silicate, humectant materials such as sorbitol or glycerin, suitably at concentrations of about 20-about 25% by weight of the entire composition are employed.  
         [0017]     The system can contain a fluoride such as Sodium Fluoride in amounts of about 0.243% based on the total weight of the system.  
         [0018]     The system can also contain sweeteners flavors, colorants, preservatives, medicaments, desensitizers such as various nitrate systems, anti-tartar materials, etc.  
         [0019]     According to the present invention, the stable foam of the present invention is produced using a propellantless mechanical pump. Such a pump precisely mixes water and air upon actuation to produce a foam. While it may be possible to use a conventional mechanical foam dispenser, such as a squeeze bottle foamer, the best results have been achieved with the finger activated pump foamer.  
         [0020]     Preferably the foam is produced using the F-2 Finger Pump Foamer™, manufactured by Air Spray International, Inc. of Pompano Beach, Fla. Such a spring loaded valve system operates without the use of gas propellants or the like. Upon actuation, precise amounts of air and liquid are mixed and a foam capable of maintaining its structure for a substantial length of time is dispensed. In addition, the dispenser can deliver a variable amount of foam so as to just fit a variable size of toothbrush.  
         [0021]     The F-2 Finger Pump Foamer™ is similar in design and operation to conventional propellant less finger actuated mechanical pump foamers such as described in U.S. Pat. No. 5,443,569 issued on Aug. 22, 1995 and U.S. Pat. No. 5,813,576 issued Sep. 29, 1998, the disclosure of which are incorporated by reference herein. Such propellantless finger actuated mechanical foamers can be employed to dispense the stable dentifrice foam of the present invention.  
         [0022]     The F-2 Finger Pump Foamer™ is an easy to use dispenser with excellent performance and provides a clean single stroke action, zero VOC formulations and high quality. Shaking the container will not affect the foam quality. Precise dosage per stroke is possible and the container is refillable  
       EXAMPLES  
     Example 1  
       [0023]     Propellant free foamable toothpaste  
                                                             %                                    1.   Fumed Silicon Dioxide (Aerosil 200 ®, Degussa)   2.000       2.   Fumed Aluminum Oxide (Alum C ®, Degussa)   2.000       3.   Amorphous Synthetic ppt. Silica (Sident ®, Degussa)   6.000       4.   Sorbo Solution (70% Active)   12.500       5.   Glycerin   12.500       6.   Sodium Saccharin   0.100       7.   Sodium Fluoride   0.243       8.   Sodium Lauroyl Sarcosinate, 30% Active   4.000           (Hamposyl L-30 ®)       9.   Poloxamer 407 ® (BASF Corp.)   2.000       10.   Methyl Paraben   0.200       11.   Propyl Paraben   0.050       12.   Colloidal Magnesium Aluminum Silicate   0.400           (Veegum ® Regular)       13.   Deionized Water   58.007               100.000                  
 
 Procedure: 
 
 In a tank, add water, Sorbo solution and Glycerin. Stir well. 
 
 With high speed stirring, add the fumed Silicon Dioxide and fumed AluminumOxide C followed by the Sident abrasive. Mix well with high speed stirring and/or in tank homogenizer. Mix until smooth and uniform. 
 
 Add the Sodium Saccharin and Sodium Fluoride and continue mixing. 
 
 Add the Methyl and Propyl Parabens and continue mixing. 
 
 Add the Veegum Regular to the batch and mix until the batch is uniform. 
 
 Slow the mixing speed and add the Sodium Lauroyl Sarcosinate to the batch. 
 
 Avoid entrapping air in the batch. 
 
 Start heating the batch. Keep the mixing speed slow to avoid entrapping air. 
 
 When the temperature of the batch rises to 50 C slowly add the Poloxamer 407. Continue heating the batch to 70 C. The Poloxamer 407 should be completely dissolved in the batch. Start cooling the batch to room temperature. Add the flavor at 40° C. 
 
 Submit the batch for packaging in the F-2 Finger Pump Foamer™ manufactured by Air Spray Int., Inc. of Pompano Beach, Fla. 
 
       Example 2  
       [0024]     Propellant free foamable toothpaste  
                                                             %                                    1.   Fumed Silicon Dioxide (Aerosil 200 ®, Degussa)   2.000       2.   Fumed Aluminum Oxide (Alum C ®, Degussa)   2.000       3.   Amorphous Synthetic ppt. Silica (Sident ®, Degussa)   6.000       4.   Sorbo Solution (70% Active)   12.500       5.   Glycerin   12.500       6.   Sodium Saccharin   0.100       7.   Sodium Fluoride   0.243       8.   Sodium Lauroyl Sarcosinate, 30% Active   4.000           (Hamposyl L-30 ®)       9.   Methyl Paraben   0.200       10.   Propyl Paraben   0.050       11.   Colloidal Magnesium Aluminum Silicate   0.400           (Veegum ® Regular)       12.   Deionized Water   60.007               100.000                  
 
 Procedure: 
 
 In a tank, add water, Sorbo solution and Glycerin. Stir well. 
 
 With high speed stirring, add the fumed Silicon Dioxide and fumed AluminumOxide C followed by the Sident abrasive. Mix well with high speed stirring and/or in tank homogenizer. Mix until smooth and uniform. 
 
 Add the Sodium Saccharin and Sodium Fluoride and continue mixing. 
 
 Add the Methyl and Propyl Parabens and continue mixing. 
 
 Add the Veegum Regular to the batch and mix until the batch is uniform. 
 
 Slow the mixing speed and add the Sodium Lauroyl Sarcosinate to the batch. 
 
 Avoid entrapping air in the batch. Add the flavor. 
 
 Submit the batch for packaging in the F-2 Finger Pump Foamer™ manufactured by Air Spray Int., Inc. of Pompano Beach, Fla.