Abstract: A self-lubricating wear part is formed of a polyacetal resin composition that includes (A) a polyacetal base resin, (B) an inorganic powder having an average particle diameter of 50 micometers or less, and a particle diameter distribution such that at least 95 percent of the particles have a diameter of 100 micrometers or less and (C) a fatty acid ester. The wear parts are particularly useful for slidable parts such as guide roller or guide pole.

Abstract: An insert injection molding method is characterized by using an insert member having an applied surface coating comprised of an organic polymer compound, and at least one compounds selected from the group consisting of spiro ortho ester compound, spiro orthocarbonate compounds, trioxacylooctane compounds, and ketal lactone compounds.

Abstract: A molded article of a thermoplastic resin is printed by impressing characters, symbols or figures on a thermoplastic resin molding. These characters or the like are first printed upon a resin molding. A high-temperature compressed gas is then directed against the printed surface of the molding so that the temperature and pressure of said gas is between 100.degree. to 300.degree. C. and 0.05 to 5 kg/cm.sup.2, respectively.

Abstract: A method of producing characters, symbols, patterns (hereinafter referred to as "characters, etc.") on a thermoplastic resin molded article is characterized in that in order to produce characters, etc. on the molded article, a dye-impenetrable cover is first applied to that part of the surface of the molded article which corresponds to the characters, etc. to be produced, impregnation dyeing being then affected on the molded article surface including at least the peripheral area of the covered part of the surface by using a sublimative dye, the cover being subsequently removed, whereby the characters, etc. are produced as such.