Colorless toner formulated to improve light fastness of ink jet ink prints

Abstract

The present invention is drawn to colorless toner compositions for overcoating a print having an ink jet ink image printed thereon. The colorless toner can comprise: a toner resin and at least two additives independently selected from the group consisting of ultraviolet absorbers, free radical inhibitors, thermal stabilizers, and combinations thereof, wherein the ratio of toner resin to total additive is from 1:1 to 99:1 by weight. The colorless toner can also be comprised of a charge control agent and/or a low-melt wax.

We claim:  
     
         1 . A toner composition for providing a colorless overcoating on an ink jet print comprising a toner resin and at least two additives independently selected from the group consisting of ultraviolet absorbers, free radical inhibitors, and thermal stabilizers, wherein the ratio of said toner resin to said additives is from about 1:1 to 99:1 by weight.  
     
     
         2 . A colorless toner composition as in  claim 1  wherein said at least two additives comprise an ultraviolet absorber and a second additive selected from the group consisting of the free radical inhibitors, the thermal stabilizers, and combinations thereof.  
     
     
         3 . A colorless toner composition as in  claim 2  wherein said second additive is the free radical inhibitor.  
     
     
         4 . A colorless toner composition as in  claim 1  wherein said second additive is the thermal stabilizer.  
     
     
         5 . A colorless toner composition as in  claim 1  wherein said toner resin is selected from the group consisting of styrene resins, styrene copolymer resins, polyethylenes, polyethers, polyols, acrylic resins, vinyl resins, ethylenic resins, polyamide resins, polyester resins, phenolic resins, silicone resins, xylene resins, epoxy resins, terpene resins, rosins, modified rosins, and combinations thereof.  
     
     
         6 . A colorless toner composition as in  claim 5  wherein the toner resin is a styrene selected from the group consisting of polystyrenes, polychlorostyrenes, polyvinyltoluenes, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-acrylonitrile copolymers, styrene-butadiene copolymers, and styrene-maleic acid ester copolymers.  
     
     
         7 . A colorless toner composition as in  claim 1  wherein at least one of the at least two additives is an ultraviolet absorber containing a functional group having the structure:  
       
         
           
           
               
               
           
         
       
     
     
         8 . A colorless toner composition as in  claim 1  wherein at least one of the at least two additives is a free radical inhibitor containing a functional group having the structure:  
       
         
           
           
               
               
           
         
       
     
     
         9 . A colorless toner composition as in  claim 1  wherein at least one of the at least two additives is a thermal stabilizer having the structure:  
       
         
           
           
               
               
           
         
       
     
     
         10 . A colorless toner composition as in  claim 1  wherein at least one of the at least two additives is a thermal stabilizer selected from the group consisting of phenols, phosphates, and combinations thereof.  
     
     
         11 . A colorless toner composition as in  claim 7  wherein the ultraviolet absorber is defined by a structure selected from the group consisting of  
       
         
           
           
               
               
           
         
       
       wherein n is an integer from about 1 to 5.  
     
     
         12 . A colorless toner composition as in  claim 8  wherein the free radical inhibitor is defined by the structure:  
       
         
           
           
               
               
           
         
       
     
     
         13 . A colorless toner composition as in  claim 1  further comprising an effective amount of a charge control agent.  
     
     
         14 . A colorless toner composition as in  claim 13  wherein the charge control agent is selected from the group consisting of alkylsalicylic acids, hydroxynaphthoic acids, quaternary ammonium salts, oxides of metal alkyls, salicylic acid metal complexes, calixarene compounds, and organic boron compounds.  
     
     
         15 . A colorless toner composition as in  claim 1  further comprising a low-melt wax.  
     
     
         16 . A colorless toner composition as in  claim 15  wherein the low-melt wax is selected from the group consisting of carnauba waxes, microcrystalline waxes, paraffin waxes, rice waxes, low molecular weight polypropylenes, low molecular weight polyethylenes, and oxidized polypropylenes modified by acidic monomers.