| 摘要 |
PURPOSE:To obtain a high-quality resin foam at a high production rate, by allowing an aqueous medium to adhere to porous aggregates comprising partially fused thermoplastic resin powders or particles coated with a hydrophilic fine solid powder, melt-mixing the mixture under pressure, and expanding the molten mixture. CONSTITUTION:Powders or particles of a thermoplastic resin such as polyethylene or polypropylene are mixed with a hydrophilic fine solid powder which does not melt at the melting temperature of the resin (e.g., talc or silica) by means of a mixer or the like, whereupon the surfaces of the resin powders or particles are coated with the hydrophilic fine solid powder and at the same time a number of the powders or particles are brought together to form porous aggregates. A resin compound comprising these porous aggregates is treated with an aqueous medium (e.g., water) to allow said medium to adhere to the porous aggregates. This compound is melt-mixed under an elevated pressure under which evaporation of the aqueous medium is controlled, and expanded by releasing it from the pressurized state to obtain the purpose resin foam. |
