| 摘要 |
PURPOSE:To obtain thermoplastic resin prefoamed homogeneous particles having fine voids by a method wherein thermoplastic resin particles containing volatile foaming agent and inorganic nucleator are heated under a specified pressure and temperature and then discharged into a low pressure zone. CONSTITUTION:In a prefoaming method of thermoplastic resin wherein expandable thermoplastic resin particles containing volatile foaming agent dispersed in water is heated up to the resin softening temperature or more at the vapour pressure of the volatile foaming agent or more in a pressure resisting container and then the mixture of the above-mentioned particles and water is discharged to a low pressure zone, thermoplastic resin particles in which inorganic nucleate of 0.01-5pts.wt. are added to thermoplastic resin 100pts.wt. are used. When the addition quantity of inorganic neucleate does not exceed 0.01pts.wt., the desired homogeneous pulverization effect of voids can hardly be obtained and even though 5pts.wt. or more are added, a remarkable effect due to large quantity addition can not be available. Talc, potassium carbonate, alumina, barium sulfate, etc. are used as the inorganic nucleate. |
