| 摘要 |
PURPOSE:To obtain a low-density flame-retarding foam suitable as a construction material or the like, by irradiating a sheet containing a vinyl acetate/ ethylene copolymer, an inorganic substance, a halogenated flame retardant, a blowing agent and a chemical crosslinking agent with an ionizing radiation and expanding the sheet by heating. CONSTITUTION:100pts.wt. resin (A) based on a vinyl acetate/ethylene copolymer of a vinyl acetate content of 50-90wt.% is mixed with 30-300pts.wt. inorganic substance (B) (e.g., aluminum hydroxide), 5-50pts.wt. halogenated flame retardant (C) (e.g., decabromodiphenyl oxide), a blowing agent (D) (e.g., azodicarbonamide) and a chemical crosslinking agent (E) (e.g., dicumyl peroxide). The mixture is molded into a sheet and at least one surface of the obtained expandable sheet is irradiated with an ionizing radiation (e.g., electron beams). The treated sheet is expanded by heating to obtain a flame-retarding foam of a high expansion ratio. |
