A heat resistant colorant for mass-coloring polyester such as polyethylene terephthalate, containing 100 parts of pigments and/or dyes and 42.about.2,000 parts of a liquid aliphatic polyester dispersing medium having a viscosity at 25.degree. C. not exceeding 150 poises and a hydroxy
A black liquid colorant for dope dyeing of polyester fibers, comprising 5-50 wt % carbon black obtained by wet-oxidation with peroxide and subsequent neutralization of a gas phase oxidized carbon black, and 95-50 wt % liquid dispersion medium such as liquid polyester. Black polyester
