| 摘要 |
The present invention relates to a process for preparing a spray-dried powder comprising
(i) anionic detersive surfactant;
(ii) from 0wt% to 10wt% zeolite builder;
(iii) from 0wt% to 10wt% phosphate builder; and
(iv) optionally from 0wt% to 15wt% silicate salt;
wherein the process comprises the steps of:
(a) forming an alkaline slurry in a mixer, the slurry having a viscosity of from 0.5 to 50.0 Pa€¢s at a temperature of 70°C and at a shear rate of 50s -1 , wherein the alkaline slurry is shear thinning; and
(b) transferring the alkaline slurry from the mixer through at least one pump to a spray pressure nozzle;
(c) contacting a viscosity increasing agent to the alkaline slurry after the mixer and before the spray pressure nozzle so as to increase the viscosity of the alkaline slurry to form a viscous alkaline slurry, step (c) being carried out at an average shear rate of from 10s -1 to 150s -1 ;
(d) spraying the viscous alkaline slurry through the spray pressure nozzle into a spray-drying tower;
(e) spray-drying the viscous alkaline slurry to form a spray-dried powder; and
(f) optionally, contacting an alkalinity source with the alkaline slurry and/or the viscosity increasing agent, and/or the viscous alkaline slurry. |
