Stable lipophilic emulsions for acrylic coating and method of making

Abstract

Emulsions of lipophiles such as glycerol monostearate which are compatible with acrylic copolymer emulsions are made stable by using an emulsion stabilizer such as polysorbate 80 in an amount by weight between 1% and 5% of the lipophile and homogenizing the emulsion wherein the emulsion micelles are less than 50 microns. The ability to make a stable emulsion of a lipophile is important in the coating process as it enables preparation and shipment of the lipophilic emulsion to the coater rather than the preparation of a lipophilic emulsion at the time of the coating process which involves a heating and cooling process.

1 . An emulsion, comprising: 
 a lipophile chosen from the group consisting of glycerol monostearate, glycerol monooleate, glycerol monolaurate, propylene glycol monolaurate, propylene glycol monooleate, propylene glycol monostearate, sorbitan monooleate, sorbitan monostearate, diacetylated monoglyceride and vegetable oils;    an effective amount of an emulsion stabilizer; and    wherein said lipophiles and emulsion stabilizer are homogenized in water to form micelles having a size of 50 microns or less.    
     
     
         2 . An emulsion in accordance with  claim 1  wherein said emulsion stabilizer is selected from the group consisting of polysorbate 80, sodium lauryl sulfate and polysorbate 60.  
     
     
         3 . An emulsion in accordance with  claim 1  wherein said effective amount of an emulsion stabilizer is by weight between 1% and 5% of the lipophile.  
     
     
         4 . An emulsion in accordance with  claim 1  which includes a plasticizer.  
     
     
         5 . An emulsion in accordance with  claim 4  wherein the plasticizer is selected from the group consisting of triethyl citrate, triacetin, glycerin, propylene glycol and polyethylene glycol.  
     
     
         6 . An emulsion in accordance with  claim 1  wherein said emulsion is stable for a period of at least three months.  
     
     
         7 . An emulsion in accordance with  claim 6  wherein said emulsion is compatible with an emulsion of copolymers of acrylic and methacrylic acids and their alkyl esters and alkyl amino alkyl esters.  
     
     
         8 . An emulsion in accordance with  claim 1  wherein said emulsion stabilizer is polysorbate 80 at about 0.2% and a lipophile is glycerol monostearate at about 10% and wherein triethyl citrate at about 9.8% is used as a plasticizer, the remainder being water.  
     
     
         9 . An emulsion in accordance with  claim 1  wherein said effective amount of an emulsion stabilizer is by weight about 2% of the lipophile.  
     
     
         10 . An emulsion in accordance with  claim 1  wherein said emulsion stabilizer is polysorbate 80 at about 0.2% and the lipophile is glycerol monooleate about 19.8% and the remainder is water.  
     
     
         11 . An emulsion in accordance with  claim 1  wherein said emulsion stabilizer is polysorbate 80 at about 0.3% and the lipophile is glycerol monostearate at about 10% and further including triethyl citrate as a plasticizer at about 9.7% with the remainder being water.  
     
     
         12 . An emulsion in accordance with  claim 1  wherein said emulsion stabilizer is polysorbate 80 at about 0.1% and the lipophile is glycerol monostearate at about 10% and further including triethyl citrate at about 9.9% as a plasticizer, with the remainder being water.  
     
     
         13 . An emulsion in accordance with  claim 1  wherein the emulsion stabilizer is polysorbate 80 at about 0.2% and the lipophile is glycerol monostearate at about 10%, and further including polyethylene glycol 8000 at about 9.8% as a plasticizer, with the remainder being water.  
     
     
         14 . An emulsion in accordance with  claim 1  wherein the lipophile is 5% to 20% by weight.  
     
     
         15 . An emulsion in accordance with  claim 4  wherein the plasticizer is up to 20% of the formulation.  
     
     
         16 . An emulsion in accordance with  claim 1  wherein the emulsion stabilizer is about 0.1% to 2% of the formulation.  
     
     
         17 . An emulsion in accordance with  claim 1  which is adaptable to be stirred into an acrylic copolymer emulsion to form a stable coating suspension with a lipophile to resin ratio of between 1:10 and 1:50 for coating in side vented pans and fluid bed columns onto powders, granules, tablets or capsules.  
     
     
         18 . An emulsion in accordance with  claim 1  which is adapted to be stirred into an acrylic copolymer emulsion containing colorants at 10% to 50% of the resin content of the formulation.  
     
     
         19 . An emulsion of a water insoluble lipophile produced by: 
 heating the water to a temperature of between 60 and 80 degrees centigrade;    adding a lipophile to the water while stirring;    adding an emulsifying agent;    stirring vigorously for approximately five minutes;    passing the mixture through a homogenizer for between about 10 to about 120 minutes;    cooling the emulsion to room temperature while stirring;    wherein said emulsion is stable for a period of at least three months.    
     
     
         20 . A method in accordance with  claim 19  wherein said step of passing the mixture through a homogenizer for between about 10 to about 120 minutes comprises passing the mixture through the homogenizer for between 3 and 10 cycles.  
     
     
         21 . A method in accordance with  claim 19  wherein said step of passing the mixture through a homogenizer for between about 10 to about 120 minutes is carried out to produce micelles of less than 50 microns.