Matsumoto Yushi-seiyaku Co., Ltd.

Takashi Fujie

Toshiaki Masuda

Katsushi Miki

Ichiro Takahara

Ikuo Yosejima

The present invention provides a process for producing thermo-expansive microspheres comprising a thermoplastic resinous shell and a blowing agent being encapsulated in the shell, the blowing agent which is a fluorine-containing Ccompound 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. The thermo-expansive microspheres have preferably an average particle size ranging from 1 to 100 &#x3bc;m 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.

Thermo-expansive microspheres, their production process and their application

A production process for heat-expanded microspheres includes the step of providing a gaseous fluid containing heat-expandable microspheres, which includes a shell of thermoplastic resin and a blowing agent encapsulated therein having a boiling point not higher than the softening point of the thermoplastic resin and have an average particle size from 1 to 100 &#x3bc;m. The gaseous fluid is fed through a gas-introducing tube having a dispersion nozzle on its outlet that is fixed inside a conduit having a hot gas flow flowing therethrough. A jet of the gaseous fluid is emitted through the dispersion nozzle. Further, the gaseous fluid is collided on a collision plate fixed under the dispersion nozzle so as to disperse the heat-expandable microspheres in the hot gas flow. The dispersed heat-expandable microspheres are heated in the hot gas flow at a temperature not lower than their expansion initiating temperature and thus expanded.

Heat-expanded microspheres, production process thereof, heat-expandable microspheres and application thereof

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 Ccompound 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 &#x3bc;m 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.

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Yao, Japan

Takashi Fujie