Kneading of powdered materials [1][2][3] has been widely used in the pharmaceutical, agriculture, food, chemical, forage and fertilizer industries. Most of the cases, kneading is conducted before the granulation and molding processes, and the performance of kneading seriously affects the quality of the final product or process efficiency. Therefore, it is very important to quantitatively monitor kneading conditions during the kneading operation. With the present technical levels, however, most operations in the manufacturing process are controlled by an expert's decisions, relying on empirical knowledge based on past experience involving "a sense of feeling determined by the hand".In the previous study, we developed a compression tester to measure pressure transmission among a wet kneaded mass.4) It has been demonstrated that the pressure transmission can predict the water dispersion condition among the mass, the degree of kneading attained, and properties of dry pellets prepared by extrusion granulation after the kneading. In the kneading operation, a binder should be used and its additional weight varies depending on the applications. The binder additional methods (solution or powder) and properties of starting materials (soluble or sparingly soluble to water) seriously affect the water dispersion as well as the kneading condition during the kneading. Therefore, it is very important to investigate the effects of these parameters on the water dispersion, kneading condition and on the properties of final dry pellets. However, there has been no research that has studied the effect of binder on the water dispersion, much less on the final products' qualities.The present study investigates the effects of binder content, its methods of addition and properties of starting materials on the water dispersion, pressure transmission characteristics of wet kneaded masses and on the properties of the dry pellets obtained through extrusion granulation after kneading. The mechanism of water dispersion during the paddle kneading is also discussed.

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