Metallic ink composition and writing instrument containing same

Abstract

Metallic ink compositions for use in capillary-action markers are provided. More particularly, a metallic ink composition includes a polar solvent, an encapsulated metallic pigment, and a resin component.

What is claimed is: 
     
       1. An ink composition comprising:
 (a) a polar, protic solvent; 
 (b) a metallic pigment dispersed in the solvent; and 
 (c) a resin component dissolved in the solvent, 
 
       wherein the polar, protic solvent is present in an amount of about 35 wt % to about 95 wt % based on the total weight of the ink composition, the metallic pigment comprises a metal particle encapsulated with a coating that is substantially insoluble in the solvent and the coating comprises silicon dioxide and an organic polymer comprising a urea-aldehyde polymer resin, an alkyl- or aryl-substituted derivative of a urea-aldehyde polymer resin, or a condensation product of urea with an aldehyde. 
     
     
       2. The ink composition of  claim 1 , wherein the solvent is an alcohol solvent. 
     
     
       3. The ink composition of  claim 1 , wherein the solvent comprises one or more C1 to C15 alcohols. 
     
     
       4. The ink composition of  claim 1 , wherein the metallic pigment comprises a metallic pigment selected from the group consisting of copper, zinc, aluminum, bronze, mica, oxides thereof, anodizes thereof, and combinations of any of the foregoing. 
     
     
       5. The ink composition of  claim 1 , wherein the metallic pigment comprises aluminum. 
     
     
       6. The ink composition of  claim 1 , wherein the metallic pigment comprises a copper/zinc alloy. 
     
     
       7. The ink composition of  claim 1 , wherein the viscosity of the metallic ink composition at 25° C. is less than about 40 centipoises (cps). 
     
     
       8. The ink composition of  claim 1 , wherein the metallic pigment has a substantially planar morphology. 
     
     
       9. The ink composition of  claim 1 , wherein the metallic pigment has an average thickness between about 0.01 microns to about 1 micron. 
     
     
       10. The ink composition of  claim 1 , wherein the metallic pigment has an average diameter between about 0.5 microns and about 12 microns. 
     
     
       11. The ink composition of  claim 1 , wherein the metallic pigment is present in an amount between about 5 wt % and about 40 wt %, based on the total weight of the ink composition. 
     
     
       12. The ink composition of  claim 1 , wherein the ink composition has a total resin content between about 1 wt % and about 20 wt %, based on the total weight of the ink composition. 
     
     
       13. The ink composition of  claim 1 , wherein the resin component comprises one or more resins selected from the group consisting of polyvinyl butyral resins, polyacrylic acid resins, styrene-acrylic acid resins, polyamide resins, shellac resins, terpene phenolic resins, ketone-aldehyde condensation resins, polyurethane resins, polyester resins, and mixtures thereof. 
     
     
       14. The ink composition of  claim 1 , wherein the coating comprises an organic polymer comprises a urea-formaldehyde resin, a phenyl urea-formaldehyde resin, a methyl urea-formaldehyde resin, acrolein, butyraldehyde, formaldehyde, paraformaldehyde, methylhemiformal, butylhemiformal, formaldehyde sodium bisulfite adduct, glyoxal, acetaldehyde, benzaldehyde, furfural, phthalaldehyde, or terephthaldehyde. 
     
     
       15. The ink composition of  claim 1 , wherein the ink composition is substantially free of resins containing substantially hydrophobic domains. 
     
     
       16. The ink composition of  claim 1 , wherein the polar solvent comprises a C2-C5 alcohol, and the metallic pigment comprises an aluminum particle encapsulated with a coating comprising silicon dioxide. 
     
     
       17. A marker comprising:
 an ink reservoir and a porous nib, 
 the ink reservoir containing an ink composition comprising a metallic ink composition comprising: 
 (a) a polar, protic solvent; 
 (b) a metallic pigment dispersed in the solvent; and 
 (c) a resin component dissolved in the solvent, 
 wherein the metallic pigment comprises a metal particle encapsulated with a coating that is substantially insoluble in the solvent and the coating comprises silicon dioxide and an organic polymer comprising a urea-aldehyde polymer resin, an alkyl- or aryl-substituted derivative of a urea-aldehyde polymer resin, or a condensation product of urea with an aldehyde. 
 
     
     
       18. A method of making a written mark, comprising:
 providing a capillary-action marker comprised of an ink reservoir and a porous nib, the ink reservoir containing an ink composition according to  claim 1 ; and 
 contacting the nib of the capillary-action marker to a substrate surface to make a written mark. 
 
     
     
       19. The ink composition of  claim 1 , wherein the polar, protic solvent is present in an amount of about 40 wt % to about 90 wt % based on the total weight of the ink composition. 
     
     
       20. The ink composition of  claim 1 , wherein the coating consists of silicon dioxide. 
     
     
       21. The ink composition of  claim 1 , wherein the coating is in contact with the polar, protic solvent. 
     
     
       22. The marker of  claim 17 , wherein the ink reservoir is wrapped with a sheet comprising polypropylene density polyethylene. 
     
     
       23. The ink composition of claim 1, wherein the polar, protic solvent is present in an amount of about 55 wt % to about 85 wt % based on the total weight of the ink composition.  
     
     
       24. The ink composition of claim 1, wherein the organic polymer consists of a urea aldehyde polymer.  
     
     
       25. An ink composition comprising:
 (a) a polar, protic solvent;   (b) a metallic pigment dispersed in the solvent; and   (c) a resin component dissolved in the solvent,   wherein the polar, protic solvent is present in an amount of about 40 wt % to about 90 wt % based on the total weight of the ink composition, the metallic pigment comprises a metal particle encapsulated with a coating that is substantially insoluble in the solvent and the coating comprises silicon dioxide and an organic polymer comprising a urea-aldehyde polymer resin, an alkyl- or aryl-substituted derivative of a urea-aldehyde polymer resin, or a condensation product of urea with an aldehyde.    
     
     
       26. The ink composition of claim 25, wherein the solvent is an alcohol solvent.  
     
     
       27. The ink composition of claim 25, wherein the solvent comprises one or more C1 to C15 alcohols.  
     
     
       28. The ink composition of claim 25, wherein the metallic pigment comprises a metallic pigment selected from the group consisting of copper, zinc, aluminum, bronze, mica, oxides thereof, anodizes thereof, and combinations of any of the foregoing.  
     
     
       29. The ink composition of claim 25, wherein the metallic pigment comprises aluminum.  
     
     
       30. The ink composition of claim 25, wherein the metallic pigment comprises a copper/zinc alloy.  
     
     
       31. The ink composition of claim 25, wherein the viscosity of the metallic ink composition at 25° C. is less than about 40 centipoises (cps).  
     
     
       32. The ink composition of claim 25, wherein the metallic pigment has a substantially planar morphology.  
     
     
       33. The ink composition of claim 25, wherein the metallic pigment has an average thickness between about 0.01 microns to about 1 micron.  
     
     
       34. The ink composition of claim 25, wherein the metallic pigment has an average diameter between about 0.5 microns and about 12 microns.  
     
     
       35. The ink composition of claim 25, wherein the metallic pigment is present in an amount between about 5 wt % and about 40 wt %, based on the total weight of the ink composition.  
     
     
       36. The ink composition of claim 25, wherein the ink composition has a total resin content between about 1 wt % and about 20 wt %, based on the total weight of the ink composition.  
     
     
       37. The ink composition of claim 25, wherein the resin component comprises one or more resins selected from the group consisting of polyvinyl butyral resins, polyacrylic acid resins, styrene-acrylic acid resins, polyamide resins, shellac resins, terpene phenolic resins, ketone-aldehyde condensation resins, polyurethane resins, polyester resins, and mixtures thereof.  
     
     
       38. The ink composition of claim 25, wherein the organic polymer comprises a urea-formaldehyde resin, a phenyl urea-formaldehyde resin, a methyl urea-formaldehyde resin, acrolein, butyraldehyde, formaldehyde, paraformaldehyde, methylhemiformal, butylhemiformal, formaldehyde sodium bisulfate adduct, glyoxal, acetaldehyde, benzaldehyde, furfural, phthalaldehyde, or terephthaldehyde.  
     
     
       39. The ink composition of claim 25, wherein the ink composition is substantially free of resins containing substantially hydrophobic domains.  
     
     
       40. The ink composition of claim 25, wherein the polar solvent comprises a C2-C5 alcohol, and the metallic pigment comprises an aluminum particle encapsulated with a coating comprising silicon dioxide.  
     
     
       41. A method of making a written mark, comprising:
 providing a capillary-action marker comprised of an ink reservoir and a porous nib, the ink reservoir containing an ink composition according to claim 25; and   contacting the nib of the capillary-action marker to a substrate surface to make a written mark.    
     
     
       42. The ink composition of claim 25, wherein the polar, protic solvent is present in an amount of about 55 wt % to about 85 wt % based on the total weight of the ink composition.  
     
     
       43. The ink composition of claim 25, wherein the coating is in contact with the polar, protic solvent.  
     
     
       44. The ink composition of claim 25, wherein the organic polymer consists of a urea aldehyde polymer.