Patent ID: 9376540
Filing Date: 2016-06-28
CPC Classification: C08J

Claim Text:
1. A porous particle comprising one or more organic polymers that provide a polymer that provides a continuous solid phase including an external particle surface, and at least first and second discrete closed pores that are isolated from each other and dispersed within the continuous phase, the first and second discrete closed pores having first and second average sizes, wherein: the second average size is greater than the first average size by at least 50%, the first or second discrete closed pores are free of detectably different marker materials selected from the group consisting of colorants (dyes and pigments), metallic pigments, fluorescing materials, radioisotopes, metal oxides, metal hydroxides, metal sulfides, metal oxyhydroxides, and luminescing compounds, the porous particle has a mode particle size of at least 2 μm and up to and including 50 μm, and the first and second discrete closed pores comprise first and second discrete pore stabilizing hydrocolloids, respectively, which provide different osmotic pressures of at least 0.4 psi.