Phase change inks comprising fatty acids

Abstract

A solid ink composition suitable for ink jet printing, including printing on coated paper substrates. In embodiments, the solid ink composition comprises both a crystalline compound and an amorphous compound, and a fatty acid, which provides for a robust ink wherein the phase change ink crystallizes faster from the liquid state than the same composition without the fatty acid.

What is claimed is: 
     
         1 . A phase change ink comprising:
 an amorphous compound, wherein the amorphous compound comprises a first ester of tartaric acid of Formula I or a first ester of citric acid of Formula II   
       
         
           
           
               
               
           
         
       
       wherein each R 1 , R 2 , R 3 , R 4  and R 5  is independently an alkyl group, wherein the alkyl can be straight, branched or cyclic, saturated or unsaturated, substituted or unsubstituted, having from about 1 to about 40 carbon atoms;
 a crystalline compound, wherein the crystalline compound comprises a second ester of tartaric acid of Formula III 
 
       
         
           
           
               
               
           
         
       
       wherein each R 6  and R 7  is independently an aryl or a heteroaryl optionally substituted with a lower alkyl and alkoxy, each n is independently 0 to 3; and
 a fatty acid; wherein the phase change ink crystallizes faster from the liquid state than the same composition without the fatty acid. 
 
     
     
         2 . The phase change ink of  claim 1 , wherein the tartaric acid backbone is selected from L-(+)-tartaric acid, D-(−)-tartaric acid, DL-tartaric acid, or mesotartaric acid, and mixtures thereof. 
     
     
         3 . The phase change ink of  claim 1 , wherein each R 6  and R 7  is independently selected from the group consisting of 
       
         
           
           
               
               
           
         
       
       and mixtures thereof. 
     
     
         4 . The phase change ink of  claim 1 , wherein the crystalline compound is present in an amount of from about 60 percent to about 95 percent by weight of the total weight of the phase change ink. 
     
     
         5 . The phase change ink of  claim 1 , wherein the amorphous compound is present in an amount of from about 5 percent to about 40 percent by weight of the total weight of the phase change ink. 
     
     
         6 . The phase change ink of  claim 1 , wherein the crystalline/amorphous ratio is from about 60:40 to about 95:5. 
     
     
         7 . The phase change ink of  claim 1 , wherein the fatty acid is selected from the group consisting of palmitic acid (hexadecanoic acid), palmitoleic acid (9-hexadecenoic acid), stearic acid (octadecanoic acid), oleic acid (9-octadecenoic acid), ricinoleic acid (12-hydroxy-9-octadecenoic acid), vaccenic acid (11-octadecenoic acid), linoleic acid (9,12-octadecadienoic acid), alpha-linolenic acid (9,12,15-octadecatrienoic acid), gamma-linolenic acid (6,9,12-octadecatrienoic acid), arachidic acid (eicosanoic acid), gadoleic acid (9-eicosenoic acid), arachidonic acid (5,8,11,14-eicosatetraenoic acid), erucic acid (13-docosenoic acid), and mixtures thereof. 
     
     
         8 . The phase change ink of  claim 1 , wherein the fatty acid comprises stearic acid or behenic acid. 
     
     
         9 . The phase change ink of  claim 1 , wherein the fatty acid is present in an amount of from about 0.1% to 25% by weight based on the entire phase change ink. 
     
     
         10 . The phase change ink of  claim 1 , wherein the amorphous compound is a first ester of tartaric acid of Formula I, wherein each R 1 , R 2  is independently a cyclohexyl group or a cyclohehyl group substituted with one or more alkyl group(s) selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, and t-butyl. 
     
     
         11 . The phase change ink of  claim 10 , wherein R 1  and R 2  are 2-isopropyl-5-methylcyclohexyl, and a mixture of 4-t-butylcyclohexyl and cyclohexyl, 
     
     
         12 . The phase change ink of  claim 1 , wherein the amorphous compound is a first ester of citric acid of Formula II. 
     
     
         13 . The phase change ink of  claim 1 , wherein the crystalline compound is a second ester of tartaric acid of Formula III, wherein each R 6  and R 7  is independently a phenyl optionally substituted with methyl or methoxy. 
     
     
         14 . The phase change ink of  claim 1  having a viscosity of less than about 22 cps at a temperature of about 140° C. 
     
     
         15 . The phase change ink of  claim 1  having a viscosity of greater than about 10 6  cps at room temperature. 
     
     
         16 . The phase change ink of  claim 1 , wherein the phase change ink crystallizes in less than 15 seconds. 
     
     
         17 . A phase change ink comprising:
 an amorphous compound, wherein the amorphous compound comprises a first ester of tartaric acid of Formula I or a first ester of citric acid of Formula II   
       
         
           
           
               
               
           
         
       
       wherein each R 1 , R 2 , R 3 , R 4  and R 5  is independently an alkyl group, wherein the alkyl can be straight, branched or cyclic, saturated or unsaturated, substituted or unsubstituted, having from about 1 to about 40 carbon atoms;
 a crystalline compound, wherein the crystalline compound is selected from the group consisting of dibenzyl L-tartrate, diphenethyl L-tartrate, bis(3-phenyl-1-propyl) L-tartrate, bis(2-phenoxyethyl) L-tartrate, diphenyl L-tartrate, bis(4-methylphenyl) L-tartrate, bis(4-methoxylphenyl) L-tartrate, bis(4-methylbenzyl) L-tartrate, bis(4-methoxylbenzyl) L-tartrate, dicyclohexyl L-tartrate, bis(4-tert-butylcyclohexyl)-L-tartrate and mixtures thereof; and 
 a fatty acid. 
 
     
     
         18 . A method of printing comprising:
 providing an phase change ink in an ink jet printing apparatus;   melting the phase change ink; and   
       causing droplets of the melted ink to be ejected in an imagewise pattern onto an intermediate transfer member or a final recording substrate, wherein the phase change ink comprises
 an amorphous compound, the amorphous compound comprising a first ester of tartaric acid of Formula I or a first ester of citric acid of Formula II 
 
       
         
           
           
               
               
           
         
       
       wherein each R 1 , R 2 , R 3 , R 4  and R 5  is independently an alkyl group, wherein the alkyl can be straight, branched or cyclic, saturated or unsaturated, substituted or unsubstituted, having from about 1 to about 40 carbon atoms,
 a crystalline compound, the crystalline compound comprising a second ester of tartaric acid of Formula III 
 
       
         
           
           
               
               
           
         
       
       wherein each R 6  and R 7  is independently an aryl or a heteroaryl optionally substituted with a lower alkyl and alkoxy, each n is independently 0 to 3, and
 a fatty acid, and further wherein the phase change ink crystallizes faster from the liquid state than the same composition without the fatty acid. 
 
     
     
         19 . The method of  claim 18 , wherein the final recording substrate is selected from the group consisting of paper, transparency materials, fabrics, textile products, plastics, polymeric films, metals and wood. 
     
     
         20 . The method of  claim 18 , wherein the intermediate transfer member or the final recording sheet are heated to a temperature below that of the melted ink in the ink jet printing apparatus.