Abstract: An injection-molded gear for an utility engine has a high reliability, tenacity, and accuracy, capable of being manufactured at low cost without requiring cutting, and ensuring a substantial reduction in noise. An inner part of a cam crankshaft gear is formed of an insert ring of a sintered iron alloy. An outside portion and a toothed crest portion of the gear are formed by injection-molding a polyamide resin such as nylon 66 and heat-treating the resulting molded product so that its relative viscosity is equal to or larger than 3.5. The relative viscosity is defined as .eta./.eta..sub.0 where .eta..sub.0 is a viscosity of sulfuric acid of 98% concentration and .eta. is a viscosity of a solution of the 98% sulfuric acid in which the polyamide resin is dissolved at a concentration of 1.0%.

Abstract: An antistatic resinours composition comprising (A) graft copolymers prepared by emulsion polymerization of (a) monomer mixture consisting of (i) from 50 to 100 percents by weight of monomers having polyalkylene oxide chains and (ii) from 50 to 0 percents by weight of vinyl monomers in the presence of rubbers and (B) thermoplastic resins compatible with the graft copolymers, has permanent antistatic performances, superior mechanical properties and high flowability.