To provide a process for manufacturing a high quality diene-based graft copolymer powder which enables a stable and economical spray drying of a diene-based graft copolymer latex while controlling the self-oxidation of the powder, even when the powder sticks to the inside wall of a drying chamber and stays there for a long period of time, and to provide a spray dryer used thereby.
The process for manufacturing the polymer powder comprises a drying step in which the diene-based graft copolymer latex is sprayed into the drying chamber of a spray dryer and dried with heated gas for drying. At least a part of the drying chamber is cooled from the outside by a cooling means while the drying step is in operation so that the dew point Td (°C) of the heating gas for drying at the exit of the drying chamber, the surface temperature Ts (°C) of the diene-based graft copolymer stuck to the inside wall of the drying chamber and the starting temperature Trs (°C) of the self-oxidation reaction satisfy the relationship: Td < Ts < Trs.
TORITANI AKIHIRO
Tadashi Takahashi
Takashi Watanabe
Masakazu Aoyama
Suzuki Mitsuyoshi
Kazuya Nishi
Yasuhiko Murayama