Patent ID: 8403474

Claim:
A pretreatment agent for pre-treating cloth comprising silk or a polyamide series fiber prior to the cloth being printed by ink jet printing with an ink composition comprising an acidic dye, the pretreatment agent comprising: hydroxyethyl cellulose; ammonium salt; a hydrotropic agent which is urea; and water, wherein the weight-average molecular weight of the hydroxyethyl cellulose is in the range of 50,000 to 500,000, and wherein the hydroxyethyl cellulose is present in the pretreatment agent in a range of 1 to 5 wt %, the ammonium salt is present in an amount effective to improve color density of the acidic dye when the dye is printed on the cloth, said amount being in a range of 1 to 6 wt %, and the hydrotropic agent is present in a range of 8 to 12 wt %.