Writing ink containing nonanoic acid

Claim 2

A writing ink as set forth in claim 1 in which said liquid vehicle is essentially formamide.

Claim 3

A writing ink as set forth in claim 1 in which said liquid vehicle is essentially ethylene glycol.

Claim 4

A writing ink as set forth in clain 1 wherein said pigment is a metal organic complex pigment.

Claim 5

A writing ink having a viscosity between about 3-50 centipoises at 25* C. comprising in the range of from about 0.05 to 35 percent by weight of a pigment dispersed in a liquid vehicle which is a mixture of a small amount but not more than 5 percent by weight of nonanoic acid, 0-30 percent by weight of water and 65-99.9 percent by weight of a molecular associated liquid selected from the class consisting of: a. glycols selected from the class consisting of ethylene glycol, diethylene glycol, triethylene glycol, hexylene glycol and mixtures thereof; b. cyclic compounds selected from the class consisting of butyrolactone, methyl pyrrolidone, 2-pyrrolidone and mixtures thereof; c. propylene carbonate; d. N-2-hydroxyethylformamide; and e. mixtures of (a), (b), (c) and (d) liquids; said pigment being insoluble in said vehicle.

Claim 6

A writing ink having a viscosity between about 3-50 centipoises at 25* C. comprising in the range of from about 0.05 to 35 percent by weight of a pigment dispersed in a liquid vehicle which is a mixture containing by weight about 65-99.9 percent of formamide, nonanoic acid in a small amount but not more than 5 percent by weight of said mixture and water in a small amount but not more than 30 percent by weight of said mixture, said pigment being insoluble in said liquid vehicle.