Expandable or pre-expanded thermoplastic particles, e.g. polystyrene particles, used to form foam containers e.g. cups, bowls, are coated with a coating composition comprising a liquid part consisting of a) liquid polyethylene glycol with an average molecular weight of 200 to 800; and a solid part comprising components selected from the group consisting of b) polyolefin wax, e.g. polyethylene wax, c) a metal salt of higher fatty acids, e.g. zinc stearate or calcium stearate; d) polyethylene glycol with an average molecular weight of 900 to 10,000; and e) a fatty bisamide or fatty amide, e.g. ethylene bis-stearamide; and combinations of b) through e). The coating composition prevents or resists leakage of liquids and foods with oil and/or fatty components and improves the rim strength and ATF properties of foam containers.