Patent ID: 7915431

Claim:
A method for producing flake-like dried 2-(5-ethyl-5-hydroxymethyl-1,3-dioxan-2-yl)-2-methylpropan-1-ol (hereinafter referred to as “DOG”) represented by the following formula: which comprises making DOG containing from 10 to 50% by mass of a liquid (hereinafter abbreviated as “liquid-containing raw material DOG”) go through the following continuous melt-drying step (i), to obtain DOG having a liquid content of from 0.8 to 5% by mass (hereinafter abbreviated as “continuously melt-dried DOG”); making the continuously melt-dried DOG go through the following vacuum-drying step (ii) or the following ventilation-drying step (iii) while holding a molten state thereof, to obtain DOG whose liquid content is reduced to not more than 0.5% by mass (hereinafter referred to simply as “dried DOG”); and flaking the obtained dried DOG in a flake production step: (i) Continuous melt-drying step: a continuous melt-drying step of heat melting the liquid-containing raw material DOG in the range of a temperature which is the higher of a melting point of the liquid-containing raw material DOG and a boiling point of the liquid, or higher and not higher than 160° C. (hereinafter referred to as “melt temperature range”), to remove the liquid and feeding the residue into a next step and at the same time, continuously or intermittently feeding the non-molten liquid-containing raw material DOG into a molten liquid-containing raw material DOG such that the temperature of the whole liquid-containing raw material DOG does not fall outside the melt temperature range, thereby regulating the liquid content of DOG to be continuously or intermittently fed into a next step to 0.8 to 5% by mass; (ii) Vacuum-drying step: a vacuum-drying step in which a relation between a temperature X (° C.) and a pressure Y [kPa (abs)] is satisfied with the following expression: 10 (−3708.7/(X+230)+9.11) ≦Y≦ 0.0025exp (0.0574X) +10, wherein X is from 125 to 160; and (iii) Ventilation-drying step: a ventilation-drying step of not only ventilating a gas at from 10 to 160° C. for 0.5 hours or more but regulating the total ventilation amount of the gas relative to the continuously melt-dried DOG charged in the ventilation drying step to 10 times or more (volume ratio) and carrying out the foregoing in the melt temperature range.