| abstract |
The present invention provides a thermally expandable microsphere having a high encapsulating rate of a foaming agent and excellent in thermal expandability, a method for producing the thermally expandable microsphere with good reproducibility, and uses of the thermally expandable microsphere. The heat-expandable microsphere is a heat-expandable microsphere composed essentially of an outer shell made of a thermoplastic resin and a foaming agent included in the outer shell, and the silicon content is 500 ppm or less, and the aluminum content The rate is 350 ppm or less, the total content of silicon and aluminum is 600 ppm or less, and the foaming agent retention rate at the average temperature of the expansion start temperature and maximum expansion temperature of the thermally expandable microspheres is 70% or more. |