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AssigneeAsahi Glass Company, Limited
InventorsHachirou Hirano, Takako Hirano, Hisakazu Arima, Shintaro Kikuchi, Fumiaki Nakashima, Shigeru Sakurai
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Sodium hydrogencarbonate crystal particles excellent in anti-caking property and anti-thermal decomposition property, and its production process, are provided. Sodium hydrogencarbonate crystal particles whose color 1 second after dropping of a phenolphthalein solution having a predetermined composition, is R=245 to 255, G=243 to 255 and B=245 to 255 in RGB 256 tone notation. The sodium hydrogencarbonate crystal particles are produced by subjecting sodium hydrogencarbonate crystal particles to a bicarbonation treatment in a humidified carbon dioxide gas atmosphere.
High purity sodium hydrogencarbonate crystal particles characterized in that coloration of the particles does not occur for 1 second after drop of a phenolphthalein solution consisting of 1.15 mass % of phenolphthalein, 62.23 mass % of ethyl alcohol and 36.62 mass % of water, due to color change of phenolphthalein.
High purity sodium hydrogencarbonate crystal particles characterized in that their color after 1 second after dropping of a phenolphthalein solution consisting of 1.15 mass % of phenolphthalein, 62.23 mass % of ethyl alcohol and 36.62 mass % of water, is R=245 to 255, G=243 to 255 and B=245 to 255 in RGB 256 tone notation.
A process for producing high purity sodium hydrogencarbonate crystal particles, comprising a step of contacting sodium hydrogencarbonate crystal particles in a state that they are heated at a temperature of from 40 to 95° C. with humidified carbon dioxide gas having a relative humidity of from 5 to 95% and a carbon dioxide gas partial pressure of from 0.05 to 0.5 MPa at the temperature to carry out bicarbonation treatment of the sodium hydrogencarbonate crystal particles.
Dependencies are inferred from the claim text.