Plastic products comprising: a thermoplastic resin or a thermoset resin; and from 0.1 to 10 wt% of at least one type of particles selected from ferric oxide hydroxide particles, hematite particles, magnetite particles and maghemite particles; wherein: (1) the ferric oxide hydroxide particles have an average major axial diameter or a plate diameter of from 0.02 to 2.0 mu m and an average aspect ratio or a plate ratio of from 2 to 20; and (2) the hematite, magnetite and maghemite particles have an average particle size of from 0.01 to 1.0 mu m, a BET specific surface area of from 1 to 120 m<2>/g and a surface water content of not less than 0.02 wt%/m<2>/g.
