Peroxide dispersions

Abstract

The viscosity of aqueous dispersions of normally solid organic peroxides may be advantageously lowered through the use of surfactants which are polyglyceryl esters of C6-C12 fatty acids. The reduction in viscosity facilitates milling the peroxides to reduce particle size and also provides dispersions of small particle size peroxides which may be readily poured or pumped.

What is claimed is: 
     
         1 . An aqueous pumpable or pourable dispersion comprising a) about 35% by weight or more of water-insoluble, solid benzoyl peroxide having an average particle size of less than 5 μm and b) 0.1 to 2.0 weight percent of surfactant having an HLB value of 12 to 18 and which is a polyglyceryl ester of one or more saturated C6-C18 fatty acids selected from the group consisting of octanoic acid, decanoic acid, and mixtures thereof. 
     
     
         2 . The aqueous pumpable or pourable dispersion of  claim 1 , wherein the polyglyceryl ester of one or more fatty acids contains a polyglycerol moiety having 8 to 12 glycerol repeating units on average. 
     
     
         3 . The aqueous pumpable or pourable dispersion of  claim 1 , wherein the surfactant is based on a polyglyceryl having hydroxyl groups with from about 25% to about 60% of the hydroxyl groups of the polyglyceryl being esterified. 
     
     
         4 . The aqueous pumpable or pourable dispersion of  claim 1 , wherein the surfactant is selected from the group consisting of polyglyceryl-10 caprylate/caprate, polyglyceryl-10 caprylate, and polyglyceryl-10 laurate, and mixtures thereof. 
     
     
         5 . The aqueous pumpable or pourable dispersion of  claim 1 , wherein the surfactant is a polyglyceryl-10 caprylate/caprate. 
     
     
         6 . The aqueous pumpable or pourable dispersion of  claim 1 , wherein the surfactant is a food grade surfactant and/or a pharmaceutically acceptable surfactant. 
     
     
         7 . The aqueous pumpable or pourable dispersion of  claim 1 , additionally comprising a macromolecular gelling agent. 
     
     
         8 . The aqueous pumpable or pourable dispersion of  claim 7 , wherein the macromolecular gelling agent crosslinks in the presence of polyvalent cations, 
     
     
         9 . The aqueous pumpable or pourable dispersion of  claim 7 , additionally comprising base. 
     
     
         10 . The aqueous pumpable or pourable dispersion of  claim 7 , additionally comprising salt. 
     
     
         11 . The aqueous pumpable or pourable dispersion of  claim 1 , wherein the surfactant has structure (I):
   R 1 —[CH 2 —CH(OR 2 )—CH 2 O] n —R 3    (II)
   
       wherein the average value of n is from about 6 to about 14 and R 1 , R 2  and R 3  are each independently a C6-C18 fatty acid moiety or hydrogen, provided that at least one of R 1 , R 2  or R 3  is a C6-C18 fatty acid moiety. 
     
     
         12 . An aqueous pumpable or pourable dispersion comprising:
 g) 37.5 to 42 weight % benzoyl peroxide having an average particle size of less than 5 μm;   h) 53.5 to 62 weight % water;   i) 0.25 to 1.5 weight % gelling agent;   j) 0.1 to 2.0 weight % of surfactant selected from the group consisting of polyglyceryl-10 caprylate/caprate, polyglyceryl-10 caprylate, and polyglyceryl-10 laurate, and mixtures thereof;   k) 0.01 to 0.05 weight % crosslinking agent; and   l) 0.25 to 1.0 weight % base.