PURPOSE: To obtain a polymer having a high intrinsic viscosity with good heat transfer efficiency without increasing stirring torque accompanied by polymeriza tion, by thermally polymerizing a bis (ω-hydroxyalkyl) terephthalate in the presence of a specific dispersion stabilizer in a silicone oil.
CONSTITUTION: (A) A vinyl polymer (e.g. vinyl acetate, etc.) as a backbone is graft-polymerized with (B) a polysiloxane having ≥500 molecular weight and a terminal vinyl group, etc., in the presence of a radical polymerization initiator to give a dispersion stabilizer, which is then dispersed in (D) a silicone oil, unreactive to the component (C) and physically and chemically stable at ≥150°C with (C) a bis (ω-hydroxyalkyl) terephthalate to provide a dispersion of fine particulate form, preferably having ≤300μm average particle size. The resultant fine particles are then thermally polymerized e.g. at 180W300°C, to afford the aimed polyester.
MORI HIROSHI
FUJIMOTO MASAHARU
