| 摘要 |
PURPOSE:To obtain a polystyrene foam having fine cells and high ridigity and strength, by mixing a volatile blowing agent with a polystyrene resin contg. an inorg. powder and Ca or Ba salt of a higher fatty acid in an extruder under pressure. CONSTITUTION:In a process for producing a foam by mixing a volatile blowing agent with a molten polystyrene resin in an extruder under pressure and extruding the mixture, an inorg. powder and at least one member selected from calcium or barium salts of higher fatty acids are mixed with said polystyrene resin. Among polystyrene resins, polystyrene resin and p-methylstyrene resin are preferred because of high rigidity and strength, and the latter is particularly preferred because of good heat resistance. The quantity of the volatile blowing agent to be used varies depending on the expansion ratio and the use of the foam. As the inorg. powder, talc is preferred from the viewpoint of the fineness of cells and low cost. |
