Dispersions of Crystalline Polyesters Having Polar Groups

Dispersion properties of hydrophobic polyesters can be controlled by introducing small amounts of hydrophilic groups into the polymer skeleton. Such crystalline polyesters were prepared by introducing a few mol% of sodium 5-sulfonatoisophthalic acid. The copolyester solutions in 2-butoxyethanol formed stable dispersions with particle sizes under 1000 nm by adding water. Dispersibilities and stabilities of the dispersions were discussed in terms of the heat of fusion and the melting and softening points of the copolyesters used.