Thermo-expansive microspheres, their production process and their application

摘要

The present invention provides thermo-expansive microspheres comprising thermoplastic resinous shell and a blowing agent being encapsulated in the shell, the blowing agent which is a fluorine-containing C_2-10 compound having ether linkage, being free of chlorine and bromine atoms and gasifying at a temperature not higher than the softening point of the thermoplastic resin; and also provides the production and application processes thereof. The thermo-expansive microspheres have preferably an average particle size ranging from 1 to 100 mum and a CV, or coefficient of variation, of particle size distribution being 30% or less, and a retaining ratio of blowing agent encapsulated being 90% or more. The thermo-expansive microspheres have low environmental loading and superior flame-retardant or flame-resistant performance, and have particle sizes distributing in narrow ranges. Those thermo-expansive microspheres and foamed hollow microspheres are suitable for applying to fire-proof paints, flame-retardant or flame-resistant thermo-insulating materials, flame-retardant or flame-resistant lightweight fillers, and flame-retardant or flame-resistant lightweight molded products, in addition to the conventional application field.