反应详情

温度

70 °C

In 95 parts of hot water at about 80° C. was dissolved 5 parts of partial sodium salt of polyvinylbenzenesulfonic acid (National Starch, VERSA, TL500, average molecular weight 500,000) with stirring in about 30 minutes, followed by cooling. The resulting aqueous solution having a pH of 2 to 3 was adjusted to pH 4.0 with a 20 wt% aqueous solution of sodium hydroxide. Separately, 4 parts of the same leuco dye as that used in heat-sensitive recording material A was dissolved in a mixture of 100 parts of diisopropylnaphthalene and 25 parts of ethyl acetate with heating to 70° C. and the resulting hydrophobic solution was dispersed in 100 parts of a 5% aqueous solution of the partial sodium salt of polyvinylbenzenesulfonic acid to give an emulsion with an average particle diameter of 4.5 μm. Separately, 6 parts of melamine, 11 parts of a 37 wt% aqueous solution of formaldehyde and 83 parts of water were mixed by stirring at 60° C. for 30 minutes to give a clear mixed aqueous solution of melamine, formaldehyde and melamine-formaldehyde precondensate. This mixed aqueous solution had a pH value of 6 to 8.

1. temperatureby cooling
2. customto give an emulsion with an average particle diameter of 4.5 μm
3. stirringby stirring at 60° C. for 30 minutes